HVAC School - For Techs, By Techs

• The History of the Thermostat - Short #267

  In this short podcast, Bryan gives another history lesson and goes over the history of the thermostat. Before 1883, automatic temperature control simply did not exist; we shoveled fuel into the furnace and opened windows. If a room got too hot in a commercial building, the janitor would go downstairs to choke the draft damper; this person was responsible for manually controlling comfort. Warren S. Johnson, a Milwaukee-based college professor, sought to do something about his classroom's sweltering heat. He created a pneumatic thermostat that mounted to the wall, sensed temperature, and used air pressure and mechanical systems to control dampers. This invention grew in popularity, and he founded Johnson Controls. Compressed air ran entire HVAC networks by adjusting dampers and valves before electricity went mainstream. Engineers experimented with bi-metallic strips, which could open or close an electrical circuit based on temperature changes, which made thermostats smaller and cheaper. Honeywell came on the scene by hiring industrial designer Henry Dreyfuss, who invented the mercury thermostat: the T87 round thermostat. When the bimetal coil tilted, mercury rolled from one end to the other to complete or open the circuit. These thermostats had a heat anticipator, which kept them from overshooting the temperature. Unfortunately, when these thermostats were disposed of, the mercury polluted the environment and affected the central nervous system. The digital thermostat came on the scene to replace the mercury thermostat, which led to the development of the Nest smart thermostat. However, all this time, comfort has been associated with the number on the thermostat; smart comfort controls that learn our routines and monitor dew point, relative humidity, and IAQ are the next step to create true comfort and health.   Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool. Purchase your tickets or learn more about the 7th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Subscribe to our podcast on your iPhone or Android. Subscribe to our YouTube channel. Check out our handy calculators here or on the HVAC School Mobile App for Apple and Android.

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• Tech Support Highs and Woes w/ Roman

  In this candid and comprehensive episode, Bryan sits down with Roman to tackle one of the most frustrating yet crucial aspects of the HVAC industry: technical support. What starts as a conversation about their own tech support nightmares quickly evolves into a deep dive examining the entire ecosystem—from manufacturers and distributors to technicians and sales reps—and how each player can improve the support experience. Roman opens up about his recent tech support struggles, including having to search Russian websites just to find service manuals for major brand equipment. This leads to a broader discussion about the fundamental problem: as HVAC equipment becomes increasingly complex with proprietary controls and advanced technology, manufacturers have simultaneously made it harder to access the information needed to service that equipment. The conversation highlights how the old "I never called tech support" mentality of veteran technicians is no longer viable when you're dealing with VRF systems, building automation, and equipment-specific protocols that require specialized knowledge. The hosts emphasize that good documentation isn't just helpful—it's essential, and manufacturers who hide behind "brand protection" are actually damaging their reputation in the long run. The episode doesn't just complain about problems; it offers real solutions. Bryan and Roman discuss what technicians need to do before calling tech support (hint: know your superheat, subcooling, and basic electrical readings), what makes great tech support personnel, and why investing in these roles pays dividends. They share inspiring examples of distributors and reps who go above and beyond, like the Johnstone team in Louisiana who actively seek out field experts when manufacturers can't provide answers. The conversation also touches on why tech support and education roles are chronically underpaid, and how properly compensating and supporting these positions could transform the industry. Perhaps most importantly, the hosts emphasize that everyone in the HVAC ecosystem is working toward the same goal: keeping end clients comfortable and satisfied. When manufacturers, distributors, reps, contractors, and technicians recognize this shared objective and work collaboratively rather than defensively, everyone wins. The episode concludes with practical advice for sales professionals, including the importance of ride-alongs and adopting the "I got it" mentality that turns good salespeople into indispensable partners. Topics Covered Service Manual Accessibility: The critical need for manufacturers to make documentation easily searchable and available online, not hidden behind outdated processes Manufacturer Responsibilities: Why "protecting the brand" often backfires and how transparency builds loyalty Technician Preparation: What basic measurements and troubleshooting steps should be completed before calling tech support Tech Support Personnel: The importance of properly compensating and supporting tech support staff to reduce burnout and turnover Distributor and Rep Excellence: How the best wholesalers and reps go beyond just forwarding emails to actively solve problems The "I Got It" Sales Approach: Why taking ownership of customer problems is the key to building lasting relationships Cross-Brand Part Referencing: The need for universal parts cross-referencing across sister brands and product lines Field Ride-Alongs: Why B2B sales professionals should spend at least one day per month in the field with technicians Legacy Product Support: The frustration when manufacturer partnerships dissolve and orphaned equipment becomes unsupportable AI in Tech Support: Why throwing technology at support problems without understanding the root issues is a waste of money   Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool. Purchase your tickets or learn more about the 7th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Subscribe to our podcast on your iPhone or Android. Subscribe to our YouTube channel. Check out our handy calculators here or on the HVAC School Mobile App for Apple and Android.

