HVAC School - For Techs, By Techs

In this episode of the HVAC School podcast, host Bryan dives deep into the topic of vacuum in HVAC and refrigeration systems. He addresses two questions from social media about vacuum, expanding them into a comprehensive discussion of best practices, common issues, and techniques for effective vacuum procedures.

Bryan starts by explaining where to ideally locate a vacuum pump when working on a refrigeration system. He emphasizes the importance of pulling from the largest volume locations possible, often at multi-position service valves on the compressor or wherever accessible ports are available. He notes that systems that have...

In this short Q&A podcast episode, Bryan answers a question about drain traps and static pressure. This question was sent by Stephen with The Comfort Squad when he noticed an uptick in nuisance calls on retrofit systems that kept having their secondary drain pans filled.

In negatively pressurized systems (i.e., straight-cool or heat pump units, not gas furnaces), air can pull water back into the drain line. The evaporator coil is under negative pressure because the blower is on top of the evaporator coil.

The rule of thumb for trap depth is that...

In this informative episode, Bryan Orr speaks with Andre Patenaude from Copeland about CO2 refrigeration systems. They dive deep into the unique characteristics and challenges of working with CO2 as a refrigerant, providing valuable insights for HVAC and refrigeration professionals looking to expand their knowledge in this growing field.

Andre explains the reasons behind the increasing adoption of CO2 systems, including regulatory pressures and environmental benefits. He details the peculiarities of CO2 refrigerant, such as its high triple point and lower critical point, which create unique operating conditions not seen in traditional refrigerants. The conversation covers the...

In this short Q&A podcast episode, Bryan answers Kenton's question about how to stop vents from condensating, especially when sealing and insulation don't do the trick.

When approaching a condensation problem, we have to consider the source of moisture and where the condensation is happening. Moisture that builds up on top of the vent comes from attics with a high dew point. (It's not because hot meets cold! Relative humidity and dew point are a lot more important, though hot air is able to hold more moisture.) Warm, moist air with a high dew point hits...

In this episode, Bryan and Max discuss commercial supermarket startup and commissioning with comparisons to residential HVAC work. Max, who has transitioned from residential air conditioning to supermarket refrigeration, shares his insights on the unique challenges and requirements of this specialized field.

The conversation begins by emphasizing the critical importance of safety in supermarket refrigeration work. Unlike residential jobs, technicians often work alone in potentially hazardous environments with high-voltage equipment and large quantities of refrigerant. Hearing protection is stressed as a crucial safety measure due to the extremely loud environments in motor rooms.

Max then...

In this episode, Matthew Taylor joins the podcast to dive deep into the world of pressure-limiting valves and regulators used in refrigeration and air conditioning systems. They explore the intricacies of Maximum Operating Pressure (MOP) expansion valves, Evaporator Pressure Regulators (EPR), and Crankcase Pressure Regulators (CPR), discussing their functions, applications, and differences.

The conversation begins with an explanation of MOP expansion valves, which are commonly used in low-temperature refrigeration applications and air conditioning systems. Matthew describes how these valves work by using a vapor-charged thermal element to limit the suction pressure, protecting compressors from operating outside their...

In this episode of the HVAC podcast, Bryan and Max Johnson from Kalos discuss the critical role of a startup and commissioning technician in the HVAC industry. Max, who has experience in both residential and commercial HVAC, shares his insights on the importance of understanding the scope of work, equipment specifications, and code requirements.

One of the key responsibilities of a startup and commissioning technician is to prevent any costly issues that may arise during the installation process. This includes identifying and addressing potential problems with ductwork, refrigerant charge, electrical wiring, and airflow. A comprehensive checklist ensures...

In this short podcast of the Q&A series, Bryan answers a question about "stubborn old techs" (submitted by Luke via Speakpipe).

In several cases, old-school techs are "being positional," which means they feel that they have a piece of turf to protect; they see challenges to the status quo as a threat. They may want to defend the way that they do and have always done things. Many of these people also have insecurities and have dealt with a lot of frustration and disrespect over the years, but they also have a lot to offer. Younger...

In this episode, Josh Souders from Copeland joins the HVAC School Podcast to discuss modulating and variable capacity technologies in HVAC systems. Josh provides an in-depth look at the different levels of modulation available in residential HVAC equipment, from traditional fixed-speed systems to two-stage, multi-stage, and true variable-speed compressors.

The conversation covers the benefits of modulating systems, including improved energy efficiency, better comfort, and enhanced humidity control. Josh explains how modulating technologies allow systems to more closely match the actual cooling or heating load of a building, reducing temperature swings and providing more consistent comfort. He also...

In this short podcast episode of the Q&A series, Bryan answers a question about testing dehumidifiers (submitted by Steven via Speakpipe). 

Dehumidifiers run air over a cold evaporator coil (to pull moisture out of the air and drain it out) and then reheat it over a condenser coil. The air leaving a dehumidifier is of a higher sensible temperature than the air going in, but there are fewer overall grains of moisture.

To see how well a dehumidifier is working, you will need to know the dehumidifier's rating and have the manufacturer's charts at y...

In this episode, we dive deep into the world of residential HVAC installations and improving changeout outcomes with Matt, a senior technician and residential install supervisor at Kalos Services. Matt brings a wealth of experience from both the service and installation sides of the business, offering valuable insights into improving installation processes and workmanship.

The conversation highlights the importance of thorough planning and communication in today's HVAC industry. With younger, less experienced technicians entering the field, there's a growing need for detailed instructions and oversight. Matt emphasizes the role of pre-installation videos, photos, and careful site assessments...

In this short podcast, Bryan talks about how to pay close attention to airflow issues and use your "spidey sense" when you're doing a visual inspection or commissioning a system. He also covers some causes of common airflow problems and some services and upgrades you can offer to your customers.

The skill of being able to use your senses and notice when something isn't quite right is a valuable one, especially when you're getting ready to set the charge. Not every technician has access to the tools to do a comprehensive airflow assessment, but every tech can...

In this episode, Bryan and Bert dive deep into the world of low voltage wiring in HVAC systems. They discuss common mistakes, best practices, and troubleshooting techniques that technicians and contractors should be aware of when dealing with control wiring.

The conversation begins with a focus on mechanical issues, such as running wires in places where they can be damaged and poor splicing techniques. Bryan and Bert emphasize the importance of proper wire stripping, both for the outer jacket of control cables and individual conductors. They share tips on how to avoid damaging wires during installation and...

In this short podcast from our Q&A series, Bryan answers a viewer question and implores you to STOP overthinking in the trade! He also shares a parable and some tips to help stop overthinking, especially if you're just starting out in the trade.

In many cases, the simplest assumption is the right one (this is called Occam's Razor). We can always start with the most obvious or simplest possible answer. We can become mindful of our tools, such as by making sure our seals are intact, and we become masters of the obvious.

Perfecting...

In this podcast episode, Bryan and Dre discuss the challenges and opportunities of stewarding younger techs in the HVAC industry. They explore the growing interest among young people in trades like HVAC, noting a shift away from traditional four-year college paths. The conversation highlights the satisfaction that comes from working with one's hands and the tactile nature of the trade.

The discussion delves into the attributes of younger workers, both positive and challenging. They also address the need to help young technicians understand the seriousness and responsibility of their roles, especially when transitioning from less demanding jobs...

In this short podcast, Bryan answers a listener-submitted question about duct smoke detector facts and wiring. He focuses on Honeywell duct smoke detectors (namely the D4120W), but there are some general best practices that can be applied to most duct smoke detectors.

The power supply may be 24v or 120v AC or DC and may have multiple inputs. You should not break that constant power source. There are also fan shutdown contacts, which may be normally open (alarm condition) or normally closed (non-alarm condition). Supervisory contacts open to indicate a trouble condition to the panel when...

In this episode of the HVAC School podcast, host Bryan and guest Jesse Stewart from NAVAC discuss the generational divide in the HVAC industry and the importance of embracing new technologies and processes. They explore the challenges faced by both experienced technicians who may be set in their ways and newcomers to the trade who need proper mentoring.

Jesse emphasizes the importance of respecting traditional methods while making way for new techniques. He discusses how bad habits can be passed down from mentors to apprentices, highlighting the need for continuous learning and adaptation in the rapidly evolving...

In this short podcast episode, Bryan dives into soft start & solar technology, which often work together. He also talks about how we can install ductless systems in homes that rely on solar power.

Soft starts are NOT hard starts. Hard starts add more current to the start (auxiliary) winding, which creates a stronger phase shift. Instead, soft starts control the current on the start and run windings and provide just enough of a phase shift to ramp up the motor slowly; it provides a regulated power supply, which means that a slow startup doesn't necessarily cause overheating...

In this episode of the HVAC School podcast, host Bryan Orr welcomes Matt Bruner to discuss the concept of a "summer survival guide" for HVAC professionals. They explore strategies for maintaining work-life balance during the busy summer season and share personal experiences on prioritizing family and personal well-being while managing the demands of the HVAC industry.

The conversation delves into the importance of intentional planning before the summer rush begins. Matt shares how he and his family implement practices like scheduling an end-of-summer vacation, utilizing daycare services, and outsourcing lawn care to create more family time. Bryan...

In this short podcast episode, Bryan answers a listener-submitted question: How do inverter air conditioners work?

Inverter-driven systems have variable capacity to match loads. We can provide cooling or heating BTUs to match the needs of the space without overcompensating or undercompensating and causing temperature swings. Load matching also helps us get better efficiency out of the system. High-humidity climates also benefit from load matching, as equipment doesn't dehumidify well unless it has been running the entire time.

When set up and designed properly, variable frequency drives (VFDs) improve comfort, efficiency, and even dehumidification. You...

In this episode of the HVAC School podcast, host Bryan Orr interviews Tim De Stasio, an experienced HVAC practitioner and consultant. Tim shares his journey in the HVAC industry, from his early days in vocational school to running his own contracting business for 12 years. He now focuses on consulting, design, and contractor training, allowing him to pursue his passion for HVAC while sharing his knowledge with others.

The conversation delves deep into the world of dehumidifiers, exploring their importance in modern HVAC systems, especially in humid climates. Tim emphasizes the need for supplementary dehumidification in many homes...

In this short podcast episode, Bryan shares some strategies for teaching communication confidence, which may come in handy if you have newer techs who feel nervous or struggle to communicate with other people.

The main way to build confidence is to get them to talk in the first place. Scripts and roleplay scenarios during training can help get people used to speaking and give them a reference. Whether we're in sales or not, we have to share information and complete business transactions. Roleplaying those conversations in a controlled, familiar setting allows your more timid team members to...

This episode focuses on understanding and effectively utilizing various refrigeration system charts and measurements for troubleshooting and diagnostics. Joey Henderson, an HVAC veteran and trainer, shares his wealth of knowledge and experience on this topic.

Joey starts by discussing the challenges he faced early in his career when trying to make sense of the confusing charts with arrows indicating high, low, high head, low head, etc. He emphasizes the importance of knowing the "supposed to be" values before attempting any measurements or referencing charts. Without this baseline understanding, the measurements become meaningless.

He then delves...

In this short episode, Bryan talks about wiring in condenser fan motors, including aftermarket motor considerations and the different wire configurations.

When condensing fan motors fail, we need to know what to use to replace them. We often use PSC motors, though in cases when we replace a motor with an ECM, we still need to match the horsepower despite the increased flexibility. The motors we typically keep on our truck are 1/3 or 1/6 HP motors. 

Frame size (diameter) and depth also come into play; you may encounter a 42-frame motor or a 48-frame motor. You c...

This podcast episode focuses on the critical shortage of HVACR technicians and installers across the industry. The hosts discuss the massive gap that exists, with estimates of nearly 200,000 open roles expected in the next few years. They are joined by Lenny Diaddario from Copeland's contractor services department and Chris Harris from the educational nonprofit National Coalition of Certification Centers (NC3).

Lenny and Chris explain the various initiatives Copeland and NC3 have undertaken to help attract more people to the HVACR trades. This includes STEM education outreach to get kids interested from an early age, partnerships with organizations...

In this episode of the HVAC School Podcast, Bryan interviews Rachel Kaiser, a chemist with a passion for making science more accessible and understandable, especially when it comes to the topic of combustion. Rachel shares her background of how her family's restaurant business sparked her early interest in chemistry and the science behind mixing ingredients to produce desired results.

Rachel dives deep into explaining the fundamental chemistry behind the combustion process. She breaks down the three key components required for combustion to occur - fuel, oxygen, and a heat source - and how the ideal chemical reaction...

In this short episode of the HVAC School podcast, Bryan talks about hoses and their various types and applications, particularly focusing on NAVAC hoses.

Charging hoses (NAVAC: NH5 and NH5L) ideally shouldn't be longer than 5-6 feet, as the longer the hose, the more refrigerant it will hold. Manifold gauges also have leak points, so it's usually better to use probes instead of manifolds to help with charging. Charging hoses with ball valves (NH5S and NH5SC) can help you control the flow and are great for recovery. Whenever you use charging hoses, they will...

In this episode of the HVAC School podcast, Bryan interviews Pat Ward, an HVAC technician who specializes in servicing and maintaining computer room air conditioning (CRAC) units for data centers. They dive deep into the unique challenges and setups involved in cooling these critical facilities.

Pat provides an overview of data centers, explaining that they are essentially industrial-scale computer rooms that generate immense amounts of heat from the servers and need precise environmental controls. CRAC units are specialized air conditioning systems designed to maintain the temperature and humidity within tight parameters suitable for electronic equipment.

...

In Part 2 of the Rack Refrigeration Class at Kalos Services, Matthew Taylor discusses safeties, service, and more. Part 1 focuses more on the basic refrigeration circuit of a rack refrigeration system.

When safeties are piped together, we have to keep in mind that they're a bit more complex than most HVAC refrigeration systems, especially when it comes to the oil side. All of these safeties and their proper installation can be located on the wiring diagrams. Safeties often respond to pressure, both in the refrigerant circuit and the oil circuit, but they may also respond to amperage or...

This episode dives into an interesting and pragmatic discussion about how HVAC contractors can better balance their workload throughout the year. Kevin from Haven shares insights from observing HVAC businesses across the country and how some are taking a more strategic approach to triaging work.

The main idea is to get systems up and running in the peak summer months when demand is highest, while also collecting data and making notes for more in-depth commissioning, ductwork upgrades, IAQ improvements, etc. that can be tackled in the fall "shoulder season." The hosts discuss the market forces that drive...

In this insightful episode of the HVAC School Podcast, Ty Branaman, an exceptional educator and trainer, shares his unique approach to making learning not just effective but also engaging and memorable. He delves into the art of connecting with students, unlocking their curiosity, and fostering a love for learning.

Ty emphasizes the importance of understanding that not all students learn in the same way. He advocates for finding creative ways to capture their attention and spark their interest, whether through hands-on experiments, relatable analogies, or thought-provoking demonstrations. By tapping into students' existing experiences and curiosities, Ty creates...

This podcast episode is Part 1 of a Kalos class on rack refrigeration given by Matthew Taylor. This first segment focuses on the basic refrigerant circuit and oil management of a parallel rack system, common in market refrigeration.

Parallel racks follow the same general process as any other compression refrigeration system. However, they contain multiple compressors on a single rack. These systems have multiple suction lines that tie into one single suction header that feeds into multiple compressors. The suction side of the piping is usually a long distance with varying elevations; risers are vertical stretches of piping...

Standard 310 is a technical workflow created by ACCA, ResNet, and ANSI for grading the installation of HVAC systems, typically in new home construction. It plays a crucial role in obtaining Energy Star certification, which can qualify homeowners for tax credits under the Inflation Reduction Act. The five steps of Standard 310 are design review, duct leakage test, total system airflow, blower fan watt draw, and refrigerant charge verification.

In this podcast episode, host Bryan Orr is joined by guests Chris Hughes and Eric Kaiser to discuss Standard 310 and its implications for HVAC contractors.

The standard aims...

In this short Q&A podcast episode, Bryan answers Gunther's question about kitchen exhaust and makeup air. Gunther asked if there were any studies that showed that makeup air should come very close to the hood to avoid infiltration. He also asked how to educate others who push back against the idea, particularly in kitchen exhaust systems of around 600 CFM.

Commercial facilities, especially restaurants, bring in makeup air to balance out the air being exhausted. There are costs associated with makeup air, but there are plenty of valid reasons to add it to residential structures. Being able...

This episode featured Bryan Orr interviewing Sam Myers, the building science consultant at Retrotec. Retrotec manufactures products like blower doors and duct testers for measuring air tightness and leakage in buildings.

Sam discussed his role at Retrotec, which involves training contractors on using their tools properly, product design, software testing, presenting at conferences, and running trade show booths. He talked about the demanding travel schedule this requires but also the rewards of educating the industry.

The main topic was duct leakage testing - why it's important, how it's done, interpreting the results, and investigating and...

In this short Q&A podcast episode, Bryan answers Jeremy's question about checking the charge on rooftop units, and he gives some RTU tips.

Rooftop units often come in sets, so you can use a thermal camera to look at all of the RTUs and compare them. A thermal imaging camera may even show you where subcooling begins in the condenser, which can be a useful diagnostic hack. Try to avoid hooking up gauges each time you check the charge on a rooftop; RTUs have a fixed factory charge, and losses from your gauges can add up...

This episode features an insightful conversation with Brynn Cooksey, an experienced HVAC contractor and trainer from Southeast Michigan. Brynn shares his expertise in conducting proper load calculations, sizing the equipment correctly, improving duct design, and addressing common issues contractors face.

Brynn emphasizes the importance of performing accurate load calculations, especially in older housing stock where equipment is frequently oversized by 50% or more. He discusses how oversized equipment leads to short cycling, poor efficiency, and increased utility costs for homeowners. His approach involves educating customers by involving them in the measurement process and using metrics like "duct deficiency"...

In this short Q&A episode, Bryan answers podcast listener Cooper's question about starting an internal training program. Eugene Silberstein has been on the podcast before to offer his perspective on this topic, which you can listen to HERE. 

Bryan recommends a combination approach: instructor-led, hands-on, and self-paced learning, all deployed together. Hands-on learning often gets missed, and we can give inexperienced techs experience with some basic troubleshooting tasks or breaking down and reassembling things. The Socratic method can also be employed here; the instructor can ask their trainees questions instead of the other way around. When th...

This podcast episode is Bryan Orr's presentation at the 6th Annual HVACR Training Symposium: "Humility in Thought Leadership." Bryan reflects on his own journey as a trades educator, business owner, husband, and father, sharing personal anecdotes and insights that resonate with anyone in a position of influence.

Bryan begins by acknowledging the challenge of maintaining humility in the face of success and recognition. He emphasizes the need to continually shift our focus from a mindset of "deserving" to one of "serving" others. By embracing humility, we not only become more effective leaders but also create an environment...

This short podcast is a Q&A based on a question submitted to us by Andy Holt. Bryan gives some tips on how to go from service tech to service manager. Service managers may have better pay, but they also have different sources of stress than service technicians, and not all service tech skills will translate well to management.

Service techs and service managers have completely different skill sets, and they have to be able to gain satisfaction from different sources. Service techs are satisfied by solving problems, and they get immediate dopamine hits whenever they use...

This episode was recorded live on location at the 2024 ACCA conference in Orlando. Bryan starts by interviewing Marissa, a co-founder of Conduit Tech, a software company providing load calculation and sales tools for HVAC contractors.

Marissa shares insights into what it takes for contractors to successfully adopt new technology in their businesses. She emphasizes the importance of having support at multiple levels of the company, a willingness to thoroughly learn the new software, and providing feedback to the developers. Marissa stresses that Conduit actively seeks input from contractors to continue improving their product's workflow integration. Learn more...

In this insightful podcast episode, the host delves into the crucial aspects of positive and productive client communication, drawing from his extensive experience in the residential air conditioning industry. He emphasizes the importance of setting the right tone, bringing energy, building trust, and adapting to different customer personalities when interacting with clients.

The host highlights the key elements of positive communication, such as maintaining a consistently upbeat and enthusiastic demeanor, while also being mindful of the client's preferences. He stresses the importance of active listening, to truly understand the customer's needs and concerns, rather than simply waiting...

Roman Baugh, Matthew Condron, and Luke Peterson discuss the importance of proper condensate drain installation and maintenance, particularly in commercial applications. The conversation begins with the hosts examining the typical drain configurations seen in different regional markets, highlighting the significant variations in practices across the country.

Sizing and configuration of condensate drains can have a significant impact on system performance, especially in high-static pressure systems. He emphasizes that the "one-size-fits-all" approach of using a 2-inch trap is often insufficient, as the static pressure within the system can overcome the trap's ability to prevent air from being sucked...

In this short podcast episode, Bryan explains electronic expansion valve (EEV) types. EEVs perform the same function as TXVs, but they operate electronically, not mechanically.

The EEV makes sure that the evaporator is full of the right amount of refrigerant at saturation; it doesn't just affect evaporator pressure. We don't want high superheat (due to inefficiency), and we don't want zero superheat (due to the risk of compressor failure).

EEVs commonly have a stepper motor with a set of discrete settings depending on how many rotations the motor has made. It can be fully open...

This episode of the HVAC School Live Stream covers the key concepts around heat pump efficiency and understanding the coefficient of performance (COP). Eric Kaiser from TruTech Tools and Jim Fultz from White-Rodgers provide valuable insights into how heat pumps operate and how to optimize their performance, especially in colder weather conditions.

The discussion begins by exploring the COP of heat pumps and how it compares to the efficiency of electric resistance heat. A COP above 1 means the heat pump is delivering more heat for the same amount of energy input compared to electric resistance heat. Many...

In this short podcast episode, Bryan talks about motor protection types, including overloads.

The most common overload we see in residential HVAC is a built-in thermal overload, which is usually a bimetallic disk that flexes in response to heat (such as from a locked condition, electrical problem, or simply running hot) and opens the circuit. The two metals have different expansion and contraction rates, which causes the flexing; they will return to their original position once the motor cools down. In some cases, these can fail when they open and close too often; they are not designed...

This podcast features a lively discussion on expansion valves, particularly thermostatic expansion valves (TXVs or TEVs), with a panel of expert guests - Corey Cruz (a market refrigeration tech), Matthew Taylor (head of refrigeration service at Kalos), and Joe Shearer (with Precision Air Conditioning).

The conversation kicks off by busting some common myths surrounding expansion valves. The guests agree that minutiae like the precise clocking (rotational orientation) of the sensing bulb or whether it's mounted horizontally or vertically tend to be overemphasized. The key is ensuring good thermal contact between the bulb and refrigerant line.

...

In this short podcast episode, Bryan answers an audience member's question and explains how to learn superheat & subcooling, two fundamental aspects of the HVAC/R trade. You can submit questions of your own at https://www.speakpipe.com/hvacschool. 

Saturation is when a substance is in the liquid and vapor state in the same place. Eugene Silberstein likes to help us envision it by encouraging us to think of a horizon line on the ocean; anything below it is fully liquid (subcooled, what a submarine would travel through), and anything above it is a vapor (superheated, which a...

In this episode of the HVAC School Podcast, Bryan Orr and Trevor Matthews delve into the importance of setting goals, focusing on them, and taking actionable steps to achieve them. They emphasize that goal-setting is crucial for personal and professional growth and that it requires introspection, prioritization, and sacrifice.

Trevor shares his experience of setting a goal to buy his first house and how writing down the specifics, such as the number of bedrooms and bathrooms, helped him achieve that goal within a few years. He stresses the need to start small, with easily achievable goals, and...

In this short podcast episode, Bryan talks about when to switch to emergency heat. He talks about coefficient of performance (COP) and how it's a deciding factor when to run emergency heat, which is when a system ONLY runs the backup heat; it doesn't use it as supplementary heat.

When we have a heat pump with backup electric heat, we shouldn't ever rely just on emergency heat; we want the heat pump to run. Electric heat is just designed to supplement the heat pump's heating because it's inefficient. Hybrid or dual-fuel systems can use gas or hydronic...

Shelby Breger, co-founder of Conduit Tech, joins Bryan Orr on the HVAC School Podcast to discuss her company's innovative lidar-enabled design and sales software tool for HVAC contractors.

Conduit Tech's software utilizes lidar sensors in iPads and iPhones to scan homes and create 3D models and 2D floor plans. It overlays load calculations factoring in property data, orientation, cooling/heating degree days, and building materials. This allows contractors to perform detailed load calculations on-site in just 15 minutes or less while engaging homeowners visually.

Breger explains that the core goal is to empower contractors to deliver...

In this short podcast episode, Bryan talks about the four different combustion venting categories for gas appliances as set by ASHRAE and where you'll see them. He also shares some notes about pressurization.

These categories deal with the pressurization and temperature ranges of the vents. Category 1 venting is used for old-school open-combustion gas furnaces; they have high flue gas temperatures and are considered low or mid-efficiency furnaces. This venting category is not positively pressurized, and it has a single-wall flue and operates more like chimneys, as the appliance is usually under negative pressure; a draft is created...

In this episode of the HVAC School Podcast, host Bryan Orr speaks with Jennifer Manzo, founder of HVA-Chicks Coalition. Jennifer shares her unique background as a longtime teacher and homeschooler who stumbled into the HVAC trade while researching vocational options for her homeschooling students.

They discuss the inspiration behind HVA-Chicks, a free training coalition offering technical, career, and personal support to women in HVAC. This includes customized training plans, connecting members with childcare assistance, legal support for discrimination issues, job search help, and more. Jennifer also manages a free 24/7 tech support phone line with several experienced volunteers...

In this short podcast episode, Bryan dives into some belt talk, including some bits about pulleys and sheaves. He also shares some belt tensioning tips for your next commercial HVAC job.

Belts are less common than they used to be, but we find them in ventilation fans, RTUs, and AHUs. Squealing belts indicate slippage, which indicates fan inefficiency and energy losses. Belts transmit energy from the motor (pulley) to the fan or blower wheel being driven by it. Motor mounts may be adjustable, but there will be a means of adjusting the tension of the belt. Before w...

In this episode of the HVAC School Podcast, host Bryan Orr speaks with Chris Hughes of The Energy Conservatory (TEC) about using the Roomulator card and DG-8 manometer for room pressurization testing.

Chris provides background on how he came up with the idea for the Roomulator. He wanted an easy way for technicians to properly size passive returns to relieve pressure imbalances between bedrooms and the main body of a home. The Roomulator card enables technicians to quickly measure door undercuts and size transfer ducts, grilles, etc., to reduce room pressures to 3 Pascals or less per ENERGY...

In this short podcast, Bryan dives into a gas heating topic: primary & secondary air in combustion.

Primary air is the air and oxygen content that enters the furnace BEFORE combustion. In older furnaces, prior to induced combustion, air was drawn in through the front. These older furnaces had adjustable shutters that we could modify to bring in more or less primary air based on our combustion analysis readings. We could also use flame color to get an idea of the CO content (yellow tips on the flames indicate higher carbon monoxide content).

In systems like...

This podcast episode is a live rebroadcast of a livestream with Craig Migliaccio (AC Service Tech) and Ty Branaman (love2hvac). It focuses on different types of learning and how to make the most out of learning experiences.

The hosts discuss the differences between random learning, goal-driven learning, and forced learning. Random learning involves casually exposing yourself to new information without a specific end goal. It can be useful for sparking curiosity. Goal-driven learning is focused on achieving mastery of a particular topic in order to solve a problem or accomplish something concrete. This type of learning...

In this podcast episode, Bryan has an enjoyable conversation with his wife Leilani about navigating family relationships while building a business. They discuss the challenges and benefits of mixing family and work, setting boundaries, and maintaining perspective.

Bryan starts by admitting he felt intimidated to have Leilani on the podcast before, joking about her “big muscles and dominating presence.” Leilani jokes back, saying Bryan seems less intimidated now that they’ve been together so long. They then dive into the topic of starting their family business, Kalos, back in 2005.

Leilani remembers feeling excited but also some “...

In this solo podcast, Bryan provides an introduction to heat pumps, explaining the basics of how they work and key considerations in a way that is easy for anyone to understand. He starts by reviewing some core HVAC principles - that heat moves from higher temperatures to lower temperatures, the three main methods of heat transfer, and the concept that temperature is really just a measure of molecular movement.

He then explains that a heat pump works by taking heat from a place that doesn't matter, like the outdoors, and putting it where it is wanted, like...

This podcast brought together several women working in the HVAC industry to discuss their experiences and offer advice. The conversation focused on the positives of working in HVAC as a woman, the importance of community, and the resources available.

The women talked extensively about how welcoming and supportive the HVAC community, and particularly HVAC men, have been towards them. Several got into the industry because of their husbands' work. They agreed the perception that it's difficult for women to break into HVAC does not match their largely positive realities. The biggest challenges they identified related more to...

In this short podcast, Bryan explains the history of AWG, or American wire gauge, which is the sizing system we use for conductors in the United States.

Wires weren't standardized before the 18th century (1700s). As fencing, telegraph, and electrical wires started coming out, there was a need for a standardized system. In England, a standardized system called the Birmingham wire gauge (BWG) was developed in the 1800s. The American Telegraph Company developed the American equivalent, the AWG, shortly afterward. These systems standardized wiring diameters, and the AWG's wire sizes get bigger as they get lower (including...

Don Gillis and Dr. Chuck Allgood from Chemours join the show to discuss their new easy as "1,2,3" branding around the A2L refrigerants R454A, R454B, and R454C. They explain that A2Ls are not actually flammable like hydrocarbons; they are just mildly combustible with much lower burning velocity and energy than propane or butane. The key is that A2L refrigerants can only be used in equipment specifically designed and tested for them.

They outline several equipment changes, like the inclusion of sensors that detect leaks and mitigate risks by shutting down systems. Service...

In this short podcast episode, Bryan tackles the following question: What is DX? 

In short, DX stands for "direct expansion," which means that you cool the end product via the refrigeration cycle. We blow air over an evaporator coil, which allows the refrigerant to take up heat from the air and directly expand. Chillers, boilers, and chilled water systems are NOT direct expansion systems; they use a secondary fluid like water or glycol to move the heat throughout the structure, not an evaporator to take up heat directly. They also have heat exchangers to move heat from t...

In this podcast, Bryan Orr interviews Jesse Stewart from NAVAC about A2L refrigerants and compatible tools and safety procedures.

They discuss how NAVAC has a full line of A2L-compatible tools for evacuation and recovery, including the new NR7 and upgraded models of the NRDDF and NRDD. Jesse explains key features that make tools A2L compatible, like DC motors, sparkless designs, insulated electrical terminations, soft power switches, and fans. He notes that NAVAC has been designing tools this way in preparation for wider A2L adoption.

The conversation covers some evolving questions around...

This podcast covers refrigeration technologies' growth and focus on providing safe, high-performing chemicals for HVAC technicians without hazardous ingredients.

Mike Pastorello discusses the 2017 rebranding that gave their products a more modern, cohesive look. He also talks about bringing on new marketing talent like Ashley and Becca to amp up refrigeration technologies' social media presence and connect more directly with end users. Throughout, Mike emphasizes enabling the marketing experts to drive strategy rather than micromanaging.

Regarding products, Mike highlights their priority of keeping technicians safe while effectively doing their jobs. He mentions constantly improving formulas to...

This live podcast from AHR Expo 2024 discusses the costs of truck rolls for HVAC technicians and how technicians and companies can reduce those costs. Jim and Bryan highlight that every time a tech has to go to the supply house to get parts, the company loses money in potential service calls that could have been completed. They emphasize stocking trucks properly so that technicians can complete repairs efficiently without leaving jobsites.

Jim talks about the White Rogers 50M56X8-43 universal control board, which auto-configures itself to different furnace models. He explains how it simplifies installations and...

In this podcast, Bryan chats with Tony Gonzalez of Fieldpiece about their latest innovations for service tools, including the redesigned VCRT, as well as the training resources they offer.

They start off discussing Fieldpiece's philosophy of developing solutions for technicians' real pain points, not just making products. Understanding workflows and obstacles lets them design better tools. Tony then reveals their new line of valve core removal tools aimed at faster, easier access to system ports. Features include integrated ball valves to isolate gauges, sight glasses to confirm capture of the core, and improved ergonomics for gripping.

In this short podcast episode, Bryan covers the differences between absolute and gauge pressure, as well as measuring pressure with a micron gauge or a manometer.

Compression ratio deals with absolute suction and absolute discharge pressures. Absolute pressure requires us to add atmospheric pressure to the gauge pressure. We usually measure gauge pressure in pounds per square inch (PSI). PSIG is the gauge pressure (zeroed to atmospheric pressure), and PSIA is the gauge pressure plus the atmospheric pressure (usually around 14.7 PSI). 

When we measure vacuum pressure, we have "negative pressure" with respect to the atmosphere. W...

In this HVAC School podcast, Bryan and Tom Buescher with Copeland discuss dual-fuel heat pump systems as an intermediate step towards more sustainable heating solutions.

They talk about the overall goal of reducing greenhouse gas emissions from residential heating and cooling, which accounts for over half of home energy use. While heat pumps can provide higher efficiency, simply switching everyone to electric isn’t realistic in the short term. Factors like grid capacity, infrastructure, and consumer comfort have to be considered.

Dual fuel systems allow for a hybrid approach - utilizing heat pumps to provide th...

In this short podcast episode, Bryan dives into NTC, PTC, and thermocouples. NTC and PTC are two types of thermistors, and all three tools are used to sense temperature.

Thermistors are resistors that change their resistance based on a change in temperature. They must be powered, and the resistance changes the amperage. You can test a thermistor with an ohmmeter at a fixed temperature. The best temperature for testing is the thermistor's rated temperature, typically 77 degrees Fahrenheit. 

NTC thermistors are negative temperature coefficient thermistors; as the temperature decreases, the resistance increases, and vice versa. Temperature a...

This podcast episode focuses on practical ways to save energy with grocery store refrigeration systems, with Matthew Taylor from Kalos Services sharing insights from both a technician and business owner perspective. The hosts emphasize that proper, consistent operation and preventing short cycling of compressors can have a major impact as the largest power consumers.

Proper control strategies, like ensuring evaporator pressure regulators (EPRs) are working, maintaining subcooling, and preventing excessive compressor staging and rapid on/off cycling, are critical for reducing energy consumption. Often, technicians troubleshooting issues bypass these controls when they could be tuned and optimized...

The podcast is a conversation between Ed and Bryan about using the ACCA Residential Plans Examiner Review Form, an ACCA form you probably never heard of, to demonstrate that proper HVAC system design procedures were followed based on the Manual J, Manual S, and Manual D guidelines.

Ed introduces the Residential Plans Examiner Review Form as a one-page document that allows contractors to show they gathered the minimum necessary information to complete a proper HVAC system design. The form doesn't teach how to actually do the design calculations but can help explain the design to others not...

In this HVAC podcast episode, hosts Bryan Orr and Matthew Taylor (refrigeration leader and trainer at Kalos Services) discuss oil management and considerations in supermarket refrigeration systems, with a focus on solving & preventing oil issues. They talk about the importance of stable system operation and how oil flows through both active and passive systems in these larger built-up racks.

Matthew explains that in a rack system, oil is actively separated and returned to the compressors through a dedicated system. However, not all oil gets captured this way, so the passive system of oil returning through the refrigeration...

In this podcast, Bryan and Clifton discuss the upcoming transition to A2L refrigerants, like R-32 and R-454B, and what A2L mitigation is going to look like.

These mildly flammable refrigerants will be used in place of R-410A for residential air conditioning systems due to an HFC phase-down driven by legislation and international agreements. They explain what mitigation means with A2L systems - sensors will detect refrigerant leaks, and the system will shut off and turn on the blower fan to dissipate any leaked refrigerant. The mitigation helps minimize flammability risk.

...

Bryan and Kevin discuss indoor air quality solutions in terms of healthy air supplements vs. pillars of IAQ, drawing an analogy between IAQ supplements like electronic air cleaners and fitness supplements. They talk about why discussing these supplemental products can be controversial since many companies profit from selling them. However, the fundamentals of good IAQ - ventilation, filtration, and humidity control - are proven to work well, just as diet, exercise, and hydration promote good health.

Most contractors focus more conversations and training around supplemental IAQ products versus the fundamentals, which parallels how society embraces fitness supplements...

In this short episode, Bryan discusses the unique features of hot deck, cold deck systems. These systems have separate heating and cooling components (if not entire systems).

Older systems may have completely separate duct systems: one for heating and one for cooling. These ducts would go to each space, and you'd essentially have twice the ductwork you'd expect nowadays. Some systems also have a separate hot deck and cold deck in a single appliance (a bit like gas furnaces with case coils).

We also use the term "hot deck, cold deck" to refer to systems...

In this episode of HVAC School, hosts Bryan Orr and Bert discuss practical tips for preventing callbacks and failed inspections in residential HVAC installs and maintenance.

Bryan and Bert stress the importance of getting the basics right, like properly cleaning condensate drains, ensuring proper drain pitch, and sealing ducts completely before relying on tapes and mastic to cover gaps. They emphasize verifying full system operation at the end of a job, from checking that drains flow freely to testing float switches and pressure testing for leaks. Bryan and Bert also cover wire and breaker sizing for equipment...

In this short episode, Bryan talks about the situations when permits are not needed to install HVAC/R (or HVAC/R-related) components.

A few codes are universal in residential HVAC, including the International Residential Code (IRC) and the International Mechanical Code (IMC). The local municipality, also known as the authority having jurisdiction (AHJ), chooses which codes to adopt. 

You do not need a permit to install plug-in, cord-connected appliances. However, you need UL-listed plugs. You can also replace plugs without needing a permit, but the ratings need to be correct. Anything less than 25v that do...

In this podcast, Bryan Orr and Bert discuss various aspects of pool heaters, focusing on issues that make them different from typical HVAC systems. They cover the basics of pool heaters - the main types (heat pumps and gas heaters) and how they operate similarly or differently from things HVAC techs work on regularly.

The bulk of the 45-minute podcast looks at common service and troubleshooting situations with pool heaters, which are usually installed by pool contractors initially and not HVAC contractors. Bryan and Bert talk through typical causes of common error codes and problems like units...

In this short episode, Bryan explains the fundamentals of capacitance, focusing on the unit of measure: farads, including micro and pico.

Farads are named after scientist Michael Faraday and measure capacitance; one farad represents the capacitance of a capacitor in which one coulomb of charge causes a potential difference of one volt across the plates. Farads measure the storage of electrical energy and indicate the capacitor's ability to create a phase shift.

Since farads are large units, our capacitors are rated in microfarads (1/1,000,000 farads). Bigger capacitors have higher microfarad ratings and store more charge.

Bryan Orr hosted a live podcast discussion all about 90% efficient furnaces with HVAC professionals Ty Branaman, Adam Mufich, and Matthew Bruner. They covered the basics of how 90% furnaces work compared to traditional 80% furnaces, troubleshooting tips, and best practices for installation and service.

A key difference with 90% furnaces is the addition of a secondary heat exchanger that extracts more heat from the exhaust gases before they go out the flue. This allows the furnace to achieve at least 90% efficiency. The condensing of water vapor in the exhaust also releases latent heat. However, the acidic condensate must be properly...

In this short podcast, Bryan breaks down the differences between analog and digital sine waves.

Analog readings deal with an unlimited number of values; they are very precise and can have any number of decimals. As a result, the alternating current (AC) analog sine readings have very smooth curves when we read them on an oscilloscope (in the US, we see 60 peak-and-valley cycles per second because the frequency is 60 hertz). 

Variable frequency drives (VFDs) and ECMs work with digital outputs instead. The alternating current (AC) input is flattened out and then replicated as a direct c...

Bryan Orr interviews Tyler Nelson, an HVAC expert with over 20 years of experience as a contractor. They have an in-depth discussion about combustion analysis and why it is becoming increasingly important for HVAC technicians to utilize this process.

The conversation provides an overview of combustion analysis benefits and why HVAC pros should incorporate it into their standard operating procedures. Tyler offers insightful perspectives from his decades of contracting experience, including his knowledge of how field conditions vary and factory settings may not translate perfectly.

Carbon monoxide poses several dangers to customers and HVAC technicians. Tyler...

In this short podcast, Bryan talks about checking the charge of a heat pump in heat mode. This skill will become more critical as ambient temperatures get cooler.

The most reliable way to check and set the charge regardless of operating mode and season is to weigh the charge. This method is most practical during installation and commissioning, and proper commissioning can prevent issues with charge levels later. Weighing the charge is recommended for big repairs, like major component replacements.

But in many cases, we don't need to check the charge by hooking up gauges...

Nikki Krueger and Genry Garcia return to the podcast to talk about a recent IAQ & dehumidification case study on a vintage home in Miami. The home was very clean but had a musty odor and VOC concerns. You can read the case study in the “Literature” section at https://www.santa-fe-products.com/about-us/media-resources/ or https://hvacrschool.com/case-study. 

Blower door tests and ZPD revealed that the home was leaky, and the crawlspace was also not properly encapsulated. The options were to tighten the building and/or mitigate the problem by improving the HVAC system. The homeowners chose...

Skilled trades entrepreneur Tommy Mello joins the podcast to talk about creating a business where everyone wins: business owners, employees, vendors, AND customers.

Tommy's main motivations in business are relationship-building and helping employees make a good living. Those motivations contribute to the development of company culture; even though cultures build themselves naturally, developing the right leaders will help build a positive company culture that values all employees equally. Tommy trains leaders to develop their strengths, shows them that they are valued, and gives them the resources they need to succeed.

