HVAC School - For Techs, By Techs

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 homeowners mistakenly believe they should switch to emergency heat once the outdoor temperature drops, thinking the heat pump is no longer efficient. However, even at very low outdoor temperatures, a well-designed heat pump can still operate with a COP above 1, making it a more cost-effective heating option than emergency heat. The conversation then delves into the concept of the thermal balance point, which is the outdoor temperature at which the heat pump can no longer meet the heating load of the home. The guests discuss how to calculate this balance point and how to set up controls to optimize the use of the heat pump and any supplemental heating sources, such as electric resistance heat or a gas furnace in a dual-fuel system. They emphasize the importance of proper air distribution and avoiding blowing cold air directly on the occupants, which can be a common complaint with heat pumps. Key Topics Covered: Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool. Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.” Subscribe to our YouTube channel at https://www.youtube.com/@HVACS. Check out our handy calculators HERE or on the HVAC School Mobile App (Google Play Store or App Store).

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 for switching duty. Many circuit breakers have a similar thermal design and may be prone to nuisance tripping in the summer. A lot of commercial motors rely on external overloads; some are even built into the electrical box rather than the compressor. These external magnetic overloads are often integrated into the contactor, which turns the motor on and off; this type of contactor is called a starter. These starters may have adjustable overload settings based on current, not just temperature (which may also respond to nuisance sources of heat and require a cooldown period). Some circuit breakers also trip magnetically and are less likely to be affected by temperature. Thermistor-based overloads usually consist of a PTC (positive temperature coefficient) resistor; as temperature goes up, resistance goes up, which can take a motor winding out of the circuit. NTCs are in separate parallel circuits with relays; as the resistance decreases, it pulls in a coil that opens the circuit. Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool. Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.” Subscribe to our YouTube channel at https://www.youtube.com/@HVACS. Check out our handy calculators HERE or on the HVAC School Mobile App (Google Play Store or App Store).

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. They dive into the operating principles of an expansion valve, explaining how it's essentially a balanced system of forces between the inlet (liquid) pressure, the outlet (suction) pressure, the pressure in the sensing bulb corresponding to superheat, and the adjustable spring force. Getting the superheat dialed in properly is crucial for efficient system operation. The experts share valuable insights on best practices like avoiding heat damage during brazing, using the right valve for the application, not adjusting the valve unnecessarily, allowing stable operation before making adjustments, and considerations like external equalizers. Real-world examples and demonstrations with failed valve components illustrate the importance of proper installation and maintenance. Topics covered include: Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool. Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.” Subscribe to our YouTube channel at https://www.youtube.com/@HVACS. Check out our handy calculators HERE or on the HVAC School Mobile App (Google Play Store or App Store).

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 flying superhero would travel through). Superheat and subcooling can tell you a bit about how the HVAC system's main components are operating. High superheat indicates that there's more vapor in the evaporator, and you're not getting as much efficiency out of your evaporator as you probably could. High subcooling indicates that you're stacking more liquid refrigerant in the condenser, which can be good for efficiency but may also reduce the area of the condenser dedicated to condensing the refrigerant. Superheat and subcooling are NOT just there to help you set the charge; they can tell you a lot about a system and its components. Ty Branaman has a great webpage about superheat, subcooling, and saturation at https://www.love2hvac.com/saturation-superheat-subcooling. You can also visit his YouTube channel at https://www.youtube.com/@love2hvac. Craig Migliaccio (AC Service Tech) also has an excellent book on the topic, which you can learn more about at https://www.acservicetech.com/ac-book. You can also visit his YouTube channel at https://www.youtube.com/@acservicetechchannel. Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.” Subscribe to our YouTube channel at https://www.youtube.com/@HVACS. Check out our handy calculators HERE or on the HVAC School Mobile App (Google Play Store or App Store).