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• The Current War - Tesla, Edison & Westinghouse - Short #266

  In this short podcast episode, Bryan is back for yet another history lesson. This time, the subject is the current war with Tesla, Edison, and Westinghouse. The current war was fought in the late 1800s with lightbulbs, electrocutions, and a World's Fair that dazzled the entire world. Edison didn't necessarily invent the lightbulb, but he made it commercially viable by inventing the infrastructure needed to make it work; electricity worked one way and performed well in small cases. However, voltage drop was a problem with direct current (DC) circuits; Edison was okay with decentralized (localized) power generation with centralized control under the Edison Electric Light Company.  Tesla proposed a system using alternating current (AC), which could be sent hundreds of miles with minimal loss thanks to a transformer (which could step down high voltages from the utility source). AC power steps up at the utility and then down at several points between the utility source and the end user. This vision was at odds with Edison's DC system. Tesla, who had worked under Edison, sold his patents to George Westinghouse. Edison began a propaganda campaign against AC power, emphasizing its dangers. However, Tesla harnessed the powers in his lab to demonstrate its potential; while impressive, it didn't necessarily prove the safety to the public. The Chicago World's Fair was the battleground of the current war: both Edison and Westinghouse submitted bids, and the latter's was half the price. The World's Fair was lit purely by AC power and proved its usefulness to the world (primarily to Westinghouse's financial benefit). DC faded into obscurity as a means of powering cities, and although Edison was a showman and salesman, his invention was upstaged when it mattered most. However, DC made a comeback over a century later, particularly with the rise of electronics, LED drivers, and solar power. It can now move power over ultra-long distances, too.    Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool. Purchase your tickets or learn more about the 7th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Subscribe to our podcast on your iPhone or Android. Subscribe to our YouTube channel. Check out our handy calculators here or on the HVAC School Mobile App for Apple and Android.

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• An R-454B Ramble w/ Elliot