When companies grow, communication tools...

Refrigeration Mentor Trevor Matthews returns to the podcast to share some of his tips for supermarket rack service. The supermarket refrigeration world is ripe with high-paying opportunities and uses similar skills that HVAC technicians use daily.

Switching from HVAC to refrigeration will require a little bit more attention to some new components, especially controls and control systems. Technically-minded people tend to do well in the refrigeration field regardless of where they come from.

When you're sent to a job site, you'll need to investigate the store and the case (where the refrigeration happens) before checking...

In this short episode, Bryan covers traps, vents, and drains. He explains some common misconceptions and best practices for fabricating drains, especially in residential and light commercial structures in Florida.

Cleanouts and vents are commonly confused with each other, and people often cap vents and leave cleanouts open. However, cleanouts (which must be capped) will always be before the trap, and vents come after the trap. When you have an indoor air handler, furnace, or fan coil, vents must be higher than the drain pan to allow the float switch to trip when the drain backs up. (R...

HAVEN IAQ founder and CEO Kevin Hart returns to the podcast to discuss cracking the home health comfort code, diving into IAQ’s illusory ideals.

Even though the industry has been generating well-thought solutions to common problems, it’s difficult to put those solutions into practice on a large scale. As a result, it’s common to rely on selling “bolt-on” IAQ products, which don’t actually solve systemic IAQ problems. HAVEN’s recent work has also shown that only a few HVAC technicians are proactively offering IAQ solutions to homeowners; the vast majority wait for the owner to ask a...

In this short podcast episode, Bryan goes over a few tubing insulation tips. Tubing insulation is also commonly known as Aeroflex, Armaflex, and Thermaflex—all brand names for black copper line set insulation.

We typically have to insulate just the suction line in typical residential split HVAC systems, but you'll typically have to insulate both lines in ductless/VRV/VRF or refrigeration applications. The insulation should be on the tubing before brazing, gluing the ends together (only using a specialty tubing insulation adhesive, NOT duct tape!). Since these adhesives are types of contact cement, you will need to...

Jim Fultz returns to the podcast to talk about the new HSI module from White-Rodgers, the 50E47U-843. You can learn more about this new universal HSI module at https://hvacrschool.com/hsimodule. 

Hot surface ignition modules control the burner for gas appliances that use hot surface ignition, not just furnaces. Since the HSI module doesn't need to work with a blower fan, it can be used in water heaters, pool heaters, and many more appliances that don't primarily move air (except for combustion). It also controls the inducer blower and monitors the pressure switch.

A...

In this short podcast episode, Bryan talks about locked compressors and hard starts. He explains what actually happens when a compressor locks and covers when and how to use hard starts appropriately. 

Locked compressors are compressors that trip on overload during startup; they're considered "locked" because the rotor doesn't turn inside the stator and generates heat instead. The overload opens, but the compressor shell typically does not heat up very much when the overload opens. 

When you have a locked compressor, you need to start investigating the root cause with a thorough visual inspection. Then, ch...

Licensed mechanical engineer Tony Amadio joins the podcast to talk about residential exhaust codes and best practices. He also put together a presentation about the topic, which you can view at https://hvacrschool.com/exhaust. 

When choosing duct materials for residential exhaust, you will want to stick to sheet metal and mind the gauge; flex ductwork can easily be damaged and will rack up a high total equivalent length in a way that sheet metal will not.

Exhaust air should always discharge outdoors, not into an attic or crawl space, and that air needs to be...

Phil Barr and Nathan Orr join the podcast to talk about wiring refrigerated cases in commercial spaces, including convenience stores and supermarkets.

Cases may be medium-temp (or high-temp, in some cases) or low-temp. Medium-temp cases can typically defrost on their own during the off cycle, and low-temp cases may have electric or hot-gas defrost to help get ice off the coil at set intervals. Each system has an evaporator (and fans), compressor, condenser, and metering device (often a TXV or EEV), and low-temp refrigeration may have anti-sweat heaters, EPRs, and other components to manage.

Challenges...

This podcast is a class taught by Bryan: Things to Keep Out of the System. He covers some installation best practices along the way to keep contaminants and non-condensable gases out of the system.

We want to keep air, water, dirt, copper shavings, solvents, and nitrogen out of an operating system. All we want in an operating system is the appropriate oil and refrigerant for the system. Unfortunately, the POE and PVE oil we mostly use in residential systems nowadays are very hygroscopic; they attract water, and POE mixes with water to form acid, another thing we...

In this short podcast, Bryan talks about air changes per hour, also known as ACH, and what it means in HVAC design and indoor air quality (IAQ) discussions.

ACH tells us how frequently the entire volume of air in a room or structure is replaced; we are referring to the cubic feet of air leaving a space and then being replaced within that same space. If we have a balanced number of cubic feet per minute (CFM) of air supplied to and returned from the room in one hour, we would multiply that CFM by 60 to get...

Roman Baugh joins the podcast to talk about oil return and the refrigerant charge in VRV systems.

VRV systems—also known as variable refrigerant volume (or variable refrigerant flow/VRF) systems—have one outdoor unit, one or multiple compressors, and multiple indoor units. The outdoor unit modulates to meet the indoor units’ fluctuating demands. They are versatile and flexible systems.

Like parallel racks, VRV systems have long lines and a lot of piping, so oil return and refrigerant charge are especially critical. VRVs have specific control protocols, as they need refrigerant volume and velocity to move o...

In this short podcast, Bryan talks about oxidation and all the buzz behind “magical air-cleaning oxides” and other similar IAQ products.

Oxidation is the loss of electrons, and reduction is the gain of electrons; oxygen commonly loses electrons. Rusting is a common example of oxidation; it happens when iron and oxygen interact in air or water. Metals that are more likely to react with oxygen (or corrode) are “less noble” than more noble metals. Less-noble metals, known as anodes, are sometimes used sacrificially to prevent the oxidation of nobler base metals, known as cathodes.

While iron oxi...

In this short podcast, Bryan talks about filtration and IAQ, especially as they relate to virus control. He also answers the age-old question: “Can filters capture viruses?”

While it may seem like particle size matters when it comes to filter efficacy, filters are not nets that strain air particles and prevent pollutants from passing through. When we talk about particles, we tend to focus on ones that are 0.3 microns in diameter, which tend to be medium-sized particles. Viruses tend to be among the smallest particles that we aim to control when it comes to IAQ.

Filt...

Joey Henderson returns to the podcast to talk about heat pumps and inverters.

The reversing valve, defrost cycles, and auxiliary heat can cause confusion for people who have primarily worked with furnaces or straight-cool A/C systems. Heat pumps use defrost cycles and bring on the auxiliary heat when the coil is ice-bound, which can present a challenge; we need to maintain cold coils without going into defrost all the time. 

Even though heat pumps were significantly less effective in years past, we will still see reduced performance in very cold conditions with the newer i...

Joey Henderson joins the podcast to talk about airflow and how we can get air where it needs to go.

Duct design is one of the subjects that fuel Joey's passion for HVAC. In many cases, people focus too heavily on the equipment when diagnosing airflow problems; sometimes, the equipment simply can't perform as it should due to a poorly designed duct system. In residential HVAC, many duct systems aren't adequately planned out, and the airflow can't overcome restrictions like filters. We also need to keep in mind that flex ducts need to be as straight and...

This podcast episode contains some of the questions and topics from the Business Round Table at the 4th Annual HVACR Training Symposium. Panelists include Tersh Blissett, Luke Peterson, and Andy Holt.

One of the most critical parts of HVAC business ownership is knowing when to grow your business (i.e., hiring more techs and incorporating standalone maintenance and install departments). Ultimately, we need to think about how many service calls we're assigning to each technician per day and how many customers we have to turn down due to a busy schedule. Getting family members involved in the...

In this short podcast, Bryan goes over some information about cap tubes (capillary tubes) and flow facts.

Cap tubes are metering devices; they're long tubes with small diameters, and their flow rates are dictated by the tubing diameter size and tube length. Pistons and TXVs are some of the most common metering devices in residential HVAC, and flow restriction doesn't just happen at the metering device; distributors also contribute to the pressure drop and act like small capillary tubes in addition to the metering device. Older units, simple refrigerators, and window units are more likely to have...

Jim Fultz and Jim Hagl from Copeland join the podcast to talk about filter driers and system cleanup. Filter driers come in many types and sizes; they typically go on the liquid line (bi-flow filter driers are used on heat pumps), but suction line filter driers also exist. 

Copeland’s liquid line filter drier models include the EK (premium), BSL (smaller diameter), BOK (with HH desiccant to assist with burnout cleanup), and CU (copper spun). Bi-flow filter driers in Copeland’s lineup include the BFK and BSB categories. These liquid line filter driers protect the metering device and s...

In this short episode, Bryan goes over the fourth chapter of his new book, Unconformed. The chapter is called "So... What Do You Do?"

Parents always want to be proud of their children, but it seems as though children are more proud of children who attend college than take up apprenticeships. However, these feelings largely seep in due to peer expectations; we want our children to measure up to our friends' standards or success, not necessarily our own. Parents are also less likely to encourage their children to get into the trades and value the time and...

This podcast is based on a Kalos meeting about pipefitting best practices, particularly in commercial refrigeration applications. It begins with a few words about quality workmanship by the Kalos founder and CEO, Robert Orr.

Pipefitting consists of repairs and joining metals; when joining metals, we need to liquify the alloy and draw it into the joint via capillary action. When pipefitting, oxygen can present some problems by coating the inside of the pipe with oxides that can contaminate the system. We can reduce the likelihood of oxide formation by flowing nitrogen while brazing; purging nitrogen displaces the...

In this short episode, Bryan talks about filter driers and their important role in HVAC/R system protection, especially in accordance with Copeland's (formerly Emerson's) AE24-1105 R5.

We can really start keeping our systems contaminant-free by handling tubing properly, purging and flowing nitrogen, and keeping copper shavings out of the tubing when deburring or reaming. Suction and liquid filter driers protect the system during operation and are designed for specific purposes.

We typically don't install suction filter driers in residential systems unless we're fixing a system with compressor burnout or acid contamination; in those...

This podcast episode is one of Alex Meaney's HVACR Training Symposium presentations: HVAC Design Backwards, Forwards, and In Between.

Load calculation factors in all three means of heat transfer: conduction, convection, and radiation. It doesn't directly tell you the tonnage; it just tells you how many BTUs (sensible and latent) are entering or leaving a structure. When designing systems after doing load calculations, we need to be mindful of industry standards and their pitfalls, as well as the climate conditions and the difficulty of obtaining manufacturer data.

Equipment selection by tonnage is only part of...

This podcast is the Santa Fe Panel from the 4th Annual HVACR Training Symposium. The panel focused on dehumidification, was moderated by Nikki Krueger, and featured Andy Ask and Ken Gehring.

"Matchmaking" a residence to the climate requires us to design and install equipment that keeps occupants healthy and comfortable. HVAC contractors need to focus on the dew points, especially as they remain high at night and in the shoulder seasons. Humidity loads tend to hold steady (even peak dew points), while sensible loads increase and drop, making it difficult to control latent heat loads the same...

In this short podcast, Bryan talks about where to place the micron gauge during evacuation and how to think about micron gauge positioning.

Evacuation (deep vacuum) doesn't remove solid contaminants, and vaporizing liquid water is a time-consuming process; its main purpose is to remove water vapor, air, and nitrogen gases from the HVAC/R system. When you pull down below 500 microns and hold that pressure, we can make sure we have a clean, dry, and tight (leak-free) system. As we started using R-410A and POE oil, water in the system became a much bigger issue than i...

Brett Wetzel joins the podcast to talk about his journey from resi tech to industry-leading refrigeration trainer.

Brett is best known for his educational content, but he is also the manager of technical troubleshooting and training at CoolSys. The skills gap is widening, and CoolSys was inspired to create a solution to that problem. Brett's goal is to offer training that provides education and a sense of community all at once. Since he likes to keep his training simple and establish a solid foundation for his students, one of Brett's favorite training practices includes going over a...

In this short podcast episode, Bryan gets into some oil talk, covering some common refrigerant oil terms and types.

Esterification is the process by which organic acid and alcohol come together to form polyolester (POE) oil and water. Hydrolysis refers to the decomposition of a substance when it comes into contact with water; when POE mixes with water, it will break down into esters, organic acids, and alcohol. Once POE oil undergoes hydrolysis, the process can't be reversed to get the same original oil.

POE oil is also hygroscopic; hygroscopicity refers to the ability of...

In this short podcast episode, Bryan talks about using a megohmmeter on a scroll compressor (or "megging" a scroll).

Scroll compressors are among the most common compressor types nowadays, and they come with their unique needs and best practices. You can't pump them down into vacuums (in many cases, you can't do that anyway due to internal protections), run them in a vacuum, or run a high-voltage megohmmeter or hipot test.

Scroll compressors differ from reciprocating compressors. A scroll compressor's motor is located at the bottom of the compressor, meaning it is immersed in refrigerant...

Matt Bruner joins the podcast to talk about what it's really like being an HVAC creative. Matt is a young HVAC business owner who has recently written several HVAC School tech tips and pursued creative interests in the trade.

Being creative in any industry or aspect of life requires us to be aware of what's around us and think deeply about how things can be better. Creativity requires us to channel our dissatisfaction into finding a solution, not just complaining, similar to how children channel boredom into projects.

While the industry relies on processes and...

In this short podcast episode, Bryan talks about TXVs and their impacts on energy efficiency ratings (EER and SEER).

EER (Energy Efficiency Ratio) is calculated based on fixed conditions (an outdoor temperature of 95 degrees Fahrenheit and an inside temperature of 80 degrees with 50% RH). EER is a ratio of cooling-only capacity in BTUs per hour to the total electrical input in watts. SEER (Seasonal Energy Efficiency Ratio) is the ratio of an HVAC system's cooling output during a typical cooling season to the seasonal electrical input in watts.

Both energy efficiency ratios use non-proportional units (BTUs...

Jim Ball from NCI joins the podcast to talk about high-performance maintenance contracts and agreements.

A high-performance maintenance agreement requires you to take system measurements and present solutions to maximize performance accordingly and exceed customers' expectations, not just make assumptions about the performance parameters. Key measurements we should know include the charge levels, total external static pressure, filter & coil pressure drop, and CFM per ton.

Many HVAC contractors and technicians don't really believe in maintenance procedures; some contractors merely want to keep customers or secure work during the shoulder months and don't aim to optimize...

This episode of the HVAC School podcast Steve Coscia's symposium presentation: HVAC Soft Skill Training Resources.

Likability is a superpower in any job that requires you to interface with customers or students. Every word and mannerism your customer or student sees will matter, and it's important to be likable. Those impressions can heavily influence their decision-making.

Making a good first impression is one of the most important areas where we can focus our soft skills, and being on time is an easy way to make a good first impression on customers. When we are pleasant...

Roman Baugh returns to the podcast to talk about the time he installed an A2L system and lived to tell the tale.

Roman used most of his same R-410A tools to install the first A2L-based ductless mini-split in Florida. Flare blocks, wrenches, and torque wrenches will all stay the same; you just have to be sure that your vacuum pumps and recovery machines are rated for use on A2L refrigerants. A2L-based mini-splits use flared fittings with no brazing necessary; this is currently the A1 status quo. 

Purging and flowing with nit...

In this short podcast episode, Bryan talks about motor speed and other basic electrical topics as they relate to motors in HVAC equipment.

In a typical single-phase PSC-type (induction-driven) motor, the speed is primarily determined by the electrical cycle rate, also known as the hertz. The hertz represents the speed at which the electrical current changes direction (positive to negative) per second; in the USA, that number is typically 60 hertz. Unless we're dealing with ECMs and VFD-driven motors, the motor speed will be partially influenced by the hertz or frequency as determined by the utility company or...

Trevor Matthews returns to the podcast to talk about growing in productivity and confidence as a tech to avoid feeling stuck in your career. They talk about personal development within your organization and in communities or training courses beyond your organization.

Confidence and productivity work hand in hand, and techs can grow in both areas when they prioritize the one that matters most to them. In many cases, repetition helps build confidence, especially in the trades and other professions where you work with your hands. Scheduling is another strategy that improves your productivity, which can boost your...

This podcast episode is Alex Meaney's 2023 HVACR Training Symposium session: "The Art of Unteaching."

We may have flawed understandings of HVAC concepts, including the understanding that "heat rises." Our world is constantly shaped by the things we see and believe, and we are hard-wired to defend our observations and beliefs if we feel that those are threatened by new information. Instructors need to be sneaky about "unteaching" flawed ways of understanding the scientific principles of HVAC.

When we communicate concepts to others, we need to watch our language and make sure our messages are clear...

In this short podcast episode, Bryan talks about compression ratio and efficiency, particularly how floating or fixed suction and head pressure affect those things.

Compression ratio (absolute head pressure divided by absolute suction pressure) closely correlates to efficiency in all sorts of compression-refrigeration HVAC/R systems; the most efficient systems have high mass flow with less compressor work. High compression ratios indicate a greater differential between the head and suction pressures. A lower compression ratio is desirable, but the number has to be realistic; a compression ratio of 1 indicates that the system is off. Medium-temp refrigeration compression...

This podcast episode is Nikki Krueger (Santa Fe Dehumidifiers) and Bryan's 2023 HVACR Training Symposium session about how we can optimize dehumidification and efficiency to create an HVAC design and humidity utopia.

While we attempt to achieve comfort and high indoor air quality in humid climates, we may find challenges integrating these with the HVAC system and getting customers to understand the need for proper dehumidification. Older homes that are built "leaky" allow for uncontrolled infiltration and exfiltration, but newer constructions are a lot tighter and rely on mechanical ventilation to control where the outdoor air comes from...

This is the episode for you if you've ever asked, "What the flux?" In this short podcast, Bryan explains the basics of flux in soldering and brazing, as well as magnetism.

Flux means "flow." In HVAC, "flux" may have two meanings. It may refer to the substance that helps the molten alloy flow and bond to base metals more effectively when you're soldering or brazing. However, flux may also refer to magnetic flux, which is the lines of force that emanate from a magnet; this concept is important in inductive loads like transformers.

In soldering...

Steve Rogers from The Energy Conservatory (TEC) returns to the podcast to discuss the impacts of duct leakage on occupant comfort and HVAC system performance.

Duct leakage has more significant negative effects in heat pump systems than in furnace systems, especially in climates with high heating, cooling, or latent loads, due to pressure imbalances and moisture problems. You can measure duct leakage by masking off all supply and return registers, attaching a calibrated fan, and running the duct blaster to pressurize the duct work to 25 Pascals. 

Exhaust-only ventilation presents many of the same problems as d...

Tom Lorenz from Sensi joins the podcast to talk about the launch of the Sensi Touch 2 thermostat. The Sensi Touch 2 smart thermostat is compatible with room sensors, which makes it an efficient and effective thermostat.

Smart thermostats are becoming more common in homes, especially as we focus on HVAC efficiency. Designers are aiming to make smart thermostats user-friendly, aesthetically pleasing, easy to install, and driven by data (via sensors).

Installation is easy for contractors, as it relies on push terminals and cleanly covers up the previous thermostat's installation site. The Sensi Touch 2 requires a common...

Eugene Silberstein from ESCO Group returns to the podcast to discuss why and how to create an internal training program for your HVAC/R company.

HVAC/R has so many niches, and information and practices are always evolving, so lifelong learning is necessary for the industry. In-house training is a form of education that can come with many benefits, including control over scheduling, building community within the organization, and convenience. However, creating an in-house training program also comes with many challenges, including time and money expenses.

For an internal training program to work, there needs...

In this short podcast, Bryan talks about the times when subcooling is meaningless. It is important to understand subcooling fully before using it as a charging or diagnostic method, particularly in refrigeration systems.

When we need to charge TXV systems in residential HVAC, many technicians rely on subcooling to set the charge. However, refrigeration systems don't quite work the same way; charging a refrigeration system by subcooling may lead you to overcharge the system.

We take subcooling on the liquid line between the condenser and the metering device. The condenser takes superheated vapor and rejects...

Craig M (AC Service Tech) returns to the podcast to talk about solving work-life imbalance, especially for HVAC/R technicians who have children and families of their own.

Our actions tend to be driven by our priorities, which vary at different stages of our lives. Someone's work-life balance could also vary depending on different parts of the year. When we let the right people into our lives and are surrounded by supportive communities, we can reconfigure our personal and career trajectories to keep them in line with our priorities. To create a healthy work-life balance, we must b...

In this short podcast, Bryan explains how rules of thumb (ROT) can cause duct issues. He talks about the role of friction rate in duct design as well as its intent and limitations.

Friction rate is a value located on duct calculation tools, including Ductulators. We use friction rate to predict the operating static pressure of the system, but it is often misapplied when people design their ductwork around rules of thumb. The friction rate is expressed in inches of water column ("WC), which we also use to measure static pressure. However, the operational static pressure and...

Craig Migliaccio (AC Service Tech) returns to the podcast to talk about what it means to have the heart of a teacher.

Craig discovered his passion for teaching while instructing apprentices on the job, and he went into institutionalized teaching from there. He chose to overcome several administrative obstacles to become eligible as a teacher at technical schools, and that perseverance is one aspect of the "heart of a teacher."

One of the most rewarding aspects of teaching is the investment in others. For Craig, HVAC is a tool for supporting someone's family, and a...

In this short podcast episode, Bryan explains why saturation can be CONFUSING and clears up some common misconceptions.

Saturation applies to dehumidification and refrigerant inside the system. Generally, saturation is the state at which a substance can no longer hold or absorb any more of another substance. When air is saturated with water vapor and can hold no more, it is at the dew point or 100% relative humidity; it will condense on any surface below the air temperature.

Air isn't like a sponge that absorbs water vapor; saturation deals with vapor pressure, particularly the pressure...

Kevin Hart from HAVEN returns to the podcast to talk about ventilation in humid climates and some best practices for working on systems that focus on the V in HVAC. HAVEN focuses on IAQ management with the use of software technology.

HAVEN started off with its central air monitor, and the company then developed a central air controller to help customers make their homes healthier. Fresh-air ventilation is one IAQ, but humid climates make it tricky to bring that air in; dumping “fresh” air into the structure without taking extra precautions can lead to high indoor humidity and...

Dominick Guarino from NCI joins the podcast to talk about the High-Performance HVAC Summit, an upcoming event hosted by NCI from April 17–20. The National Comfort Institute (NCI) is a training organization that helps technicians learn crucial skills and succeed through high-performance contracting.

High-performance contracting is based on the mindset of “don’t just promise performance; prove it.” To maximize technicians’ potential, NCI teaches technicians how to test equipment properly and monetize their skills. Techs can then use their knowledge to teach the homeowner about the system and solve problems with sales; they can earn money while being solutions...

In this podcast from AHR 2023, Tony Gonzalez from Fieldpiece joins Bryan to talk about training, combustion, and more.

Fieldpiece has a new combustion analyzer that reduces the cost of tool ownership and maximizes the tool's uptime, namely by using a long-lasting sensor. The combustion analyzer's oxygen and CO sensors seal up when the combustion analyzer is turned off, which pauses degradation. The sensors are also field-replaceable and come with a 4-year warranty. The CAT85 also has a built-in dual-port manometer (which can measure static pressure) and can measure a live draft pressure during combustion analysis.

...

In this podcast from AHR 2023, Brandon Marshall from Chemours and Chris Forth from JCI talk about the future of refrigerants and Opteon XL41 (R-454B).

Refrigerant regulations are changing to pave the way for lower-GWP refrigerants, but M1 is also in full swing. M1 refers to the U.S. Department of Energy's implementation of the new efficiency standards for A/C units and heat pumps (SEER2, EER2, etc.). These standards changed the equipment testing procedure to match field conditions more closely.

Opteon is the next-generation portfolio of low-GWP refrigerants for Chemours as a successor to...

In this podcast from AHR 2023, Jim Bergmann and Joe Medosch talk about measureQuick and the ways it's EXPLODING with growth and new features. They also talk about heat pumps, electrification, and other hot topics in the industry.

Jim Bergmann recently released an open letter about heat pumps on LinkedIn; he addressed the shortcomings of the industry from a skill standpoint. The lack of training and standards may be mitigated with proper training (and an understanding of building science fundamentals) or by embracing hybrid systems. Heat pumps may also perform relatively poorly during extreme weather events and may...

Genry Garcia returns to the podcast to talk about pressures in the building envelope, namely the infiltration skeletons behind closed doors.

When doing load calculations (Manual J), we need to know how much of the heat load, especially the latent heat load, comes from leakage in the building envelope and the ducts. Opening/closing doors and windows can also worsen the issues that stem from infiltration due to upsetting the balance of pressures in the home. Smoke pencils and other similar tools can give you an idea of the pressure in a home and how it could...

In this episode recorded live at AHR Expo 2023, Nick from INFICON joins Bryan to talk about leak detectors and how we can improve our understanding of them.

Some leak detectors, including the INFICON Stratus, measure concentrations in PPM (parts per million). When measuring PPM, we have to keep in mind that it doesn't indicate the size of the leak or leak rate, but it does help us pinpoint the leak location. In some cases, we also have to watch for automatic zeroing capabilities.

Leak detectors come in many varieties, including heated-diode, ultrasonic, and infrared; each...

In this episode recorded live at AHR Expo 2023, Dustin and Jim from Copeland/White-Rodgers join Bryan to talk about the use of heat pumps in cold climates. They talk about the history of heat pump innovation and talk about changes to come.

Variable-speed and two-stage compressors, as well as advanced controls, make it easier for contractors to control sizing and for heat pumps to perform to acceptable standards in cooler climates. Contractors in cold climates also rely on dual-fuel models that use electric and gas heat, which makes it easier for the system to move the desired...

In this episode recorded live at AHR Expo 2023, Matthew Schlegel, the Commercial Product Manager of Ducted Systems from JCI (Johnson Controls) joins Bryan to talk about rooftop unit (RTU) retrofit facts and considerations.

When doing an RTU retrofit, you want to make sure you know the budget before anything else; larger budgets will allow you to implement things like VFDs and even VAV technology. In many cases, you may consider adding an economizer for "free" cooling and energy savings. You also want to know what you will get out of a retrofit in terms of value, especially...

Chris Mohalley returns to the podcast to talk about troubleshooting the modern ECM (or EC motor) and give diagnostic tips. ECMs are electronically commutated motors; they are mechanical motors with an electronic control module that dictates everything the motor does.

As with all motors, ECMs have inputs and outputs. If the motor is not running, the first step is to check the line voltage and make sure that it is correct and connected continuously, as that's one of the main inputs on all ECMs; there is no relay or switch on the line side. The motor itself...

Clifton Beck of ESCO Group returns to the podcast to talk about training for the future. He also talks about how he became an educator, what it's like to be a trades educator with ESCO Group, and how educators can handle the recent HFC phasedown and the rise of A2L refrigerants.

Especially with the COVID-19 pandemic, mass media has changed the way the industry thinks about training. Organizations like ESCO have evolved, and that is evident in their curricula; changes are being made to keep up with field tools and equipment to make sure technicians are...

ECM expert Chris Mohalley joins the podcast to talk about the balance between selecting air filtration and motor performance, also known as "MERV vs. Motors."

As the industry realizes that filtration is more important, we're starting to see an interest in filters with MERV ratings of 13 or higher. However, there are some design challenges associated with static pressure drops across filters, motor responses to static pressure, and airflow. If the airflow isn't set properly, that could affect the refrigerant charge and temperature rise.

PSC motors' performance directly follows the load; as static pressure increases, the...

John Ellis, a business consultant who specializes in IAQ training, joins the podcast to talk about effective filtration, product development, and more. John has recently worked with an OEM to bring field practicality and application to the engineers who design products.

Filtration design is a relatively poorly understood concept in the industry; we tend to overlook a filter's ability to remove particulates from the air when we prioritize static pressure drop. We have to understand how the duct design can make higher-MERV filters work and how the face velocity plays into design and comfort.

John...

Dr. Allison Bailes from Energy Vanguard joins the podcast to answer the age-old question: do houses need to breathe? He also talks about his new book, A House Needs to Breathe... Or Does It? You can purchase that book directly through the Energy Vanguard site at https://energyvanguardstore.com/ or on Amazon.

HVAC professionals can benefit from learning about building science because there is a lot of overlap between the two, and an HVAC technician who knows about building science can set themselves apart in the market.

In short, Dr. Bailes doesn't think a house...

David Holt with the National Comfort Institute (NCI) returns to the podcast to talk about high-performance HVAC and what the heck it even is. 

High-performance HVAC is all about delivering the highest possible equipment performance out of the box. High-performance HVAC is a key element of NCI's work; equipment should be able to deliver the health, comfort, safety, reliability, and efficiency expected by the occupants, and equipment that can't do that often has root issues we need to troubleshoot and fix. In many cases, the root cause has something to do with airflow issues.

As c...

Ed Janowiak returns to the podcast to talk about setting realistic customer expectations when designing residential HVAC systems across climates, seasons, and load conditions.

Being honest and aggressive is one of the best ways to set realistic expectations, and our load calculations and equipment selection need to reflect that. Manual J calculations must consider non-design days, not just the design conditions, including partial load conditions. Partial load conditions that aren't accounted for may make it more difficult for the HVAC system to control latent heat, potentially leading to moisture problems indoors.

We have to set...

Craig Migliaccio, aka AC Service Tech, returns to the podcast to share his knowledge about mini-split install & service. He also talks a bit about his upcoming book, “Inverter Mini-Split Operation and Service Procedures.”

Mini-splits are unique because they are compartmentalized in ways that traditional central-air ducted systems are not. Mini-splits come in many varieties, including ducted and ductless types, as well as multi-zone types. Many are inverter-driven and have more electrical efficiency as a result and can vary their capacities based on load variation. 

Mini-splits have metering devices at their outdoor units, and these devices may b...

David Richardson from NCI returns to the podcast to talk about why CO (carbon monoxide) doesn't leak and what it does instead.

CO is a highly dangerous gas that is colorless and odorless, and we can keep ourselves safe by staying aware of it with personal low-level CO monitors. However, CO doesn't leak; it spills, especially via backdrafting, a blocked flue, or updrafting. Whenever the flue gas comes back inside the structure unintentionally, there is room for a potential CO problem. With proper testing, we can determine the cause of that spillage and make the best choice...

Jim Fultz with Emerson White-Rodgers returns to the podcast to talk about one HSI furnace control to rule them all, the 50M56X-843 Universal Single Stage Integrated Furnace Control.

The 50M56X does not come with wiring harnesses; the control comes with the plugs that the majority of manufacturers use, making it a versatile and user-friendly universal part. It also works with the White-Rodgers Connect app to help you configure the part with the burners. You can also do some basic configuration when it comes to the blower motor. With the 50M56X and Emerson White-Rodgers Connect...

Yaron Ben Nun from Nostromo Energy joins the podcast to talk about ice banking, a way of using ice to balance energy consumption. Nostromo Energy is an Israel-based company that has recently started working in California.

Water has a very high latent heat of fusion, meaning it can absorb and store a lot of energy between its solid and liquid states of matter. By storing ice, Nostromo Energy can support commercial and industrial structures that utilize chiller-type applications by offering a clean and sustainable battery thanks to water and its physical properties. Load balancing or management will...

Eric Kaiser and Ty Branaman return to the podcast to talk about why we need to pay technicians and field workers better in the HVAC industry and how small and medium businesses can help current employees.

When the pay for entry-level HVAC positions can't compete with fast-food, retail, or warehousing jobs, we can't expect people to flock to the industry, especially since so much skill is required. Overtime is also almost unavoidable in many places, and it's a problem that requires a more nuanced solution than getting more trucks on the road. The tricky part about paying...

Dr. Chuck Allgood from Chemours returns to the podcast to do some refrigerant myth-busting.

Many people don’t understand why high-GWP HFCs can impact the atmosphere if the refrigerant is heavier than air. High-GWP HFCs exist for a long time, and they last long enough for natural mixing and the wind to distribute their molecules throughout the atmosphere. HFOs, by comparison, are more reactive in the atmosphere and have relatively short lifespans, meaning they have less of an effect on the environment.

Even though refrigerants with lower GWPs are entering the market, it’s always been...

Ty Branaman and Eric Kaiser return to the podcast to discuss the good, the bad, and the ugly of trade schools. They cover the opportunities and challenges they've observed in trade schools.

As with for-profit colleges, for-profit trade schools market programs aggressively and can take people who are at a crossroads in their life and saddle them with debt. In some cases, trade schools are hesitant to fail people and end up passing people who don't have the technical proficiency to be effective tradespeople. Sometimes, trade schools don't emphasize practical skills and contractors' experiences as much as...

John Pastorello from Refrigeration Technologies returns to the podcast to talk about selecting proper cleaners for various HVAC/R jobs.

From the beginning, the goal of Refrigeration Technologies has been to make cleaners that are safe but have the same effectiveness as the strong, hazardous varieties in the industry. The more hazardous cleaners are not food safe and may be corrosive, dangerous to inhale, or irritating to the skin or eyes. Some cleaners can also damage components; brighteners aren’t recommended for use on aluminum coils for that reason. 

John is a fan of foaming cle...

Eric Kaiser and Ty Branaman return to the podcast to talk about the progression from technician to service manager and if a good tech always makes a good service manager. They discuss career paths, differing skills between technicians and service managers, and how HVAC/R companies can support techs who wish to remain techs.

In many cases, top technicians are pulled into service manager positions to keep them with the company. Sometimes, older technicians who have lost some mobility and strength over the years end up going to managerial positions to stay in the industry. Some people...

Kimberly Llewellyn from METUS joins the podcast to talk about the value system around the trades and why the trades aren’t more respected.

In many cases, the people who are involved in engineering and design miss the practical details that the tradespeople would be able to pick up on. In many cases, tradespeople aren’t consulted early enough in the design process, and their input deserves to be brought to the table. Often, not everyone on a project team is on board with the project's goal, and the trades need to be on board from the begi...

Eric Kaiser and Ty Branaman return to the podcast to talk about getting more people into the trade. They focus on how the HVAC/R industry could be better at attracting and training skilled workers, not just getting more bodies to fill HVAC/R tech and installer positions. 

People are starting to see more value in skilled trades careers, but it's difficult to find people who share your company's values and want to grow as HVAC/R professionals. Skilled tradespeople need time, education, and money invested in them, so it can be difficult for HVAC/R business o...

Genry Garcia returns to the HVAC School podcast to talk about what becoming a complete tech really means and entails. He talks about his professional journey and what we must do to address our deficiencies.

Career progression looks a bit different for everyone, with some technicians going to trade school and others starting as helpers and working their way up. We get used to taking readings and start noticing patterns. Then, we start understanding why we see certain pressures. Our experiences are our most valuable tools for becoming better technicians, but they can be reinforced with other...

In this short podcast in our electrical myths series, Bryan talks about some inductive current myths.

There is a common myth surrounding voltage drop in inductive loads. When you decrease the voltage in a circuit with a resistive load, you'll see a relatively proportional drop in resistance (ohms) and current in accordance with Ohm's law. So, we'll see a decrease in current, but we have to keep in mind that load temperatures also affect the resistance (and the current, by extension).

Some people will claim that reducing the voltage in an inductive load (like a...

Alex Meaney returns to the podcast to explain why it REALLY gets hot upstairs and what we can do about it. He also talks a bit about his new business.

Heat technically doesn’t rise; warm air is less dense than cooler air, so cooler air sinks as warmer air rises. In many cases, people blame stratification and the stack effect for warm upstairs areas, but there may actually be other issues at play, especially if the issue only seems to happen in the summer. 

Many apparent convective problems are actually due to building science err...

In this short podcast, Bryan busts the common electrical myth that single-phase 240v power is really two-phase power.

When power goes into a structure that runs 240v appliances, we may understand that two 120v sine waves are 180 degrees out of phase with each other, but that isn’t 100% accurate. If we were to use an oscilloscope to watch the electrical sine waves, we would see two sine waves 180 degrees out of phase because the transformers are center-tapped. Center-tapping creates a neutral center point that becomes our reference.

The transformer has two sides: a primary and a...

Moe Hirsch joins the podcast to discuss the hydronics side of the industry, particularly focusing on Dan Holohan’s Pumping Away and exciting developments in the hydronics market, especially regarding electrification.

Pumping Away is many people’s entry point to hydronics. It contains some good basic information about boilers, especially when it comes to learning about the pressures involved in pumping and how the components manipulate pressure throughout the system. 

Boilers use many of the same fundamentals as compression-refrigeration HVAC systems; pressure drops are similar, as are phase changes in steam boilers. Boilers also employ pumps...

In this short podcast, Bryan busts the myth that hard starts reduce the start current on the run winding of a compressor.

A single-phase motor’s main winding is the run winding; it has a lower resistance and a higher current than the auxiliary winding, also known as the start winding. 

Hard start kits are often used on HVAC systems with single-phase compressors (which usually have PSC motors). These kits usually consist of a start capacitor and a potential relay, which takes the start capacitor out of the circuit. We don’t typically use hard start...

Andy Holt joins the podcast to talk about what it means to be a 24-Hour Technician. We talk about what it means to be HVAC/R technicians AND deal with the human aspects of our lives at the same time.

Service technicians differ from installers in that they do much of their work solitarily. They spend a lot of time by themselves. They’re also on their feet very often and may do emotionally exhausting work, but they can earn a respectable living and accumulate savings for the future. To make our work and the emotional burdens th...

Andy Holt joins the podcast to talk about what it means to be a 24-Hour Technician. We talk about what it means to be HVAC/R technicians AND deal with the human aspects of our lives at the same time.

Service technicians differ from installers in that they do much of their work solitarily. They spend a lot of time by themselves. They’re also on their feet very often and may do emotionally exhausting work, but they can earn a respectable living and accumulate savings for the future. To make our work and the emotional burdens th...

Jim Bergmann returns to the podcast to talk about furnace commissioning procedures and the development of measureQuick 2.0.

MeasureQuick 2.0 has been a collaborative effort between Jim Bergmann and Joe Medosch, and it comes with an upgraded user interface that allows for faster operation and easier system data access and storage, and it works with more tool manufacturers’ tools.

Gas furnaces need to be commissioned to reach their maximum potential (and lifespan). MeasureQuick 2.0 provides commissioning instructions and recommends starting with a visual inspection, including the flame rectification system (rod, circuit board, and grounding). Electricity is conducted during th...

Mike Klokus and Jeff Crable walk us through Kalos Services' light commercial PM process. 

First, we verify that everyone is clear on the agreement. Then, we start the PM with a thorough visual inspection, taking copious notes about things that look concerning. 

Once we’ve done a visual inspection, we clean the condensers. We try to use only water when possible, though safe cleaners may be necessary in some cases.

When checking the electrical components, we make sure the wires are neat and have tight connections. We take our electrical readings and check the...

In this short podcast, Bryan covers a common electrical myth about wire length and its relationship with the National Electrical Code. The NEC is concerned with safety—protecting buildings and people—but less so with making sure things work.

Wire sizing is a common topic, and length is important because it can contribute to the voltage drop in a circuit. In many cases, we refer to the MCA (minimum circuit ampacity) to select an appropriate wire size. 

If you run more current through an undersized conductor, it gets hotter and will experience a voltage drop—though...

Trevor Matthews, the founder of Refrigeration Mentor, returns to the podcast to talk about why CO2 matters in commercial refrigeration and even HVAC applications.

CO2 (R-744) has entered the residential HVAC sphere in some places around the world, though it hasn’t come to the North American markets yet. CO2 is one of the most eco-friendly refrigerants on the market, with a GWP of 1, and it’s very good at moving heat. However, CO2 has some challenges, including its low critical point and higher pressures.  

CO2 comes with some safety concerns, and its systems have a comp...

This podcast is Bryan’s full-length electrical basics class for the Kalos technicians. He covers electrical theory and circuit basics.

Volts, resistance, and amps all affect the behavior of electricity in circuits. These are also critical factors in electrical safety. Watts and kilowatts come from the multiplication of the volts and amps, though not every volt-amp does work; the power factor indicates how much work the volt-amps are actually doing. Some of the volt-amps are reactive (kVAR) and don’t do the real power of watts.

Electrons move by interacting with other atoms. Substances can be c...

In this short podcast, Bryan debunks the myth that electricity only takes the path of least resistance.

It is true that more current will typically take paths of lower resistance; it’s much easier for more electrons to flow through a path with lower resistance, which is consistent with Ohm’s law. Ohm’s law states that a circuit will have higher current with you have lower resistance so long as the voltage stays the same. 

In most cases, the voltage stays relatively constant; transformers don’t often need to limit their currents, so there usually i...

Nikki Krueger from Santa Fe Dehumidifiers returns to the podcast to talk about dehumidification equipment and strategies in the shoulder seasons (spring and fall). The shoulder seasons (and the weeks leading up to them) are when many homeowners begin to notice moisture problems in their homes.

HVAC units and dehumidifiers should have a king-queen relationship. The HVAC unit is the king and controls the bulk of temperature and humidity during the day, but the dehumidifier can take care of the humidity when the king needs help. To remove moisture optimally, an HVAC unit needs longer runtimes and...

In this short podcast episode, Bryan gives some quick tips for time management. You can save a lot of time by prioritizing what really matters and delegating tasks.