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 then gradually build up to larger, more ambitious ones. Bryan and Trevor also discuss the importance of finding your "why" – the deeper motivation behind your goals – as it provides the drive and determination to stay focused and overcome obstacles. They suggest techniques like the "five levels of why" and creating vision boards to help clarify and visualize your goals. Here are some key topics covered in the podcast: · The importance of assessing what you truly want and setting clear goals · Techniques for finding your "why" and staying motivated · Prioritizing tasks and managing distractions to maintain focus · Setting short-term and long-term goals, both personal and professional · The power of small wins and positive reinforcement · Investing in yourself and taking ownership of your career growth · Managing expectations and aligning your goals with your employer's · Overcoming the mindset of waiting for the "right" time to start · Practical strategies like scheduling, time-blocking, and budgeting to achieve financial goals Overall, the podcast encourages listeners to take control of their lives, continuously learn and grow, and make consistent progress toward their goals, no matter how small the steps may seem. Check out Trevor's Refrigeration Mentor program at https://refrigerationmentor.com/. Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.” Subscribe to our YouTube channel at https://www.youtube.com/@HVACS. Check out our handy calculators HERE or on the HVAC School Mobile App (Google Play Store or App Store).

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 fuel-based heat, and they work well on their own (such as if the heat pump is broken). You can't usually run the fuel-based emergency heat at the same time as your heat pump, so it makes sense to run just the emergency heat if it is fuel-based. The thermal balance point is the point at which the heat pump can no longer keep up with the heating load by itself; the temperature in the space will start to drop, but the heat pump will still produce heat. The thermal balance point can give us a clue about client comfort, not efficiency. COP is a measure of efficiency, and an electric heater has a COP of 1. A heat pump with a COP above 1 saves energy (compared to using just electric heat). COP is the heat delivered in BTUs divided by the energy supplied; it's a ratio. You can read the "Good COP - Bad COP" tech tip at https://hvacrschool.com/good-cop-bad-cop/. Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.” Subscribe to our YouTube channel at https://www.youtube.com/@HVACS. Check out our handy calculators HERE or on the HVAC School Mobile App (Google Play Store or App Store).

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 better-designed systems more efficiently while enhancing the customer experience. Homeowners get to see the level of work and customization involved, building appreciation for the contractor's services. The visuals help communicate potential comfort issues and how the proposed solution uniquely addresses their home's needs. Breger emphasizes that Conduit Tech is focused on solving fundamental industry pain points identified through continuous feedback from their contractor user base. The software has evolved to provide more flexibility to adapt to the realities of home visits. New features like augmented reality equipment visualization further enhance the customer engagement capabilities. Topics covered include: Contractors interested in trying out Conduit Tech can visit https://www.getconduit.com/, or they can email shelby@getconduit.com or info@getconduit.com to learn more and schedule a demo. Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.” Subscribe to our YouTube channel at https://www.youtube.com/@HVACS. Check out our handy calculators HERE or on the HVAC School Mobile App (Google Play Store or App Store).

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 and draws the flue gas out. It's non-condensing, negative-pressure venting. Category 2 venting is not common anymore; they operate with negative pressure in the vent, and condensation is still likely. Category 3 venting is non-condensing positive-pressure venting. These are more common in older through-the-wall appliances. Category 4 venting is condensing, positive-pressure venting for high-efficiency or condensing gas appliances with lower-temperature flues and sealed combustion. PVC is the most common venting material for these furnaces. We can recover some energy from the condensation process. Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.” Subscribe to our YouTube channel at https://www.youtube.com/@HVACS. Check out our handy calculators HERE or on the HVAC School Mobile App (Google Play Store or App Store).

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. She explains why she dedicates endless hours to serving others in the industry at no cost - to provide the help and community she wished for when first starting out. Jennifer actively works to build women up by first offering them psychological safety and security. When women feel unconditionally cared for, they gain the internal strength and courage needed to push past obstacles in this male-dominated field. Key topics covered: · Jennifer's journey from teaching to HVAC · Lifelong learning · Overview of HVA-Chicks Coalition offerings · Managing a free 24/7 tech support phone line · Motivations for serving the industry with no payment · Providing psychological safety/security for women technicians You can learn more about the great resources HVA-Chicks has to offer at https://hvachicks.com/, visit Skillcat to check out the blog where Jennifer writes, and find Jennifer on social media as Hvachicks Jennifer. You may contact Jennifer by her public email at jennifer@skillcatapp.com. Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.” Subscribe to our YouTube channel at https://www.youtube.com/@HVACS. Check out our handy calculators HERE or on the HVAC School Mobile App (Google Play Store or App Store).