  In this raw and unfiltered episode, Bryan sits down with Elliot, a senior service tech and newly minted install supervisor, to discuss the realities of working with R-454B refrigerant in the field. What starts as a technical discussion about the new A2L refrigerant quickly evolves into a candid conversation about industry frustrations, manufacturer accountability, and the practical challenges technicians face with the latest refrigerant transition. With four years of hands-on experience, Elliot brings fresh perspectives on everything from charging procedures to equipment reliability issues. The conversation takes an honest look at the R-454B rollout, which Bryan describes as a massive industry failure. Unlike typical manufacturer talking points, this episode dives into real problems technicians are experiencing: extended charging times, subcooling drift, and equipment component failures. Bryan and Elliot discuss how R-454B systems can take up to an hour to stabilize compared to the 15-20 minutes they were accustomed to with R-410A. This isn't just an inconvenience—it's affecting how technicians approach charging procedures and follow-up visits. The episode also explores theoretical explanations for R-454B's unusual behavior. Bryan presents two hypotheses about why the refrigerant takes so long to reach equilibrium: either density differences between R-32 and R-1234yf are causing stratification in the condenser, or one component is settling at the top and acting like a non-condensable. While admitting he's "not a mathy details guy," Bryan encourages field technicians to investigate these phenomena using thermal imaging cameras and careful observation. This practical, boots-on-the-ground approach to understanding new technology exemplifies the podcast's commitment to real-world problem-solving. Beyond technical discussions, the conversation touches on broader industry issues, including the politics behind refrigerant selection, manufacturer warranty support (or lack thereof), and the challenges faced by contractors trying to maintain fair pricing while dealing with new equipment failures. Bryan and Elliot also address the reliability concerns with new A2L safety components like dissipation boards and refrigerant sensors, noting that while failure rates aren't dramatically higher than other components, they represent additional potential failure points that weren't previously necessary. Topics Covered R-454B Charging Behavior: Extended stabilization times (up to 1 hour vs. 15-20 minutes for R-410A) and subcooling drift over time Field Charging Strategy: Why technicians are intentionally undercharging slightly and relying more on line length specifications A2L Safety Components: Dissipation boards and refrigerant leak sensors—their function, failure rates, and nuisance alarms Refrigerant Stratification Theory: Potential explanations for delayed equilibrium involving density differences and non-condensable behavior Industry Politics: The R-454B vs. R-32 debate, GWP legislation, and lobbying efforts that shaped current refrigerant standards Manufacturer Accountability: Warranty support issues, untested components, and the financial burden on contractors Recovery and Reuse Concerns: Questions about blend consistency when recovering R-454B and tank contamination issues Future of HVAC: Discussion of heat recovery chillers, secondary fluid systems, and emerging refrigerant-free technologies Pressure Testing Requirements: New legislation requiring extended pressure tests and improved brazing practices Practical Field Advice: Using thermal imaging to diagnose condenser behavior and verify proper refrigerant distribution   Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool. Purchase your tickets or learn more about the 7th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Subscribe to our podcast on your iPhone or Android. Subscribe to our YouTube channel. Check out our handy calculators here or on the HVAC School Mobile App for Apple and Android.

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• Psychrometrics and the Magic Line - Short #265

  In this short podcast episode, Bryan talks about psychrometrics and the magic line inside a messy-looking chart. The psychrometric chart is a key tool for understanding the relationship between air and water. "Psychrometric" comes from the Greek roots for "cold" and "measurement." As such, a tool called the psychrometer (with paired wet-bulb and dry-bulb thermometers) could measure two different temperatures, and we could use these to determine how much water vapor the air can hold (even though the air doesn't "hold" water vapor; it's all about vapor pressures).  The psychrometric chart was developed with the contributions of James Apjohn and William Ferrell in the 1800s, but Willis Carrier was the one who drafted the paper titled "Rational Psychrometric Formulae" in 1911. He created a chart that plotted temperature, humidity, and enthalpy on a single piece of paper. The horizontal axis represents the dry-bulb temperatures, the curved lines represent relative humidity, the left axis represents humidity ratios, the diagonal lines represent wet-bulb temperatures, and the other angled lines represent enthalpy. Every possible air condition can be plotted on the chart. Moving horizontally changes sensible heat (temperature), and moving vertically changes latent heat (moisture content); both are critical to human comfort. The "magic line" is the dew point. When this line is crossed, that's when surfaces like ducts or HVAC coils begin to sweat, as air can't hold any more moisture. You can use this information and the psychrometric chart to help you make sense of customer complaints (e.g., "clammy") and predict how air and moisture will behave if you adjust airflow or add insulation.   Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool. Purchase your tickets or learn more about the 7th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Subscribe to our podcast on your iPhone or Android. Subscribe to our YouTube channel. Check out our handy calculators here or on the HVAC School Mobile App for Apple and Android.

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