One of the simplest but most effective ways to manage your time is to use a calendar. You can even apply the calendar to your personal life; you can get into a habit of scheduling important appointments, deadlines, and tasks. Google Calendar also allows other people to see and interact with your schedule, so it’s a great tool for scheduling performance reviews, interviews, and meetings.

When yo...

Eric Kaiser returns to the podcast to talk about how to become a better mentor. He explains the topic from the perspective of a mentor and a mentee.

The goal of mentorship is to pass your knowledge on to someone else. When you give someone the knowledge to succeed in the HVAC/R trade, you move the trade forward and allow yourself to try new career opportunities when someone can replace you.

Some of the most effective mentorship strategies establish the mentor as a guide rather than someone who spoon-feeds the mentee. Mentorship is about...

Eric Kaiser joins the HVAC School podcast to talk about HVAC measurement types and the benefits of taking each one. He also talks about point measurements and data trends.

Point measurements include static pressure, voltage readings, and readings provided by gauges. We only take those measurements once. However, when you track those on several occasions over time, you can build data trends. Single-point measurements give us information about what is happening at the moment, but they don’t give us a long-term view of the system's health.

Absolute and differential measurements also have different purposes en...

Genry Garcia joins the podcast to give an intro to ASHRAE Standard 62.2. He and Bryan also share a nice rant about accountability in HVAC design. Standard 62.2 is the ventilation standard for low-rise residential buildings, which dilutes airborne contaminants like VOCs and CO2.

Before coming up with a ventilation strategy, we need to assess the leakage rate of the building, such as via a blower door test. However, we also need to consider how bringing in outdoor air might negatively affect efficiency and comfort if we don’t do it right. 

Exhaust ventilation removes air from the...

RACT manual co-author Eugene Silberstein joins the podcast to talk about the titular topic of his book, Pressure Enthalpy Without Tears. 

Pressure Enthalpy Without Tears is a book that introduces engineering concepts to HVAC technicians in a way they can understand and apply in the field. Enthalpy is a fancy way of saying “heat,” and we use it to refer to the total heat content (BTUs).

The pressure-enthalpy chart shows the relationship between the refrigerant pressure and enthalpy in a system; it’s like a P-T chart that shows the relationship between heat content instead of temp...

In this short podcast, Bryan talks about THOR, total heat of rejection. He explains what it is and why we should care about it when working on HVAC/R systems. THOR is another aspect of pressure-enthalpy calculations, along with net refrigeration effect (NRE) and total heat of compression.

When we talk about system capacity, we’re often referring to heat absorbed in the evaporator coil (NRE).  Heating is on the opposite side of the coin; when we bring heat into a home, we care more about how much heat is rejected than absorbed. That’s where THOR comes...

Matteo Giovanetti from Micro-Air joins the HVAC School podcast to talk about the differences between a hard start and an EasyStart.

Micro-Air’s “EasyStart” provides a soft start rather than a hard start. A hard start abruptly ramps up the voltage and current to the motor start; a soft start is a much gentler start that results from a gradual voltage and current increase on the start AND run windings. 

The EasyStart marks a paradigm shift in how we think about “saving” compressors. It attempts to avoid drawing unnecessary inrush current, which is very common with hard s...

In this short podcast, Bryan explains what the heat of compression is and why we should care about it as HVAC/R professionals.

More heat is rejected in the condenser than absorbed in the evaporator coil, and that’s because the compressor adds heat. That added heat is called “heat of compression.” That heat does NOT contribute to the net refrigeration effect (NRE), as it doesn’t contribute to cooling.

When we compress something, we increase the system entropy during that process. Entropy is the waste and disorder associated with work. There is some inefficiency, which we...

Ed Janowiak joins the podcast to introduce us to ACCA Manual T.

Compared to other manuals, Manual T is one of the least-considered ACCA manuals. However, it’s the manual that advises us on how not to blow high-velocity air on people and has maintained the same standards since the mid-1900s. Unlike Manuals J, S, and D, Manual T is not recognized in code compliance.

Manual T deals with air distribution; it helps us find out the throw and spread, which informs our ductwork design in Manual D. We need to know the customer’s ex...

In this short podcast, Bryan explains what the net refrigeration effect (NRE) is and how it affects HVAC systems.

The net refrigeration effect (NRE) is what happens in the evaporator coil. The evaporator is the heat absorber; as air passes over the coil, the cooler refrigerant within the evaporator absorbs that heat and boils. The NRE is the net energy change that occurs during that process. You can plot the NRE on a pressure-enthalpy chart.

When air moves over the evaporator coil, there is a change in enthalpy or BTUs per pound in the refrigerant...

Eric Kaiser returns to the podcast to talk about how we can use systems thinking to approach gas appliances and combustion in HVAC installation and service.

Gas lines can be made of a few different materials, including black iron, copper, and CSST. These all have benefits, setbacks, and appropriate applications. For example, copper is common in propane (LP) systems but not natural gas. In coastal environments, galvanized pipe tends to be most common due to the increased likelihood of corrosion. Gas lines may also need sleeves to prevent them from interacting with moisture.

The piping...

Some admins from the HVAC School Facebook group join the podcast to discuss the art of moderating a successful community. Bryan is joined by Eric Kaiser, Ty Branaman, Michael Housh, and Neil Comparetto.

A community based on a skilled trade gives people an inviting space to share information and ask questions. It’s also a space that allows people to practice how they present information. Groups also connect people across geographical locations, and we can get regional perspectives that change the way we think about things.

However, community standards are necessary to keep groups professional an...

Eric Kaiser returns to the podcast to discuss high-voltage wiring, low-voltage wiring, and condensate assemblies as they relate to systems thinking.

On the high-voltage side, the disconnect should be in a secure location, and it should be able to keep water out. The wires should be appropriately sized, have an appropriate level of tension, and should not be vulnerable to chafing or abrasion. Overall, best practices include using proper grommets and ensuring that you have a solid connection. Do not run high voltage wiring in parallel with low-voltage or control wiring. It’s also worth noting that do...

Eric Kaiser returns to the podcast to talk about how copper, piping, and line sets play into systems thinking.

Nowadays, we have to think about POE and PVE oil, and we need to design line sets in a way that assists with oil carry while preventing liquid refrigerant migration. The height of the evaporator relative to the condenser is a major factor to consider during the design phase.

Especially when chases are run underground, we need to watch for possible threats to the copper. Water softener discharge and excess pool water may damage the copper...

Eric Kaiser joins the podcast to talk about systems thinking in HVAC. Systems thinking allows us to solve problems and address customers’ comfort holistically instead of focusing on just the equipment. The key to systems thinking is to think outside the appliance.

System design plays a major role in performance. Duct design, drain placement, and equipment placement all matter, and we can only do so much to mitigate factors of poor design. We need to assess the building envelope and consider how the HVAC system interacts with it. Building envelope and duct leakage will significantly affect HVAC pe...

Nathan Orr joins Bryan to talk about some logical fallacies, namely the false cause and strawman. They explain how those fallacies show up in the trade.

It’s difficult to present arguments without using fallacies, but people tend to rely on fallacies to uphold extreme religious or ideological viewpoints or conspiracy theories. Fallacies are also often easier to communicate than nuanced science and data.

“False cause” relates to the phrase “correlation does not equal causation.” It can be tempting to link coincidences and say that one thing causes the other, but that could very well not be tru...

Refrigeration Mentor founder Trevor Matthews returns to the HVAC School podcast to talk about personal development and training, including tips for learning in HVAC/R.

When you’re looking at a problem in the field or in training, it pays to take a step back, cool down, and reevaluate your mindset. Trevor recommends thinking about the worst-case scenario and seeing how you can either prevent it or grow from it. It’s good to walk away for a little bit anytime you feel like you’re overanalyzing anything so that you don’t make blunders. 

Trevor ha...

In this short podcast episode, Bryan shares some of his top threaded connection tips. He also clears up some confusion about connection types.

Threaded connections include flare and compression-type fittings (like chatleff or Aeroquip fittings). The threads don’t actually make the seal; the pressure pushing the surfaces together is what makes a seal. 

Bryan doesn’t recommend putting traditional thread locks on flares, but refrigerant oil or mild assembly lubricants can help the flare come together more smoothly without imperfections. However, you need to be careful when using a torque wrench and use the lowes...

Bryan explains how parents and educators can succeed at giving kids the tools for any job they want. This podcast was originally a presentation at the 2022 FPEA Florida Homeschool Convention.

Jobs, careers, and vocations have changed a lot over the years. Even though those have changed over the years, parents still want their kids’ vocations to develop character, foster growth, and bring joy. While kids are young, parents can instill values of grit and diligence; however, parents have to overcome the challenges presented by the instant gratification provided by technology. 

Interest-guided learning is a double-edged swo...

In this short podcast episode, Bryan talks about ERV and HRV technologies, including their appropriate applications and limitations.

HRVs are heat recovery ventilators (not to be confused with heat recovery units or HRUs), and ERVs are energy recovery ventilators. The main difference between these two lies in the type of heat they move; HRVs only move sensible BTUs, whereas ERVs move sensible and latent BTUs. 

As you bring air in from outside, you’re discharging roughly the same amount of air (though modern technologies allow you to manipulate the pressure a bit more). The goal of...

Rajan Rajendran and Jennifer Butsch from Emerson join the podcast to discuss the Helix and some refrigerant changes that are coming. Jennifer is the Director of Regulatory Affairs, and Rajan is the Global Vice President for Environmental Sustainability and former director of the Emerson Helix.

Lately, there have been more environmental efforts to reduce greenhouse gas emissions, and plenty of large corporations have “net zero” initiatives. Sustainability requires a holistic, systemic approach in our industry; the Helix Innovation Center conducts the research needed for us to handle these sustainability initiatives as effectively and safely as possible.

Ho...

In this short podcast episode, Bryan talks about pilot controls. He talks about the old-school ignition systems on gas appliances and some similar pilot functions on residential A/C units and heat pumps.

When we think about a pilot light on a gas appliance, we can think of it as a small standing flame that sits there ready to ignite the burner whenever gas is flowing. Pilot lights were necessary for old-school gas furnaces, and many of those pilot lights worked with a thermocouple. In many older furnaces, pilots also prevent excessive carbon monoxide from unspent gas...

Bryan and Robert Orr continue their discussion about ethics by talking about what it means to have grit and discipline in business. They talk about what those characteristics look like in business and in life, and they mention some good books.

Grit is a trait that can contribute to an ethical way of life; showing grit means that you follow through with a project until you get the results you want. Both physical and emotional grit are strengths, and those things tend to be more important than talent in our field. 

Compared to discipline, grit i...

Bryan and Robert Orr talk about ethics and what it means to have integrity when running a family business. Robert is a lifelong tradesman who is a licensed construction contractor, and he has overseen the construction side of Kalos for many years.

Robert initially started off at the Air Force Academy and realized that he didn’t feel that the military was right for him. While in Florida, Robert fell into the trades and learned both hard skills and ethics in the process. He started his own house-wiring business at age 21. Later, he went into home inspection an...

In this short podcast, Bryan talks about distributors and external equalizers and why we need to use them together.

When older Carrier heat pumps (with pistons) would run in heat mode, the metering device would be outside. In those cases, the port on the liquid line would be on the opposite side of the metering device. So, you wouldn’t actually be measuring the liquid line pressure (high-side) if you measured it at that port while the system runs in heat mode.

However, that pressure would be higher than the common suction pressure. That’s beca...

In this short podcast episode, Bryan talks even more about sine waves and center-tapped transformers.

Power is generated at the power plant when an energy source (such as steam) is used to drive a drive shaft. The resulting current can be mapped as sine waves, which actually represent points on a circle; there is a rotational magnetic field around stationary conductors, and the sine waves allow us to envision the positive and negative alternations as the rotation happens.

Center-tapped transformers use “neutral” as a reference point. The secondary winding on a center-tapped transformer may have 240v po...

Bryan describes the tricky concept of power factor and why we should care about it. He also compares power factor to a beer mug to make the topic easier to understand.

Power is often represented on a sine wave, which is a curvy line that marks the state of electrical energy at different points on a circle. Power gets stronger and weaker, and it goes above and below the neutral line depending on the excess or deficit of electrons.

Unity power factor refers to a power factor of 1, indicating that voltage and amperage are perfectly...

Bryan lays down some motor speed facts in about 10 minutes in this short podcast episode.

We can figure out how quickly a single-phase motor (PSC) will run if we understand how many cycles it will make per second. In the USA, the standard hertz is 60 Hz (60 rotations or magnetic alternations per second). Motors are inductive loads that create an electromagnetic field with a spinning rotor and stationary stator; the amount of poles on the stator determines how quickly the rotor spins (RPM).

In the RPM counts, there are some allowances for slip. Slip varies depending...

Neil Comparetto and John Semmelhack of the Comfort Squad join Bryan to discuss high-quality value design in a high-performance home. They explain how they design HVAC systems (heat pumps) for low-load homes in ways that are affordable, efficient, and comfortable.

High-performance, low-load homes need to be energy-efficient AND comfortable, and it can be a challenge to get both. Manual J calculations aren’t as common as they probably should be, and it can be difficult to get accurate data about air leakage, power consumption, and radiant gains as well. So, John and Neil try to collect their ow...

Lacey Dietz with METUS and Scott Arnold with Rycor HVAC join the podcast to talk about how the industry can start putting contractor success first. They talk about Mitsubishi Electric (METUS)’s commitment to contractor success and what that looks like.

METUS’s contractor program aims to provide training, support, and recognition to create a community of successful contractors. Support comes in the form of marketing, training, tech support, and customer service, and those services are available to contractors who sell and represent Mitsubishi’s products.

As a contractor who works with Mitsubishi, Scott has been a...

Sam Myers with Retrotec talks to Bryan about pressures in the home and why they matter for HVAC solutions at IBS 2022.

Technicians focus a lot on ductwork and airflow, but many of them don’t focus on how the building envelope impacts HVAC performance. A lot of the HVAC equipment’s performance is affected by the push and pull of air caused by leaky areas in the building envelope.

If you have a room with too much air and another room with too little, you will have unbalanced pressures. Unbalanced pressures may result in discomfort and...

This podcast is a class that Bryan taught for BTrained in Birmingham, AL. He covers troubleshooting, installation, and commissioning best practices with a focus on the fundamentals.

To be a good troubleshooter, you must be able to find the problem, identify the source of the problem, fix the problem, and optimize performance based on your data, the customer’s comments, and your observations. The Five Pillars of diagnosis aren’t comprehensive diagnostic or charging criteria, but they can help you charge or diagnose a system.

Isolation diagnosis works best for electrical components; you isolate the prob...

Bryan has a bit of an industry nerd out with Ross Trethewey from “This Old House” and TE2 Engineering at IBS 2022 (the International Builders’ Show). Ross’s education and career have focused on mechanical engineering, especially with sustainable solutions.

In building science, the key mindset is to think of the building as a system. Using that school of thought, Ross has developed building science and HVAC solutions that also consider indoor air quality and ventilation, such as hybrid VRF systems. 

Many of Ross’s solutions take the best aspects of air-source and ground-source heat pumps and apply t...

In this podcast, Bryan goes through the entire process of replacing a compressor step-by-step. This process is what the Kalos team uses to replace a failed compressor and make sure it doesn’t fail again.

Before replacing a compressor, you must figure out how the compressor failed; grounded conditions often lead to acid, so it’s a good idea to test for acid and see if you need to address a burnout. In any case, make sure you have the correct tools for the job (including a compatible replacement compressor).

When you arrive at the job...

In this short podcast, Bryan explains what it means to top off, drop in, and retrofit refrigerants. He describes the differences between those three things to dispel some of the confusion they may cause.

Topping off a system means that you add refrigerant to a low existing charge to get it back up to a normal level. In some cases, people top off systems with dissimilar refrigerants (e.g., topping off R-22 systems with cheaper R-407C). Topping off a system with a dissimilar refrigerant is unacceptable, as it’s against EPA guidelines and leaves you with an...

Trevor Matthews, the founder of Refrigeration Mentor, is back on the podcast. This time, he and Bryan talk about the value of networking for HVAC techs as the conference season comes to a close.

Many trade events are networking opportunities that allow you to build relationships with other tradespeople, educators, mentors, and even other companies. You can also learn many trade and business tools that help you as a technician. Many technical and business conversations occur at trade events, and there is a lot to learn from those, whether you’re directly involved or just listening. It ca...

David Richardson of NCI joins the HVAC School podcast to talk about how we can implement educational growth effectively throughout the trade. NCI started as a premium training resource about airflow testing, but the organization eventually started teaching about combustion testing as well.

When we improve the industry, we need to be able to have concrete ways to see what we’ve been doing wrong or what we can do better. Test instruments allow us to see the whats and whys behind what we do. Education needs to be focused on bringing those test instruments into training AN...

Corbett Lunsford of Home Diagnosis joins Kaleb to record a podcast about comfort investigation on TV. The two of them discuss how comfort investigation works on TV shows, what Home Diagnosis hopes to accomplish, and some building performance tips.

Home Diagnosis is mostly aimed at homeowners, but HVAC technicians would also benefit from the show, as it dives into science and testing. The show promotes consumer education and contractor accountability.

Diagnostics and testing are absolute MUSTS for providing the best possible solutions and transforming your business. You put yourself in another league when you take...

A commercial HVAC system may include air handlers, chillers, boilers, RTUs, and all sorts of energy-consuming technologies. These systems also have controls that help direct the infrastructure, and artificial intelligence can help optimize the controls, make performance predictions based on...

Chris Micallef, the CEO of Falkonair, joins Nathan Orr at AHR to discuss energy savings for three-phase equipment. They also explore some of Falkonair’s controls for compressors, especially on DC inverter equipment.

Falkonair has software that allows users to control all types and brands of three-phase compressors with compatible variable frequency drives (VFDs). The software recommends the compatible VFD based on the amperage readings. Falkonair aims to bring this software to the refrigeration industry and then move on to HVAC contractors and data centers.

The control unit adjusts the compressor speed to respond to ch...

Air Doctors Heating and Cooling LLC has its own in-house apprenticeship program based on Department of Labor guidelines. The apprenticeship program caters to new techs out of trade school and focuses on rigorous training. There is some administrative paperwork, but there are no additional administrative expenses. The only expenses of the apprenticeship program come from training and wages. Most of...

Alex and Nicole of Faraday join Kaleb Saleeby and Ty Branaman to talk about new educational formats and options in the HVAC industry. Alex is the founder of Faraday, and Nicole is the head of operations. Ty is a notable HVAC educator who supports Faraday and its mission.

Faraday is a free educational program that prepares apprenticeships for fieldwork, allows them to get EPA 608 certification, and helps place them in jobs with paid training. Although the program is free, there is a rigorous selection process to make sure only the most serious candidates join the program. The...

Ashley (aka hvac_ash) joins the podcast to talk about how HVAC fits into social media, AHR 2022, and AmRad capacitors. Ashley works with Global the Source on the sales and distribution side of the business.

Becoming an HVAC influencer is smart, especially when there is a dedicated audience in the industry. When you gain traction online, that can branch into marketing, which helps get the word out even more. It’s also a great way to make connections organically once you have traction and learn from others’ industry-related content.

Ashley also has firsthand experience with the...

Bill Spohn joins Eric Kaiser and Kaleb Saleeby at AHR 2022 to talk about his experiences designing and living in a home with NetZero HVAC. 

NetZero HVAC refers to system design with tight coordination with the house to make it as efficient as possible. Some of these systems are so tight and efficient that they approach passive house standards (0.6 ACH50). Bill lives in a modular home that also generates more energy than it consumes, and it doesn’t rely on natural gas.

The greatest expenses of Bill’s NetZero home came from all the custom factors, as it...

Collin Olson, the staff physicist of The Energy Conservatory (TEC), joins Eric Kaiser at AHR 2022 to talk a bit about data logging.

Data logging refers to the act of using sensors to record data over time and then analyzing that data. TEC dipped its toes into data logging with the APT and then TECLOG. Data logging allows us to take and store multiple readings as well as extrapolate data into graphs, making it easier to analyze performance. The TECLOG4 software is the most up-to-date version.

TECLOG is a simple software to use with basic training...

Mark Tozzi from Carrier comes on the HVAC School podcast to talk about unique HVAC incentives in K-12 schools.

When schools closed down during COVID-19 lockdowns, a new series of incentives came out for schools. Many of these incentives include access to technology, and improvements to HVACR equipment are covered under those programs.

Schools can benefit from geography-tailored solutions, including air-cooled chillers in the Southeast and products meant to improve IAQ, including filtration upgrades and dehumidification strategies.

To provide valuable solutions to schools, HVACR professionals and manufacturers need to get involved in local...

Chris Forth, the VP of regulatory codes and environmental affairs at Johnson Controls, joins Bryan for a live podcast at AHR 2022. This time, they discuss changing HVAC regulations and what that will mean for contractors, technicians, and installers.

Johnson Controls focuses on institutional chillers, controls with digital platforms, air handlers, filtration, and alarm systems. Lately, Chris has gotten the industry ready to convert existing products and systems to high-efficiency equipment for low-GWP, A2L refrigerants.

The transition to A2L refrigerants will be different from the transition from R-22 to R-410A. We needed to...

Kevin Hart, the CEO of HAVEN, joins Kaleb Saleeby live from AHR 2022 to discuss how we can control IAQ with central air monitors and controllers. HAVEN, formerly TZOA, is an IAQ company that focuses on protecting building occupants’ health by controlling air quality.

HAVEN’s approach to managing IAQ starts with collecting data about the air. Without that data, we can’t come up with solutions tailored to individual buildings. We need sensors to gather that data, which would traditionally mean that we’d need a decentralized system with sensors everywhere. However, HAVEN takes a centralized approach to measu...

Jacques Beaudry-Losique, the CEO of Enginuity Power Systems, joins Nathan Orr live at AHR 2022. Enginuity manufactures energy-efficient engines that produce more power than traditional engines and recover waste heat to act as water heaters. Enginuity engines can run on propane and natural gas to help you run almost entirely off the grid and participate in electricity buyback programs. These units operate independently of the electrical grid and can act as generators during power outages and have a small footprint. However, a backup battery system is recommended for these units to maximize efficiency. Enginuity has a residential and commercial line...

Rick Nadeau, Director of Training and Technical Services at Samsung, talks with Kaleb Saleeby live from AHR. He explains some of the exciting ductless solutions that Samsung has to offer.

Samsung’s WindFree mini-split systems work with VRF systems or as normal ductless units. The WindFree product line is best known for preventing drafts due to microholes. These systems come in one-way and four-way cassettes and work very well for sensitive environments like nursing homes and bedrooms. 

These units also have humidity sensors that let the units know when it would and wouldn’t be accep...

Steve Rogers from The Energy Conservatory (TEC) joins Eric Kaiser to talk about airflow measurement at AHR 2022. Steve is an expert in fluid dynamics and flow measurement, and he is a trainer in addition to being the president and CEO of TEC.

Airflow is one of the most critical elements of an HVAC system; it allows us to move the correct amount of BTUs to condition the air properly. We have various ways of measuring system airflow and airflow to a space. We can use the TrueFlow grid for the former and flow hoods for the latter.<...

Brett Wetzel and Kevin Compass from the Advanced Refrigeration Podcast join us to discuss commercial rack refrigeration and identify components.

In supermarket racks, we typically have anywhere from 2-5 compressors on a single rack (with multiple evaporators, metering devices, and sometimes even condensers). These compressors may come in several varieties (including screw and scroll) and be digital or have VFDs. They also have common suction and discharge headers. 

The compressors all share oil from a single system. Oil separators can come in three varieties: centrifugal, impingement, and coalescing (most efficient). The separator would feed into t...

Jim Fultz from Emerson joins Eric Kaiser at AHR to share his knowledge of universal boards and controls. Jim’s work focuses on electronic controls within the White-Rodgers brand.

Common White-Rodgers universal controls include the SureSwitch and universal defrost controls. The SureSwitch also has sealed contacts, which prevents insects and debris from shorting out the contacts. 

This past year, White-Rodgers debuted the All-Spark, which doesn’t need electricity to be powered up and can be programmed right out of the box. The All-Spark works on all sorts of appliances, not just boilers and furnaces.

Uni...

In this short podcast from AHR 2022, Leilani Orr and Eric Kaiser talk with the president and CEO of Malco Tools, Rich Benninghoff. Rich discusses some of the exciting new tools that Malco is bringing to the market and some plans for the future, especially when it comes to education.

Malco has developed the Eagle-Grip, which is a set of locking-handle pliers made in the USA with American steel. The tool is currently in a soft launch; it is currently receiving a lot of interest, so Malco has been building up inventory, forming partnerships across industries, and collecting...

Jason Obrzut joins Nathan Orr with the HVAC School podcast live from AHR. In this episode, they discuss A2L refrigerants and upcoming regulations. They explain what a “flammable” refrigerant really is and why the industry may be making a bigger deal of the new regulations than is really necessary.

Whenever regulations are passed, we need to understand that there is a notable transition period. This period will mostly be about training, and the only people who should be working on the new equipment should be the most experienced technicians.

A2L refrigerants are mildly flam...

David Holt with NCI returns to the podcast to discuss the evolution of HVAC training; we cover the past, present, and the possible future of training in the industry.

In the past, we had a lot of hands-on training, whether it was one-on-one or in a traditional classroom setting. These learning practices remain beneficial today, especially since many uninformed practices are still prevalent in the industry today (charging to beer-can cold, condemning TXVs without a second thought, etc.).

However, the pandemic has forced us to consider online and remote training in the present. The content...

Successful system commissioning starts with the mindset. A good commissioning organization broadens its vision; instead of focusing on the appliance, techs and installers focus on the system. Commissioning early on saves time later; you can focus on installs and maintenance instead of callbacks, and your organization can make more money as a result.

When installing and testing new piping, make sure you insulate the tubing properly and keep the...

Russ King joins us for a short podcast episode about using 3D load and energy calculations with duct design. Russ has developed the Kwik Model 3D software program with the help of his son, Connor.

Kwik Model 3D uses a video game platform to build a house out of boxes instead of a sketch. The software has evolved and been integrated into EnergyGauge to do load and energy calculations based on a house’s geometry. Kwik Model makes it easy and fun to create that geometry profile for a home, which makes building design and load calculation at...

From the beginning, Refrigeration Technologies has focused on solving problems instead of jumping on product trends. Before Big Blu was introduced, technicians had to rely on less-than-reliable electronic leak detectors and poor-quality soap bubbles. So, John Pastorello learned about the fundamentals of foaming and bubbles to create a leak reactant that works, even creating microbubbles for tiny leaks.

Nylog...

When assessing a system for replacement, it’s a good idea to look at the airflow side by measuring static pressure AND using a flow grid; these practices set you apart from others and supply you with good data about system sizing. Filtration is another area where you can consider upgrades and proposals; customers generally want to keep their air clean and ma...

In this short podcast episode, Clifton Beck joins us to talk about Bluon’s free tech support and resources available to technicians and installers.

Clifton has been very in touch with the HVAC technician community since he got his start in the trades, and he has taken that into tech support. He has noticed that the inefficiency in our industry tends to come from poorly learned practices, and working in tech support is a way for him to do his part to spread better practices while helping others.

Lately, Bluon has become more of a te...

Genry Garcia returns to the podcast to talk about blower doors and why ACH50 may needlessly complicate efforts to tighten a building envelope.

A large element of indoor comfort comes down to controlling the load, especially the latent load. Even though we can control indoor humidity sources, we may also deal with infiltration, which contributes to a high latent load and decreases comfort. The blower door test comes in when we can no longer control the load and need to determine how much infiltration is happening.

When using blower doors, we would typically use an...

To understand psychrometrics, we need to be able to quantify air: its weight, humidity, pressure, etc. We can do a better job as technicians if we figure out the air’s content and see how it relates to the CFM and overall unit performance. That way, we can have a more holistic view of HVAC performance instead of just focusing on...

Brandon Marshall, Chemours’s North American marketing manager for thermal and specialized solutions, joins the podcast to discuss refrigerant changes that are coming and how we can prepare for those. Brandon started in the industry by going to a technical school when he was 14 and has been hard at work ever since, studying light commercial design and going to college in between.

Local and global regulations have changed a lot over the years and continue to change as we continue maximizing our equipment’s efficiency. California will soon start switching to low-GWP refrigerant on new equipment in 2025; even...

Chuck Allgood with Chemours joins the podcast to cover the history of refrigerants and discuss what the future might hold.

In the late 1800s, before Freon, the only refrigerants that were used were industrial chemicals like ammonia, CO2, and sulfur dioxide. DuPont stepped in to provide a better refrigerant for industrial refrigeration (which then spurred the rise of domestic refrigeration), so they created a non-toxic, non-flammable chemical called Freon-12 (CFC R-12) in 1928.

However, in the 1970s-1980s, it was discovered that R-12 and other CFCs depleted the ozone layer due to the chlorine content. R-12...

Andy Holt joins the podcast to discuss the ever-relevant topic of overcoming conflict at work.

Some people end up in conflicts often, so Andy recommends paying attention to how others react to the conflict you have perceived; if you are much more stressed than everyone else, then you need to look internally, not externally. The first step to overcoming conflict is to slow down and think about your reactions to perceived conflicts.

Partaking in bickering and gossip with coworkers creates a negative environment for the entire team; the best way to avoid or resolve conflicts...

Matthew and Nick Wavra join the podcast to discuss everything that goes into job estimation in commercial HVAC. Nick has a lot of fieldwork and project management experience, and Matthew has marketing, software, and sales experience, which helps bring in and retain clients.

Commercial estimation begins when a mechanical contractor asks for a bid on a job. The estimators go through the spec books, bidding documents, and any addendums to come up with takeoffs and a price. The estimator seeks approval from manufacturers to build the materials, and they use software to come up with an estimate...

In this short podcast episode, Bryan goes over the basic gas furnace sequence of operations. There are a few variations, but the sequence of operations tends to stay consistent across most furnace types.

First, a W call from the thermostat calls for heat. The circuit board will then assess the safeties to see if it can bring on the heat without causing flame rollout or other dangerous conditions. If the safety switches are all closed, then the furnace can bring on the heat. However, in some cases, the induced draft motor may come on first in some 80...

Trevor Matthews, the founder of Refrigeration Mentor, returns to the podcast to talk about starting up an internal training program for an HVAC/R company.

In some cases, the best lead technicians don’t want to be head trainers if the responsibility is forced upon them. However, when there is a solid training plan in place, those senior technicians might actually find the task enjoyable.

The first step to starting a training program is to ask the apprentices and technicians where their skills are at and how they want to develop their skills. That way, yo...

In this short podcast, Bryan explains the basics of flame sensing, also known as flame rectification.

Flame sensing/rectification is a form of proving flame. When you can’t prove flame, your furnace might be dumping unspent gas into the heat exchanger, which can cause an explosion.

Flame sensing rods are common in hot-surface (HSI) and intermittent-spark (ISI) ignition. These rods stick out into the flame and connect to the furnace board. The flame creates a path between the rod and ground, which allows a very small current to flow to the board. Without a fl...

This podcast episode is a throwback to one of Bryan’s first small business podcasts. In this old episode, Australian electrician and businessman Joshua Nicholls explains how he built a business by focusing on customer experience and branding. Bryan grew Kalos similarly, so they talk about the journey of going from “man-in-a-van” businesses to larger businesses with several employees.

Joshua wanted to bring old-school manners and integrity to the business world, and that’s how he branded his business. The focus on customer service over marketing earned the customers’ respect, and customers were happy to remain loya...

In this short podcast episode, Bryan covers the differences between defrost termination and failsafe. He also covers the basics of defrost in refrigeration applications.

In medium-temp applications (also called coolers), the box stays above freezing temperatures, but the coil may drop below freezing. When the air is above freezing, we can use off-cycle defrost. The coil defrosts when the system naturally cycles off. We may also use timed defrost, which pumps down or cycles the compressor off at set times to force a defrost cycle.

In low-temperature applications, the box will ty...

This podcast episode is a throwback to one of Bryan’s first podcasts about small businesses. Cesar Abeid, former VP of construction camera company Remontech, joined this podcast to discuss the basics of project management and a book that can help you step into that side of the business.

Project management is a framework or set of tools to turn an idea into reality. Projects have a beginning and end to create something new, and project management is how we get from the beginning to the end while factoring in schedules and a budget. In essence, project ma...

Bryan discusses impostor syndrome, what it is, and how it may actually be useful for us.

When we feel that we’re frauds and that others wouldn’t like to be led by us if they knew how much we don’t know, we’re experiencing impostor syndrome. Contrary to what others might believe, impostor syndrome isn’t all that bad and may even be necessary for a healthy self-image.

On the other side, we have the Dunning-Kruger effect, which is when people are confident in the things they have very little actual knowledge of. They think...

Amrit Robbins of Axiom comes on the podcast to discuss how we can use data science to transform grocery and cold storage.

Axiom Cloud uses cloud analytics and AI to map data and analyze trends on refrigeration racks. It can be particularly useful to keep track of readings all the time because it’s impractical to rely on a human to take and record readings 24/7.

Grocery stores are unique because they have so much product at stake and are relatively inflexible in their usage of energy. If something goes wrong on a rack, thousands of do...

In this short podcast, Bryan goes over the basics of superheat and explains why it matters to us.

Superheat is the temperature increase above a substance’s saturation temperature or boiling point. When a substance is superheated, that means it is 100% vapor; there is no liquid at all. We can look at our superheat to determine how much refrigerant is feeding our evaporator coil.

A lower superheat indicates that our evaporator is more full of refrigerant than a high superheat, meaning that the refrigerant is feeding the evaporator coil well. Generally, a lower superheat value wi...

In this podcast episode, Bryan and Eric Mele talk about sight glasses, the significance of subcooling in refrigeration, and liquid quality.

While we measure subcooling quite often in HVAC work, we rely on sight glasses and liquid line receivers far more often in refrigeration. You need a sight glass to determine the liquid quality in a refrigeration system. Subcooling is one way to assure liquid quality without a sight glass or a receiver. 

Subcooling refers to the temperature drop below liquid saturation. Head pressure can dictate subcooling, and several other factors can dictate the condensing t...

In this short podcast, Bryan explains the basics of repairing aluminum, such as on coils or tubing.

Repairing aluminum can save lots of time on mission-critical calls and can help stop refrigerant leaks that lead to ozone layer depletion or global warming. Soldering makes almost all of the aluminum repair work we will do. (Brazing is possible, as aluminum has a melting point of 1200 degrees, but that’s still a bit too close to the brazing threshold.) 

When working with aluminum, we need to recognize that it melts at a lower temperature than brass, steel, and...

In this short podcast, Bryan goes over energy transfer and heat, specifically specific heat.

BTUs per ton is a common measurement; a BTU (British thermal unit) is the amount of heat it takes to raise the temperature of one pound of water by one degree Fahrenheit. 12,000 BTUs per hour is equal to one ton in heating or cooling technology. It takes one “ton” of heat to melt a ton of ice, but we kept the measurement and terminology as we moved away from using ice in industrial refrigeration.

When it comes to specific heat, we have...

In this podcast, Steve Rogers from The Energy Conservatory explains some pro tips for pressure measurement.

There are three common types of pressure measurements: absolute, gauge, and differential. Absolute pressure is the pressure in a particular space in reference to a complete vacuum. (All absolute measurements use the zero point as a reference.) Gauge pressure uses atmospheric pressure as a reference point (which varies with altitude and location). Differential pressure relies on two connections (one of them is a reference point to the other).

The Energy Conservatory recently designed a manometer (DG-8) that differs from...

Trevor Matthews from Refrigeration Mentor comes on the podcast to talk about Copeland reciprocating CS compressors. He and Bryan cover Bulletin AE4-1433 (found HERE) as they look at the operating envelopes for the CS compressor.

The CS compressors are hermetic reciprocating compressors that can work with some of the newer refrigerants. You will likely see these compressors in applications with smaller tonnages.

You’ll usually want to charge these compressors with liquid refrigerant. If you have more than 6 pounds of charge in the system, using an accumulator is recommended. Under those charge conditions, the syst...

In this short podcast episode, Bryan explains the science behind adiabatic cooling. Adiabatic cooling occurs in specific HVAC/R applications and in our environment as air temperatures and pressures change.

When we think of cooling, we refer to the loss of heat; we are either referring to the change in the total BTU content of the air mass or the temperature change. Adiabatic cooling takes sensible heat and transforms it into latent heat.

The most simple forms of adiabatic cooling can be seen in cooling towers and swamp coolers. In evaporative or swamp coolers, you...

In this short podcast episode, Bryan shares his top tips for fighting boredom at work. You can use these tips to help you get out of a rut if you don’t feel productive or get bored easily.

The first tip for fighting boredom is to see the art or creativity in your work. Even in the HVAC industry, there are plenty of opportunities for artisan skills and craftsmanship. When you see your work as an art that you need to refine, it’s easier to get engaged in your work and feel proud of it. That's espe...

In this podcast episode, Bryan goes through the addendum to the book Review of Vacuum for Service Engineers. He and Jim Bergmann had the honor of revising the latest edition in 2020. You can get the latest edition of Review of Vacuum for Service Engineers from TruTech Tools HERE.

Pulling a Schrader core before evacuation makes a big difference in the speed of the evacuation. You can use a core remover tool to pull the cores when the system is NOT pressurized.

There are three common types of ports to access the system: the Schrader core, high...

In today’s short podcast, Bryan discusses electric heat, how we use it in our work, and what it does.

Also called heat strips or heat elements, electric heat is a supplemental heat source that we usually see on heat pumps. We generally see them in fan coils within a cartridge or a kit at the top of an air handler. However, not all systems have backup heat.

We want to avoid running electric heat as much as possible because it is inefficient. There is almost nothing we can do to make heat strips more ef...

Trevor Matthews comes on the podcast to discuss his newest project, Refrigeration Mentor. Refrigeration Mentor uses Trevor’s experience as a trainer and field technician to guide others in their careers.

Trevor’s goal is to help commercial refrigeration technicians grow and become more confident in their skills. He wants them to become the best technician they can be, and he believes that mentorship is one of the things that make our industry great. Mentorship can help people advance their careers, sharpen their skills, and ease their anxiety about work.

When we share knowledge, we brin...

In this podcast, Ben from HAVEN IAQ, Kaleb, and Bryan discuss how to control indoor air quality and take effective, meaningful, accurate measurements.

HAVEN is a platform that offers hardware and software delivered to a homeowner through an HVAC professional. HAVEN’s goal is to give its customers a healthier, more comfortable home using IAQ solutions.

The hardware (controls, etc.) works with the HAVEN software to give customers and contractors data about IAQ and the performance of the HVAC equipment. Right now, you may install up to two HAVEN controllers and one monitor per zone to...

Ryan Gorman comes on the podcast to discuss the differences between a college education and early career opportunities in the skilled trades.

Many parents feel pressured to send their children to college and encourage them to get a four-year degree. Despite what society may lead us to believe, there is no shame in thinking that college may not be suitable for you or your child; the skilled trades have many opportunities for people to learn throughout their lives and make a good living.

In many cases, parents may see college as a ticket to the...

Jason Obrzut comes on the podcast to discuss A2L refrigerant facts. Jason is a member of AHRI’s Safe Refrigerant Transition Task Force and author of the RACT manual.

ASHRAE designates refrigerants into categories based on toxicity (A or B) and flammability (traditionally 1, 2, and 3). So, the new A2L designation indicates that a refrigerant is relatively non-toxic but has a flammability value between 1 (low) and 2 (moderate). While propane (R-290) is a good refrigerant because it is natural and has low toxicity, it is very flammable (A3).

Future refrigerants will likely fall under the A2L...

In today’s podcast, Bryan and some Kalos employees discuss how to deal with difficult bosses and coworkers in HVAC/R work.

Whether your coworkers have anger issues, are careless, or are miserable people, you don’t want that negativity to affect your job satisfaction. Addressing the behavior may likely help, but you don’t want to attack the other person. The key to dealing with difficult coworkers is to communicate boundaries respectfully with the goal of improving the work environment. Boundaries are also important when dealing with sarcastic people or those who make inappropriate remarks.

Any...

In today’s podcast, Ed Janowiak comes onto the podcast to talk about the Air Conditioning Contractors of America manuals. Ed started off in the field and has recently become the new Manager of Design Education at ACCA. You can follow him on Snapchat (skinnyed).

ACCA (Air Conditioning Contractors of America) is responsible for publishing and setting the standards in all of the books we use for residential and light commercial HVAC work. (Residential work typically encompasses Manuals J, S, D, and T).

The manuals can be very math-heavy. Many software programs have come on th...

In today’s podcast, Bryan and Jesse talk about how technicians can have conversations about finances and money in the HVAC business.

The first step for any successful business is to provide customers/clients with a product or service of value. However, there must be a balance between providing something of value to customers and providing excellent customer service.

When starting an HVAC business, one of the biggest mistakes is making money the top priority. Money can only become a factor after a business establishes the value of its services and communicates its value to it...

In today’s short podcast, Bryan explains the differences between sleeve and ball bearings. Techs often make some avoidable mistakes because they either don’t know the difference between the two or don’t notice the bearing type on their equipment.

