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...

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...

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...

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...

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...

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...

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...

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...

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...

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,...

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...

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...

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...

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...

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...

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...

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,...

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...

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...

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 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...

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...

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...

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...