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 we change or replace a belt, we need to make sure the belt is properly aligned (centers should have the proper distance and pitch). Common sense and good observation skills will be your best tools. Adjustable sheaves shouldn't be touched when you're changing the belt; the adjustment of the sheave is for airflow based on the RPM of the fan motor, not tensioning or setting amperage. We set belt tension by tensioning with a specific tool: a belt tensioner. Belts should be as loose as possible without slipping, but belts will loosen a bit over time and with everyday use, and they may slip eventually. Wear on the pulleys may also cause belts to slip. Cogged belts, also called notch belts, may bend more easily, last longer, and be more efficient due to reduced resistance (compared to non-cogged belts). Belt efficiency can also be affected by alignment and tightness (being too tight). Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.” Subscribe to our YouTube channel at https://www.youtube.com/@HVACS. Check out our handy calculators HERE or on the HVAC School Mobile App (Google Play Store or App Store).

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 STAR guidelines. When paired with the DG-8 micromanometer, the system provides precision room pressurization measurement. They discuss reasons why excessive room pressures can cause comfort, efficiency, and indoor air quality issues. Removing positive pressure helps reduce airflow through leaks in exterior walls, lighting fixtures, etc. Chris also talks about how the Roomulator is an affordable “gateway tool” for technicians to get started with building science and air pressure dynamics. DG-8 allows technicians to perform several other tests beyond room pressurization as they advance their skills. Key topics covered: You can learn more about the Roomulator and purchase a few at https://store.energyconservatory.com/roomulator.html. Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.” Subscribe to our YouTube channel at https://www.youtube.com/@HVACS. Check out our handy calculators HERE or on the HVAC School Mobile App (Google Play Store or App Store).

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 those, air is drawn in via Bernoulli's principle; there are areas of low pressure around areas of high velocity. There is pressure associated with the natural gas, which draws air into the burner. Nowadays, we have induced draft systems (not to be confused with power-vented systems) to draw air in at a fixed rate for more consistent combustion. These inducer fan blowers are necessary for the more complicated heat exchangers we see in more recent furnaces. Secondary air is the air after combustion. We only want to adjust primary air if we have the correct gas pressure, so we will want to make sure we perform combustion analysis. We can also clock the meter (if applicable), but you will not always have a meter, and you will want it to be informed by combustion analysis. Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.” Subscribe to our YouTube channel at https://www.youtube.com/@HVACS. Check out our handy calculators HERE or on the HVAC School Mobile App (Google Play Store or App Store).

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 requires effort but tends to be the most effective. Forced learning is when someone else compels you to learn certain material, often for compliance reasons; this type lacks intrinsic motivation. They emphasize surrounding yourself with a community of curious people who can provide encouragement, accountability, and inspiration. Events like the HVACR Symposium and AHR Expo facilitate making these connections. Building personal relationships and enjoying the humanity in the field sustains interest and passion. Key topics covered: Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.” Subscribe to our YouTube channel at https://www.youtube.com/@HVACS. Check out our handy calculators HERE or on the HVAC School Mobile App (Google Play Store or App Store).

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 “pain” around Bryan turning down a big raise to go out on his own instead. She was impressed he felt so confident to leave the security of a paycheck, which made her believe Kalos would succeed. However, as a young couple they were already not making much money, so the pay cut hurt. Other topics they discuss: Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.” Subscribe to our YouTube channel at https://www.youtube.com/@HVACS. Check out our handy calculators HERE or on the HVAC School Mobile App (Google Play Store or App Store).