On a basic sensory level, ball bearings tend to be louder than sleeve bearings. So, if you replace a sleeve bearing motor with a ball bearing motor, then excess noise may not indicate any problems after all. Lubrication is usually more consistent with ball bearings; those bearings have a far smaller contact area than sleeve bearings.

...

In today’s podcast, Trevor Matthews from Emerson talks about horizontal scroll compressors. Throughout the podcast, we refer to Bulletin AE4-1338 (R3). You can find that bulletin HERE.

Horizontal scroll compressors are common in mobile applications, like buses and trains. They’re shorter in height than other compressors, so they fit into tighter spaces and are ideal for transport refrigeration.

Scroll compressors are particularly susceptible to overheating, and you need some controls to protect your compressor from damage. To prevent overheating, scroll compressors require pressure relief controls. You can typically use an OEM high-pressure cont...

In today’s short podcast, Bryan discusses buck-boost (auto) transformers and what they do.

Autotransformers are not automatic; the “auto” prefix comes from the fact that autotransformers only have one inductive winding. That winding is shared by the primary and the secondary, so it is not an isolation-type transformer. These transformers run current through the same winding used for induction.

Buck-boost transformers rise or decrease voltage. When the transformer “bucks,” it decreases voltage from primary to secondary, and a “boost” increases the voltage from primary to secondary. In other words, a “boost” is a step up, and a “buck” i...

In today’s podcast, John Ellis joins Bryan to talk about indoor air quality (IAQ). He also explains the ideal process for providing IAQ solutions. John has a lot of experience working as a consultant for people who have respiratory issues, so he has valuable perspectives.

The HVAC and IAQ fields intersect in the areas of thermal comfort, humidity, building pressures, ventilation, filtration, and source control (which pollutants are present, where they come from, and how we can remove them).

John does not believe in throwing IAQ products at a problem. He believes in a th...

In today’s podcast, Scott Krasman from TZOA, Andrew Greaves, and Kaleb Saleeby join Bryan for a conversation about mental health in the trades. We have a greater awareness of mental health than we ever did before, and although some of us may make fun of the topic, it is something we should focus on as HVAC technicians and business owners.

“Toxic” is a common buzzword these days, but it’s relevant here. A work environment with toxic traits will wear you down over time as you are exposed to disillusioned or selfish journeymen or senior techs at work...

In today’s podcast, Jim Bergmann talks about troubleshooting the entire system. He takes a holistic approach to the art of troubleshooting, NOT just an equipment-centered one.

According to NIST, the most common HVAC system problems are duct leakage, refrigerant undercharge, and oversized equipment (often for undersized ducts).

Duct leakage heavily affects the envelope; the equipment only plays a part in conditioning a space. As such, you will want to seal up holes that lead to unconditioned spaces, such as behind the thermostat, to avoid creating negative pressure. When there is that negative pressure, especially cl...

In today’s podcast, Steven Rogers joins Bryan to talk about measuring total system airflow.

Fluid measurement is NOT restricted to liquids; a fluid is anything that flows, including liquids and gases. In HVAC, we deal with both of them, but airflow is strictly limited to the flow of gas. The airflow we experience in HVAC is exclusively turbulent flow, NOT truly laminar flow.

Total system airflow is difficult to measure directly; we can use flow hoods, but they have their limitations, especially on systems that have multiple returns. So, we measure pressures that give us...

In today’s short podcast, Bryan explains how growth happens in an HVAC/R career. He also gives tips to get “unstuck” if you feel like you aren’t moving forward.

You won’t move forward if you haven’t set a goal to move forward. Making a “vision board” helps you determine what matters in your life, and it helps you clarify what you’ll need to do in order to achieve your life goals. That way, you can use your career to help achieve those goals and see whose support you need.

Having a growth mindset a...

In today’s podcast, Bryan and a team of Mitsubishi Electric Trane HVAC US (METUS) managers (Mike Schaefer, Charles Miltiades, and Sly Grimm) discuss mini-split controls strategies.

Some contractors misunderstand what mini-splits are. Mini-splits CAN be ductless, but not all of them are ductless. Mini-split systems also have handheld controls, but those are not the only control options for mini-splits. Mini-split controls also come in wi-fi, wall-mounted, and wired varieties.

Another common misconception about mini-splits is that they do not work in the cold. While that used to be accurate, modern mini-splits can function well as...

In today’s short podcast, Bryan discusses the key factors for system performance WITHOUT doing a deep dive into system commissioning. “Performance” refers to system efficiency, capacity, air filtration/cleanliness, longevity, and the ability to match the latent and sensible loads of a space.

System airflow is the main performance factor to consider. To determine proper airflow (CFM), consult Manuals S, J, and D to perform calculations. In general, the absolute lowest limit is around 275 CFM (in extreme dehumidification mode), and the highest limit should be around 525 CFM (in arid climates or at altitude).

You can de...

In today’s podcast, Trevor and Bryan discuss Copeland Scroll Compressor Multiples for Air Conditioning. “Multiples” refer to equipment setups with multiple compressors that have connected suction and discharge lines, so they resemble parallel rack refrigeration setups. Multiples typically come in tandem (2) or trio (3) sets.

Compared to having a single giant compressor, multiples are more efficient, more reliable, and have the ability to keep running in case if there’s a compressor failure. As a result, we often use multiples in rooftop units, makeup air units, and chillers.

When you’re working on multiples or troublesho...

In today’s short podcast, Bryan clears up the differences between markup and profit margins in HVAC businesses.

The number one mistake that people make in business is confusing markup and gross margin. For example, you can double the price of a $50-part and sell it for $100. That would be a 100% markup. However, your gross margin is NOT 100%; your gross margin is only 50%; you only made a 50% profit on the total sale. 

In the same case you have above, you have a 50% cost of goods sold (COGS). COGS is the direct cost of the expenses you...

In today’s podcast, Eric Mele and Bryan explain the planning, layout, and execution of HVAC projects. They mostly cover commercial ductwork but also touch on piping and some residential projects.

Planning

The first step is to review the construction plan WITH a site visit. It is best to see how a plan works within the space; plans may be feasible on paper but may not work out as planned in the actual space. 

During the site visit, you also want to establish solid communication with everyone else on the project. As such, it...

In today’s short podcast, Bryan explores the differences between startup and commissioning.

Startups typically involve going in during the construction phase after the drywall has been sealed up. (Vents, ducts, and copper piping typically go in before the drywall.) A technician can then perform a startup. The startup includes testing the drain line, checking the charge, checking for leaks, and seeing if the equipment performs its most basic function. (Does the gas furnace make flame? Does the A/C unit blow cold air?) 

The startup’s goal is to get the equipment working. A start...

In today’s podcast, Eric Kaiser and Bryan talk about mentorship in the HVAC industry. They discuss what it means to be a good mentor, how to find a good mentor, and what it means to be mentored. 

Mentorship is an organic process. Most mentees don’t go up to someone they respect and formally ask that person to be their mentor. Respect is the foundation of the mentor-mentee relationship; formal mentorship often resembles friendship in many ways. 

However, mentorship can take more forms than the traditional mentor-mentee relationship. In the digital age, podcasts and YouTub...

In today’s podcast, Bryan explores the upsides of choosing a career in the skilled trades instead of going to college. He also covers ways to prepare your child for a trades education and career while they are still deciding what to do with their lives.

When we think about what we want for our kids, the following goals come up quite often: purpose, financial upside and reward, freedom from debt, and joy. The trades can offer a lifestyle that covers all of these bases. However, the opinions of our friends and the fear of failing as a...

In today’s short podcast, Bryan explores triple evacuation. Many people believe that we don’t like triple evac, but that’s simply NOT true. We’re here to set the record straight.

If the manufacturer tells you to follow triple evacuation processes, then it’s a good idea to do what they say. We won’t argue with that. However, our argument is that the procedure can be more time-consuming than it’s worth when it’s NOT necessary.

Deep vacuum technically counts as a vacuum pulled below 500 microns (in residential, that target is usually 200-300...

In today’s podcast, Bryan explains how he teaches physics. He believes that teaching physics is about continuously building a mental model, and he covers the methods and mindsets that facilitate that learning style. 

The basic Wikipedia definition of physics states that it is a science that deals with matter, energy, and their interactions. Even then, we can simplify “matter” to “stuff.” Simplifications like these help students feel more familiar with the subject and NOT feel intimidated by the material. Students learn best when they feel like they can grasp the topics out of the gate. That is why the...

In today’s short podcast, Bryan explores the dangers of cold tanks during refrigerant recovery.

Whenever you have a recovery tank, you only want to fill it to 80% capacity in the liquid state. The same goes for all sorts of vessels (coils, etc.). 

However, capacity isn’t the only factor to consider for safety. We need to know what our maximum temperature will be. You will be in greater danger of overfilling a tank when it is cold because higher temperatures increase the pressure. High pressure in a closed space may lead to explosions. When you f...

In today’s podcast, Nikki and Bryan discuss dehumidification. They cover the relationship between cooling and dehumidification, humidity control, and dehumidifier installation practices.

If the A/C unit is the king, the dehumidifier is the queen. The A/C unit controls cooling and humidity, but it can only do so much. A dehumidifier helps the A/C manage comfort under more demanding conditions. Many factors contribute to comfort, including sensible heat ratio (SHR), relative humidity (RH), and ventilation. Dehumidification reaches all of those factors.

Humidity control requires a holistic approach. Band-aid fixes DO NOT work. De...

In today’s podcast, Trevor and Bryan discuss how to troubleshoot thermostatic expansion valves (TXVs/TEVs). They also dive into the various types, applications, and components of TXVs.

TXVs are metering devices that control evaporator superheat to protect compressors from harm. Controlling heat also regulates pressure, which improves efficiency and prevents issues like floodback and overheating. TXVs contain several components that manage the forces that open and close the valve. These components include powerheads, diaphragms, springs, and more. The components all contribute to a delicate balance that can be broken when they fail or are installed improperly. TX...

In this short podcast episode, Bryan discusses push-pull recovery, how it works, and what we need to know about it.

Push-pull recovery is a somewhat counterintuitive method of recovering liquid rapidly. We simply do that by pulling refrigerant out of the system and pushing it into the tank. However, when we pack refrigerant into a tank, the tank pressure and temperature increase. So, it can be more difficult to get refrigerant into the tank as the job goes on.

When we recover liquid refrigerant on large systems (20+ pounds of charge), you connect a line from...

In this short podcast episode, Bryan goes over one of his most valuable tips for pulling a vacuum on a small system.

It can be very difficult to pull a vacuum on a small system, especially when you're dealing with a low-temperature application like a freezer. When you pull a vacuum, you're creating a low-pressure area that affects molecule behavior. So, you're creating a situation where the molecules push their way out of the system and into your vacuum pump. The low temperature and small tubing, especially capillary tubes, make this process exceptionally difficult. A very good...

In this podcast episode, Bryan and Eric Mele explain how HVACR technicians can END callbacks with a few best practices.

Rushing through calls will often lead to callbacks. One of the most common mistakes techs make is failing to check the condensate drain before walking away from a job. To end callbacks, technicians would be wise to check the entire system and note any possible problem areas; in commercial HVAC and refrigeration, pay attention to variation across evaporators, condensers, and drainage systems.

Customer service is a huge component of residential HVAC; you can prevent callbacks...

In this podcast episode, Bryan and Eric Mele discuss the diagnosis and prevention of compressor overheating in HVAC and refrigeration.

The main causes of compressor overheating are inadequate cooling back to the compressor, low charge, restrictions, and sometimes even poor suction line insulation. We want to keep the suction temperature low while maintaining appropriate superheat. If the suction line temperature is too high, the compressor can't cool down well enough. Dirty condenser coils, low voltage, weak capacitors, or an inadequate condenser fan can also lead to compressor overheating.

Electrical problems, including too little capacitance, will...

In this short podcast episode, Bryan and Eric Mele talk about re-tapping transformers for single-phase equipment in 208v applications.

Most single-phase equipment can work for 230v or 208v, meaning that they can operate with low voltage. However, we typically see 208v in commercial buildings. The sine waves of 208v equipment are 120 degrees out of phase, not 180 degrees (as in split-phase applications). We get lower voltage from leg to leg (208v, though the voltage can be a little higher or lower). Power companies generally put out slightly higher voltage to reduce line losses.

Most systems can...

In this podcast episode, Ben Reed from TZOA, a disruptive air technology brand, joins us to discuss the indoor air quality map and compass.

We spend a majority of our lives indoors, so TZOA tries to improve IAQ in homes to keep us healthier. HVAC manages airborne chemicals, so indoor air quality ties right into our industry; HVAC technicians will become more valuable when they become well-versed in IAQ technologies.

In residential HVAC, we are already used to listening to customer complaints and observing the home. Technicians (and even IAQ products) can "map" out the...

In this podcast episode, Bryan and Trevor Matthews of Emerson Canada discuss the Copeland 2-stage ZPS scroll compressors. Please join us by following along in bulletins AE4-1428 and AE4-1365.

The ZP91KCE to ZP143KC Copeland compressors don't have internal pressure reliefs (IPRs). Those higher-pressure compressors make very loud noises when they go off, and it'll blow hot discharge gas on the internal overload to shut down the compressor. Some scroll compressors have temperature operating disks (TODs), which are bimetal disks that open upon a temperature increase and reroute the gas. Other compressors have advanced...

In this podcast episode, Bryan, Trevor Matthews, and Jim Dick of Emerson talk about the screw compressor and how it works. This time, they focus on the Vilter single-screw compressors.

Vilter is an industrial compressor division of Emerson (compare to Copeland). Vilter also makes reciprocating compressors, but the screw compressor is its claim to fame; you may want to consider using a screw compressor when you want greater capacity and control than a reciprocating compressor. Screw compressors also work well for applications with constant loads; they do, however, have microprocessors that can monitor system performance to maximize...

In this short podcast episode, Bryan talks about condensation and how HVAC technicians can solve condensation-related problems. He also discusses humidity control and how that can affect sweating.

We may have heard the phrase, "Condensation is where hot meets cold." That's not necessarily true; while it may seem that sweating happens where hot meets cold, the dew point is the main cause. We won't see condensation unless we have air that reaches the dew point. When air flows across surfaces that have a temperature below the dew point, you'll start to see sweating on the surface.

In this podcast episode, Bryan and Chris Mohalley of Regal Beloit discuss the different types of ECM. They also cover applications where you can expect to find ECMs.

In the HVAC industry, we typically use three types of motors: constant-torque, constant-airflow, and constant-speed. Every ECM works on electronic commutation, so constant-torque motors use that to maintain torque output (X13). The constant-airflow motor is also known as the variable-speed motor, and it is one of the first ECM types. We typically only use constant-speed motors in outdoor fan motor applications. Likewise, we generally use the first two motor...

In this podcast episode, Bryan and Eric Kaiser discuss the right and wrong way to do HVAC/R jobs and approach HVAC/R work.

Breaking things down into "right" and "wrong" categories is a rather simple way to approach a problem; we throw nuance and alternatives out the window, which can be worse than doing something "wrong." Instead of viewing things as right and wrong, we would be better off if we looked at our objectives and focused on solving problems instead of being right.

Although there are surely correct ways to pull a vacuum...

In this podcast episode, Bryan and Chris Mohalley from Regal Beloit discuss EC motors. They also describe ECM applications and how those motors work.

EC motors (ECMs or "ECM motors") are electronically commutated motors. These motors are generally three-phase AC motors operated by a drive; that drive is a combination of an AC-to-DC converter, microprocessor, and frequency drive. So, the frequency delivered to the motor is generated electronically.

When it comes to inputs, the ECM works like a printer. One input provides power (from the wall to the printer). The other cable tells the printer...

In this short podcast episode, Bryan compares strategies for increasing the subcooling, including stacking liquid and mechanical subcooling.

Subcooling is a consequence of condensing; when we change the refrigerant from a vapor to a liquid, it will drop below saturation temperature after it becomes completely liquid. There are three phases in the condenser: desuperheating, condensing, and subcooling. The first few rows of the coil reduce the superheat of the vapor entering the condenser. Once there is no more superheat, heat rejection helps the saturated refrigerant transform into a liquid entirely. Near the end of the coil, liquid...

In this podcast episode, Bryan, Chad, John, and Allison discuss proper design for ductless and ducted HVAC systems, especially mini-splits. They also discuss potential future improvements to equipment and duct designs.

Mini-splits are smaller than traditional HVAC units, so they make zoning a bit easier. However, load calculation plays a huge role in equipment selection and zoning because you must get the right number of zones to match the equipment capacity and meet your load requirements.

Proper design is difficult, and a common mistake includes using one piece of equipment to serve the whole house...

In this short podcast episode, Bryan explains what atmospheric pressure really is, pressure units and conversions, and why those are matter.

Atmospheric pressure is the weight of the air around us pushing down on us. We normally see that value expressed as 14.7 PSI (or 0 PSIG). Before we dive too deep into atmospheric pressure, we should understand some basic pressure units.

We may see pressure expressed in microns when we're pulling a vacuum; we are trying to pull the atmosphere out of the system, so our goal is to get as close to 0 as possible. Whenever...

In this podcast episode, Bryan and Trevor Matthews discuss compressor short cycling. They discuss how to diagnose and prevent that issue. Trevor and Bryan primarily refer to the Bulletin AE17-1262 throughout this episode, which you can find HERE.

Compressor misdiagnosis is very common, but we generally encounter two types of compressor failures: electrical failures and lubrication failures. Short cycling causes a loss of oil in the compressor, which may lead to lubrication-related failure. Each time a compressor starts, there is a reduction in suction pressure; the pressure drop then causes the saturation pressure to drop. That...

In this podcast episode, Bryan and Craig Migliaccio (AC Service Tech) discuss some HVACR recovery tips and best practices.

When you select a recovery tank, you need to know which refrigerant is in the tank. So, it's a good idea to make sure you label each recovery cylinder. You don't want to contaminate refrigerant in the recovery tank, use a recovery tank with contaminated refrigerant, or have too much air inside the cylinder. If the tank is empty, you'll have to pull a vacuum on it before you use it for the first time.

Tank...

In this episode, Bryan and Craig Migliaccio (AC Service Tech) talk about some best practices you can use while swaging and flaring copper.

There are a few different ways you can flare copper. Craig likes using a round deburring tool before flaring the copper. After the burr has been cleanly removed, Craig likes using an eccentric flaring tool for the actual flaring. Bryan's favorite flaring tool is the NAVAC battery-powered flaring tool for quick, accurate flares. Both Craig and Bryan agree that it's better not to deburr if you're likely to drop the burr or copper shavings...

In this podcast episode, Bryan and Jim Fultz discuss the White-Rodgers SureSwitch and determine whether contactors are obsolete or not.

Contactors are electrical controls; they started off very expensive and usually outlasted equipment, so they are currently smaller, cheaper, and less durable than they used to be. Modern contactors have open contacts and are susceptible to insect damage. Sometimes, an electrical arc can cause contactor pitting, which can weld the points together and render the contacts useless.

The SureSwitch is more than a contactor; it is also a brownout monitor, short cycle timer, and a...

In this episode, Bryan and Craig Migliaccio (AC Service Tech) discuss all the ways that nitrogen can make your job easier.

Nitrogen is an inert gas that we can use for purging refrigerant lines and completing scale-free brazing jobs. As techs, we should have at least one inert gas in our trucks to help us do the best job possible. We can use inert gases for purging refrigerant from tubing, flowing and preventing oxidation while brazing, and pressurizing a system for leak detection or a pressure test. You'll also find nitrogen useful for getting oil out of...

In this podcast episode, Bryan and Craig Migliaccio, AC Service Tech, talk about ultrasonic leak detection. They discuss its effectiveness and if it's worth the hype.

Ultrasonic leak detection works best when there's oil on the inside of the tubing; it works best when the system is equalizing after shutoff. Oil or moisture can create a squealing noise, which is an indicator of a leak. Ultimately, lack of success with ultrasonic leak detection comes down to user discomfort and a lack of proficiency. Bubbles alone won't be enough, so it's good to use an ultrasonic detector, even...

In this podcast episode, Jim Fultz with White-Rodgers joins us to discuss universal defrost controls. He also explains when and why you might use universal controls. Bryan and Jim cover a universal defrost control for heat pumps (Model #: 47D01U-843). You can follow along by reading the manual HERE.

Universal defrost controls can replace OEM defrost controls. Universal controls are sometimes more readily available than OEM parts, so they can be good repair options.  The White-Rodgers universal heat pump defrost control comes with the board, installation instructions, two wiring harnesses, two thermistor-style sensors, and a bag with s...

In this short podcast episode, Bryan and Craig Migliaccio discuss why you maybe don't want to buy new tools.

Whenever you get new tools, you have to account for a learning curve and potential change to your practices. Changing your practices and procedures isn't necessarily a bad thing, but you have to practice with the tool and account for different setup and cleanup procedures. However, once you find a good process, you don't want to mess with it too much. You will also want to account for changes to your tool maintenance procedures.

When you...

In this podcast episode, we find out how Craig Migliaccio became "AC Service Tech." He makes educational materials and has even written a book. You can check out his website HERE and his YouTube channel, AC Service Tech, HERE.

Craig got into the HVAC trade after coming from a construction background; he mostly worked on existing homes and had to handle some HVAC tasks. From there, he got into service and went headfirst into the HVAC industry by starting his own business: a carpentry and HVAC business.

Craig also got into the teaching side of...

In this short podcast episode, Bryan and Craig Migliaccio discuss the skills and knowledge you should have to start in the HVAC industry.

Of course, basic mechanical skills and knowledge are important before you get into the HVAC trade. You'll greatly benefit from knowing where and how to hammer nails, tighten screws, and identify all sorts of tools. When getting into the HVAC industry, one of the low-hanging fruits that you need to consider is your sheet metal skills. Know how to cut sheet metal, use shears, use a duct knife, and make a decent sheet metal...

In this podcast episode, Bryan and Trevor Matthews of Emerson Canada discuss strategies for controlling liquid refrigerant in A/C and refrigeration systems. They also read through the AE22-1182 bulletin, which you can find HERE.

Liquid refrigerant is one of the most common causes of compressor damage and even failure. It can also cause a loss of oil, which leads to reduced lubrication and subsequent damage. Compressors are vapor pumps, and they are not designed to handle much liquid refrigerant at all.

Off-cycle refrigerant migration is one of the main causes of liquid refrigerant...

In this short podcast episode, Bryan talks about the TXV power element or power head. He explains what it does and why it's important.

A TXV power element threads onto the top of the valve, and it's where the sensing bulb attaches to the valve. It is the component that applies the opening force to the TXV.

When you lose the charge in the element, it stops exerting an opening force on the valve. So, the valve completely shuts and doesn't allow refrigerant to get to the evaporator coil. You'll get high superheat and a...

In this episode, Bryan and Alex Meaney talk about value engineering. They discuss what it means to value engineer better when it comes to construction projects.

Value engineering is about finding ways to reduce the costs of a project. However, we don't want to do a bad job or use extremely cheap materials just to bring the price tag down. In many cases, builders will want to reduce the cost as much as possible, but we also want to make sure the construction project works in the end. In other words, 2+2 doesn't quite have to equal 4, but...

In this short podcast episode, Bryan talks about the placement of the TXV sensing bulb. He also explains how it affects the opening force on the TXV.

The TXV sensing bulb (or sensor on an EEV) provides the opening force for the valve. The warmer the bulb gets, the more the valve opens; the colder the bulb gets, the more the valve closes. The TXV also has a closing force provided by the spring pressure and equalizer (usually the external equalizer).

So, if you have a bulb that has been poorly mounted or insulated, you...

In this podcast episode, Bryan, Erich Vinson, and Anthony Marino talk about dealing with difficult customers in the HVAC industry.

When working with customers in general, it is best to make eye contact with the customer, listen to them, and put yourself in their shoes.

When dealing with difficult customers, we must remember that there are several potential causes for their "difficulty." You can't control that; you just have to let the anger run its course and diffuse the situation as much as possible. Some customers also try to stir up drama; in those cases...

In this short podcast episode, Bryan explains how hydrostatic pressure can build up in refrigerant cylinders and present a hazard to technicians.

Your refrigerant cylinders have tare weight and water capacity values stamped on the tank. You'll want to use these when weighing the refrigerant you recover because you don't want to exceed 80% capacity. However, capacity changes when the liquid density changes; that density will change with pressure and temperature.

Hydrostatic pressure builds up when you have overfilled refrigerant vessels. When those vessels get warm, the density will decrease, and the liquid refrigerant expands. At...

In this podcast episode, Bryan, Trevor Matthews, and Jim Dick from Emerson give us all an introduction to industrial refrigeration. Jim works with contractors to provide tech support. He also does the startup and commissioning of refrigeration compressors and gas compression units.

Industrial refrigeration refers to warehouses and distribution networks. Grocery refrigeration is commercial refrigeration for the end-user, but industrial refrigeration is commercial refrigeration for the distribution network before the product reaches the end-user. Many of these large systems use natural refrigerants (including ammonia) and are easier to work on because of their scale and easy-to-access valves...

In this short podcast episode, Bryan talks about the strategies we can use to prevent refrigerant migration during the off cycle.

We often see refrigerant migration when the compressor is lower than the evaporator, especially in low-ambient conditions when the refrigerant can condense in the crankcase. When the compressor starts up, you get a violent reaction as the refrigerant boils off and ejects oil. That can wear out the compressor and reduce the lubrication.

Crankcase heaters are some of the most common devices we use when preventing refrigerant migration. These can be of the insertion...

In this podcast episode, Eric Mele joins Bryan for some weird transformer talk. They discuss corner-tapped transformers and some thought experiments.

We hadn't been able to get our heads around corner-grounded transformers until recently. "Grounding" doesn't necessarily change the phase or lead that you ground. If you take the secondary of a 24-volt transformer and measure from your two colors, you'll measure 24v. However, if you connect a lead to ground, you'll still read 24v. (Don't ground both, or you'll get a short.) Ground is just a path back to the power source. Electrons don't suddenly "leak"...

In this short podcast episode, Bryan compares internal and externally equalized valves. He also covers how forces act upon the TXV.

Equalization does not happen on the off cycle. When we talk about equalization, we are merely talking about a force that balances against the bulb force. A TXV sets the superheat within an operating range at the evaporator outlet; the sensing bulb on the TXV detects temperature and pressure at the evaporator outlet. So, those readings apply an opening force to the bulb. (Think of this process as being quite similar to you measuring the superheat...

In this podcast episode, Bryan talks with Bill Spohn about his most recent project, SpohnHome. SpohnHome explores Bill's journey in custom home performance.

Projects are complicated because so many trades work together to accomplish a building. However, custom homes are particularly challenging, especially in Bill Spohn's case. His home is a "personalized performance home," so he's prioritizing energy efficiency, indoor air quality, and comfort as well as aesthetics. The home's design and purpose resemble that of a passive building.

Although much of the construction went smoothly, there was a misunderstanding about the sewer conditions; unbeknownst...

In this short podcast episode, Bryan talks about some tips you can use when working with a multi-position service valve.

A service valve will have a line connection, which connects the valve to your line set. You also have a gauge port that you can connect to, a valve stem, and a packing gland nut (directly beneath the valve stem).

If your stem is completely back-seated, then your gauge port is completely closed from both the line and system connection. If you crack the stem off the back seat, then the gauge, line, and system...

In this podcast episode, Bryan and Trevor Matthews from Emerson talk through scroll compressors in commercial refrigeration equipment.

Scroll compressors are not a monolith; although they all function similarly, they have different fine details and manufacturing protocols by application. Low-temp, medium-temp, high-temp, and A/C scroll compressors each have unique designs, operating conditions, and service considerations.

Copeland has a medium-temp scroll compressor line (ZB and ZS) for medium and high-temp applications. They also have a low-temp line (ZF). Within those lines, there are also small displacement and large displacement compressors, advanced scroll temperature protection devices...

In this episode, Bryan and Bert talk about soft skills. They also discuss why soft skills are important in highly technical trades.

Bert's class defined "soft skills" as communication skills; these can be verbal but may also include body language and how we respond to emotional situations. Bert thinks these skills are some of the most important skills you can develop in the HVAC industry and in life overall. You will only be able to make the most of your talents and career if you work on your communication and people skills.

You can start...

In this podcast episode, Bryan and Jim Bergmann talk about gas furnace diagnosis and inspection. They cover the ins and outs of furnace assessment.

A gas furnace diagnosis requires a few important measurements, but a solid visual inspection is perhaps even more vital. You'll want to look at the venting and condensate disposal systems. You'll want to make sure the flue gas can escape properly and that the terminations are correct and safe; if you're not looking at the manual and checking the venting, you can put your customers at risk of serious CO poisoning and even...

In this short podcast episode, Bryan talks about the differences between pitot tubes and static pressure probes. He also explains how each one works.

People often mix up static pressure probes and pitot tubes. A pitot tube is a tube within a tube, and a static pressure probe is just a tube with holes in the side but not at the end. When we measure static pressure, we're measuring the pressure against the duct. (Think of it as balloon pressure rather than air velocity.) We use static pressure probes to look for a differential between a probe...

In this podcast episode, Bryan and Nathan discuss balancing evaporators in a multi-coil circuit. They specifically focus on using the TXV to do so.

When we say "balancing evaporators" in a multi-coil circuit, we're referring to the temperature of the air leaving the system; we are worried about the air keeping the product cool in grocery refrigeration. If everything works correctly, the evaporators on a rack can have different temperatures due to different refrigerant flow rates. That's when we can turn out attention to the expansion valves, which meter the refrigerant into the evaporator and manage the...

In this short podcast episode, Bryan discusses the difference between mass flow and volume flow when referring to HVAC equipment processes.

When you are confused as to whether you're dealing with mass or volume flow, think about the units. For example, cubic feet per minute (CFM) is a measure of volume because we're talking about cubic units. We care about the volume when we think about air mixing and velocity, but volume isn't much of an indicator of the actual cooling power.

The mass or weight of the air matters more when we think about c...

In this episode, Bryan and Sam discuss freezing evaporator coils. They explain why frozen coils happen and how to address them.

When the coil's surface temperature drops below freezing (32 degrees), the moisture in the air that condenses on the coil can freeze to the coil. In those situations, your suction saturation will probably be in the mid to high twenties.

Generally, freezing evaporators will occur when you have less load on the evaporator. When there is less heat, the evaporator temperature will drop accordingly. The return air temperature is usually around 35 degrees, though that number...

Mike Klokus and Corey Cruz from Kalos come on the podcast to talk about drain cleaning. They discuss their tips and some best practices.

Approximately 50% of the calls in the light commercial division have to do with drains, and drain cleaning is a common PM procedure. The procedure starts off when you pull the panel off the air handler and look in the drain pan. Muck can accumulate in the pan and in the back and side channels. Pay attention to the unit orientation and the drain pitch before you even start cleaning. If you need to...

In this short podcast episode, Bryan talks about the differences between single-phase and two-phase refrigeration. This particular episode is about the fundamentals of physics, chemistry, and science in general.

When we talk about phases, we're referring to the changes in the states of matter. We typically think of the states of matter as solid, liquid, and gas. In refrigeration systems, the refrigerant usually changes from a liquid to a vapor in the evaporator and then from a vapor to a liquid in the condenser; that is an example of two-phase refrigeration. We get two-phase refrigeration anytime we're...

In this episode, Bryan talks with Peter Capuciati and Bryan Johnson from Bluon. They discuss how refrigerant regulations keep changing and how technicians can make sense of it.

We've begun phasing out R-22; the refrigerant can no longer be imported or manufactured in the United States. We can still recover and reclaim R-22, but the recovered refrigerant on the market can't meet the usual demand. R-22 went through a phaseout because of its ODP; R-410A has 0 ODP and was the main replacement.

However, refrigerant regulations are still changing, as R-410A will soon be...

In this short podcast episode, Bryan talks about the differences between single-phase and two-phase refrigeration. This particular episode is about the fundamentals of physics, chemistry, and science in general.

When we talk about phases, we're referring to the changes in the states of matter. We typically think of the states of matter as solid, liquid, and gas. In refrigeration systems, the refrigerant usually changes from a liquid to a vapor in the evaporator and then from a vapor to a liquid in the condenser; that is an example of two-phase refrigeration. We get two-phase refrigeration anytime we're...

Don Gillis joins us again to talk more about common types of CO2 systems and how they differ

In this episode, we are joined by three people who know a lot about heat pumps and cold weather. We also cover everything from the way technologies have changed, some of the pitfalls to keep away from, and why heat pumps work even in really cold climates nowadays.

Chad Gillespie: Chad is a senior manager, part of Mitsubishi Electric’s Performance Construction Team. He currently leads a national team of business development managers tasked with growing the new construction market for high-performance heat pumps. He has also worked in the construction industry for 26 years and has been wi...

Trevor Matthews is back and dropping more compressor knowledge on us. This time, he talks about demand cooling and liquid and vapor injection.

In low-temperature applications, the discharge temperature would get very high and lead to oil breakdown and thermal overload, so demand cooling is a means of cooling the compressor. Demand cooling injects saturated refrigerant into the compressor body to cool it down. You're not jamming liquid into the compressor; the refrigerant flashes, which achieves a cooling effect.

A demand cooling system consists of a module, temperature probe, liquid line solenoid valve, and injection...

Don Gillis with Emerson joins us on the podcast to teach us the basics of CO2 as a refrigerant. He explains how it works and its applications.

Carbon dioxide is a colorless, odorless gas that is becoming an important refrigerant for commercial refrigeration (R-744). It is desirable because it has a low critical point and high triple point, so we can use subcritical (below the critical point) and transcritical (above the critical point) CO2. Carbon dioxide also has a very low global warming potential (1), is inexpensive, and is very efficient at transferring heat.

Above the...

Sam Myers of Retrotec joins Bryan and Kaleb on the podcast to discuss building performance. He also answers some of our listeners' questions.

Checking airflow is important for building science as well as HVAC. However, "airflow" is vague and can refer to static pressure readings (which isn't actually "airflow" at all), air from whole-home ventilation systems, or CFM per ton. We can also look at total system airflow with flow hoods. Equipment settings also matter when it comes to measuring airflow as it relates to building performance.

Leakiness (of the ducts or structure) is a...

The great Ed Janowiak (Jon-Oh-Wok) joins us to talk about what correct airflow really looks like. He also explains how to design for it appropriately.

The ACCA design series (Manuals J, S, and D) all go hand in hand to design HVAC systems properly for a given space. Correct airflow will depend on how a technician or designer uses the ACCA design series. When we say "correct airflow," we mean that the CFM per ton matches the sensible and latent load for a space while maximizing comfort for building occupants. In many cases, 400 CFM per ton is...

Have you ever heard a compressor that keeps changing in sound as it runs? Trevor with Emerson tells us more about what that is all about and how the digital compressor operates.

Joe and Eric join us, and we have a general conversation about small self-contained refrigeration units, including residential and commercial. Small refrigeration includes self-contained reach-ins and small walk-ins. These units typically use capillary tube metering devices.

Some of the biggest failures that occur in small refrigeration systems happen because of dirty condensers and user error (leaving doors open, etc.). You'll also want to check that the fans are working, the compressor is running, the coil is free of ice, and that the airflow isn't blocked. Inspection is the key, and gauging up is typically a last resort.<...

Kaleb, Joe, and Eric join us again to discuss some myths about single-pole contactors. We also cover some weird crankcase heater wiring configurations.

When you have a single-pole contactor on a unit with no other resistance crankcase heater attached, the contactor energizes the compressor but is NOT a source of crankcase heat. That myth about single-pole contactors likely stems from a misunderstanding of Ohm's law and resistance heat.

We care about crankcase heat because we want to prevent refrigerant from migrating into the compressor during the off cycle. A crankcase heater keeps the compressor shell...

Trevor Matthews with Emerson Canada comes on the podcast once again to talk about electronic expansion valves (also known as EEVs). He explains how they work, what they do, and how to diagnose them.

Trevor compares electronic expansion valves to TXVs on steroids; they accomplish similar tasks, but EEVs have faster response times, better accuracy, and can improve system efficiency. The valve operates on a controller, which is the "brain" of the EEV that tells it to open or close. EEVs can come in the on-off variety (pulse-width modulation) and stepper valves, which rely on a motor...

Trevor Matthews from Emerson Canada joins us on the HVAC School podcast again to talk about CoreSense by Emerson.

Each CoreSense module has the potential to protect compressors. The technology can detect issues like overheating, short cycling, locked rotor, missing phase, low oil, and more. In short, the goal is to notify the technician or mechanic that something happened; sometimes, the control can also shut the compressor off and lock it out. Overall, it wants to communicate with the technician; different flashing codes indicate different sets of issues.

If you have CoreSense software on a...

Alex Meaney from MiTek/Wrightsoft joins us again because he’s an awesome trainer and knows a thing or two about how to more out of online education for the trades.

During the COVID-19 pandemic, we've seen a dramatic shift from in-person to online education. The transition has been hard on students and educators alike, but there are still ways to make it work.

Preparation is the key. Before you enter a class, make sure you look at the agenda and required or suggested reading. It's also a good idea to make sure you have th...

Our good friend Trevor Matthews from Emerson Canada joins us to talk about compressors, mostly preventing compressor failure and troubleshooting issues.

Whenever we're installing or servicing a compressor, we need to think about possible systemic issues right off the bat. The compressor is the heart of the system, but everything else in the system affects how the compressor runs. You'll want to know which type of compressor you're working with as well as the manufacturer. As always, you'll want to check the superheat, subcooling, amps, TD across the condenser, and (especially) discharge line temperature.

The...

In this short podcast episode, Bryan discusses the importance of suction line temperature and what it can tell you about an HVAC system.

There are two main places to take your suction temperature: at the evaporator outlet and right where the suction line goes into the condensing unit. When the former number is high, you could have a starved/underfed evaporator. When the latter number is high, you may have poor suction line insulation. If the refrigerant is too hot when it goes into the compressor, you can overheat the compressor over time.

Under normal...

In this podcast episode, Neil Comparetto from Comparetto Comfort Solutions joins Bryan and Kaleb to discuss some duct installation best practices he has learned. You might be able to take away some of his duct installation tips and apply them in the field.

Neil used to focus a lot on making the ducts look good, but nowadays, he focuses a lot more on performance; the work of art is in the data, not the beauty of the building materials. The quality of the seal on the duct is more important than the duct's appearance. Neil focuses a...

In this short podcast episode, Bryan explains what happens to a compressor when it's overheating. He also covers possible causes and troubleshooting strategies.

One of the Kalos techs came across an overheating compressor case that looked like a textbook TXV problem: the superheat was high at the condensing unit on the compressor side. However, the air handler superheat was appropriate, and the suction pressure was low. TXVs, however, respond to the superheat dropping and reduce the pressure even more. Overall, the mass flow rate and velocity drop, meaning that the refrigerant temperature can increase as it spends...

In this podcast episode, Kaleb, Joe, Eric, and Bryan answer some troubleshooting and commissioning questions from Facebook.

Whether we're talking about troubleshooting, commissioning, or any other HVAC/R task, the best training is on-the-job training. Meetings, educational videos, and quizzes also help to a lesser extent, but bypassing training altogether is a mistake. Senior techs can also become better diagnosticians when they teach others. "The Diagnostic Game" is an especially useful tool to help teach newbies how to troubleshoot a system.

However, training is something that is ultimately what you make of it. When you...

In this podcast episode, Ty Newell from Build Equinox comes on to discuss the CERV2 and how it embodies "advanced fresh air." The CERV2 is the second-generation version of the CERV.

A basic ERV allows for discharge air leaving the home to pass the intake air. When the airstreams cross through a core, there is an exchange of sensible and latent energy. The ERV may promote dehumidification and cooling of the incoming air. The CERV is a form of ERV technology, but it addresses the issues that may arise from crossing the airstreams. For example, we don't...

Our main man, Bill Spohn, joins us again to talk specifically about combustion. He also explains how to select and properly utilize a combustion analyzer.

It's critical to do combustion analysis when you service equipment for the first time or just after installation. We need benchmarks, so that's when our combustion analyzers can come in handy. (Of course, you also want to use your senses to inspect the equipment.) Commissioning is another good time to bust out your combustion analyzer.

Combustion analyzers should properly measure oxygen, temperature, and CO. Oxygen and temperature sensors tell you...

In this short podcast, Bryan shares some of his advice for people looking to get into the trades by starting an HVAC/R career.

When you step into the HVAC/R trade, you must remember that you'll acquire a mix of skills and talents that all work together. You must reflect on yourself and see if you'll be a good fit for the trade. Do you enjoy working with your mind and your hands? Do you enjoy working to some degree? If you don't like pressure or dislike working with your mind or hands, then the HVAC...

Jaden Lane joins us to discuss some best practices when using an air flow hood. She also explains how the Dwyer Smart is innovating in the hood space.

An air flow hood is an excellent tool, but we can't just assume that it'll work correctly in any system. Various vents and diffusers can cause different flow patterns to reach the hood, so you can get an incorrect reading if the flow hood is not aware of the flow pattern. Unless we give the hood background on what's going on in the duct, there's no way the hood...

Russ King joins us to discuss simplifying duct design for residential contractors. We focus on using 3D software for duct modeling.

While computers are great tools for duct design, you must be careful with them. Computer technology doesn't correct your mistakes; it allows you to make mistakes more quickly. Russ made 3D software specifically for duct modeling, and its goal is to help technicians/contractors with duct designs and equipment sizing. The software is good for quick duct design, can determine flex duct design, and is ideal for broad usage in residential HVAC.

Russ has...

Bill Spohn with TruTech Tools joins us to talk about why being “approximately correct” is better than being “exactly wrong” when it comes to test instruments.

When you see a number, that doesn't necessarily mean that you're dealing with a number you're supposed to see. For example, nitric oxide can present as "false CO" to a carbon monoxide sensor. Test instruments that mistake nitric oxide as carbon monoxide will give a different reading than ones that don't pick up nitric oxide as CO, but that doesn't necessarily make either of them wrong. So, some instruments can give you fals...

Bernadette Shahin of Aeroqual joins Bryan and Kaleb as they all dig very deep into indoor air quality (IAQ) sensors and instruments. They also cover the certainty and uncertainty of measurements.

Reference method instruments generally have to operate within a set of parameters, notably a temperature range. Gas laws make the gases act differently, so you want the temperatures and pressures to stay within a range that allows you to measure the air conditions effectively.

While we can use reference methods for full-scale instruments, there are no reference methods for IAQ sensors. The only way...

Jordan Cummings is back to discuss some of the most important points in the proper installation of VRF and VRV systems. We especially cover piping best practices.

When it comes to piping, the biggest concerns on VRF and VRV systems are making sure the piping can handle the refrigerant velocity and ensuring proper oil return. Most VRF systems use PVE oil, but you still want to be cognizant of oil type, as not all manufacturers use PVE. You must consider fittings, length, and elevation changes when you pipe a VRF or VRV system.

In our...

Bryan and Eric Mele have a relaxed conversation on time management on the job. They also explain how to manage time in life as a whole.

Some people are naturally fast because they cut corners in the name of time management. Instead, something Eric has learned to do is optimize his processes. He gets his work done a lot more quickly because he knows how to get the most out of the trips to his truck. Eric is also familiar with the tasks to perform them confidently, and he knows which diagnostic tools he'll probably need. Overall...

In this short podcast episode, Bryan explains what suction line traps and inverted traps are. He also covers the purposes they serve.

It's a bit hard to find literature on suction line traps, so it's always best to read the manual and follow the manufacturer's guidelines. We traditionally use P-traps on suction lines to hold oil and let it go up the walls of the refrigerant piping. You need enough velocity to lift oil (mineral or alkylbenzene) up the riser. We know that POE carries much easier with refrigerants than mineral oil; it is very miscible with...

In this short podcast episode, Bryan explains how you can prevent and overcome price objections in your HVAC business.

You can prevent price objections by avoiding the "budget" reputation. If your company establishes itself as a "budget" or "cheap" company, you will attract coupon-clipper customers. Coupon-clippers can be difficult to work with because of how cost-conscious they are. Customers who aren't looking for a deal will be less likely to object to pricing. You also don't want to shy away from money conversations with friends or family members.

Once you get your business model and...

In this short podcast, Bryan explains why latent capacity is prone to disappearing. He also explains what actually happens when the latent capacity drops.

When you measure enthalpy split across the coil, you'll learn that the equipment design makes it perform to AHRI design conditions. Those design conditions are 95-degree outdoor temperature and 80-degree indoor temperature at 50% indoor relative humidity. So, the A/C system must remove a lot of moisture. However, we don't usually run A/C units for 80-degree indoor temperatures; we usually aim for a 75-degree indoor temperature. When we have 80 degrees, the sensible...

In this podcast, Jeremy Smith joins us to discuss demand cooling in low-temperature applications that use R-22 refrigerant.

R-22 is NOT an ideal low-temperature refrigerant because it leads to high compression ratios. The discharge gas also gets really hot and can burn up the oil in the system. (The head of the compressor is even hotter than the discharge line, so if the temperature is high enough to cause oil breakdown in the discharge line, it's almost surely worse inside the compressor). However, R-22 is starting to go away in rack refrigeration.

Demand cooling injects...

Bryan and Kaleb cover the basics of low-voltage electrical applications. They focus on the practical stuff, not just the theory that confuses techs.

Many techs have a hard time with low-voltage electrical concepts and components because it's not easy to visualize what happens; we only see wiring diagrams, not metaphors that help us understand what's going on.

The low-voltage control circuit starts with the transformer. The transformer has a primary side (where the high voltage comes in) and a secondary side (where the lower voltage comes out). The secondary is only connected to the primary...

In this short podcast, Bryan talks about the impacts of compression and airflow changes. He also discusses some of the ramifications of those changes.

In order for us to energize the second stage of a compressor, we need to energize both Y1 AND Y2. On stage 2, we're running that compressor at full speed (350-450 CFM per ton). The compressor will also perform at rated capacity. When you stage down to stage 1, your blower should ramp down, and the compressor should produce less capacity (move less refrigerant). When moving less refrigerant, the compressor should use less current but...

In this podcast episode, we ONCE AGAIN talk about superheat and subcooling. This episode is a recap to help people who struggle with the concept.

You get superheat when you have 100% vapor, and you have subcooling when you have 100% liquid; any liquid-vapor mixtures are in a saturated state.

We usually measure superheat outside at the suction or vapor line. It's best to take the superheat reading as close to the port as possible. Anything in the saturated state is boiling; you can only get the mixture at the boiling point of a refrigerant. Anything above...

In this psychrometric basics podcast, Bryan and Kaleb talk about the properties of air. They also discuss dry-bulb, wet-bulb, dew point, and relative humidity. Psychrometrics is the study of the relationship between air and its properties.

The psychrometric chart can be a bit intimidating, but you can use it in a variety of ways. A technician should care about this chart because it helps with whole-home diagnosis. You can't see the whole picture of someone's comfort unless you know the properties of the air. The left side of the chart is centered on wet-bulb and enthalpy, and...

Many contractors make a huge pricing mistake: confusing markup with margin. The distinction between those two things can be the difference between being profitable and losing it all.

If you want to mark up something that costs $10 by 50%, you multiply it by 1.5 to get $15. So, did we make a 50% gross margin? No; we only made $5 on a $10 transaction; if we take 10/15, we get o.66. So, we really only made a 33% gross margin.

When we factor overhead in, 33% is normally nowhere near enough. Not everything in the business will make money, and those costs become overhead...

In this podcast, Ron Saunders from Fresh-Aire UV comes on and answers questions about UVC. He clears up misconceptions and pulls no punches. Fresh-Aire UV (Triatomic Environmental) used to manufacture and sell ozone solutions, but the business evolved to sell UV and carbon-based IAQ solutions.

UV lights exist on a spectrum of varying wavelengths. Some UV lights at the higher end of the spectrum produce ozone, but UVC light does not. UVC's frequency (~250 nanometers) is outside the range of light that produces ozone (shorter than 185 nanometers).

Like any other IAQ product, UVC lights have advantages...

In this free-flowing conversation, the Trethewey family talks about growing up with This Old House, what the show is like behind the scenes, what Rich misses about the past, what the future holds for the trade, and some nerdy specifics between Bryan and Ross.

The show business is a collaborative effort between the producers and talent (even though they're real people, not actors), and the Trethewey boys find the end result almost cathartic. This Old House was never scripted; there were beats and predictions about the content, but the content is all authentic.

As the t...

Two of the great air and infiltration expert minds of our time, Gary Nelson and Steve Rogers from TEC (The Energy Conservatory), come on the podcast to talk about blower doors. They also discuss blower door testing and how it compares to real-life infiltration.

A blower door has a fan to measure the air flowing through it, and you generally install it in a doorframe. Blower doors hook up to manometers to measure the pressure differential between the inside of a building and the outside. Generally, you need to adjust the fan speed to bring the pressure...

In this short podcast episode, Bryan explains how to keep your humanity and make moral decisions when selling IAQ products.

As the COVID-19 pandemic has started to grab hold of the world, we've seen an uptick in IAQ interest. When you have greater consumer interest, there are opportunities to hoodwink customers. While some IAQ products are indeed not very effective against viruses, there are some good products that you can sell to customers to benefit their health.

Pretty much every product has an appropriate application, but sales and marketing can lead to inappropriate, ineffective usage...

Nikki Krueger joins us to talk about how humidity impacts indoor health and some ways to make our indoor air quality better (for real).

Indoor air quality is all about manipulating the air in our homes to reduce pollutants and keep our air quality high. From air dilution to running bath fans to air purifiers, there is a lot more we can do to make our homes healthier. We can't entirely isolate ourselves from viruses, bacteria, and fungi. However, there are many other things inside our homes that can suppress our immune systems, and we can address...

In this short podcast episode, Sal Hamidi of ProductsByPros joins Bryan to discuss what manometers are and how they measure pressure.

Manometers measure pressure at a much higher scale than a micron gauge but lower than that of a pressure gauge; they measure pressure differentials by comparing static pressure to another source of pressure as a reference. Across all segments of the industry, we use manometers to measure static pressure. Static pressure is the pressure of air against the duct, not the actual air velocity. (Static pressure can give you an idea of the airflow, but you...

Michael Housh and Jim Bergmann join Bryan to look into the crystal ball to see the future of air conditioning and design the PERFECT residential system.

Self-contained propane heat recovery chillers are futuristic devices that do simultaneous heating and cooling. While they may not be suitable for all climates, they can switch between heating and cooling modes, like heat pumps. They may also be able to service domestic hot water centrally as well. Although propane heat recovery chillers are impractical for residential use right now, they could hold the key to the future of air conditioning.

Thomas Talhelm, the founder of Smart Air, joins Bryan on the podcast to talk about how a filter and a fan in China sparked an IAQ revolution. The simple device changed his thinking about air purification.

As a graduate student in China, Thomas witnessed the Beijing "Air-pocalypse" firsthand. That was when he became aware of the issue of air pollution and the potential health issues it can cause. So, he dove into the world of air purification. The most popular air purifier on the market was about $1,000, but Thomas felt that the price tag was way too...

In this short podcast episode, Bryan talks about the steady-state voltage problem that can take out inverter boards and what to do about it. Inverter-driven equipment refers to a variable-frequency drive with ECM compressors and fans.

We're talking about modern split-phase equipment rated for 208v or 230v power. However, the split-phase power will yield 240v. Most motors and components for 240v equipment have ratings for 230v AC power. L1 and L2 power can also be significantly higher than 240v, sometimes going as high as 250v.

Inverter boards have a widespread failing problem in locations with...

Jim Bergmann and Michael Housh join Bryan to talk about testing A/C vitals. They discuss the new vitals mode in MeasureQuick and how it works. As with many of MeasureQuick's other functions, vitals mode is an invaluable tool for green and experienced HVAC techs alike.

The new vitals mode helps us with charging, airflow, and other staples of A/C testing and commissioning. Vitals mode allows the user to give MeasureQuick some information about the system; when they provide that information, MeasureQuick can instruct them to use the most appropriate charging method.

When you...

In this short podcast episode, Bryan explains how to use liquid line temperature as a quick diagnostic indicator on split A/C systems.

Liquid line temperature is one of the first things to check when you approach a system. Checking that temperature is also a great way to get into non-invasive testing. The temperature should be between 4 and 15 degrees warmer than the outdoor temperature (unless it is wet). If the liquid line is cooler than the environment, then there could be a restriction. If there is a restriction, you could have a clogged liquid line drier or...

In this live podcast episode, we discuss viruses, bacteria, and fungi. We also explain how they interact with HVAC equipment, their effects on indoor air quality, and how businesses can protect their customers and employees.

Since we work with the public, we can minimize the risk of viral transmission by keeping our distance between others and avoid handshakes and other forms of contact. However, we also have to respect the feelings of the customers we're serving.

Many people confuse viruses, bacteria, and fungi (mold). All particles are small and would typically pass right through a...

In this short podcast episode, Bryan talks about science and how to balance practice and experience with the “why” behind what we do. He also explains how either one can cause an error if you aren’t careful.

Science is not just about reading nerdy theories in books; it's all about understanding why the processes in our world. In that sense, many of us field technicians are scientists. When we use problem-solving skills in the field, we try to understand what is going on and why our proposed solutions might fix the issue. We partake in experimentation all th...

We discuss some of the new, possibly strange-sounding business processes we've decided to implement at Kalos in 2020.

First of all, we are going to add terms and conditions that our customers must agree to. These terms and conditions include a "hold harmless" disclaimer regarding viruses, fungi, and bacteria. Florida forbids us from discussing mold, so a "hold harmless" disclaimer protects us from liability for something we aren't even allowed to discuss.

We also have to reinforce automobile safety to protect ourselves and our employees. Small fender-benders can spiral into serious legal problems when we lack...

Ben with Infinitum Electric comes on to tell us more about his super-innovative, groundbreaking PCB (printed circuit board) motor technology that we saw at AHR 2020.

The Infinitum motor is a relatively simple permanent magnet motor that can also work as a generator. Infinitum got its start with generators, and the groundbreaking new motor technology works quite similarly to generators. These motors can also work with variable frequency drive technology.

In this groundbreaking motor, the traditional stator has all of the iron and copper taken out, and copper is etched into the circuit board. When you t...

Rick from Certified Refrigerant Services joins us to talk about recovery and refrigerant management. He also explains what to look for and do to get the most from your program.

A refrigerant management program offers recovery services, reclamation, and other options for processing refrigerants. Rick's company also buys and sells refrigerants. With his line of work, there are also plenty of opportunities to educate contractors. The goal is to reduce refrigerant mixing and keep high-quality refrigerant in circulation.

Mixing refrigerants kills their value, though it is sometimes inevitable. On the contractor's side, you can take...

Chris LaPietra, vice president and general manager of Honeywell Stationary Refrigerants, joins us to talk about some new releases from Honeywell. He also covers refrigerants in general.

As our industry reduces its reliance on R-22 (and eventually R-410A), we have turned to more flammable solutions. There is a tradeoff in safety for the lower GWP, though. However, along with some slightly less flammable A2L refrigerants, Honeywell is releasing two new A1 refrigerants: R-466A and R-515B (N-15). These are non-toxic, don't catch fire, and have a lower environmental impact than R-410A and R-22.<...

Eric Kaiser comes on the live podcast to talk through some commonly repeated EPA myths. We also discuss how to get the most from your recovery machine and tanks. The EPA exists to interpret broad laws into specific standards, such as by translating climate initiatives into venting guidelines.

One of the most common EPA myths is that you cannot charge a leaking system. If you can repair the leak and get the leak rate below the specified percentage, then you can recharge the system. Not every country allows this procedure.

On the subject of refrigerant...

Gurminder Sidhu joins us from NATE to talk about what NATE is all about and bring us some news about the new changes and improvements.

NATE was created for the industry by the industry; the organization arose from a need to promote education and standardize HVAC qualifications. Today, NATE continues to address the industry's needs by offering education and certification for technicians. NATE also understands the need of explaining the "why" behind our daily work.

The people at NATE also believe in continuing education and offer learning materials to techs of all levels, as well...

Alex Meaney from MiTek/Wrightsoft joins us at AHR 2020 to talk about some HVAC design myths and how to bust them in your mind. It was a really fun talk with a great guy.

One common HVAC design myth worth busting is that we can use a set friction rate with a Ductulator to make duct systems work. The friction rate only applies per 100 feet, and it has different degrees of impact based on duct sizing and fan speeds. We CANNOT guarantee that a system will work if we subtract losses to filters, coils, and grilles until...

Andrew Greaves joins us again from AHR 2020. This time, he discusses what mentors and role models do in our trade and why they're important.

Mentors are not just the grouchy senior techs who throw hammers at apprentices. Mentors have an active role in others' professional development; they spend a lot of time with their mentees and actively aid their growth. Not everyone is cut out to be a mentor, as the role comes with a lot of responsibility (and possibly stress). Role models indirectly influence others by doing good work and inspiring others to do the highest...

In this podcast, HVAC School team members Kaleb and Leilani walk the floor and talk to various people about their products and companies at AHR 2020. Bryan also has a quick conversation with Frank from HVAC Outlawz.

The newest RectorSeal surge protection (RSH-50 with the 60A disconnect) uses MOVs and gas discharge tubes, which work together to fight off power surges. The effectiveness of the product has allowed RectorSeal to give customers a lifetime warranty on their product. RectorSeal also has a new drain cleaner, Nu Line. Nu Line eliminates the biofilm in drains AND protects the drain...

In this live recording from the AHR Expo, Kaleb Saleeby, Nate Adams, Michael Housh, and Steve Rogers discuss building performance.

The building science world is an exciting place; we're all excited about improvements to reheat dehumidification, which is when we use waste heat to take care of humidity without cooling. As equipment becomes more efficient, we also look forward to tackling new challenges that make us think more broadly. New people are also stepping up, using new tools, accessing more knowledge, and doing better work.

Building performance is becoming more important in HVAC via HVAC 2.0...

Mike from Refrigeration Technologies talks to us about his journey in business, some new and old products, and how well the business is growing.

Refrigeration Technologies tries to make products that do the job correctly the first time and are safe for techs to use. The products are odorless, don't burn skin, and are safe around food. John and Mike Pastorello are passionate about using chemistry to make quality products that make techs' lives easier. Mike joined his father's business full-time when he was 23; he performed a lot of the menial tasks while his father developed the...

Richard Trethewey from This Old House joins Bryan on the podcast and tells his incredible story and shares some encouragement and laughs.

Richard works with his sons, Ross and Evan. He has always worked in a family business and then left it to start his own with his sons. Family businesses truly are the backbone of this industry, as our business attracts lots of family-oriented business owners. Richard's sons volunteered to join the business early on.

This Old House started off with a phone call from PBS about a home-renovation show idea; Richard had to s...

This podcast is by Sal at Products by Pros, featuring Bryan Orr of HVAC School. In this episode, Sal asks Bryan all about micron gauges.

Products by Pros

Guest: Bryan Orr

What should technicians look at when deciding on a micron gauge?

You should look for superior accuracy and resolution, especially if you'll be doing decay testing. You need to see what the trends are in clear detail. (The Bluvac app makes that easy.)

Why should a tech even use a micron gauge?

Yo...

Rachel and Eric Kaiser join us to talk about connecting STEM concepts to the trades. They also explain how to teach STEM in a way that sticks.

STEM refers to science, technology, engineering, and math. In traditional classroom settings, teachers usually tout these subjects as the ones that lead to the most promising careers. However, STEM concepts are not limited to their respective subjects; we use many of those scientific and mathematic concepts in the trades as well.

Rachel believes that undergraduate programs would be more effective if they focused more on teaching critical thinking...

This short episode is a review of a list of installation reminders made by Kalos manager Jeff Crable. Kalos is doing a bunch of these installs for a commercial customer. Hopefully, the business leaders can take a few things from our checklist and help out their installers.

Whenever we do an install for our large commercial customers, we give our installers a long checklist of reminders; that way, they can do the best install possible.

Some of those install reminders include:

In this face-to-face discussion, Bryan and Kaleb share some tips for diagnosing and replacing the reversing valve on a heat pump. These valves may also be known as four-way valves.

Kaleb and a trainee recently had to diagnose a heat pump with a scroll compressor. The motor was also over-amping due to a failed capacitor, and the compressor was making a metallic grinding noise. Because reversing valves are pilot-activated, they need a pressure differential to shift, so the scroll plate can sometimes pop up and make noise during bypass. Another possibility was that the compressor could have...

In this short podcast episode, Bryan talks about the times he has been hoodwinked in his career. It's time to name and shame.

One time at a trade show, Bryan came across a product called KVAR. KVAR is already an electrical term for kilovolt-amps reactive; those are volt-amps that show up and generate heat but don't do anything useful, just like foam in a beer mug. So, the product supposedly balanced out the power factor to save energy. However, power companies don't charge based on VA; they charge based on wattage, which already accounts for the power...

This live podcast episode is all about pool heater talk. We cover gas pool heaters and pool heat pumps, explaining how they work and common issues.

Pool heat pumps work a lot like air conditioners, but they have heat exchangers that help transfer their heat to the water. Instead of having a typical condenser, a pool heater has a unit that works like a heat pump's outdoor coil in heat mode. There is usually an option to cool the water, but there are almost no cases where someone would want to use that mode.

The...

Alejandro Rios from True Refrigeration comes on to talk about self-contained R290. He explains what it is, why to love it, and how to service the sealed system.

R290 is pure propane, and it has recently made a name for itself as an emerging refrigerant. It is an A3 refrigerant, meaning that it is non-toxic and highly flammable. As we move away from HFCs and other refrigerants with high global warming potential (GWP), we will encounter more flammable refrigerants, usually A2L and A3 refrigerants. R290 is a natural refrigerant and has a GWP of only 3, making...

In this short podcast episode, Bryan explains what happens when your low-voltage circuit puts out a lower voltage than it should.

Bryan recently received an email asking about the low voltage on a 20-ton split system with a long control wire; the voltage coming back to the condenser is only 19 volts, so there was some contactor chattering. First, in a case like that, you'll want to figure out why the voltage isn't as high as it should be. The control wire and line sets could be longer than the design specs, which may contribute to the problem...

In this live podcast from the Castbox app, we talk about codes and common causes for failed inspections. We talk about these topics both broadly and with some specifics.

Many of the places where we fail to meet codes are on the electrical side. Electrical components have fire and electrical shock hazards, and codes are stringent for arc and ground fault protection. Leaking current to ground can shock someone, and arcs can cause damage to property and human life. We commonly see failed inspections due to improper marking on the air handler.

In the HVAC...

In this live podcast episode from the Castbox app, we have four techs join us to talk about common furnace issues and best practices.

Those of us in heat-pump-dominant markets rarely have to worry about common furnace issues related to gas pressure and flow. In that same vein, we also don't have to worry about clocking the gas meter, which is a common practice on gas furnaces. Checking input and performing combustion analysis is critical to the diagnostic process AND can give you an idea of the unit's safety. There is no reason NOT to do combustion...

David Richardson with NCI, author of Duct Dynasty, joins us on the podcast to talk about mixed air temperature and more topics of interest.

When you bring outside air into the home, you introduce positive pressure into the home. That way, you can offset air lost via mechanical ventilation or through cracks, improving air quality. We often assume that the building will "breathe," but tighter constructions make it difficult for the home to bring in enough fresh air to offset harmful chemicals and VOCs.

We need to measure two different kinds of airflow: fan airflow a...

In this short podcast, Bryan briefly explains why we use a voltmeter to measure “voltage drop” across loads and switches. He also covers some of the differences between passing and consuming power.

Many of us are naturals at using voltmeters already. Voltmeters have two leads, and those exist to measure the difference or potential between them. Voltage is a reference to what is going on between the leads; whenever resistance exists, we have a voltage drop. Resistance can sometimes be designed or undesigned.

When we think about power passing and consuming, we should note that "cons...

Ty Branaman from NTI comes on the podcast to share his passion for teaching. He also discusses his approach to impactful HVAC/R instruction.

It can be difficult for instructors to create an appropriate balance between teaching theory and practical knowledge. Students and trainees need to have technical skills in the field, but they also need a solid foundation. Impactful HVAC/R instruction requires a balance of the nerdy stuff and physical skills; good instructors put the theoretical parts simply and give students the opportunity to apply theory to hands-on skills.

Engagement is another important...

In this short podcast, we take a quick look at Bryan’s take on practical safety improvements. He also discusses the safety year in review at Kalos.

Kalos had a great year in terms of safety. As the managers look back on the year, they attribute their success to having a practical approach to safety. To make practical safety improvements, we must be safety-conscious without obsessing over the risks of our job. Our jobs always have an element of danger, and our goal should be to minimize those and abide by OSHA standards.

As an in...

Tim Fregeau from Goodway joins us to talk about descaling large equipment. He also discusses best practices and why they matter to you.

Scale refers to mineral deposits that build up in any water source. Water can be brackish, rusty, muddy, or otherwise high in mineral content, and those minerals begin to accumulate on heat-transfer surfaces on large equipment. Scale can cause metallic components to weaken and leak, and it can block microchannel coils. The large equipment can't reject the heat efficiently or function as it should when it has scale buildup, so that's where descaling comes...

In this short podcast episode, Bryan talks a bit about brazing temperature. He also covers how to heat your copper to the proper temperature. You can use torches with oxyacetylene or air-acetylene tips.

Joining two metals with an alloy above 840 degrees classifies as brazing; anything that uses an alloy to join two metals below 840 degrees is technically soldering. When you join two similar metals by melting the base material (not using an alloy), that's welding.

Another temperature of interest is 500 degrees; oxygen rapidly bonds to copper at temperatures above 500 degrees, so we will want to...

In this live episode, we talk about heat pumps, why Bryan likes them, why other people don’t, charging and diagnosing them, and defrost.

Even though heat pumps work best in warmer climates, they can theoretically work as long as the temperature is above absolute zero (-460 degrees F). Viewers across the USA install heat pumps in their markets, even in places with cold winters like Wisconsin. Ideally, the discharge line should be around 100 degrees above the outdoor temperature in heat mode. Although this rule of thumb appears to work in many different climates, it is only re...

In this crossover episode (rantcast), Bryan talks with Gary from HVAC Know It All. They vent about some of the phrases that techs throw around that are often false.

Technicians often throw around the phrase, "[X] will void your warranty." However, the truth is that manufacturers can't really void a warranty. Some modifications may go beyond the scope of the warranty, but you don't simply make modifications that "void" the warranty. Techs may say that something voids the warranty to shut down the conversation or to create a selling point (preventive maintenance).

In many (but...

In this short podcast, Bryan discusses the differences between air, nitrogen, and oxygen. He also explains why we should only use nitrogen for purging, flowing, and pressurization.

You DON'T want to pressurize line sets with air because air contains water vapor and oxygen. Water acts as an oxidizer, and moisture can turn POE oil acidic via hydrolysis. You cannot dry out POE oil, and the acid can lead to compressor burnout.

Nitrogen is non-reactive (unlike oxygen) and does not contain water vapor (unlike air). It also does a good job of chasing water vapor out...

In this LIVE episode, we talk about diagnosing inverter-driven systems. We also discuss some of the issues and solutions for over-voltage.

Inverter-driven systems, also called variable frequency drive equipment, provide comfort control across multiple zones in a building. Some systems may have multiple branch boxes that control various units throughout a building. These systems require a lot of patience; the diagnostic process can last a long time because you must test all of the terminals. Since these systems are very electrical-component-heavy, you may also encounter issues presented by lightning, power outages, or continuous high voltage. Installation errors...

Jim Bergmann is back on the podcast. This time, he talks about common faults with high-efficiency 90+ condensing gas furnaces and their installation.

Like A/C units, 90+ furnaces often suffer from clogged drain lines. Other common problems stem from issues with inputs, temperature rise across the appliance, trapping, and venting. On high-efficiency gas furnaces, procedures like clocking the gas meter are much more important than on an 80% gas furnace; you must clock the gas meter to get the proper inputs. To get the furnaces to condense properly, you need to make sure you control excess air and get...

Bryan explains the core differences between followers and leaders. There is nothing wrong with being a follower, but if you are ready to move into leadership roles, here are his tips.

Leaders primarily leverage the work of other people. Conversely, followers have limits to their abilities and their earning potential; the leaders are the ones who set those limits. Good leaders create opportunities for others.

Followers who attempt to be leaders are more likely to wait rather than move, complain rather than change, and assume rather than ask. Leaders actively seek out opportunities and tend...

Some great live guests join the podcast to discuss the advantages, disadvantages, and challenges of ductless and VRF equipment.

We started off working on ductless equipment with Mitsubishi, especially installing them in lanais. Sunrooms have large amounts of radiant heat coming in, and the heat load often warrants getting an A/C system just for the sunroom/lanai. We even began oversizing them a bit (which was a lesson learned). We also learned that mini-split ductless systems tend to have filthy blower wheels because moisture tends to build up on them. However, bib kits make cleaning the...

Jamie is back on the podcast. This time, he talks about the merits and pitfalls of floating head pressure and why you might care.

There is a relationship between floating head and floating suction, though the latter is easier to understand. You can stage fans to come on at certain temperatures, but you'll always be running fans above a certain temperature. When temperatures are below that temperature, you can save energy by not running the fans. However, you still have to worry about feeding the evaporator coil sufficiently. Floating head pressure refers to dropping the pressure differential...

In this short podcast episode, Bryan talks about circuit breaker facts. He also explains why they trip, what they do, and some different types and considerations.

Circuit breakers break the circuit during an overcurrent situation. These do NOT handle all overloads, such as locked rotor amps (LRA); these handle significant overloads, such as shorts (when current takes undesigned paths). In air conditioning, we can size our fuses and circuit breakers a bit larger than usual, which prevents tripping from small spikes instead of truly dangerous or prolonged overload conditions.

There are thermal and inductive circuit...

In this episode from the archives, Dan Holohan joins us on the podcast and talks about his vast experience in the lost art of steam learned from long-dead men.

Steam heating is a "lost art" nowadays; it has become increasingly uncommon and has been disappearing since the Vietnam War. Many people who understood steam heating either retired or died after the Vietnam War. Many elements of steam heating are difficult to understand or surprising. (For example, steam pressure has a surprising relationship with velocity: low-pressure steam moves through piping much more quickly than high-pressure steam.) So, Dan...

In this honest—maybe overly honest—live podcast, we talk about the dark side of white shirt techs. We also discuss ways the industry can make money while doing the fundamentals well.

The term "white shirt" refers to a sales technician who prioritizes selling equipment over fieldwork; these technicians don't necessarily sell expensive products, but they lack technical expertise. The surefire way to tell if someone is a "white shirt" is to see if they can solve problems with their hands or if they just pull solutions from a menu of new products.

However, "white shir...

In this podcast episode, Bert joins Bryan to talk about what he has learned to help prevent the dreaded callback on the job.

Callbacks are bad news for customer service, time, and profit. However, the highest cost is the inconvenience caused to the customer. To reduce callbacks, Bert recommends communicating your expectations to your customer clearly; explain what the expected performance should be and how a customer should use their system. We need to do better at having conversations with the customer where we listen to them; we should not explain everything through the paperwork and walk...

This short podcast is for the newbies out there. For HVAC trade newbies, Bryan recommends applying 7 tips to help you win.

When you start off in the trades, you'll want to check your mindset. Successful HVAC technicians are usually humble; recognize that you don't know everything. The truth is that nobody knows everything, and every other person has wisdom and knowledge to offer you. (However, don't mistake humility for a lack of confidence.) You'll also want to hang out with good people; you are the sum of the five people you spend the most time with, so...

Jim Bergmann returns to the podcast to talk about the power quality meter. He also discusses what it is good for and how to use one.

A power quality meter accounts for the power factor in its measurements, and it measures true power in watts. We can notice failing capacitors and other issues that can cause a device to draw higher wattage. In inductive loads, the power factor will be less than 1. However, we can measure the power factor because the capacitor counteracts the inductive reactance and gets the power closer to unity; the current and voltage...

In this short podcast, Bryan talks through (once again) what REALLY causes capacitors to fail and what we can do about it.

High temperatures and overvoltage (NOT undervoltage) are what cause capacitors to fail. (There are also some poor manufacturing practices out there. Remember: they should be just foil and oil.) Capacitors create a phase shift to assist split-phase induction motors. Normally, a three-phase motor can start and run just fine because the sine waves are all angled. That is not the case for split-phase motors. Start capacitors help startup, which is difficult for the motor.

Eric Mele, Eric Kaiser, and John Oaks come on the podcast to talk about commercial PM best practices and what matters most.

Drain cleaning is a critical part of the standard commercial PM. You must assess the drainage situation (pitch, length, location, etc.) to plan your cleaning strategy and arrive at the best result: the entire drain gets cleaned. If you use chemicals, you need to be very careful not to let them back up into other units.

Condenser coil cleaning is another important PM procedure in both residential and commercial HVAC. However, you don't...

In this live podcast from CASTBOX, we discuss the skills gap and how we are going to get more people into and trained in the HVAC/R trade.

Instead of gaining skills early in life and then looking for a job, many of us in the HVAC/R trade started our careers and gained skills along the way. The most successful technicians (and Bryan's favorite job candidates) have the "growth" mindset and care about their work, not just connecting a paycheck. Many people have experience working with their hands (or working any job), but they don't go...

In this episode, Nate Adams and Michael Housh give the HVAC 2.0 rebuttal to the idea of standard load calculations. They take a different, possibly more radical approach to proper sizing.

Michael and Nate believe in doing real-world load calculations, not just relying on models for load calculations. They are on the side of replacing equipment like-for-like unless the customer will pay for the proper load calculation; customers should have the option to get a free quote for a like-for-like or slightly smaller replacement or a full consultation, but they will often opt to choose the free quote...

In this true story from Bryan's teen years, you learn about the "Freon Sniffer:" what inspired him to become an HVAC/R technician (maybe).

When Bryan was working with his uncle at age 14, he was an electrical apprentice who worked in grocery stores. He installed "pink lights," which were lights that hung on aircraft cable over produce displays. (The aircraft cable came from Bryan's grandfather's aircraft junkyard.)

The pink lights were difficult to install, and many people were unwilling to do the installation. However, Bryan and his family were willing to install that difficult equipment...

In this podcast, Jim explains how to use a combustion analyzer. He also talks through the process of combustion analysis using Accutools BluFlame.

The beauty of BluFlame is that it can do CAZ testing, help you set the inches of water column in your furnace, and measure static pressure drop. BluFlame is a tool you can use year-round, not just when you need to measure stack gas.

To learn how to use a combustion analyzer on a typical gas furnace, you have to understand why you're doing it. Combustion analysis is necessary to monitor the...

Duct and air handler (unit) sweating is a common issue in humid climates. Bryan talks about what causes it and what to do about it.

Many people try to keep their ducts and equipment either very cool or very warm to prevent sweating. Despite the good intentions, neither of those methods is great for sweat prevention. If a ceiling grille is sweating, people try to insulate the top of the boot to stop the sweating. The real reason why the grille continues to sweat is that those sweating areas have hit the dew point.

If...

Alex from Wrightsoft is back to discuss duct design. He also explains a common mistake made when designing ducts using a Ductulator.

The Ductulator is a common entry point for technicians who get into duct design, so it sticks with technicians despite its flaws. It makes more sense to reverse the process by picking a friction rate and pressure drop as the first step when designing ducts. Figuring out how to overcome restriction is the key to commercial duct design, but it can also work well in residential duct design.

However, we can't pull our...

In this short podcast episode, Bryan explains what you need and the things you need to consider if you want to start a business in HVAC/R.

When you start a business, you need to have a healthy reserve of money already. Kalos started with $100,000, and that money went towards vans and tools needed for a GC and HVAC business. Even if you start a business with just one person and a truck, it's best to have at least $50,000 available at the start.

In the business world, you MUST care about money. Otherwise, you'll go...

Alex Meaney from Wrightsoft joins us to talk about Manual J and S. He also discusses how load calculations and equipment selection apply to real-world situations where contractors are tempted to replace “like-for-like.”

Load calculations have been a staple of new installations, but they are becoming important in retrofits as well. We consult Manual J when we do load calculations for residential HVAC designs. We determine where the heat loads are coming from to see how equipment can address those heat loads; in heating, we want to replace heat losses. The technicians who do load calculations also tend...

In this live podcast from the Castbox app, we talk about analog vs. digital, digital vs. probes, and probe vs. non-invasive testing of A/C and refrigeration. We also talk about apps and various Bluetooth tools.

Although analog gauges are old, reliable tools, digital gauges tend to be a bit more accurate than analog ones. However, the jury is still out on which one has the durability edge. Digital gauges also have batteries to worry about, whereas analog ones don't. Ultimately, the only reason to use analog gauges over digital ones is a personal preference. Probes work...

In this short podcast episode, Bryan talks about ambient CO. He also explains why it matters and what you do to check for it.

CO, carbon monoxide, is a colorless, odorless, and toxic gas that can result in death. It should not be confused with CO2, carbon dioxide. Although our bodies inhale oxygen and not carbon dioxide, the latter isn't toxic if it gets into our bloodstream. CO, on the other hand, displaces oxygen, which proves deadly. Carbon monoxide can also build up in your bloodstream over time, so you want to avoid repeated exposure.

...

In this podcast, Michael Housh joins us to discuss his years of experience with geothermal heat pumps and their special considerations.

"Geothermal" is a rather generic term, similar to how people say "Freon" to refer to any kind of refrigerant. Those heat pumps don't necessarily have to be underground; you can have water-source heat pumps in ponds or wells, and there are also ground-source heat pumps. The ground provides a steady temperature under many conditions, which helps heat pumps work effectively in cold climates. Like other heat pump systems, geothermal pumps come in split or package types...

In this short podcast episode, Bryan explains what water vapor diffusion is. He also explains why it matters to the everyday HVAC technician.

Vapor diffusion is the transfer and distribution of water vapor through a solid surface. New constructions sometimes have vapor barriers on the outside of buildings in hot, humid climates or on the inside of buildings in cold, dry climates. (Even so, vapor barriers are not 100% effective.) We are NOT referring to water or mist wicking through the buildings via capillary action; we are referring to water vapor.

Drywall, a common building material...

In this live conversation, we discuss some real-life situations with difficult customers. We also cover some helpful tips we learned along the way.

When Bryan started Kalos, there was one situation where a customer blamed him for lying about a customer diagnosis. So, that was how Bryan fired his first customer. However, many of us want to fire several customers, and that's when we have to look in the mirror and evaluate ourselves. When the problem truly isn't with us, we have to make a choice to say, "Sorry you feel that way," and walk away after...

In this podcast episode, Henry Papa from Sporlan joins us in person to talk about refrigeration case controllers on systems with common compressors. We focus on the Sporlan S3C case controller, but some of the information applies to other case controllers.

Case controllers control the conditions at each separate evaporator and are responsible for controlling defrost, discharge air temperature, and superheat. They can also monitor conditions at the evaporator, especially discharge air. In grocery, we tend to look at discharge air temperature instead of box temperature. Traditionally, we use EPRs to control a fixed evaporator pressure...

In this short podcast episode, Bryan talks about brazing and soldering. He also weighs in on patching and if it is an allowable repair.

Brazing is when you use a dissimilar metal to join metals at a temperature above 842°F, and soldering occurs at temperatures below that. (Welding occurs when you use the same metal as a joining metal.) In our trade, we generally use soldering on copper plumbing and brazing on line sets. We also often call brazing alloys "solders," such as silver solder.

When making a joint, you want to have a sufficient (b...

n this live podcast episode, we have a fun conversation talking with Nathan Orr and Kevin Compass about grocery refrigeration.

The most common types of calls are those where the machine is "not making temp." Usually, the cases can't maintain temperature due to frozen evaporator coils or backed-up drains. On low-temperature/freezer applications, we must rely on electrical or hot gas defrost to mitigate frozen coils.

Hot gas defrost is a complicated but quintessential part of low-temperature grocery refrigeration because the coils easily freeze. The discharge gas has to go to the evaporator coil and...

Nathan Rothenberg and Ed Janowiak join Bryan to talk about the good, the bad, and the uncomfortable of ACCA Manual J, D, and S.

Manual J load calculations exist to make the BTU inputs and outputs predictable. Then, Manual S comes in to assist with equipment selection to meet the load calculations and the customer's comfort needs. Manual D is a collection of mathematical formulas that exist to help you calculate your friction rate, which is important for comfort in terms of noise in the ducts (from excessive air velocity).

Ed believes that the best...

In this short podcast episode, Bryan compares under load vs. bench capacitor testing to find out which testing method is better.

When we test the system while the motor is running, we call that testing under load. Testing under load is fairly easy; you take the voltage across the capacitor (V), amperage off the capacitor's start winding (A), and then you use the following math problem:

(A x 2652) / V

(You can also punch those numbers into the calculator on the HVAC School app.)

While you can test under load on an...

Eric Kaiser joins the podcast again, and this time, we are talking ECM motors. We discuss types, history, diagnosis, and failure prevention.

An ECM motor has a permanent magnet rotor, which means that the magnetism never deactivates. The variable frequency-driven motor is typically an induction motor, and the rotor only becomes magnetized by the stator's field. Eric describes ECM motors as three-phase AC motors, but we can control the AC pulses, resulting in oddly shaped sine waves. Those motors essentially convert the AC power to DC power and then to controlled AC power with the help of...

In this lively discussion, representatives from Chemours and Bluon Energy join the podcast. They talk about retrofit refrigerants and what to look for in a good retrofit.

The R22 phaseout has been on the agenda for a long time due to its ozone-depleting potential. However, R-410A is also due for a phase-down in the future due to its global warming potential. While neither refrigerant will be outright banned, we will have to consider alternative retrofit refrigerants in the future, especially if reclamation rates stay low.

Almost all of the replacement options are refrigerant blends...

In this short podcast episode, Bryan discusses the importance of the trap and vent in condensate drains. He also describes some trapping and venting best practices.

Anytime you have long runs of horizontal drains, you run the risk of having a double-trap. A double-trap creates a water seal, which traps air between the two traps and prevents a system from draining properly. To avoid the complications of double-traps, you can create a proper trap at the air handler. When making a P-trap, make sure the outlet is lower than the inlet; traps need some fall. Then, you...

In this live podcast episode, Bryan talks through real home IAQ solutions with Jim Bergmann and others. They also answer audience questions. Indoor air quality is a place where the HVAC and building science industries intersect, so it is an important topic for occupant health and comfort.

Home IAQ is much more holistic than UV lighting or ionization solutions. For example, duct leakage is one of the fundamental challenges of indoor air quality in the vein of controlled ventilation. However, some more advanced IAQ devices include particulate counters, which focus on tracking pollutants in the air and...