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 inside a home. This is the opposite of an air conditioner. The only difference in the actual equipment is the addition of a reversing valve to change the direction of refrigerant flow and a defrost control board. He talks about the need to defrost the outdoor coil when ice builds up and what happens in that mode. Some key challenges and design considerations he covers when using heat pumps include: dealing with defrost and where the melt water will go, keeping the outdoor unit free of snow, supplemental heating systems for when the unit can't keep up, increased electrical load, and factors like the climate zone, home efficiency, electricity prices, and infrastructure. He emphasizes that with good design focused around heat pumps, they can work efficiently even in cold climates. Topics covered: · Basics of heat transfer · How heat pumps move heat · Reversing valve and defrost board · Defrost challenges · Supplemental heat · Sizing and design considerations · Use in cold climates Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.” Subscribe to our YouTube channel at https://www.youtube.com/@HVACS. Check out our handy calculators HERE or on the HVAC School Mobile App (Google Play Store or App Store).

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 things like clothing and bathroom options rather than discrimination or harassment. Advice offered for companies looking to hire more women focused not on targeting women specifically, which could cause resentment, but on ensuring good benefits, upholding anti-discrimination standards, and facilitating connections with other women in the industry. Several mentioned the value of groups like Women in HVAC and the Society of Women Engineers for networking and support. Attending conferences to connect with the HVAC community was also repeatedly recommended. Overall, the positive tone revealed that with the right connections, women can thrive in HVAC careers. All expressed passion for their work and eagerness to encourage more women to explore the industry. Topics covered: Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.” Subscribe to our YouTube channel at https://www.youtube.com/@HVACS. Check out our handy calculators HERE or on the HVAC School Mobile App (Google Play Store or App Store).

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 NOT wires, which are noted by the number 0 on the gauge, like 2/0). The AWG scale is a logarithmic scale, meaning that the wire sizes don't vary by a fixed amount; there is a 20% variation between diameter sizes. Our brains are programmed to understand proportionality (i.e., logarithmic values and patterns) better than discrete values. This sizing system based on a logarithmic scale makes it easier for us to observe differences between the diameters. The metric system for wire sizing is NOT logarithmic; there is a root-10 progression between sizes; this standard is called IEC 60228. Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.” Subscribe to our YouTube channel at https://www.youtube.com/@HVACS. Check out our handy calculators HERE or on the HVAC School Mobile App (Google Play Store or App Store).

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 ports will be red to denote flammability. Refrigerant cylinders will move away from colors and instead use red bands/markings to signal A2L, along with left-handed threads and updated pressure relief valves. Best practices like nitrogen purging, confined space protocols, and leak repairs will become outright requirements. Tools like recovery machines and leak detectors will need A2L ratings, but most from the past 2 years likely already have them. In closing, the guests emphasize that A2Ls contain no propane or hydrocarbons and cannot be retrofitted into existing A1 equipment. Contractors should get trained, adopt the solutions coming, and not fear progress. But they should spread the word that A2Ls are not simply being dropped into old equipment. Topics Covered: Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.” Subscribe to our YouTube channel at https://www.youtube.com/@HVACS. Check out our handy calculators HERE or on the HVAC School Mobile App (Google Play Store or App Store).

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 the refrigerant to the secondary fluid. DX systems tend to be smaller, and chillers and boilers tend to be larger. Chillers are advantageous in cases where we're working with toxic or flammable refrigerants or large refrigerant charges; we can keep the refrigerant charge away from the structure and space or product(s) needing to be heated or cooled. Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.” Subscribe to our YouTube channel at https://www.youtube.com/@HVACS. Check out our handy calculators HERE or on the HVAC School Mobile App (Google Play Store or App Store).

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 A2L systems, like requirements for strike plates to protect line sets and whether existing line sets can still be used. They agree that ongoing questions need to be directed to organizations like ASHRAE to get definitive guidance. Overall, Jesse emphasizes that best practices are now required, not just recommended, when working with A2Ls. He details several examples, like nitrogen purging while brazing, the "10-foot rule" for checking potential ignition sources, and proper confined space protocols. Topics covered: Explore NAVAC's A2L-compatible tools at https://navacglobal.com/a2l-compatible-tools/ or general products at https://navacglobal.com/. You can also ask the experts for help by emailing training@navacglobal.com. Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.” Subscribe to our YouTube channel at https://www.youtube.com/@HVACS. Check out our handy calculators HERE or on the HVAC School Mobile App (Google Play Store or App Store).