Craig of AC Service Tech on YouTube joins Bryan on the podcast to explain how to charge an A/C unit. He also discusses his excellent new book.

Before you start charging a unit, you must know about superheat, subcooling, and other means of determining how much charge is already in the system. You must also know how the refrigeration cycle works so that you can tell if the system is operating properly. Other must-understand concepts are saturation and the pressure-temperature relationship.

To start off, you'll want to pull the disconnect on the outdoor unit...

In this short and nerdy science podcast, Bryan discusses how electromagnetism impacts every part of our lives. Electromagnetism refers to the movement of electrically charged particles.

From transformers to the visible light that helps us see, the movement of electrons is a critical part of our lives. For example, light is an electromagnetic wave within the visible part of the spectrum. On the more complicated side, AC motors generate a rotating magnetic field, which generates electricity. Transformers can also step down or step up voltage via two electrical coils that transfer energy via magnetism; electricity moves on...

In this first live podcast episode, Bryan responds to audience questions and discusses moisture and humidity issues in HVAC.

Moisture leads to other problems, including fungal growth. We often see moisture problems where the surface temperature meets the air dew point, not where hot meets cold. When the customer drives the temperature down too low, many surfaces in the home can meet the dew point and begin sweating, especially ductwork in unconditioned spaces and air handlers.

When you increase airflow, you derate the HVAC system's dehumidification. That's because the evaporator coil can't get cold enough...

Eric Mele and Joe Shearer join Bryan to discuss the challenging issue of diagnosing and rectifying non-condensibles in the circuit.

Non-condensibles are gases that don't condense, including nitrogen. These are NOT moisture or contaminants, and they can be tricky to diagnose; the pressure readings will likely be normal, but the charge will actually be quite low (around 60-75% of the usual charge). These gases also don't just enter the system suddenly in significant amounts; non-condensibles typically enter the system when lots of technicians work on it, or the gases have been there all along.

One...

In this short podcast episode, Bryan quickly covers defrost termination and failsafe. He also explains what they mean in refrigeration systems.

We need to defrost evaporator coils anytime they drop below freezing (32°F, o°C). When evaporator coils have a coat of ice over them, they cannot transfer heat from the box to the refrigerant; the ice blocks the coil from the air in the box. In defrost, we add heat to the evaporator coil. We can add heat in the form of electric heat or hot gas (discharge gas); either of these can damage product if th...

John Pastorello from Refrigeration Technologies joins us to talk about testing oil and refrigerant for contamination. He also explains what each test is good for. John developed the Checkmate testing kit when he recognized a need to test reclaimed and recycled R-12 for acid and moisture.

The Checkmate method removed a small amount of refrigerant from the system for testing. The Checkmate apparatus hooks up to a refrigeration system to test the oil. You insert a tube with a rubber stopper, and you can draw refrigerant from the system when the tool pierces the rubber stopper; the...

In this short podcast episode, Bryan explains what to do when you get water in your tools. (Hint: the answer is NOT to panic!)

Some technicians try not to get water in their tools at all. Depending on the climate and line of work, that may be an impossible task. In humid or coastal climates, you may deal with a lot of rain and moisture. If you work on cooling towers and boilers, you will be working with systems that rely on heat transfer through water, so you WILL encounter water.

When your tools get...

Mike Hardy from SpeedClean joins us to talk about how SpeedClean got started. He also explains why all contractors should consider engineered solutions.

SpeedClean emerged from the need to make coil-cleaning a better experience. Mike's philosophy is to look at the "pain points" of common tasks so that his company can develop engineered solutions to reduce the issues of those "pain points." The goal of companies like SpeedClean is to make an HVAC job more efficient to boost technician productivity and provide good value. However, Mike also believes in consumer education to promote user adoption, and he...

Eric and Bryan talk through some non-standard ways of thinking about filter drier usage. They also discuss how to install these non-conventional filter drier ideas.

The humble filter drier helps us prevent gunk from moving throughout the refrigeration circuit with the refrigerant. That way, you protect the compressor and metering devices. Ideally, Eric would install his liquid line filter driers right before the metering device, but that's not always practical.

When you put a suction drier into a commercial refrigeration application, most people will want techs to remove it. Suction driers can drive up the...

In this short podcast, Bryan discusses the recent ads and news articles claiming that homeowners are in trouble and that R22 is becoming illegal.

The R22 phaseout has been on the agenda for a long time and will finally come into effect in 2020. HCFCs have ozone-depleting potential, and it is time to look at more eco-friendly alternatives, such as R410A and R407A. The phaseout has affected prices and will cease virgin refrigerant production. However, after the phaseout period begins, R22 will NOT become illegal; you will still be able to find it in supply houses...

My buddy Eric Kaiser from the ETS Group comes on to discuss a common problem we see in both students and techs as they study. We talk about issues with how they think about the trade and how to progress in it.

Eric noticed that people who take classes or plan to get certified tend to study just for the end test. The tests may be industry-standard, but the students and technicians don't learn to apply their knowledge; they merely learn with the goal of passing the test.

Many technicians look for courses to complete...

Balancing complaints are common in the HVAC industry. In this short podcast, Bryan explains how diagnostic duct design solves those issues.

"Diagnostic duct design" refers to using the duct system to locate and solve a customer's comfort problems. If a couple of rooms have problems with humidity control, then the duct system could be a culprit. However, before we even touch the ducts, we should look at the space to determine if we have issues. For example, radiant gains from a window could be contributing to comfort problems, not the duct system. Airflow may also not be a...

Eric really likes ceiling cassette air handlers, so much so that he put them in his own home. We discuss ceiling cassettes vs. highwall and other ductless-related topics.

A cassette air handler looks like a concentric fitting, and they are generally installed in acoustic or drop ceilings. Eric likes the comfort and easy installation. However, people who have low ceilings or dislike exposed equipment may not like ceiling cassettes as much as Eric does. Both cassettes and highwall ductless units work well in sunrooms or lanais, but Bryan has noticed that cassettes seem to provide fewer problems...

In this short podcast episode, Bryan breaks down the most common defense for bad practices: time in the industry. He also explains how to STOP USING IT as an excuse.

When technicians communicate with each other, especially online, they tend to justify their practices with the phrase, "I've been doing this 30 years!" What they don't realize is that their old training (and habits) don't reflect the current state of the industry and the current standards of best practices.

When technicians spend so many years in the field, they may justify bad practices by saying that...

Devin Skipper comes on the podcast to give you an introduction to make-up air systems and explain their purpose. This time, we pull out all of the initials: MAU, MUA, DOAS, and MHGRV.

Make-up air is outdoor air that we bring in to replace exhausted indoor air, usually in commercial systems. We use dedicated systems to bring in humidity-controlled air to rebalance the building to a positive pressure; hotels, restaurants, and medical facilities with significant exhaust need fresh air to compensate for that exhaust and negative pressure. Unsurprisingly, design is critical for these systems, especially in humid...

In this short podcast episode, Bryan covers multi-stage or variable-speed compressors. He also explains the impacts of staged compression. Multi-stage (or variable-capacity) compressors can come in many different forms, but they all have one thing in common: they can adjust their capacities.

We typically rate equipment for its maximum capacity. However, when you vary the capacity, you get turn-up or turn-down; the refrigerant mass flow rate increases or decreases. When a unit turns down the capacity, the output decreases; the blower should also reduce its CFM output accordingly. While the compressor staging can vary, the coils and...

Jim Bergmann is back on the podcast to talk about the effects of dew point on coil TD. He also gives us a full rundown on recent MeasureQuick updates and what to expect in the future.

When you see flags in MeasureQuick, those indicate symptoms of specific problems. MeasureQuick cannot outright diagnose equipment; it can only offer variables and educate the user based on the symptoms it notices. Red flags are major faults, and yellow flags are minor faults or functions of the installation (such as long line sets), but Jim wanted to make the flags communicate...

Bryan talks about EPR and CDS valves. We consider both to be evaporator pressure regulators, but they really function quite differently. CDS are Sporlan components that appear to be quite similar to evaporator pressure regulators (EPRs).

EPRs go in the suction line and control the evaporator pressure. The pressure and temperature relate to each other, so the goal is to keep the evaporator from freezing by controlling the pressure. However, EPRs rely on a pressure drop across them to be able to do their job, so compression ratios will increase, impacting power consumption. We primarily see EPR...

Jim talks about dew point, bubble point, and midpoint in refrigerant blends. He also covers the purpose of each and why MeasureQuick displays midpoint on the gauges.

We've formerly used mostly pure refrigerants. However, as new refrigerant blends come on the scene, we have to deal with glide, which indicates that we have a range of boiling temperatures instead of a fixed boiling point. We have bubble point and dew point, which are when the refrigerant starts to boil and finishes boiling, respectively; you generally use dew point to determine the superheat and bubble point to determine...

In this short podcast, Bryan discusses the ever-controversial topic of indoor temperature in the summer.

The old "20-degree rule" has come up many times, and it's time to put it to rest. Not to be confused with the 20-degree delta T rule, the 20-degree rule basically states that the home A/C system can only maintain temperatures up to 20 degrees below the outdoor temperature. For example, if the ambient temperature is 95°F, the indoor temperature should be able to stay around 75°F.

However, that differential is not a fixed value. For example, if the outdoor te...

Nathan Orr is back. In this podcast, we discuss suction pressure in market refrigeration and how rack techs think about it differently than HVAC.

On parallel rack systems, suction temperature helps technicians determine the cooling load and how to get that to temperature. You run your discharge air temperature a bit lower than the product temperature. Your suction pressure also lets you know if your coil is reaching the correct temperature. Coil temp, also called suction saturation temperature (SST), is a vital metric for rack system operation. Lower suction pressure indicates a lower coil temperature or SST.<...

In this short podcast episode, Bryan explains why low static pressure may be bad. He also discusses the other indicators of airflow.

When you look at fan charts, you'll notice that there will be an available static value. When you measure static pressure, you're looking for the pressure applied against the sides of the duct, not forward through the duct (velocity). Low static pressure is generally desirable because it indicates that the fan motor isn't working as hard to move the appropriate amount of air. In that same vein, slightly oversized ducts may be okay for these...

Nathan and Bryan have a rollicking conversation about Nathan's transition from residential HVAC to market refrigeration. Nathan also covers what he has learned along the way. Hopefully, his experiences can help you decide if moving to market refrigeration may work for you.

Before Nathan went into market refrigeration, he handled problem customers and repeat issues on the residential HVAC side. He worked on zoning systems and mini-splits quite often. Even in that time, he did minor work on supermarket projects if the team needed an extra person. Market refrigeration projects require full scopes of work and time...

In this short podcast episode, Bryan covers pricing for HVAC/R parts and services; he explains how to come up with a fair price.

To be able to price fairly, we need to understand what value and sacrifice look like. In the HVAC industry, we value hard work and growth in a way that some other people don't. We provide parts and labor and sell those in the free market, so we can control how much we charge for those.

The price of a part means NOTHING in the industry. Instead, we primarily set prices...

We talk with chemical and cleaning expert Ray Field on Legionnaires' disease. We discuss what it is, its history, and what we can do to prevent it proactively.

Cooling towers host all kinds of microorganisms, including harmful bacteria like Legionella. Legionella is a natural bacteria that you can find in bodies of freshwater, including lakes, but it was discovered relatively recently, in the 1970s. We become susceptible to Legionnaires' disease when we inhale droplets that contain Legionella. Legionnaires' disease causes pneumonia-like symptoms and is potentially fatal. Cooling towers, unfortunately, provide perfect conditions for Legionella to survive and...

In this short podcast episode, Bryan covers ductless or mini-split cleaning. He collaborated with SpeedClean to map out this procedure and write a guide, which you can read HERE.

Cleaning is ultimately a maintenance procedure, so one of the main goals is to keep energy efficiency high (watts per BTU). You can test energy efficiency by using two psychrometers: one up top and one going into the vanes. You can check the delta T and fan charts to determine the performance. Overall, you clean ductless units to improve system performance, equipment longevity, and indoor air quality. Be c...

Andrew Greaves comes on the podcast to give us a sneak peek into the life of a tool manufacturer. Andrew has worked in the field for a long time and has recently begun working for NAVAC. He currently works as a regional manager who oversees operations in 24 states; his main task is to establish a nationwide distribution network for NAVAC products.

Andrew recognizes the need for communication between wholesalers/manufacturers and technicians, especially in the areas of education and product demand. To bridge that gap, the sales representatives act as middlemen between manufacturers and consumers. Representatives must...

In this short podcast episode, Bryan covers the bypass factor in airflow and psychrometrics. He also explains why it matters to techs.

The bypass factor is a ratio: you take the difference between the evaporator coil temperature and outlet air temperature as compared to the inlet. In other words, you find the difference between your TD and delta T.

When air moves over the coil, only some of it contacts the coil's surface. Therefore, only some molecules will become the same temperature as the coil. Other air molecules will bypass the coil, which typically happens...

Colleen Keyworth from Women in HVAC/R comes on the podcast to talk about the importance of getting women excited about our trade.

While many women take up administrative roles in HVAC/R companies, very few women work in the field. Schools don't tend to market trade schools to women (or in general), so we can attribute part of the gender gap to how high schools present career options to people. Women in HVAC/R as an organization helps educate young women about career options in the trades. Colleen also has a very positive view of the...

In this short podcast episode, Bryan explains the ins and outs of vacuum pump maintenance, a critical component of evacuation.

The most basic part of vacuum pump maintenance is changing out your vacuum pump oil. This practice should happen very often. At a minimum, you should replace your vacuum pump oil weekly; in very wet or contaminated systems, you may need to replace it multiple times during the same job! When moisture gets into the vacuum pump oil, it can wear out your vacuum pump well before its time should be up. So, most of the maintenance...

David Holt from NCI comes on the podcast to talk about airflow testing and its importance as a customer service tool for the HVAC trade.

Charging and airflow are closely linked. Even though the charge may be correct, the system can't operate correctly if the airflow is off. For example, we can only get the most latent heat removal in humid climates if we run lower fan speeds. To get the right balance, we need contractors and technicians to be educated on airflow so that they can make the correct adjustments. (Remember your ABCs: Airflow Before Charging.)<...

In this short podcast episode, Bryan covers the basics of sunk costs. He explains what they are and what they mean for you and HVAC businesses.

Sunk costs are costs to decisions that have been made in the past. You've "sunken" money, time, or effort into a decision. Let's say you invest in tools; after you make that purchase, the cost of the tools will become a sunk cost. The cost merely occurred in the past.

It is a good idea to reflect on these costs as something that is already over; you can reflect...

Steve Rogers from the Energy Conservatory comes on the podcast to talk about residential air balancing and flow hood accuracy.

Residential air balancing is important because it contributes to comfort in the home. To achieve the most comfort possible, we need to know where the air is going inside the home. For example, some rooms may be more conditioned than others, even if they may need less conditioning than the under-conditioned rooms. A flow hood can give us some data about the airflow in the ductwork; there are cases where dampers may be closed, which blocks airflow...

In this short podcast episode, Bryan covers the unique practices of brazing steel. He also explains how it differs from brazing copper.

Brazing steel appears to be a rather uncommon practice in the HVAC industry. However, we actually do braze steel when we braze in compressors. Many compressors have copper-plated steel stubs; only the outer coating is copper, and if you burn through it, you'll reach the steel. However, steel requires a different fluxing agent than copper-to-copper or copper-to-brass brazing; you can't use a 15% silver-phosphorus rod because phosphorus doesn't react well with steel.

Instead, you...

John Pastorello from Refrigeration Technologies is back on the podcast to talk about leak detection procedures from start to finish.

Big Blu was what started the Refrigeration Technologies empire. John developed Big Blu to create a bubble leak detector with a higher sensitivity to leaks than any other bubble test solution on the market. Big Blu differs from other leak detection solutions because it detects gas leakage down to 0.65 ounces per year, putting it on the same level as some of the best electronic leak detectors.

One of the most common misconceptions in our industry...

In this short podcast, Bryan dives into enthalpy. He explains what it is and how we see it at work in the HVAC/R systems we service daily.

Enthalpy is a fancy word for the total heat energy within a substance. Don't confuse it with entropy, which is the disorganization of energy in a system. We measure enthalpy in energy per mass unit, such as BTUs per pound. Enthalpy combines both the sensible and latent heat capacity; for example, it may represent the energy that it takes to evaporate the water contained in the air. (Water vapor...

Jim Devlin from Weil-McLain joins us to talk about high-efficiency and cast-iron boilers. He also explains how to use them together in a "hybrid" configuration to serve your customers.

Cast-iron boilers are standard-efficiency boilers. These boilers are "standard-efficiency" because they have higher return water temperatures; you typically measure about 330 degrees in the flue. Conversely, high-efficiency boilers have much lower return water temperatures, only around 180-190 degrees in the flue. The goal of a high-efficiency boiler is to get more BTUs out of the fuel, so your flue gases will be cooler. However, the standard boiler can be...

Do you need different gauges for each refrigerant? In today's short podcast, we discuss the answer to this common HVAC question.

When we first started using R-410A, many people warned us that we'd have to use a separate set of gauges when working on R-410A systems. That's because R-410A systems use POE oils, not mineral oil, and they are not compatible. While it is true that R-22 and R-410A systems use different oils, there is no need to worry about using separate gauges for each type of system. Actually, some manufacturers recommend using...

In this two-part interview, Moe Hirsch goes deep and wide on buffer tanks and strategies for "parking" BTUs in hydronic systems.

Systems with a high domestic hot water load can also benefit from a buffer tank. You can pipe the domestic hot water tank as its own zone and step down the rest of the structure. However, there will be some standby losses for a tradeoff greater capacity. You also cannot use the buffer tank as an air eliminator or separator; they work only for BTU parking.

Contrary to popular belief, buffer tanks do NOT...

In this two-part interview, Moe Hirsch goes deep and wide on buffer tanks and strategies for "parking" BTUs in hydronic systems.

When we use boilers, we want to use a heat sink to "park" BTUs in a buffer tank so that we can temporarily store extra heat and avoid short cycling through load matching. However, few boilers have an actual buffer tank; many systems have a means of creating a buffer, though. Buffer tanks are good for parking BTUs in systems with zones and microzones that require varied heating needs. The amount of BTUs you store depends...

In today's short podcast episode, Bryan covers the basics of refrigerant oil in HVAC/R systems. He also discusses what technicians can do to maintain oil systems.

Oil lubricates the moving parts of the compressor. So, oil moves with the refrigerant and lubricates the parts as the refrigerant moves through the compressor. Unfortunately, oil can migrate to other parts of the circuit when it's not supposed to.

Flooding occurs when liquid refrigerant enters the compressor crankcase, and slugging occurs when liquid gets into the compressor head. When either of those happens, they can eject oil...

In today's podcast, Kevan Mayer from NAVAC comes talks about recovery and ways to make it work better and more safely for you.

Recovering refrigerant is better for the environment and safer for us. When designing recovery equipment, NAVAC's goal is to limit the gases we put into the atmosphere and leave the planet in better shape than we gound it. Recovery also ensures that refrigerants for phased-out refrigerants remain available.

Tanks require vacuums of at least 1000 microns, if not deeper. We also need to remember what the previous tank contents were to make sure...

In this short podcast episode, Bryan covers the difference between volt-amps (VA) and watts when we take electrical measurements.

We usually use VA to rate transformers, but we use watts for other electrical ratings. Even though you can multiply volts by amps to get wattage, the difference between VA and watts has to do with the power factor. Power factor is the ratio of apparent to active power. VA is the apparent power, and watts is active power. The difference between volt-amps and watts is called KVAR (kilovolt-amps reactive). The reactive volt-amps are not effective; you can...

In this episode, I talk with tech, contractor, and consultant Genry Garcia. He tells us about his experiences with independent consulting and helping other contractors in South Florida.

A chunk of Genry's work deals with independent consulting, which primarily focuses on helping other HVAC businesses and contractors instead of customers. South Florida has unique climate considerations, and Genry focuses on improving workmanship in a way that works well with the climate. Diagnosis remains important in Genry's work, as he needs to find and solve issues with HVAC companies in his work. Genry and Bryan both believe that...

In this short podcast episode, we talk about condensate drains. We get into the basics of cleaning, pitch, drain pans, and more.

Cleaning drains sounds like an easy task, but it can be a bit time-consuming and difficult to get right. Instead of just "blowing out the drain," you must check the entire drain and be aware of buildup in traps and other hard deposits that form inside the piping. Sometimes, you may need to use cleaners to dissolve the sludge and grime. Cleaning is about understanding the drain anatomy and checking it thoroughly to identify and...

Bert and Bryan discuss the commonly repeated phrase, "refer to manufacturer's specs," in HVAC work. They discuss when referring to the manufacturer's specs works and when it feels like a crutch.

Sometimes, you need to read the manufacturer's specs so that you can use the correct kits and components if specific parts or tools are necessary. Without knowing the specific product numbers given in the specs, you wouldn't be able to do the job properly. The manufacturer's literature can also explain equipment performance under certain conditions. In very specific applications, including VRF/VRV systems, you will want...

By viewer request, Bryan talks about some solar system basics in this short podcast episode.

Solar energy is an up-and-coming power source that will continue to emerge. However, oil is still very inexpensive, so the USA still depends on it quite cheaply. Many consumers also don't like the high up-front costs associated with solar energy. Photovoltaic energy creates a differential that moves electrons.

Many customers also object to the bulkiness and lack of aesthetic appeal of solar panels. However, in places with unstable electrical grids like Haiti, using the sun as an energy source makes...

Bryan and Bert talk through a real-life issue we all face as techs: work-life balance. Bert’s recent video “triggered” Bryan a bit, so they talk through it.

Bryan believes that the work-life balance doesn't necessarily exist; instead of creating balance, he believes in a focus on discipline in work and home life as you're present to each of them. Instead of setting rules for dedicating his time, Bryan focuses on setting goals that can improve multiple parts of his life. That is how he is able to work at a high level in his company, make videos...

Today's short podcast episode is all about surge protection on HVAC/R equipment. Lightning poses a severe threat to equipment, and surge suppression may or may not help.

Unfortunately, surge protection cannot protect HVAC equipment from direct lightning strikes. Surge suppression strategies connect to the high-voltage line and will protect your equipment from surges from the utility. Large, instantaneous spikes in voltage can mess up your equipment quite severely.

In general, we install MOVs (metal oxide varistors) as surge protectors in residential and light commercial equipment. Series mode (SM) acts as a low-pass filter that...

In this episode, we talk with Moe about the world of hydronics. We discuss some fundamentals and talk about various boiler and radiator types.

Hydronic systems use water flow to move heat. We can compare these systems to railroads; the water is like a train carrying BTUs, and the BTUs get off the "train" at radiators. The pump moves water in a circle, though it moves that water pretty far. Boilers generally require a certain flow, and if a single circulator pump can't achieve that flow, we sometimes need to bring on a secondary circulator.

...

In today's short podcast, we answer the following question: Should you ONLY use OEM parts? We also explain why the answer is what it is.

It can be tricky to determine the value of OEM parts in general. For example, many OEM capacitors are very prone to failure. Some non-OEM capacitors have much lower failure rates. Operating conditions may also exceed manufacturer specs, so aftermarket components may be better for equipment in extreme conditions.

When it comes to OEM parts, try to take those and the manufacturer bulletins at face value. However, you also want...

In this rather unorthodox short podcast episode, Andy gives his timeless soft skills tips. We also tell you a bit more about a special training event in Orlando in just a few weeks.

Soft skills and communication are critical parts of the HVAC industry, especially residential HVAC. Customers don't compliment you on your tools; they compliment your service and attitude. We must acknowledge that we are in the people business and just happen to use tools when we work.

Andy recommends being on time for every job; if you think you might be late, call...

In today's podcast, Bryan covers some of the facts about humidity. He also explains how to keep humidity under control in all climates. Humidity refers to water vapor in the air and is a component of the air. Changes in temperature and pressure affect the density of the air. The air density determines how much moisture air can hold.

Relative humidity refers to the ratio of water vapor in the air. An RH value of 100% indicates that the air is saturated with water vapor; it has reached the dew point. At that point, the wet-bulb and dry-bulb...

In this short podcast episode, we talk about the myth that time at a job or in the business equals or deserves pay increases.

Many people believe that showing up for a long time justifies a raise. They aren't necessarily progressing in their field, but they think they've spent enough time to warrant a raise. A business relationship is an agreement that you will perform specific tasks for a specified rate. If you don't go above and beyond or progress, then there's no reason for that pay rate to change.

Soft skills, cleanliness, and overall...

In today's podcast episode, Mark Roth from Goodway talks about chiller and cooling tower cleaning best practices and techniques. Goodway makes industrial maintenance equipment for the HVAC industry, especially tube-cleaning equipment.

A chiller has water running through the tubes, and debris from the cooling tower can build up in the tubes. When scale or debris buildup occurs, heat exchange becomes much less efficient. Water hardness can also interfere with heat transfer; harder water will lead to more mineral deposits. So, tube cleanliness is important, especially in high-traffic areas. In those areas, cleaning should happen at least once...

In this short podcast episode, we address the myth that IAQ is a joke. We also discuss how to think about IAQ correctly in HVAC work.

Indoor air quality is NOT a joke. However, it has a bit of a bad reputation in our field due to the overuse of accessories and bells-and-whistles to solve whole-home air quality issues. (Oxidizers, UV lights, etc. can help IAQ issues, but they are not a fix-all.)

We don't want completely sterile air, just as we like to have a beneficial microbiome inside our own digestive systems. However, there...

Chris Stephens from HVACR Videos joins us to talk about his experiences with and perspective on R290 (propane) refrigerant in restaurant refrigeration.

Chris sees R290 propane on a daily basis, and his perspective as a tech differs from that of an R290 equipment manufacturer. While the temperature sensitivity contributes to flammability, R290 is also under pressure in a system. Therefore, propane refrigerant systems require a lot of caution.

R290 equipment must undergo thorough redesigning to be entirely spark-proof. Hydrocarbon refrigerants also require OEM components; aftermarket components change the design and can cause problems down the...

In this short podcast episode, we discuss the common myth about cleaning flame rods/sensors/rectification devices.

Flame sensors or rectification rods are NOT the same as thermocouples or thermopiles. Thermocouples and thermopiles use two dissimilar metals to create a temperature differential. So, we do not clean thermocouples and thermopiles because the heavy abrasives in cleaners can damage and reduce the effectiveness of those devices. However, you don't have to worry about that sort of damage on a flame sensing rod; we can indeed clean those.

The flame rod sits in the flame (regardless of...

In this podcast episode, Eric and I discuss his new home and his plans for installing central air the Eric-Mele way. Eric's home doesn't have an attic, crawlspace, or basement. So, designing and installing central A/C will be a challenge, especially since Eric doesn't like high-wall ductless systems.

Eric considered using an air handler with exposed ductwork, but he doesn't want the noise issues associated with that design. He also considered using a package system, but it has the same noise concerns as the previous option. In the end, he decided to go with ceiling cassettes...

In today's short live podcast, Bryan discusses the importance of context in education and the challenge presented by information.

When we learn, we do ourselves a disservice by searching for information alone. Just-in-time education allows us to "search instead of research," and it works in a limited and inefficient way. Instead, we'd be much more effective if we knew how to learn efficiently. To learn efficiently, we need to bring context to the learning process.

Instead of focusing on raw facts or abstract information, we need to know about the surrounding information. It's also beneficial...

In this episode, Jordan Cummings comes on the podcast to review application-based system selection considerations for VRF/VRV systems.

A VRF/VRV system works a bit like a hydronics system, but it provides hot or cold air to various zones in a space, not water. The key to having a reliable and long-lasting VRF system is a good installation. Proper maintenance practices, including pulling deep vacuums for dehydration, will also improve the performance and life of a VRF system.

When you choose a system to install, you have to determine if you want a heat...

In today's short podcast episode, we talk about specific gravity, also known as relative density. We explain why it matters to technicians.

When we talk about specific gravity, we're actually talking about density. We're actually using that value to assess how a vapor or liquid's density compares to air or water, respectively. Regardless, we are working with the pressure conditions of 14.7 PSIA, or atmospheric pressure.

In the case of liquids, we're relating them to water is at its densest, which is 39.2 degrees Fahrenheit. You may have noticed that ice cubes float in water. That's because...

In this episode, we speak with Embraco about R290 (Propane) refrigerant, hydrocarbons, and what you need to know about them. Embraco is primarily focused on compressors and is involved in the residential and light commercial market.

The greater demand for natural refrigerants or hydrocarbons has made R290 popular. Hydrocarbons have hydrogen and carbon chains; although these refrigerants are very similar to grill propane, they are much drier and purer. R170 is another hydrocarbon for very low-temperature refrigeration. In some European countries, R290 and CO2 are becoming much more prevalent than synthetic solutions. China has invested a lot in...

We talk about measuring tricky amperage on a blower and condensing fan motor. We also cover why you may be measuring inaccurately, resulting in a misdiagnosis.

When measuring amperage on a PSC blower motor, you may have noticed that amperage on the common is higher when the panel is off. Conversely, on ECM or X13 motors, the amperage is generally lower with the panel off. When measuring amperage, we recommend using a Bluetooth ammeter to take readings without letting the panels interfere with your measurements.

Anytime the amperage is low, the more difficulty the ammeter...

In this service manual talk-through episode, Eric Mele helps us discuss the Heatcraft Beacon 2 refrigeration system. We talk about what it can do and what it entails.

The Heatcraft Beacon 2 is a refrigeration system with more electronic controls than electromechanical. However, it is quite user-friendly, and it allows you to see what the system is doing at almost all times. The monitor doesn't allow you to adjust anything in the system, but it lets you see valve position, superheat, time until defrost, and more as the system is operating.

The Beacon 2 has a suction pressure...

This short podcast episode covers the why and the how of low ambient cooling and refrigeration.

Low ambient cooling refers to operating A/C equipment during low outdoor ambient conditions. Typically, the cap of operation is around 55 or 60 degrees. However, some commercial facilities need cooling when the outdoor temperature is cold. For example, those facilities may have to cool electronics or large volumes of people. In buildings that don't have economizers, running the A/C in cold ambient conditions may be the only option. The same applies to restaurants, which always need to run freezers and coolers.<...

In today's podcast, I talk to John Oaks about his experience as a VRF tech in the field, including branch boxes and two-pipe vs. three-pipe technology. John primarily works on the troubleshooting and service side rather than the installation and programming side of the field.

Variable refrigerant flow (VRF) systems, also called VRV systems when manufactured by Daikin, are commercial HVAC systems. VRF systems work best in commercial buildings with some degree of fragmentation, like offices and medical facilities. These systems are similar to multi-zone ductless systems, but they operate on a much larger scale. VRF systems...

This is a voice-over audio presentation of the article of the same title on the HVACRschool.com website ("The Trade Skills Gap: A Manifesto).

The manifesto discusses the value of technicians and the trades in modern society. It also covers the plague of snobbery that we are all too familiar with in the world.

You can read "The Trade Skills Gap: A Manifesto" HERE.

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Jason Obrzut comes on the podcast and talks us through his furnace sequence of operation training: "Take It Slow, It's Gonna Blow!"

There are 6 main steps in Jason's furnace sequence of operation training. The phrase, "Take It Slow, It's Gonna Blow!" should help you remember the sequence (Thermostat, Inducer motor, Safety switch, Igniter, Gas valve, Blower motor).

The first component in the furnace sequence of operation is the thermostat, which initiates the call for heat. So, the thermostat has to send the signal to the circuit board. After the board receives that signal, it sends 120...

In this short podcast episode, we talk through stack effect. We explain what it is and what sorts of comfort issues it can cause in a home.

Most of us understand that hot air rises even though heat itself doesn't rise. The stack effect is precisely a version of that piece of common knowledge; hotter air is less dense than cooler air, so it floats above the cooler air. In hotter air, the molecules move a lot faster than they do in cooler air, so they can start to separate from each other, which reduces the overall...

Jim Bergmann gives us a year-end review of all that is happening at MeasureQuick and his predictions for the future of app-based diagnosis. He also covers what's been going on with Redfish, BluFlame, BluVac, Supco, Testo, and Fieldpiece.

Diagnostic tools only work if the buyers understand how to use them. When apps can assist the tool buyers and users with diagnosis, the tool manufacturers can focus more on improving the technology; they can leave the software and education to mobile applications. Implementing gas appliance diagnostic education has been a challenge for Jim and other app developers. However...

What is the difference between accuracy, precision, and resolution? In today's short podcast, Jim Bergmann explains the differences and why they matter.

People commonly confuse accuracy and precision. Accuracy refers to how close a measurement is to the correct value, but precision refers to the consistency of values. For example, you can get several infrared thermometers to measure the difference between circuit breakers, and the thermometer readings all come out close to the same value. They aren't necessarily accurate, but they are precise.

In cases where we use a voltmeter to measure for the presence...

John guides us through all aspects of ventilation and system design. He gives us a review of point ventilation, ASHRAE 62.2, whole-home strategies, and much more.

Nowadays, construction protocols instruct builders to make houses tighter than the builders of the past. The goal of building tighter homes is to give us more control over the temperature, quality, and energy impact of the outside air we bring into our homes.

Common sources of ventilation are local exhaust systems, including bath fans and kitchens. However, in tighter constructions, there is a greater need for whole-home strategies to bring...

Bill and Bryan discuss gas and combustion tools. These tools include manometers, combustible gas detectors, personal CO detectors, draft gauges, and combustion analyzers.

Manometers measure gas pressure, and they require calibration but are usually quite accurate. Before using a manometer as a diagnostic tool effectively, you must understand your targets and resolution. Some digital manometers come with BlueTooth technology, so you can log, convert, and store your data on mobile devices.

Gas leak detectors are relatively inexpensive tools. These should NOT be confused with combustion analyzers, which are different tools altogether. You usually cannot calibrate...

In this short podcast episode, Bryan speed-talks through all the basics of heat pumps and how they function.

Heat pumps are not physical pumps or components on an A/C system. A heat pump is an HVAC unit that is also capable of heating a home by reversing the refrigeration cycle. When that reversal happens, the traditional indoor "evaporator" coil acts as a condenser that rejects heat in the home. As such, the traditional outdoor "condenser" acts as an evaporator that absorbs heat from the outdoors so long as the refrigerant is colder than the outside. Due...

Jason from ESCO and Cengage comes on to talk about the varying landscape of EPA 608 regulations with what you need to know for now (circa 2018).

The EPA has proposed to roll back some regulations regarding HFC refrigerants, including leak rate and leak repair mandates. There are also questions about the regulation of refrigerants that do NOT have ozone-depleting substances, not just HFCs. This choice reinterprets language within the guidelines put forth in 2016 and the Clean Air Act. However, this choice completely disregards global warming potential and limits regulations of refrigerants with global warming potential but no ozone-depleting...

In this short podcast episode, Bryan shares his experience as an entrepreneur and his tips for anyone who wants to run and grow a successful business.

When growing a business, the best thing you can do is listen to others who have started a business. It's especially useful to listen to those who have already "made it" in the business world.

Growing a business requires you to stay focused. While you may have to work in your business, you also want to make time to work on the strategic parts of your business. Make goals...

In our first ever ask-me-anything (AMA) podcast, we talk about the trade as a whole and answer random questions about Kalos and myself.

Some people ask me if I'd encourage my children to get into HVAC/R. In my opinion, the trade offers plenty of good opportunities and room for growth. So, I will definitely encourage my children to get into the trades, but I will not pressure them into it. I think more of us should encourage our children to consider a career in the trades and understand the benefits of those careers. I'd even say...

When we replace equipment, we sometimes wonder if the old unit was undersized. Here are some things to consider before replacing that old A/C with a bigger one.

When we do load calculations, we figure out how much heat to remove or add to a home based on the building's design. We need to account for how much heat is entering or leaving a building and heat gains on the inside of a space. Heat gains can come from human body heat or electronics running, and heat losses are quite rare. Those factors are perhaps even...

What is the difference between r-value and u-factor? Why should we care about the differences? In this short podcast, we'll explain what those differences between the two are and why you should care.

R-value and u-factor are actually pretty close to the same thing; they are inverse coefficients of the same phenomenon. R-value is the resistance to heat energy moving through conductance. R-value is not concerned with radiant gains, such as the sun's UV rays passing through a window; the heat gains occur strictly through conduction, molecule-to-molecule, like heat passing from the wall insulation to the actual...

This episode is very exciting to me because we get to have Dr. Allison Bailes on the show. Today, he shares his knowledge about friction rate and duct design. Allison got his start teaching college-level physics before getting into the building design industry.

If you have a forced-air system that blows heated or cooled air through a duct system, that blower creates a pressure difference. Some of the pressure is used up on the filter, registers, and dampers, so you will see pressure drops. Anything left over is the available static pressure, which pushes air through the...

Rusty Walker with Hill-Phoenix comes on and talks about CO2 triple and critical points. He also covers some best practices for refrigeration techs working with CO2.

The triple point is the temperature and pressure at which a substance can exist in all three phases of matter. CO2 has a very high triple point, and CO2 refrigeration equipment can reach its triple point during operation, unlike most other refrigerants. Solid CO2 is dry ice, and it sublimates by becoming a gas and bypassing the liquid CO2 phase under low-pressure conditions. Therefore, the relatively high pressure applied in a...

In this short podcast episode, we cover what you need to consider before you solder or braze any type of joint in HVAC/R work. We want to give special thanks to Solderweld; you can learn more about their products at solderweld.us.

When you braze or solder anything, you need to know your base metal. The base metal's temperature and composition will determine which type of flux you will use. For example, if you are working with steel, you can't use fluxing agents with phosphorus. Instead, you will need to use high silver rods and a...

Eric Mele is back on the podcast. This time, we cover hot gas as a reheat dehumidification strategy with all of the broad strokes you should be aware of.

One common dehumidification strategy is the hot gas bypass; this strategy allows you to operate under low load. Hot gas reheat is when you add discharge heat back to the conditioned space. When you use reheat for dehumidification, you cool for the purpose of dehumidification and then add sensible heat to remove moisture on the coil. So, you don't overcool the space to an uncomfortable level.

...

In this short podcast episode, Bryan covers three things you can do to level up and make you a much better tech tomorrow. Everyone will notice your improvement. Also, no matter what level you're on, you can become even better by remembering the following three tips:

1. Use a full-system diagnostic process. Every application should have a full-system diagnostic process, whether you're working on a residential ductless mini-split, a commercial chiller, or a walk-in refrigerator. Instead of focusing just on the primary problem, you'll be much more effective if you assess the entire system. You can also adopt a...

In this episode, Jim Bergmann does a deep dive into combustion analysis. He covers everything you need to know to keep a furnace running safely and efficiently.

When you go into a home, one of the first things you should do is perform an ambient CO test to check how much carbon monoxide is in the home. Combustion analyzers can typically measure CO, or you could use a dedicated CO meter. When it comes to checking for spillage, you'll want to make sure you check anything that is connected to an atmospheric draft appliance; these appliances, including...

This short podcast episode is about a simplified way to explain the basic refrigerant circuit to new techs. By explaining a component as an absorber, rejector, increaser, or dropper, you may help lock in the basic idea of absorbing and rejecting heat.

The goal of refrigeration is to remove heat from a place. Whether that place is a grocery case or a house, we're moving heat. The overall function is pretty straightforward, but the components can get a little bit complicated. At Kalos, we've found that HVAC/R apprentices tend to grasp the refrigerant circuit better when...

In this first part of the two-part combustion analysis series, Jim Bergmann covers CAZ testing or worst-case draft pressure testing in detail. He also explains why it matters to techs and customers. Once again, MeasureQuick will come in handy if you do CAZ testing in the field; Jim Bergmann is working on automating the testing process in his app.

CAZ (combustion air zone) testing will benefit the customer in both safety and efficiency. A proper CAZ test will also likely increase the furnace system's longevity. This test identifies if there is a high potential for flue gas...

In this short podcast episode, we talk about the commissioning mindset and what it REALLY takes to set up and commission a new system properly. We commonly check airflow and the refrigerant charge during commissioning.

There is a difference between mere startup and commissioning. When you commission a system, you ensure that it is working according to design. Think about how the system lines up with the manufacturer's specs and how appropriately it fits its application. In Florida, our designs typically maximize latent heat removal, so we want our systems to run optimally by those standards. We...

In this podcast episode, Rusty Walker from Hill Phoenix talks us through the three most common types of market CO2 systems and how they work: secondary, cascade, and booster.

Carbon dioxide (CO2) is one of the oldest refrigerants; it is a natural refrigerant that came about when toxic refrigerants like ammonia were common. In the 1980s, we began to rediscover the benefits of CO2 in market refrigeration, including its high latent heat capacity, low costs, and low global warming potential.

Secondary systems use an HFO or HFC on top, which acts as the primary system...

Can you really trust that temperature reading? In this short podcast episode, we talk about some common mistakes techs make when making temperature measurements and what to do about it.

Many heat pumps use heat strips as a source of auxiliary heat. However, it takes some time for the heat strips to integrate with the air. So, your superheat, subcooling, and pressures will look fine on a system that isn't cooling well enough. When you take air temperature measurements in the ductwork, try to get as close to the center of the duct as possible or take...

James Bowman returns to the podcast to talk about analog vs. digital manifolds. He also explains why both of them may still have a place in the industry.

Pricing is a key difference between analog and digital manifolds. Analog manifolds tend to be less expensive and will suffice just fine for techs who don't require readings with a lot of detail. While digital manifolds will be more expensive, they can also give you more precise, detailed readings. So, digital manifolds have a slight leg-up in terms of resolution as well; these manifolds are generally better for critical-charge...

In this short podcast episode, we share some quick tips about keeping panels and insulation in place to avoid a costly screwup.

Often, technicians will use an impact driver too aggressively. If you feel it begin to clutch, that means that the driver is actually impacting, and that means you're going too far. When that happens, you can strip out the screws, which can be a serious problem on larger equipment. On RTUs and other large commercial equipment, panels can fall off if you strip out those screws, which can be a costly screwup.

So...

John Pastorello, the HVAC chemist, comes on the podcast and discusses refrigerant additives such as acid inhibitors, oil enhancers, dyes, and leak sealants with his knowledge and some things to consider.

Acid neutralizers are refrigerant additives. Oil works best in a slightly acidic environment, and these additives can change the pH of the system. If the pH becomes neutral or alkaline (basic), then the system will not operate as it should. Acid scavengers won't change your pH, but they are usually alcohol-based, which may attack aluminum in your system and make your windings brittle. Instead of relying...

Many technicians use hard or soft copper without thinking about which application is best for which. In this short podcast, Bryan talks about where to use each. He also covers some hanging and strapping strategies.

Residential service technicians typically work with soft copper. Conversely, commercial techs are probably much familiar with the hard variety. Both hard and soft types are good for specific applications.

If you need to work the copper, then the soft type is best for that. You can bend it by hand or with a bender without too much trouble, and it...

Kevan Mayer with NAVAC comes on and talks all about flaring best practices step by step. From cutting to reaming to torque wrenches, we cover how to make a flare from start to finish. The goal of making a good flare is to reduce leaks as much as possible, especially on ductless units and in commercial HVAC/R.

When you make a flare, you have to make sure the depth is correct and consistent, especially on R-410a systems. NAVAC makes various flaring tools, including fast battery-powered ones, that can help you get a consistent depth on...

In today's podcast, Eric Mele and Bryan talk about chilled water air handlers, their valve configurations, and some key things to look out for.

In a chilled water system, we don't have the traditional evaporator and condenser in our HVAC system. Instead, we merely have a hot coil and a cold coil. We don't work with a direct-expansion refrigerant that changes state. We merely move water. These chilled water systems can be used in residential and commercial applications.

With almost all applications, both pipes will be insulated in the same size. You may also see...

In this short podcast episode, Bryan gets feedback on a podcast topic from Andy Holt. Per Andy's request, we discuss some intangible soft skills required to be a top-level technician in the HVAC trade.

Overall, a technician needs to be aware of the people and things in their surroundings. These techs are in tune with their customer's emotions, the pets, and the space where they work. A good technician is thoughtful but has the ability to let things go and not let their bad experiences overwhelm them. Many technicians that fit both of those descriptors are calm...

Chris Stevens from HVACR Videos on YouTube comes onto the podcast and talks about some refrigeration temperature controls basics. You can check out his YouTube channel HERE.

Although we have temperature controls in HVAC work, we will see slightly different ones in refrigeration work. The biggest difference is really the temperature itself; we're attempting to bring the box temperature down, so we will be dealing with much lower temperatures in refrigeration. The box and evaporator coil temperatures are the most important temperatures to be aware of in reach-in refrigeration, as they directly relate to pressures.

...

Bryan talks about the differences between mineral oil (MO) and POE oil, the advantages and disadvantages of using them, and when to use them.

Mineral oil (MO) is what we've used for a long time. We like using it because it's very stable; it may have an affinity for moisture, but it is not nearly as hygroscopic as POE oil. Vacuum pump oil is a highly refined mineral oil, and it works so well because it's able to lock in moisture as those non-condensables get sucked out of the system. It is still not much of a...

Eric Mele returns to the podcast to discuss quality cleaning and maintenance procedures for small refrigeration systems. These small refrigeration systems include reach-in refrigerators and open-air cases on grocery sales floors.

Filthy condenser coils are problems in many HVAC applications, but they're exceptionally nasty in some small refrigeration applications; proximity to food residue (grease, sugar, etc.) makes condensers get dirty quickly. Use plastic-bristle brushes to clean the bulk of the soil on the coil; you may also use shop vac extensions or even pull out coil cleaner in some cases. If you use coil cleaner, be sure...

Bryan talks about the top refrigerant leak detectors, the best refrigerant leak detection practices, and some good leak detection tips.

Leak detectors require some flow through them. Otherwise, they won't detect leaks. So, these tools have small pumps inside of them to move air through them for sampling. Leak detectors also require some time to warm up, so keep that in mind when you approach a job.

One type of leak detector is a heated diode (sometimes called a heated pentode). It is a heated electronic leak detector that takes a sample and analyzes it...

How does a vacuum pump work? When should you change the oil? What does that oil do anyway? Kevan Mayer of NAVAC comes on the podcast to answer these questions and more in this episode.

Vacuum pumps help remove moisture and non-condensables from the system. Moisture can freeze at temperature drops in the system, and it can block refrigerant flow to the system. Moisture can also combine with POE oil to become acidic, which causes burnouts. A vacuum pump uses an impeller to bring a system under negative pressure. Many of these pumps are two-stage pumps, meaning...

In today's short podcast episode, Bryan covers some tips about HVAC/R service valves and caps for new technicians. While service valves may seem simple, there are some things you should know about them before you handle them in the field.

Before you connect your gauges, ask yourself if you even need to connect gauges. If you've already benchmarked the system and know what to expect, then you may be able to suffice with line temperatures. If you have a system with caps or Schrader cores and need to hook up your gauges, be careful not to...

Jamie Kitchen returns to the podcast and talks all about hard shut off TXVs/TEVs. He discusses bleed and non-bleed valves and why the TXV type matters to your compressor.

When it comes to TXVs, there are two main types: bleed and non-bleed. The former may be referred to as a bleed TXV, and the latter may simply be called a TXV. However, OEMs may refer to TXVs as a "hard shut off TXV" (HSO), which is a non-bleed TXV.

The core difference between bleed and non-bleed TXVs is the equalization speed. That equalization speed...

In today's podcast, we cover why both compressor and evaporator superheat matter. We also address some common confusion related to each.

Evaporator and compressor superheat are two different readings that give you different indicators about the system's health. When you look at evaporator superheat, you see how far you feed boiling refrigerant into the evaporator coil. You don't want to overfeed your evaporator coil and risk flooding your compressor. However, you also don't want to starve your unit and reduce suction pressure. You'll want to stay between 5 and 14 degrees (F) of superheat at the evaporator outlet on...

In today's podcast, Jim Bergmann joins us to talk about evacuation. He discusses pulling a vacuum, conductance speed, microns, core removal, decay rate, and all that other nerdy vacuum stuff. Jim has helped develop some new BluVac hoses with AccuTools, and he's here to explain why we need those. He also explains why we need to be more educated on evacuation.

While we have many good hoses today, we still have a way to go when it comes to moisture removal. Jim Bergmann has seen the need for more durable hoses that perform better when there's moisture...

In today's short podcast episode, Jim Bergmann and Bryan answer the age-old question: Can you really freeze water in a vacuum by pulling down too fast? Is that a problem? What should you do about it?

Here is the short answer: NO. You CAN'T freeze water in a vacuum in a typical residential A/C system.

First of all, you would need to have water in the system to freeze water in the system. We typically don't see large amounts of water in JVAC systems, but there could be moisture in the evaporator coil in...

In this episode, we talk with two techs recently out of trade school. We get their perspective on their trade education and how it compares to the field. Jeremy and Blake have been kind enough to share their experiences with us and give some advice.

Schooling undoubtedly gives technicians a leg-up once they got into the field. However, the knowledge you gain isn't all practical. Bookwork is still important for a solid foundation in theory, and it would likely benefit a lot of training programs. Bookwork, like trade school itself, is a good precursor to the hands-on...

Bryan talks about MicroChannel coils, what issues could happen with them, and what the best practice is to clean them.

MicroChannel coils are kind of like car radiators; they have a small, honeycomb-like channel, and the sections that go between the crisscross fins carry refrigerant from the front surface to the back surface. These coils have a bit of a bad reputation. The refrigerant flows close to the surface of the coil. When the MicroChannel suffers damage, these coils can leak much more easily than other tube-and-fin coils. The channel is also more likely to be exposed...

In this episode, Eric Mele dives into the world of pumps, controls, cooling towers, and everything else related to the water side of a water source heating and cooling system. Many of these systems are water-to-water setups that use heat exchanges for heat transfer. You can listen to an introduction to water source heat pumps HERE.

A cooling tower is where we reject the heat that we put into water loops. Most of these towers are of the induced-draft variety, meaning that they have fans drawing/blowing air through them. Some cooling towers are "wet" towers, where...

In this short podcast episode, Bryan covers how to measure air velocity directly at a return or supply and what those readings tell you.

Since many techs like to focus on CFM and static pressure readings, they can neglect air velocity in their measurements. Air velocity is the speed at which the air is moving. Conversely, static pressure is the force of the air against the sides of the ducts, and CFM is the air volume. We measure air mass in pounds (in the USA); when air is denser, you will have more pounds, but the volume...

In today's podcast episode, Eric Mele walks us through the components of water source heat pumps, how they work, and what to look for. Water source heat pumps use water to transfer heat to and from the outdoor unit; the water takes the place of outdoor air in an air source heat pump.

These units have heat exchangers and water lines, but they otherwise operate exactly the same as any other heat pump. These units have reversing valves, which are commonplace on heat pumps, and they are energized by a typical O call. Water source heat pumps...

In this short podcast episode, Bryan Orr discusses the best practice methods for testing run capacitors in the field.

We understand the capacitor to be a voltage storage device. We can benefit from comparing the capacitor to a balloon that inflates and deflates with electrons as the alternating current changes (60 times per second). A capacitor causes a phase shift and allows there to be current on the start winding. So, when a run capacitor fails, you won't have current on the start winding.

The old-fashioned way of testing a run capacitor was to take an...

In this episode, Bryan Orr talks about how the seasons affect our HVAC work and how to manage stress during the busy season.

If you work in the trade, you will notice that we have busy and slow seasons. If you own a business, you understand the pressure that you're under to serve the community during those times. Hiring and training people for the busy seasons is difficult and may not be feasible for many companies. Fortunately, the busy season can bring out the good in other people who want to support their coworkers and community.

In today's short podcast episode, Bryan discusses the voltage drop measurement tool, also commonly known as the voltmeter. You can also find this voltage drop tool on multimeters. You use them to check voltage drops, NOT the actual voltage.

We get voltage values from a potential difference. So, we check for these differences via voltage drops. For example, you can determine if contactor pitting or carbon buildup is problematic by measuring the voltage across contact points. Your meter will read the voltage drop.

We don't often deal with intentional series circuits. However, we can see...

In today's podcast episode, we have a conversation about the pros and cons of commercial vs. residential HVAC with Andrew Greaves. (You may know him as AK HVAC on Youtube. Check out his channel HERE and his comedy channel, HVAComedy, HERE.)

In many cases, young people don't know if they want to go into commercial or residential HVAC, or residential techs may think about getting into commercial HVAC. Commercial HVAC may include RTUs, chillers, market refrigeration, or industrial refrigeration. Commercial HVAC/R also includes a lot of control systems. By comparison, residential HVAC almost exclusively deals with...

In this short podcast, Bryan covers three things that the condenser does. He also explains where those things happen and what those they mean in terms of system operation.

The evaporator coil does two things: boiling and superheating. However, a condenser does three things: desuperheating, condensing (changing state), and subcooling.

Desuperheating occurs early on in the condenser, at the top. Refrigerant enters the condenser as a highly superheated vapor. Even though we have a few degrees of superheat in the suction line, the discharge line's superheat is a lot greater. (For context, the suction line...

Many techs have said, "That's the first thing you should have learned in school." In today's short podcast, Bryan talks about the four rules that have his vote for the first things to learn in school.

These four rules don't just apply to HVAC work; they apply to science and the world as a whole. They describe how the forces in our world work in our HVAC careers and our everyday lives.

The overarching theme of these rules is that high goes to low. Gravity is the prime example of this rule; if you drop...

In this episode, we speak with the founder of Refrigeration Technologies, John Pastorello. He also tells us all about chemicals, cleaners, and HVAC coil cleaning.

John Pastorello started out working as a chemist before becoming an A/C installer. He initially planned to return to a lab job, but he found his niche in HVAC work. He took his chemistry experience to his HVAC work to develop better chemical products. It all started with his decision to make a better leak detector fluid (Big Blu). However, John knew that you can't build a company around one product...

In today's podcast episode, Jonathan Romberg comes on to discuss how the Danfoss ERC 213 works and reviews its parameters with us.

10:41 – Voltage Protection

10:56 – Compressor Protection

15:15 – App 0 No predefined application

15:28 – App 1 Medium temperature ventilated refrigeration units with timed natural defrost

15:52 – App 2 Medium temperature ventilated refrigeration units with timed electrical defrost

16:03 – App 3 Low temperature ventilated refrigeration units with timed electrical defrost

16:13 – App 4 Medium temperature ventilated refrigeration units with electrical defrost (by temperature)

16:26 – App 5 Low temperature ventilated refrigeration units with electrical defrost (by temperature)

In this podcast, we discuss the real significance of superheat and why it is much more than "a way to set the refrigerant charge on a fixed metering device."

Superheat is the temperature of a vapor above saturation. Many people use it to set the charge on a piston or fixed orifice, but that's not its only purpose. Superheat is a much more important reading than that, and you can take that measurement at a few different places. For example, most of us measure it outside. However, to determine how the system is feeding the evaporator coil...

This is the story of WITH JOSHUA NICHOLLS FROM PLATINUM ELECTRICIANS and how he went from pulling wire, to creating a franchise empire to giving back. 

In today's podcast, Jon Bennert with Air Oasis talks about photo-catalytic oxidation (PCO) air purification. He explains how it works and what it does.

The NANO products are PCO-type technologies. These technologies were initially developed for NASA storage systems on the International Space Station. Photo-catalytic oxidation (PCO) products work to reduce or sterilize pollutants or organisms in the air by using light. Sunlight produces UV rays that can kill nasty germs in the air; PCO products work similarly and may have UV lamps or not. (NANO units use UV lighting.)

The UV isn't all that...

In this episode, we talk about air as a form of matter. We cover air volume, density, weight, and mass and why it matters to you.

So, air has weight and takes up space. When we measure air, we typically measure it by volume (CFM or cubic feet per minute). When we say that air takes up space, we are referring to air volume. A cubic foot of air is equivalent to a 1'x1'x1' box of air. When we measure CFM, we measure how many boxes of air we move per minute. We usually want a...

In today's podcast episode, Ralph Wolf comes on and discusses inverter equipment. He also talks about Mitsubishi, Bosch, and what he’s been up to nowadays.

An inverter system can vary its output of rated capacity. Inverter equipment makes load matching much easier and is generally comfortable. These systems maintain temperatures in tighter ranges and remove more moisture with longer runtimes.

Mitsubishi is one of our top ductless systems at Kalos. Due to building codes, they are one of the only systems we can use in sunrooms and lanais. However, the building codes technically allow tho...

Part 2 - Bert (Kalos Tech) and Keiran (Kalos Apprentice) join Bryan in the studio to talk through the basic refrigerant circuit and how it functions. They talk compressor, condenser, metering device, and evaporator as well as the four lines and the states of the refrigerant as it travels.

The four lines that move refrigerant are the suction line, discharge line, liquid line, and expansion line. The suction line moves cool superheated vapor from the evaporator to the compressor. Then, the discharge line moves very hot superheated vapor from the compressor to the condenser. The liquid line runs...

Part 1 -Bert (Kalos tech) and Keiran (Kalos apprentice) join Bryan in the studio to talk through the basic refrigerant circuit and how it functions. They talk compressor, condenser, metering device, and evaporator as well as the four lines and the states of the refrigerant as it travels

They talk about the compressor, condenser, metering device, and evaporator as well as the four lines and the states of the refrigerant as it travels. We have already covered all of the basic components in earlier podcasts, which you can check out HERE; we focus more on accessories, refrigerant movement...

In today's podcast, I talk with Corbett Lunsford about his new show about home performance and diagnosis. Home Diagnosis airs on PBS in winter 2018. Even though Home Diagnosis mostly deals with building performance, HVAC work is a large component of overall home performance.

Corbett Lunsford used to be a pianist before becoming a building performance expert. He was already familiar with media and decided to launch a YouTube channel. The goal of the YouTube channel was to bring visual information and practices to the masses. Since then, he has been working to create a much larger mass med...

Sean Harris with Positive Energy and Aeroseal Austin sat down with me at the humid climate conference and talked about how to seal ducts from the inside with Aeroseal. We regularly see air leakage by poor connections, especially when we deal with flex ducts.

When a house comes under negative pressure, it draws a bunch of air in from the outdoors or unconditioned spaces. Unfortunately, that air can be very low-quality in humid climates. The humid air can be even worse if it comes from an unconditioned space where you have leaky supply ducts. So, we can...

Today's short episode covers five things residential techs need to consider when tasked with doing maintenance on a commercial system. We mostly talk about light commercial package unit maintenance in this episode.

If you come across fresh air filters, be sure to wash those. Some commercial units have economizers that bring in fresh air, but not all fresh air is high-quality. Wash those filters to avoid pollen and other types of outdoor gunk buildup.

Then, you'll want to check and adjust belt tension. Make sure you adjust the belt in each direction correctly; don't get...

In today's podcast episode, Lee Andrews with Andrews Filters talks about the complicated and important topic of air filters and filtration. He also explains why they should matter to you and your customers. As indoor air quality (IAQ) becomes more important in HVAC work, air filters will become even more important than they already are.

We classify air filters by MERV ratings. MERV ratings describe the ability of filters to capture finer particles; a MERV 11 filter will catch a lot more particles than a MERV 6 filter. Most air particulates are an average of 0.4 microns large, but most...

Have you ever struggled to repair a leak in an all-aluminum coil? Lance Robinson with SolderWeld talks about his product to do just that and makes a convincing case for aluminum repair.

We've been using aluminum for several decades before the shift to copper; unlike copper, aluminum is corrosion-resistant. However, copper is typically better for brazing due to its heat transfer properties and ductility. If we can get to a point where we can use aluminum for the same uses as copper, we will probably see a shift to aluminum due to its durability.

SolderWeld...

This short podcast episode covers the most misunderstood portion of Ohm's law explained masterfully from 1921: when resistance goes up, amps go down.

The American Electrician's Handbook (1921) contains a lot of electrical knowledge that holds up in the present day. (The electrical testing methods don't hold up quite as well, though...) One of those principles that hold up is the idea that amps go down as resistance goes up. Amps refer to current (electrons). The ohm is the unit of electrical resistance, and it is NOT the same as mechanical resistance, such as in a compressor with locked-up...

In today's podcast episode, Jamie Kitchen talks about refrigeration controls and applications. He also tells us about the Danfoss ERC 213 universal digital controller.

Electronic refrigeration controls tend to have greater accuracy and flexibility than traditional electromechanical controls. These electronic controls also allow you to perform many more tasks than traditional ones. Electromechanical controls also wear out and lose their accuracy over time.

When you deal with applications that require various temperature, humidity, and defrost requirements, you can use electronic controls to choose between several options for the defrost method, defrost stop temperature, fan delay after...

In this episode, Adolfo Wurts from Arbiter comes on and debates why a tech would want to use a manifold over wireless probes and vice versa.

In our industry, we are likely to see a trend of moving towards wireless equipment that connects to a single device. Wireless connections and digital displays may save us money on tools and allow us to store and interpret data more efficiently. However, a manifold can help you recover refrigerant, whereas probes cannot. Manifolds also have sight glasses, which help you check for overfeeding; probes do not offer you much help...

In this podcast episode, Phil Barr joins Bryan to explain sizing for wires and breakers in HVAC/R work. You will be able to select breakers, conductors, and fuses properly and without confusion. Phil Barr is the leader of the electrical division at our business.

HVAC/R equipment may have hermetically sealed motors. Unlike squirrel-cage motors, hermetically sealed motors have an outer shell that makes it impossible to access the inner components. Semi-hermetic equipment, such as some compressors, look like hermetic equipment but can open up. Wire sizing varies between hermetically and non-hermetically sealed motors, and the...

In today's podcast episode, Johnathan Jones from Clean Comfort, Ultra-Aire, and Therma-Stor talks to us about humidity, dehumidification, and ventilation.

Relative humidity (RH) is a moisture content ratio that depends on temperature. Hotter air can hold more moisture, and colder air can contain less moisture. You can increase or decrease the temperature to change the relative humidity, but the dew point stays the same. The safest humidity range is between 40-60%. It is typically harder to add humidity to an arid place than to remove humidity from a tropical place.

We work to control the...

In this short episode, we replace a dirty "M" word (mold) with another "M" word (moisture) that gets to the root of the problem.

"Mold" and "mildew" can freak out your customers. For years, I've refrained from saying "mold" at my own company and trained my techs to avoid it AND "mildew." Instead, we have called it "biological growth" or "organic growth." Those still aren't great. Just recently, my friend Joe Medosh suggested referring to fungal growth as a "moisture problem" instead.

"Moisture problem" is a fact-based and less disgusting term. We can focus on...

Here is part 2 of the discussion with Trevor Matthews about the causes and prevention of air conditioning and refrigeration compressor failure.

Slugging occurs when the compressor attempts to compress oil or liquid refrigerant. A telltale sign of slugging is valve plate damage. On a semi-hermetic compressor, you can remove the screws on the head to access the valve plate. Wrist pin wear occurs during slugging the wrist pin is between the rod and the piston; you should test the wrist pin to see if it makes a knocking sound before you dismiss all other possibilities and replace...

In this short podcast, we start the conversation about "Energy? Compared to What?" and explore several energy comparison examples.

When we think about energy, we can confuse some terms. For example, temperature and heat are related but NOT synonymous. Temperature is an average measurement of heat energy; when many molecules move at a bunch of different speeds, the temperature represents the average speed of those molecules. Temperature does NOT measure total heat content. Voltage and amperage are two more confusing terms, and they get even harder to understand and differentiate when you throw "power" around.

...

In today's podcast, we talk with Trevor Matthews with Emerson. He tells us about the causes and prevention of air conditioning and refrigeration compressor failure.

Most compressors don't die a natural death... they're murdered. Of course, that's to say that installation and maintenance play a major role in the compressor's operation and lifespan. Electrical and mechanical failures are the two broad causes of compressor failure.

When it comes to electrical failures, Trevor often sees single-phase compressors fail early when their electrical components don't receive proper inspections and care. For example, contactors may go too long w...

In today's podcast episode, we talk with system and duct design educator Jack Rise about ACCA Manual J load calculation and Manual S system selection.

Many people know about Manual J, but relatively few techs follow it properly. When people attempt to do Manual J calculations, many of them go wrong when they overestimate the difficulty of the equations in Manual J. However, many of these techs do better when they can use software like Wrightsoft to help with their load calculations. The best way to approach load calculations is to develop confidence in software programs and...

In this podcast, Bill Johnson shares his practical tips to make low-voltage electrical diagnosis easier in HVAC work. Bill is one of the original authors of the Refrigeration and Air Conditioning Technology manual.

A common issue that techs have in low-voltage diagnosis is that they overcomplicate the issue. Techs should take the time to trace out the system and see where all the wires lead. The techs can be more effective if they know a system's components and those parts' relationships. During diagnosis, some techs also don't allow themselves to use their hands. Bill recommends using an...

In this podcast episode, refrigeration tech Eric Mele talks us through some common characteristics of walk-in freezers and refrigerators. Eric recently discussed reach-in refrigerators on the podcast, and you can listen to him talk about those HERE.

Common walk-in applications include coolers, freezers, and wine rooms. You may even see some package units. Condensers typically go on top of the box or the roof, and evaporators are inside the refrigerators. Many of these refrigerators also have pump down solenoids on their equipment. Thermostats mostly control the opening or closing of the solenoid valve. To cycle the unit, yo...

In this short podcast episode, Bryan covers some basic best practices for wire routing and wire connections in HVAC work.

When it comes to electrical work of any kind, the wires must have proper protection. For example, the wires must be in the proper conduits. They must also work on appliances that they are rated for. HVAC technicians must also understand their qualifications against local codes to ensure they have been authorized for electrical work.

You also NEVER want to route the wire through an opening you can't shove your finger through. If you can...

In the second part of this podcast series, Jim covers the basics of furnace commissioning in more detail with some common-sense practices. (Listen to Part 1 HERE.) Even though installers set up a furnace system, the technicians help with the equipment startup and commissioning. That way, two parties can ensure that the installation is proper.

The technician is perhaps better equipped to check the electrical connections. As technicians, we can also check the polarity of the power supplies (ensuring that the sine waves are in sync). If the polarity is backward, sometimes the hot wire has been switched...

In this short podcast episode, Bryan talks about blower taps in furnace systems. He explains how to set up their fan speeds and repair them.

Before you even look at the blower taps in a system, you must know a bit about the system design. Is the system supposed to remove high amounts of sensible heat? What is the capacity? How quickly should the thermostat drop? When a system is supposed to move lots of heat and has a high capacity, it needs high airflow; to run optimally, the system needs higher fan speeds to move more...

In today's podcast episode, Jim Bergmann covers furnace commissioning, including setting up furnace input, clocking the meter, setting temperature rise, and much more. The goal of commissioning is to optimize a furnace's efficiency; we want to make sure we correctly engineer the intake/exhaust system to extract as much heat from the flue gas as possible.

The commissioning process for an 80% furnace is pretty similar to that of a high-efficiency furnace. Checking gas pressure, setting temperature rise, and combustion analysis are critical procedures when commissioning both furnace types. Moreover, you must know the heat content of the...

This short podcast episode is about saturation and what it means. Bryan covers related topics, including boiling, evaporation, and condensing.

Saturation refers to something that is "full" of something else. In science, "saturation" refers to a substance being in the middle of a phase change. (For example, boiling water stays at 212 degrees until it all boils off and becomes water vapor.) In HVAC, we often use the term to refer to refrigerant with liquid and vapor are present at the same time. The refrigerant is typically both liquid and vapor in the evaporator and condenser; phase changes...

In this discussion with Bill Spohn from TruTechtools.com, we cover the practical steps and tools for YOU to start measuring airflow today, if not sooner.

There are several ways to measure airflow; when measuring airflow, start with the "why" rather than the "how." Understand what the goal of the airflow is before you begin taking measurements in random places.

You can take a bulk measurement at a return, but you have to be prudent to avoid human error. The best way to avoid error is to use a TrueFlow grid, which replaces the filter...

Today, Bryan discusses delta T (evaporator air temperature split) what it is, what it means, and how to avoid some common pitfalls.

Delta T is NOT the air temperature rise on a furnace, and it is NOT the design temperature difference (DTD). Instead, delta T refers to the temperature split between return air entering the evaporator coil and the supply air leaving the unit. Typically, 20 degrees (Fahrenheit) is a desirable split, but there is still a range based on relative humidity, enthalpy, and airflow. The range can be as high as 24 degrees.

To measure delta...

In this simultaneously heavy and lighthearted discussion, Bryan Orr and Andrew Greaves discuss ego, Dunning-Kruger, insecurity, and apprenticeship in the trades.

In the early days, apprenticeships were quite different from the way they are today. One-on-one mentorship used to be a much more significant component of early apprenticeships, but that style of training is uncommon for today's apprentices in all sorts of trades. As a result, many young technicians enter the field too quickly and don't have the training to perform a job skillfully.

As such, many inexperienced techs become confident with bare-minimum work because...

In this short episode, we review the basics of the refrigerant circuit. The standard HVAC refrigeration circuit has four main components: compressor, condenser, metering device, and evaporator.

The compressor squeezes refrigerant vapor into a smaller volume by applying lots of pressure. It simultaneously moves and compresses gaseous refrigerant. The more a compressor has to compress a gas, the less gas it moves. The more gas a compressor moves, the less gas it compresses. Then, the refrigerant leaves the compressor via the discharge line. The discharge line is very hot because the temperature increases with pressure.

...

Jon Bennert from Air Oasis teaches us about PCO and Bi-Polar air purification and how it improves indoor air quality through ionization.

Photocatalytic oxidation (PCO) is a technology field that uses catalyst metals, hydration agents, and lights to help remove pollutants from the air. These technologies shine a light source on a photocatalyst metal that reacts with pollutants in the air. These pollutants include volatile organic compounds (VOCs), viruses, mold, and other unwanted particles in the home. Some bacteria that are good for you in your gut are NOT good in your respiratory system.

Bi-polar...

In today's podcast episode, Eric Mele comes on to talk about reach-in coolers (refrigerators), freezers, and wine coolers with some mindset and technical tips. We mostly discuss self-contained equipment.

Coolers are medium-temperature applications, while freezers are low-temperature applications. Wine coolers vary from normal coolers because they have slightly higher temperatures and controlled humidity. The cooler must control humidity to preserve the wine quality and prevent the cork from swelling.

Metering devices vary with the size and type of equipment. We typically see capillary tubes in smaller reach-in coolers and TXV in larger ones and blast...

Stephen Rardon and Neil Comparetto join the podcast to talk about their headfirst dive into building performance as HVAC techs. They discuss jobs they do, how the transition has been, and important HVAC principles in building performance.

Addressing duct leakage can help with indoor air quality and home performance overall, but it can also even help reduce noise. Building performance and HVAC both require the serviceperson to give the customer options and inform them of their specific situation. In both cases, you would give the customer a chance to improve their living situation by offering a personalized...

Dick Wirz, author of Commercial Refrigeration for Air Conditioning Technicians, talks to us about refrigerator and freezer defrost strategies. Check out Dick's book HERE.

In commercial refrigeration, we deal with much lower evaporator temperatures than residential HVAC. Although an evaporator temperature of 40°F may be commonplace in residential HVAC, you can expect evaporator temperatures from 25-30°F in refrigeration. Even though having ice on the coil is a negative thing in residential HVAC, it is perfectly normal in refrigeration.

The purpose of defrosting is to bring the evaporator temperature above freezing to melt off the fr...

In this episode, Bill and Bryan recap the 2018 AHR conference with what they learned and what you can expect to see in the HVAC/R trade in the next year. There were 2100 exhibitors who gave demonstrations and discussed products. AHR shows the real scope of the HVAC/R industry, and it is an excellent opportunity to learn more about the trade and do some networking.

At the AHR conference, there were some demonstrations that may indicate a paradigm shift in the industry's best practices. For example, the AccuTools booth projected the rate of evacuation through three hoses...

In today's podcast episode, Bryan talks to west-coast commercial tech Jim Loring about pneumatic controls and variable air volume (VAV) systems.

People sometimes confuse pneumatics and hydraulics. Hydraulics use liquid to provide pressure; conversely, pneumatics use air to provide pressure. Pneumatic controls use a bit more energy than other controls, but they are less costly all around. Nowadays, direct digital controls (DDCs) provide greater energy savings than pneumatics. However, pneumatic controls were a precursor to the DDC technologies we use on actuators today, and they are still a prevalent technology.

The air compressor is a...

Jeremy Smith goes over floating suction and floating head refrigeration strategies. He also talks a bit more about low-ambient equipment operation.

Floating suction controls developed when we started using low-pressure controls on rack refrigeration. As the electronics advanced, we developed controls that could control temperature, which impacts pressure as well. Nowadays, controls can cross data and be much more effective at controlling pressure and temperature.

Suction pressure is the greatest contributor to a system's compression ratio. The higher the compression ratio, the less efficient a system is; a high compression ratio can be costly for...

Bryan talks with Jesse and Nathan about setting up dehumidification for residential equipment in general. They also discuss some of the required and recommended settings on an Ecobee thermostat.

On typical single-stage residential equipment, dehumidification works based on CFM per ton. We control humidity by dropping the CFM across the indoor coil and extending runtime. However, as you cool the air, you reduce its ability to hold moisture. So, you increase relative humidity through cooling.

When we have achieved the desired humidity but not the desired temperature, the thermostat reduces the fan speed. Thermostats should...

In this episode, we cover the skills and traits needed to be the best residential service techs you can be. We follow up on the last episode's tips for getting a raise and discuss how to become more valuable as an employee.

All good service techs clearly have to be able to repair and maintain systems well. Commercial and residential techs need to demonstrate mechanical aptitude. However, soft skills are what separate the good residential service techs from the excellent techs.

Observational skills are imperative. Residential techs need to take a wide-narrow-wide approach to diagnosis...

As we ring in the new year, this episode focuses on how people in the HVAC/R trade can get a raise, promotion, or bonus without facing rejection or sounding selfish.

Before you think about asking for a raise or promotion, evaluate your company. Is your company pragmatic? Does the company refuse to address conflict or let tempers run high? Do your leaders care about making decisions logically and promote people who will truly help the business? A pragmatic company makes logical decisions and respects the employees who keep the business alive.

Many people want...

In this podcast episode, we discuss power distribution and some practical tips about three-phase, single-phase, and split-phase power.

The power company generates three-phase power; a power pole transformer typically has three current-carrying conductors. Each phase of power runs at 60 Hz and generates a sine wave. That sine wave peaks and valleys in a wavy formation. Power is generated in a rotating magnetic field, so it is helpful to think of a sine wave as a variation of a circle.

Transformers take high voltage and bring it down to 120V split-phase via a winding on the...

Learn about large-scale desiccant dehumidification from the expert, Tom Peterson. Tom works with CDI (Climate By Design International).

Dehumidification has several different methods and applications. Cooling is the most basic of those methods, but it has its limitations. For example, dehumidification by cooling may leave moisture on the coil and lead to freezing. Desiccant dehumidification can remove water from the air without the possibility of freezing the unit.

Desiccants are crystalline structures with pores, and they remove moisture via adsorption. Water has a pressure that pushes other water molecules into those pores. Partial pressures also...

Carter tells us why compression ratio is important, what it means, why it changes so much on heat pump systems, and the effect it has on system operation. We also talk a bit more about heat pumps and their unique challenges beyond compression ratio.

Compression ratio is a comparison of discharge pressure to suction pressure. A ratio of 3:1 indicates that the discharge pressure is three times higher than the suction pressure. The higher the pressure difference, the less gas you move and the less efficient your system is. The compressor has a fixed volume, but the gas's...

In today's podcast, Bryan talks about voltage (volts) and resistance (ohms), specifically using a voltmeter and an ohmmeter for diagnosis. We also discuss voltage drop.

In many cases, Ohm's law is impractical for field usage because of the additional resistance from inductive reactance. We also don't typically measure impedance and only care about resistance on the windings. However, Ohm's law is still a valuable concept because it teaches technicians the relationship between voltage, amperage, and resistance (ohms).

Ohm's law states that volts equal amps multiplied by ohms (E = I x R). Therefore, if the volts...

Jamie Kitchen from Danfoss talks all about variable-speed motor technology. He discusses why those motors exist, what they do, and how to think differently about the future of HVAC/R.

Most techs think about variable-speed motors as the X13 and ECM blowers in residential applications. Those motors can adjust their performance based on ambient temperatures and moisture levels. So, variable performance may result in better comfort and efficiency.

ECM motors adjust airflow based on sensor inputs, especially dehumidification calls. The sensors may pick up both sensible and latent heat content. Sensible heat is what we...

Jack Rise returns to the podcast to share some duct design facts with us and talk about his Manual D book on the ACCA website.

Before we can even start thinking about duct design, we need to think about the total effective length; even before that, we also need to think about finding the critical path. The critical path is the path with the greatest resistance to airflow (from the return to supply); the fittings in the critical path contribute to the duct's total effective length.

Flex duct is a controversial and somewhat complicated building...

Nate Adams joins the podcast to describe the method behind his madness of removing gas meters and installing heat pumps in Ohio. Nate is in the home performance business, and he focuses on its intersection with the HVAC industry

We typically find heat pumps in milder climates, so removing gas meters and replacing them with heat pumps is a bold move in cold climates. However, high-performance heat pumps have inverter technology, which allows them to run in colder climates without freezing over in the snow.

Nate predicts an eventual switch to heat pumps from fossil...

Bill Johnson is one of the great educators and writers of our time in HVAC/R. In this podcast episode, he shares some information about his career and some of his top tips on keeping systems leak-free.

Bill began his work on leak-free solutions by using Glyptal on centrifugal compressors. The Glyptal would harden around leaks and seal them up. Nowadays, this is an ineffective approach to sealing leaks in higher-pressure systems.

Bill got the idea to start manipulating pressures to minimize leaks with a standing pressure test for 24 hours at the highest test pressure...

Jim takes us all the way through the history of furnaces, from the Stone Age when he was a child to modern modulating condensing types.

The goal of a furnace is to move heat, so a furnace uses heat exchangers to facilitate heat transfer. Furnaces have primary and secondary air. The primary air goes through the burner, and the secondary air goes around the flame and is pulled in around the heat exchanger inlet. So, the flame's heat creates a draft that pulls air in.

Natural gas and oil (LP/propane) furnaces are common nowadays...

This podcast episode on electrical circuits is a class recording. In it, Bryan discusses transformers, ground, common, and line vs. load sides of a circuit.

Transformers use induction to pass alternating current signals to electrical appliances. Alternating currents (AC circuits) are tricky because the current switches direction each time. Therefore, the current flow is difficult to visualize because the direction keeps changing. Electrons naturally want to go to the other side of the transformer, not to ground. So, we have to connect both sides of the transformer to ground to send electrons to ground. (In this case...

In HVAC work, we deal with quite a few electrical components. But where does electricity come from? Why do electrons move? In this podcast episode, we talk about differential charges, sine waves, and some voltage measurement basics.

A large chunk of electrical theory is centered on electron movement. We get electrons to move with differentials in charges or energy states. Nature tends towards equilibrium, so electrons will move to restore a state of balance. A battery or transformer does not create energy; they create energy imbalances that cause electron motion to occur. Alternating current (AC) creates a...

Do you think of the building envelope as a duct? Do you test it? In this podcast episode, Joe Medosh talks to us about envelope testing and why it’s the future of building health and comfort.

The building envelope is the largest duct in the entire home. However, so many HVAC techs forget about it; they attempt to optimize comfort in the HVAC system and ducts, not the home itself. Techs use Manual J and S, but they don't use the infiltration rate in their calculations. Infiltration in the envelope is a major culprit of discomfort in...

Ductless expert Jesse Claerbout talks about his best maintenance practices for ductless air conditioners and heat pumps. This episode is part 2 of the two-part series. 

Ductless outdoor units tend to have clean condensing coils. The only real issues are grass clippings (and cottonwood, in some locations). which typically don't affect performance too sharply. Jesse likes to clean outdoor units with plain water; he does not use cleaners.

Drain cleaning is a little more involved than condenser cleaning. When cleaning a gravity drain, Jesse uses a shop vac to get rid of standing water. He does n...

Ductless expert Jesse Claerbout talks about his best practices for maintaining ductless air conditioners and heat pumps. This episode is part 1 out of 2. Ductless maintenance can be a bit more extensive than regular split system maintenance.

Ductless filters are plastic; they are not high-MERV and can simply be washed off with water. Customers can clean their own filters with nothing but water from a hose or sink.

Blower wheels are a bit more challenging than filters; the blower wheels are long, have small cups that are prone to buildup, and carry an electrostatic charge. Due...

In this episode, we cover some common misconceptions about run capacitors, some easy ways to test them, and some tips on working with them.

A run capacitor is a power storage device; it contains oil to dissipate heat and some thin metal plates wrapped in a spiral. Capacitors also contain plastic insulation between the metal plates to keep the power separate; electrons should NOT cross the insulation, and there should be a charge difference between the plates. Current also does NOT flow through the capacitor; capacitors merely store and discharge power.

Capacitors also do NOT...

James from Rectorseal talks about the IMC codes relating to tamper-resistant caps and why you may consider installing them now.

Tamper-resistant caps, also known as locking refrigerant caps, fit on refrigerant ports to prevent unauthorized access. Even though these caps can RESIST attempts to tamper with the equipment, they are not (and cannot be) fully tamper-proof.

Many new construction companies used to put the caps on ONLY to pass inspection; they then take the caps off to reuse them several times. That's an inhalant abuse risk, and it's also a liability issue for other contractors...

Many techs know just enough about economizers to bypass them. In this podcast episode, Jerry Eavenson and Bryan talk about the basics of what an HVAC economizer is and how it functions.

Economizers typically work on the air side of package units and help pull fresh air into a structure. Economizers are almost exclusive to commercial HVAC. Climate also plays a role in their usage; you will not find many economizers in hot and humid places like Florida.

An economizer is generally an energy-saving device that brings fresh air into a building if it is...

Dan Holohan is the father of modern steam heat training. This episode is a narration of his in-depth steam article "A Steam Heating Primer" from HeatingHelp.com.

Read that article HERE.

Check out more about Dan's work at heatinghelp.com.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

In today's podcast, Bryan talks with legendary Hydronics author and trainer Dan Holohan about the history of steam heating and some practical applications of old ideas. Recently, Dan has been working on more novels, having published two of them over the past few months.

Steam heating is a "lost art" nowadays; it has become increasingly uncommon and has been disappearing since the Vietnam War. Many people who understood steam heating either retired or died after the Vietnam War. Many elements of steam heating are difficult to understand or surprising. (For example, steam pressure has a surprising relationship...

This special podcast episode focuses on the tragic life and times of Spark Ranger Roy Sullivan.

Roy Sullivan was a park ranger who was born in Virginia in 1912. He grew up in the 1920s when the mining industry was in full swing and had scrapped up the beautiful mountain landscape. In 1935, Shenandoah National Park was founded, and Roy decided to become a park ranger. He wanted to help restore the land and protect it from human destruction, such as the mining industry.

One of Roy's duties was to scope out the forest on the new...

In today's podcast, Bryan and Jamie talk about the electronic expansion valve (EEV). Bryan and Jamie describe how EEVs work and the reason they exist. In the process, the hosts also review a wide range of metering devices. We made this podcast to address the rising demand for EEVs in the aftermarket element of the HVAC business.

Like the TXV, the EEV is a metering device. Metering devices create a pressure drop as refrigerant moves from the liquid line to the evaporator. Traditional refrigerators typically use capillary tube metering devices because they require a constant temperature and...

In today's podcast episode, trade school student Chris Caldwell interviews Bryan about trends in the HVAC industry, his business, and the future. Chris works in the HVAC business as a service tech and attends trade school in Alabama.

New trends include spending more money on testing instrumentation. Nowadays, there is a greater reliance on test instrumentation to produce accurate measurements. Diagnostics have certainly improved over time. On top of that, Bryan sees the industry's potential to improve other practices like evacuations.

Customers have paid more attention to indoor air quality recently, and that trend is...

In today's podcast, Chris Reeves joins Bryan to discuss filter driers, including suction driers, liquid driers, core driers, different media, and basic applications. Filter driers are simple components, but they have plenty of room for misunderstanding within our trade. We refer to Parker-Sporlan Bulletin 40-10 throughout the podcast, and you can read that bulletin HERE.

Above all, filter driers act as filters that prevent debris from reaching the expansion valves and destroying them. As such, the best place to install a liquid filter line drier is as close to the expansion valve as possible. These filter driers...

In today's podcast, Bryan covers the four basic gas laws and how they apply to you as an HVAC technician in the field, not just in theory. Remember, when dealing with pressure, you must convert the units to PSIA, not just PSIG. To do that, you merely add 14.7 to your gauge pressure.

In every equation, the "1" indicates an original value, and the "2" indicates a new value.

The simplest of the gas laws was discovered first, Boyle's law. The law states that there is an inverse relationship between absolute pressure and volume. When a gas's pressure...

Alex Figueroa is a VRF and refrigeration tech in Puerto Rico, and he talks to Bryan about his work and specialized experiences. Since Mitsubishi is a forerunner in the ductless industry, many of the units that Alex has worked on are Mitsubishi units.

Alex works on lots of ductless mini-splits and VRFs in central air in commercial buildings. He typically works on VRF units that have ceiling cassettes or fan coils. Some VRF units also have branch boxes with electronic expansion valves (EEVs), and those components help distribute refrigerant flow. These systems have expansion lines, which some...

What do you need to know to walk up and fix a VRF or ductless system? John Chavez, longtime VRF/ductless pro, covers his approach to ductless and VRF diagnosis in Part 2 of this podcast. (Listen to Part 1 HERE.)

If you believe that there is a component failure, you'll want to check the voltage going into the unit. You'll want to pay special attention to the board and see where power is going in and out. In other words, pay attention to your inputs and outputs on the board and pay attention to the documentation in the...

This episode covers some basics of matter that relate to HVAC/R. These basics include mass, weight, and volume. There will also be some talk of specific gravity and specific volume.

Matter and energy are the building blocks of the HVAC industry; we move matter around and transfer energy. Matter refers to anything that exists and takes up space, including all solids, liquids, and gases. We use three means of measuring matter: volume, mass, and weight. Volume refers to how much space an object occupies. Even though we use mass and weight interchangeably, they mean two different...

What do you need to know to walk up and fix a VRF or ductless system? John Chavez, a longtime VRF/ductless pro, explains his approach in Part 1 of this podcast.

You CANNOT have a haphazard approach to installation or service. The best thing you can do is respect VRF and ductless technology for what they are. When you take the time to understand the equipment and the processes at work, you will be successful. The best thing you can bring to a job is patience.

Unlike on typical split systems, gauges should NOT be...

Frank Besednjak talks about proper communication in conflicts between techs and managers. He also covers the potential problem with inexpensive air conditioning maintenance specials.

When it comes to communication, Frank is a proponent of honesty and straightforwardness. However, he understands and appreciates the fact that people have different communication styles. He encourages people to write down their ideas, whether those ideas benefit the company, themselves, customers, etc. Frank encourages managers to set up an email or text line for people to input their ideas via written media; the leaders should make employees feel empowered to become part...

Carter Stanfield, a co-author of Fundamentals of HVACR, talks about the entire refrigeration circuit. He also explains how to read and plot a pressure-enthalpy diagram.

The refrigeration circuit has four main components: evaporator, compressor, condenser, and metering device. When teaching, Carter likes to explain that boiling is a cooling process and condensation is a heating process. He describes saturation as the breaking point at which liquid refrigerant can no longer hold more heat (in the evaporator). The superheated vapor from the suction line then enters the compressor; the compressor adds even more superheat. So, the discharge line...

James Bowman talks to Bryan about leak sealant products, including RectorSeal's Leak Freeze product. James talks about how sealants work, what happens when they don't work, and how to be open-minded without being gullible.

Leak sealants must not react adversely with the components inside a system (oil and refrigerant). Just as mineral oil caused some issues with O-rings, POE oil has additives that cause acid to form on the system. RectorSeal's Leak Freeze is technically an oil that can work with the oil and refrigerant that already exists in an HVAC system. Leak Freeze is a high-performance...

Dick Wirz, author of Commercial Refrigeration for Air Conditioning Technicians, talks about making the switch from A/C to refrigeration.

Dick Wirz is an advocate for using rules of thumb, which is a controversial position. However, rules of thumb are an excellent way for A/C techs to dip their toes into the refrigeration world. Rules of thumb are less likely to overwhelm technicians than the exact technicalities of certain readings and measurements.

Some prime examples of using rules of thumb in air conditioning are condenser split, evaporator split/TD, subcooling, and superheat. Those all...

Camron Conlee joins the podcast to give us an introduction to ammonia chillers. He also explains what it's like to work with a poisonous refrigerant. The California division of TDI Refrigeration, where Camron works, primarily works on ammonia systems. We often see ammonia refrigeration in cold storage and food processing; ammonia refrigeration is usually in industrial applications away from the public.

Ammonia is more hazardous than CO2 and other refrigerants because it is toxic. When working on ammonia chillers, the most important thing is to keep the ammonia inside the pipes. You may even need to wear...

Adolfo Wurts from Arbiter Incorporated, designer of the UEI WRS line of Bluetooth scales, comes on the podcast. We talk all about scales and how to use them.

You'll want to pull a scale off your truck every time you add refrigerant to a system. Many technicians choose to estimate how much refrigerant they have to put in, and they sometimes put in more refrigerant than they estimated in their quote. Consequently, the business loses money. You'll also want to weigh your tanks during EVERY recovery to ensure that you do not overfill your recovery tanks and...

In this quick announcement I talk about the launch of the revolutionary diagnostic and data management tool MeasureQuick

Todd Liles of Service Excellence Training joins the podcast. He talks about techs who shouldn't be on commission, how to make the most of your career, and facial hair profiling.

Todd's skillset was mixed; he had some technical knowledge, sales experience, and communication skills. He took those skills into training, and he started his own business based on his skills; his first business didn't pan out, but he founded Service Excellence Training and has grown quite a bit. Todd develops technicians by teaching them best practices, which also boosts sales.

In the past, some technicians...

Jim Bergmann returns to the HVAC School podcast to cover some advanced topics in evacuation, including rig setups and triple evacuation.

To increase the speed of evacuation, you need two large-diameter vacuum hoses to overcome the limitations of pressure. Core removal is also critical, as Schrader cores are a significant restriction. It's also unwise to use a manifold for evacuation; a manifold will double your hose length, provide a restriction, and serve as a leak point.

The vacuum pump is full of opportunities to expand your advanced evacuation knowledge. The pump oil needs to stay...

In this episode, Brent Ridley talks about the flame-free ZoomLock fittings and why he is using them for almost everything to replace brazing. These are tools from Parker, and they can give you leak-free fittings within seconds.

ZoomLock works in residential and commercial applications. The fittings come in a wide range of sizes for the large piping of VRF systems and the smaller copper tubing of residential A/C suction lines. Brent measures the tubing to make sure there's enough room. Then, he cuts the bell end off, deburrs the copper, sands the copper down, and applies...

Jeff Neiman returns to the HVAC School podcast to explain how we can perform leak detection on a low-pressure chiller. Jeff works on systems with glycol loops or other forms of secondary fluids, which may have leaks from time to time. When the chilled water pump on the suction side runs into a vacuum, air can get into the system via the shaft seal. Then, more leaks can occur in the glycol loop as more air goes into the system.

High-pressure chiller leak detection is pretty much the same as on a package unit. However, your typical...

In this episode of the podcast, Jim Bergmann talks about the launch date of the measureQuick (MQ) app, what it will do, why he made it, who it is for, and why it's different than anything else that came before.

MeasureQuick is a universal measurement platform that incorporates Bluetooth to display, store, and interpret measurements. The initial release focuses heavily on air conditioning, but its goal is to assist with combustion analysis and refrigeration readings. It is a troubleshooting assistant that saves time and helps technicians make sense of their readings. It combines the air side, refrigerant...

James Bowman of Rectorseal returns to the podcast to discuss condensate switch codes and some best practices to comply with the codes.

The humble condensate switch actually has installation standards; although there isn't a "law" about the codes, many areas follow and enforce the contents of the International Mechanical Code (IMC). Some states, including Florida, also adopt elements of the IMC and amend it to create a set of guidelines for the state.

The IMC has widely-enforced code 307.2.3.1, which states that water-level monitoring devices must be installed in the primary drain pan; the device shall...

Les Fork returns to the podcast to discuss on-call rotations. He explains why being on call is necessary and how you can make the most of it.

We are supposed to be on call for the sake of customer service; when a customer has an emergency, it's best for the customer (and the business) when someone is available to respond to the emergency. Of course, many of us dread being on call (although the paycheck might be quite nice).

You may only have one or a few techs on call, so it can be difficult...

In this podcast episode, Jim Bergmann continues talking about standard air, air density, and mass vs. volume as well as some other methods of "directly" measuring airflow. It gets pretty deep.

Airflow hoods and vane anemometers can give you direct airflow measurements.

You use static pressure probes, not pitot tubes, to measure TESP. When measuring static pressure, you put the negative probe in the return and the positive probe in the supply. Then, you measure the TESP (away from wiring and airflow). However, air pressure fluctuates as that air moves in the duct. Velocity pressure...

Bill Spohn Jr. is a college intern working towards his business degree, but he took a week to see what it is like to work as an HVAC tech. He shares his impressions on this podcast. Bill is the son of Bill Spohn and has been a college intern working with TruTech Tools. However, he has just gotten his first real dose of the HVAC contractor experience in the full swing of summer.

Bill started off by riding with a Kalos residential tech, Tyler, who had seven calls that day, mostly for PMs; they worked from 8:15 to 9:00...

In this two-part podcast series, Jim Bergmann talks about measuring airflow in HVAC systems. He covers a wide range of airflow measurement instrumentation and readings.

In this first episode, Jim covers ECM motor considerations, delivered capacity, laminar flow, and more.

In the HVAC industry, many techs confuse static pressure for airflow. Although you need static pressure to have airflow, it is NOT airflow and can fluctuate rather wildly depending on the duct conditions.

Static pressure is an indirect airflow measurement. Airflow is actually a measurement of velocity (such as with pitot tubes) that yo...

In this podcast episode, Bryan talks about brazing basics and tips. He goes over safety, regulator settings, torch positioning, flowing nitrogen, heat control, and more.

Whenever you're going to be working with equipment that creates fire, you will want to make sure you know all of the safety procedures and have appropriate PPE. Make sure your gear is in really good condition; make sure your hoses and regulator have not been damaged. Be sure to have a fire extinguisher handy as well. When preparing copper lines, you'll want to keep things out of them. Make sure oxygen...

Bryan talks to Ralph Wolf from T&N Services on YouTube and the Working Joe's podcast. We talk about blue-collar life, how the trade has changed for us, and what experience gives a tech that can't be read in a book. Ralph started off doing sheet metal work in the Navy before going into HVAC. He started as a sheet metal installer and learned most of what he knows about HVAC on the job.

Taking accurate superheat and subcooling readings have become much more important over the years. We can't get away with "beer-can cold" rules of...

This episode is a rebroadcast of a very useful episode from the Corbett Lunsford's Building Performance Podcast at https://buildingperformancepodcast.com/. Corbett talks to building moisture control expert Lew Herriman about moisture, ventilation, and what happens when you're drying "stuff."

When we think about humidity control, we have to ask if we're drying air or drying "stuff." Dehumidification is about drying the air, but many people think about it when they actually want to dry "stuff" like fabrics and other absorptive surfaces often found in residential applications. However, drying out "stuff" does affect how we would dry...

Restaurant HVAC and refrigeration tech Nick Messick comes on the podcast to talk about restaurant equipment, especially the "hot side." The "hot side" refers to equipment that heats the food; it includes often deep fryers but has a lot of variation. The "hot side" also includes specialty equipment for frying noodles and performing other unique functions.

In Nick's opinion, the worst service call has to do with fryer pumps due to all of the grease. The grease gets all over tools and your hands, and it can be quite difficult to work on equipment with fryer grease...

Phil Zito of Building Automation Monthly comes on the podcast to discuss building automation and what HVAC techs should know about it.

Automation essentially refers to control systems; we started off with pneumatic control systems, and then we went to analog and electromechanical control systems over time. Building automation refers to the process of automating controls on a larger scale, such as for an entire building. As long as you can read electrical and mechanical diagrams, you can work on automation systems; you don't need to know about IT or robotics. 

Large buildings like malls m...

In this podcast episode, Bryan and Mike Layton of Shore Distributors explain how HVAC contractors and distributors can build a great partnership. Shore Distributors is a wholesaler in Maryland that carries Carrier, Bryant, and Payne.

The job of a territory manager is to help HVAC contractors, so they're there to help contractors. The territory manager's job is to help set contractors and dealers up for success, so they don't feel burdened by questions because it's their job to answer them. Territory managers know that the goal of business is to make money, so they understand the importance...

In this episode, Bryan talks with Jamie Kitchen from Danfoss about why and how thermostatic expansion valves (TXVs) fail and how they function in the first place.

As fixed orifices become a dying breed with the development of higher-efficiency systems, TXVs take over the mantle as the primary method of expansion. Expansion valves meter the flow of refrigerant by aiming for a certain suction line superheat value. Unlike a fixed orifice, which has an opening of a constant diameter, an expansion valve adjusts the opening size to the evaporator based on suction superheat readings.

TXVs...

In this second part of the podcast, Jim Bergmann wraps up the steps to check a system charge without connecting a gauge manifold.

You can check the charge without gauges if you use the following process (and know your DTD, CTOA, etc.):

In this episode of the podcast, we talk about gauges. Jim Bergmann from Redfish Instruments and the MeasureQuick app explains why you may want to check a charge without using a gauge manifold. (That's not clickbait; if you've already connected gauges to a unit once, you can probably check the charge of that unit WITHOUT gauges moving forward.)

HVAC units manipulate temperature and pressure in the refrigerant charge. Heat transfer occurs between the refrigerant and the environment, and various readings indicate the charge level WITHOUT necessarily connecting the gauges. So, you can check the charge if you kn...

In this episode, Jack Rise talks about duct design regarding ACCA manual D, friction rate, face velocity, duct velocity, and what is ACTUALLY wrong with flex duct.

Manual D causes a lot of confusion for technicians, and most techs have a limited understanding of it anyway. When determining a blower wheel for commercial ductwork, Jack Rise calculates pressure drops for all of his elbows in the ductwork and makes his decision based on those calculations. Residential HVAC is a bit trickier, and that's where Manual D calculations come in. Luckily, many software nowadays, including Wrightsoft, can calculate...

In this episode, Bryan speaks with Eric Shidell about some of the basics of system freezing, what causes it, and what to do about it.

Freezing is a normal part of some equipment, such as low-temperature freezers and outdoor units on heat pumps. On straight-cooling systems, freezing is NOT normal and indicates poor operation. Ice formation starts on the evaporator coil and may spread to the compressor via the suction line. The best way to remove ice and defrost the system is to pull the disconnect on the outdoor unit but let the indoor fan keep running...

Corbett Lunsford from the Building Performance Workshop and the Proof is Possible tour talks to us about the moral superiority of building performance testing, blower door testing, and much more.

Building performance and HVAC have been becoming much more closely linked lately. So, it's a good idea for HVAC techs to learn a bit about building performance.

In the HVAC world, we often see homes with extremely hot upstairs portions and cool downstairs questions. That is a complex building performance issue. A good contractor can troubleshoot the issue with the building and find cost-effective ways...

In this episode of the podcast, Bryan talks with Andre Patenaude from Emerson about CO2 refrigeration, and transcritical booster systems. Modern CO2 systems are efficient and effective due to their electrical controls and components, including case and high-pressure controls.

Carbon dioxide (CO2) is a good refrigerant to address global climate change. From a sustainability standpoint, carbon dioxide is a superior refrigerant to HCFCs and HFCs. Carbon dioxide is also an A1 refrigerant, meaning that it is non-toxic and non-flammable. It is also inexpensive and compares to HFCs in cost. Unfortunately, it can rapidly change pressures and is...

In this just-for-fun episode, we celebrate 10 years of great tools and excellent customer service with TruTech CEO Bill Spohn. We hope you enjoy this lighthearted episode with some discussions about company culture, superior service, and a commitment to quality.

TruTech's approach to service goes more beyond selling the tool. The engineers at TruTech aim to learn how technicians plan on using tools. Those engineers want to use their technological expertise to create products that make technicians' lives easier in the realm of diagnosis and measurement. TruTech Tools also works to honor its relationship with the HVAC community...

In this episode, Bryan talks with HVAC products designer Adolfo Wurts about technology, automation, and the coming robot apocalypse. Automation is a fear in many industries, and the HVAC industry isn't alone. Today, we talk about how instrumentation and AI technology may develop and what that will mean for the future of the industry.

Some recent practices that have severely impacted the job market lately have been globalization (where work moves overseas) and automation (where machines replace human labor). Globalization is not a major threat to our industry due to the local nature of our jobs. However...

In this episode of the podcast, Jeremy Arling from the EPA comes on and answers some common questions about the new rule changes that affect recovery, leak repair, recordkeeping, and evacuation on HVAC and refrigeration systems.

EPA 608 rules regulate the actions that technicians must take when it comes to refrigerants and the atmosphere, such as venting, recovery, and evacuation. It has always been illegal to vent HFCs, including R-410A. The changes to EPA 608 attempt to treat all refrigerants equally; R-410A would be on equal footing with HCFC R-22, for example. EPA 608 also clarifies the actions...

In this episode of the podcast, Jim reviews the basics of evacuation and dehydration. He also covers hoses and vacuum gauge placement.

Evacuation may just seem like a method to suck air and water out of a system. However, it is an intricate science that lacks a lot of detail in most trades education programs. The deepest vacuum we can possibly pull merely offsets the atmospheric pressure and is actually not that deep; the deepest possible vacuum is -14.7 PSI (-29.92" Hg).

The evacuation rig is the most important element of evacuation. If you want...

In this episode of the podcast, Jamie Kitchen from Danfoss talks about wet-bulb, dry-bulb, relative humidity, dew point, enthalpy, and latent heat. These are the building blocks of psychrometrics, which deals with human comfort as it relates to temperature, humidity, and heat loads.

Humidity is water vapor in the air. As the air's dry-bulb temperature increases, the more water vapor the air can hold. That is partially why dew is more common on cold mornings instead of hot ones. However, the air's weight does NOT increase with more water vapor; moist air is less dense than dry...

In this episode, Bryan and Jim discuss measuring voltage drop and what it means. They also cover some other pointers to keep from using parts to bandage a deeper issue.

A common mistake that technicians make is not understanding what an ideal measurement is before making a measurement. For example, they may not know what the refrigerant pressures should be before they attach the gauges. Electrical measurements are the same, and voltage drop falls under that umbrella.

Voltage refers to electrical pressure, and current refers to electrical flow; they are two different values. The voltage...

In this podcast, Jeff Neiman shares an overview of his chiller startup procedure and some things he looks out for when starting a chiller after the initial chiller installation.

The actual chiller startup is typically the factory's responsibility (per the manufacturer); however, the "startup" that we're talking about refers to the installation and early maintenance.

The first step is preparation. Neiman recommends having a copy of the installation manual and reading it beforehand. You should also have a "request for startup" or pre-commission checklist. You also want to make sure there is water in the...

In this episode, Bryan speaks with James Bowman from Rectorseal about hard start kits, PTCR devices, run capacitors, compressor overheating, and the Kick Start product. We also go pretty in-depth on potential relays and how they operate.

Hard start kits are mechanical potential relays connected to a capacitor, and they aid in starting the compressor. They come in two-wire and three-wire types. However, they have some pitfalls. For example, they are easy to abuse. You may also come across a "hard start kit" that does not have a mechanical potential relay (such as a PTCR), which is...

In part 2 of this conversation, we go through the condensing unit and wrap up the call with our no-fluff customer service best practices. 

A thorough inspection is critical on any residential service call. A service call is an opportunity to check the integrity of the unit and the cleanliness of the blower wheel, drain, and other components. Check the charge, safeties, and five pillars. List the problems and present the solutions as suggestions. Provide appropriate timetables and provide all necessary information. If possible, you can let the customer watch you work on their system to...

This is part 1 of 2 on the soft skills practices of approaching and completing a residential service call in the best manner possible.

Before a technician even leaves to go to work, they need to get their head in the game. Be ready to face the day by showering, shaving, and brushing your teeth. Having self-respect is also a sign of respect for the customer. The drive to work is a good place to clear your mind; you can listen to podcasts or do other things to get yourself in a g...

In this podcast episode, Bryan talks about grounding and some common misunderstandings related to ground, neutral, ground rods, and lightning.

The common phrase that "current goes to ground" is a myth. The transformer (or the power source) that feeds a building creates a potential difference in charges (voltage); current is the motion of electrons between a difference in charges.

A transformer has three terminals: two legs and the XO terminal (neutral). You have 240 volts between legs and 120 between each leg and the XO terminal. The leg of power going into the transformer is split into...

Bryan talks with Nick Messick about some ice machine basics. They also discuss how to determine when to pick up the phone and call tech support.

Ice machines have the same basic refrigeration circuit as HVAC systems. However, ice machines require a much different cleaning regimen. Many maintenance people neglect ice machines by using incorrect cleaners. You need more of a sanitizer than a cleaner; sanitizers kill germs and fungi, but cleaners work better on corrosion. When cleaning an ice machine, watch out for mold and scale buildup. Scale buildup is especially problematic because it hardens the...

In this episode of the podcast, we talk about condenser wire sizing considerations, ampacity, temperature, conductor sizing, voltage drop, and why a #10 wire doesn't always require a 30-amp breaker.

There's usually nothing wrong with OVERSIZING a wire or conductor. However, you still need to know which wires are safe for operation and comply with the National Electrical Code (NEC) protocols.

Relatively small conductors can carry relatively high voltages. Instead, amperage dictates the size of the wire. Therefore, we use ampacity (amp capacity) to determine the size of a wire. Transformers are a perfect example; wires...

In this episode of the podcast, we talk to Bill Spohn from TruTech Tools about how TruTech Tools got its start and some of the ways that techs and engineers approach problems differently.

Bill Spohn is a majority owner of TruTech Tools who became invested in the HVAC field in the 1990s. The beginning of TruTech Tools was a milestone in Bill's professional journey. After working at Superior Valve for a few years, Bill moved to Testo. While Americanizing many of Testo's products, Bill Spohn met Jim Bergmann. A German Testo employee advised Jim Bergmann's father to...

In This episode Justin talks about the trials and benefits of working out of town, long drives and this weeks boiler service calls in detail. 

Jesse and I talk about MORE best practices for installing ductless systems.

Both lines should be insulated on a ductless system because they have electric expansion valves in the outdoor unit. Insulating flares is also a critical task. When it comes to flare fittings, overconfidence is a tech's biggest enemy. Techs often undervalue the process of reaming copper or overdo it. Bubble-testing the flare joints is always a best practice to evaluate the integrity of your flares and check for leaks. Do not braze copper on ductless systems!

Ductless evacuations require deep vacuums. Removing cores...

Bryan and Jesse talk in detail about ductless applications we commonly see, best system placement, drains, and much more.

Ductless systems are unique, and their compact nature makes them a good choice for several small, controlled applications. These applications are in climate-controlled garages, lanais (sunrooms), and master bedrooms. In Florida, lanais are the primary application for ductless units, especially due to codes that regulate HVAC systems in lanais.

When installing a ductless unit, Jesse looks for aesthetics and reliability. Since ductless units are visible, making them look good inside the home is a concern that...

In this episode with BENOÎT MONGEAU, we talk about the components of combustion and what to consider when testing it on a fuel-burning appliance.

Combustion requires fuel, oxygen, and a heat source in a correct balance. We call that series of requirements the "combustion triangle." Once combustion occurs, it is self-sustaining. However, removing one element of the triangle will end combustion. (For example, you could suffocate a flame by removing the oxygen content.) Undesirable consequences of incomplete combustion include the production of carbon monoxide, a potentially fatal gas. Flash point is the temperature at which vapors c...

In this episode Justin talks about his first A/C repair of the season, his old combustion analyser and why he is enjoying the Testo Smart Probes his just got

Dan Holohan speaks to Bryan about his background and journey as a writer. He also dives into his book, Pumping Away, and describes classic hydronics as he does in his book. Bryan and Dan also briefly discuss the difference between search and research.

Dan is a prolific writer, and one of his most famous works is The Lost Art of Steam Heating. However, this episode primarily focuses on Pumping Away: And Other Really Cool Piping Options for Hydronic Systems. Although Dan has retired, his daughter has ensured that his books will continue to remain in publishing for yea...

In this episode, Ruth King shares some of her top insights on how to create a maintenance program if you don't have one. She teaches us to recognize a broken program and fix it.

The maintenance component of your company will be the part of your business that allows you to grow your business profitably. If you don't believe in maintenance agreements, your customers won't believe in those maintenance agreements either. Without maintenance agreements, your company will have sharply different slower times and busier times. You'll likely have to pay employees to stay in slow times, and...

In this episode, Ruth breaks down some of the main things an A/C contractor needs to consider when looking at their numbers and some of the major leaks that can lead to unprofitability.

Profit and loss (P&L) statements are critical for determining the profitability of your business. You can use it to find money "leaks" in your business model. When making P&L statements, ensure that the revenue AND costs for a given product are in the same month for best accuracy.

Most small businesses don't look at their profit and loss statements...

Tersh and Bryan were both techs working for other companies when they started their own businesses. This episode is a look back at what they got right, what they got wrong, and the top things that have worked over the years.

In general, there are two types of HVAC business owners: the sales/business type and the technical type. Bryan and Tersh are both of the technical variety. These types of owners may be less familiar with the ownership and business organization side. Many current technicians will find themselves in a similar position if they decide to...

In this episode, Bryan speaks with Jim Bergmann of Redfish Instruments about his path to being a test instruments business owner. He has also worked with Testo and has teaching experience under his belt.

In the past, test instruments were low-resolution and often inaccurate. Many HVAC techs of the past based all of their knowledge on inaccurate measurements. We also didn't use many of the best practices we use today. For example, technicians used tap water for sling psychrometers, not distilled water. As such, technicians of the past had serious issues with wet-bulb enthalpy calculations. Some of...

In this podcast, Bryan talks about condensing temperature, condenser split, and subcooling. All three of the values are proportional. If one changes, all three of them will change. Saturation is also a critical concept that relates to all three of those, so we also cover those relationships.

As you remember, a condenser rejects heat and turns vapor refrigerant back into a liquid.

Condensing temperature is the saturation temperature at which the refrigerant changes from vapor to liquid; it can change depending on ambient temperature. While in the condenser, the refrigerant will be at saturation and...

In this episode, Bryan talks a bit about the air side of the system. Understanding airflow is all about seeing the relationship between readings. We cover latent and sensible heat, relative humidity, wet and dry-bulb temperatures, and static pressure.

Latent and sensible heat refer to heat that we can feel (sensible) or heat that contributes to a phase change and cannot be felt (latent). Both latent and sensible heat have a major impact on equipment sizing, especially in coastal regions and other areas where humidity is naturally high. When we attempt to control sensible and especially latent...

In this first episode of a new series Justin talks about the calls he is doing before and after he does them, giving us a look inside the van of a senior HVAC tech. 

In this episode of the HVAC School Podcast, we talk about some cool technologies and controversial tools.

Joe Shearer joins us to talk about hard start kits. Some people believe that hard start kits are only suitable for one-time use, but Joe and Bryan believe that there's a lot more to it than that. If hard start kits are high-quality, then you could leave it on. However, if a unit has a hard-shutoff TXV, then it absolutely needs a hard start kit. Many techs are still hesitant about using hard start kits because they can damage the...

In this podcast episode, Jeremy Smith comes on the podcast to talk about low-ambient controls, headmaster valves, charging, and condenser flooding.

If our head pressure drops too much, we won't get enough of a pressure drop across the TXV. Pressures dictate the TXV function, so we need to make sure our systems give that valve what it needs to operate correctly. Three pressures operate a TXV: bulb pressure, spring pressure, and evaporator pressure. However, pressures throughout the system can also affect the pressures that act on a TXV.

Condensers are sized for maximum heat rejection...

Bryan takes a break from the technical talk and tells a quick story about how two brothers fueled an industry and created an empire with raw sibling rivalry. Bryan co-owns a family business, and we understand that many people in this trade work with family, so we hope you'll enjoy this story.

Many of us are competitive, and nobody enjoys failing. We especially try to avoid failing in front of our family members. However, the drive to succeed and avoid failure can sometimes get a bit out of hand.

In the early twentieth century, two...

In this episode, we talk with Jeff Nieman about chillers and how they work.

For those of you who primarily work in residential or light commercial HVAC, chillers may be unfamiliar at best and terrifying at worst. However, centrifugal chillers' parts are actually quite similar to those of HVAC units. They have an evaporator, compressor, condenser, metering device, and control system, just like the HVAC units we see every day. Jeff believes that breaking a chiller down into its parts is the easiest way to become comfortable with it.

Chillers are used for comfort cooling...

In this episode, Bryan and Bert talk about properly stripping cables and leak detection best practices. Bert is a senior technician and self-proclaimed leak detection expert.

As a slight aside, Bert CAN'T STAND when technicians strip wires. Basically, his advice is NOT to cut around the wires or use a razor knife.

Leak detection starts when you walk up to a unit and confirm that the unit is low on refrigerant. Typically, you hook up gauges and check the five pillars. You will particularly check for low superheat and high subcool. However, your senses are...

n this episode, Bryan covers evacuation, recovery, and dehydration.

Evacuation refers to putting a vacuum pump on the system and pulling it down. We use a few different measures of vacuum, including inches of mercury ("Hg) or microns (millionths of a meter of mercury). We use such small units to measure a vacuum that effectively boils off moisture in the system. You must pull the vacuum very close to a perfect vacuum. So, a measurement of 500 microns indicates that the vacuum is 500 microns of mercury above a perfect vacuum.

Dehydration is a mere component (or r...

In this episode, Bryan talks to Business and Sales Trainer Bob Gee about HVAC business practices.

Bob has watched sales and leadership evolve a lot over the years. Today, success in sales depends on your abilities to build relationships with the customers. You're no longer "selling" things; you are "helping people buy" things. Instead of pushing products to people, it's best to "ask your way into a sale" and prioritize a customer's wants and needs. There is also a stark difference between management and leadership. A leader is people-oriented and customer-oriented; they care about the human element...

In this episode, Bryan talks to YouTube star Stephen Rardon about combustion analysis.

In Florida, we mostly have A/C units and heat pumps. High-efficiency furnaces are not in our wheelhouse, but furnaces are more like A/C units than you would imagine. Stephen Rardon makes some excellent comparisons between the two.

For example, you can get an idea of how an A/C system is running without checking superheat and subcooling. With a gas furnace, you can get an idea of how it's running without checking combustion. Of course, these are both general, and...

In this unedited episode of HVAC School, Bryan and Nathan talk about some basic rules for circuit board diagnosis.

So, circuit boards are boards with circuits in them. They come in two types. The traditional printed variety contains switches, relays, and resistors. The other type contains silicon chips and uses logic and processing inside the boards. You may notice these in some high-end commercial systems (EMS), but we rarely see them in residential HVAC.

The diagnostic challenges come in when technicians are unfamiliar with what's on the circuit board. It helps to break it down...

Benoit Mongeau comes on the podcast to talk about high-efficiency gas furnace basics and maintenance practices. 

When maintaining a high-efficiency gas furnace, you typically don’t have to worry about cleanliness in the same way you’d worry about an oil furnace. However, condensate drains need regular cleaning. You’ll want to look for cracked heat exchangers and pay attention to your manifold gas pressure.

We also have to check the temperature rise, also sometimes called delta T. Bypass humidifiers will often affect your temperature split, so that's something you need to account for in cold, dr...

In this episode of HVAC School, Bryan talks with Ulises Palacios about some cool technology.

Ulises has become a technology expert through his many years of working with new tools. He has recently been involved in testing new technologies, and he has worked with Jim Bergmann.

Cutting open a compressor is one of the most useful diagnostic tools you can use on a failed compressor. It is also an excellent way to learn more about your equipment. They help quite often with burnouts and mechanical failures. Although winding damage is an electrical issue, other mechanical fa...

In this episode of HVAC School, Bryan covers the basics of heat pumps.

Heat pumps are common technologies in Florida. They reverse the sequence of the typical refrigerant circuit: the indoor coil can become the condenser, and the outdoor coil can become the evaporator. Heat pumps can achieve that transition via a reversing valve, which changes the directions of the suction and discharge lines. They also have two metering devices.

Reversing valves contain a solenoid (typically 24v) that rediverts the suction and discharge lines via shifting the slider with a pressure differential. Pilot tubes shift...

In this episode, Bryan and Nathan have a banter-filled conversation about electrical components that confuse techs. If you are looking for a serious educational episode, we suggest you look elsewhere.

Low-voltage circuits may confuse the new technician because the "common" terminology is far too common in the circuit. (See how confusing it sounds in everyday use? We don't have to say "common this," "common that," but we do.)

Single-phase power can also be confounding for technicians. One phase of line voltage comes in, and it gets split when it enters the circuit. That is why...

This podcast is a high voltage A/C electrical class that Bryan gave to some of the Kalos apprentices.

The high voltage journey begins with basic electrical theory. Basically, a difference in charge is needed for electrons to move and generate power.

Motors, which are inductive loads, are the greatest users of power that we will encounter in the field. Inductive loads generate magnetism and utilize alternating current (AC) power. AC power is generated by a rotating magnetic field, and the direction of the current alternates. Comparatively, resistive loads generate light and heat, and direct...

In this episode, Bryan talks to Justin Skinner about the standard gas furnace sequence of operation.

Regardless of the furnace type, it all begins with a heat call on W...

Then, the furnace checks the safeties to make sure ignition is possible and safe. If all systems are a go, the inducer motor comes on and clears a path for the exhaust. The furnace then proves that the path for the flue is clear, and a pressure switch closes upon sensing a pressure differential. The miracle of ignition comes next. There are a few different...

Central Florida techs know the Southern winter all too well. Let's face it. It doesn't get super cold here regularly, but when it does, EVERYONE FREAKS. We get an abundance of service calls for unpleasant but not truly problematic conditions when people use their heaters.

When people first turn on their heat, they can get a nasty surprise: a horrible dirty-sock smell and sometimes a shrieking smoke alarm. These are normal, albeit unpleasant, and do not require a service call. Another unpleasant or alarming occurrence is when a heat pump unit goes into defrost mode. Defrost mode...

In this episode of the HVAC School Podcast, Bryan talks with Jeremy Smith about refrigeration tips, terms and processes. They also cover the similarities and differences between A/C and refrigeration.

Being on-call as an A/C tech is not all that different from being on-call as a refrigeration tech. Similarly, the principles of heat transfer don't change between the A/C and refrigeration trades. Both trades follow the same basic rules, but all of those valves, adjustments, and tuning on rack refrigeration systems may make an A/C tech's head spin.

Refrigeration techs may...

In this episode of the HVAC School Podcast, Bryan talks with Tim Bagnall about flowing nitrogen.

Many techs don't flow nitrogen. Some may say that it is overkill, but it has been shown that flowing nitrogen displaces oxygen while brazing and prevents harmful scale from forming on the copper. Scale is very problematic, and it will likely ruin your copper lines if you keep those lines open to air. (The jury is still out as to whether climate/geography affect scale formation, though.)

There are many different intensities for flowing nitrogen, particularly high-pressure purging and lo...

In this episode, Bryan goes back over the basics and stresses the importance of diagnosing the whole system.

I'll cut to the chase: inspection is NOT overrated. Inspections help you become more familiar with HVAC systems and can help you catch on to minor issues before they spiral out of control. Check air filters, check the charge, check the evaporator coil... does the inspection checklist ever end?

Whether you see crunchy brown contactors or oil on the lines, none of those issues are too small to warrant investigation and repair. Those may not seem worth...

In this podcast episode, Bryan goes over best practices for diagnosing and replacing an A/C or refrigeration compressor. 

When testing for a shorted compressor, make sure the compressor is isolated from all of its circuitry. You would see low ohms to ground in a shorted compressor. Do NOT measure from winding to winding or terminal to terminal to diagnose a short.

You may also come across an open winding failure. In the case of an open compressor, the power is going to the compressor, but it’s not doing anything. 

Locked compressors also...

In this episode of HVAC School, Bryan covers the "5 pillars of refrigerant circuit diagnosis" and why they matter. They are:

These 5 readings give you a holistic idea of the A/C system. Instead of getting hooked on checking only superheat and subcool all the time and dismissing potential diagnoses, you can use these five readings to get an idea of the health of several parts of the system. Making it a priority to take these five readings also promotes open-mindedness, which is perhaps one of the...

In this episode of HVAC School, Bryan talks to his sons about basic electrical theory.

Electrical theory normally requires trigonometry, calculus, and all of those fun maths. However, the basics are so easy that a 12 and 14-year old can figure it out. Electrical theory follows many of the same principles as thermodynamics—however, electrical theory concerns charges rather than heat. Conductors and insulators behave similarly with electrical charges as they do with heat.

Ohm's and Watt's laws establish what volts, amps, power, and resistance, and they explain the relationships between those units. However, magnetism can ad...

This episode of HVAC School is a Kalos meeting where Bryan talks to his team about an incident where a leak was erroneously detected on the evaporator coil.

The system was three months old, and one of our junior techs diagnosed a leak on the evaporator coil. (What?? That never happens!) So, the customer was quoted for a new evaporator coil. One week later, the charge was low again. The junior technician quoted the customer for more refrigerant charge and leak detection. The customer freaked out.

Unfortunately, there were so many things we could have d...

In this episode of HVAC School, we discuss the entire basic refrigerant/compression refrigeration circuit.

We are in the business of moving heat. Heat refers to motion in the molecules. Temperature is the average velocity of those molecules. Heat needs a temperature differential to move. So, HVAC systems absorb heat when the refrigerant is colder than the ambient temperature. They reject heat when the refrigerant is hotter than the ambient temperature.

Remember the components and their functions in the following order:

In this episode of HVAC School, I talk with my brother Nathan... and he whines a lot about cool tools I like.

As you might have guessed, Nathan is in the camp of people who believe that proper training promotes good practices; fancy tools won't make an outstanding tech. Even though I respectfully disagree with him on some things, he has a point. Tools will only be useful if a tech knows how to use them. They should make your life easier, but they shouldn't have much bearing on performance. He doesn't like wasting money or time...

In this episode of HVAC School, Bryan talks to some apprentices about basic thermodynamics. That is the fancy scientific way of saying that we're moving heat.

The way we think of "hot" and "cold" is relative to our comfort. However, the scientific concepts of "hot" and "cold" are very different from our relative understandings of those qualities. For instance, there is only ONE value of "cold" in the universe: absolute zero (0 kelvins, -460°F). Any temperature above that contains heat.

Heat and temperature are NOT synonymous. Instead, heat refers to molecular motion, and temperature is an...

In this episode of HVAC School, Bryan talks to Leslie about the deceptive TXV.

Thermostatic expansion valves, also known as TXVs or TEVs, are metering devices that maintain superheat. They contain an external equalizer. External equalizers give the pressure reading that you would normally take with a suction gauge at the end of the evaporator coil. They supply the closing force to the TXV.

TXVs also contain a sensing bulb. The sensing bulb picks up the superheat on the suction line. When a vapor is superheated, its temperature exceeds its saturation temperature. The superheat value...