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Living in a World of Acids (and why HVAC coils are secretly crying for help)
AHRI Ratings Are Not Design Conditions
Valve Core Removal Tools
“White Shirt Techs – Manifesto” in Practice
Solving Subcool
Contactor Alternatives and Upgrades
The Chemistry of Combustion In the Wild
Why Discharge Line Temperature is a Useful Reading
Heat Pump Defrost Troubleshooting Tips
Efficiency and Production on Larger Projects
Q&A – Circuit Board Troubleshooting – Short #230
Are you using AI to Troubleshoot w/ Refrigeration Mentor
The New Sensi Equipment Interface – Short #229
The Buyout Epidemic – Manifesto
Standing Pilot – Short #228
History of Gas Furnaces – Redux
Heat Exchangers and Temperature Rise – Short #227
Manufacturer Responsibility – Manifesto
#hvac
Tech Tips:
![](https://hvacrschool.com/wp-content/uploads/2025/01/Living-in-a-world-of-acids-300x300.png)
Imagine a small IT room packed with servers, monitors, and humans. CO₂ levels easily spike to over 3000 PPM since the room lacks fresh air ventilation. Two overworked mini-split units churn away, cooling the space and unknowingly creating the perfect acidic environment. Fast forward a few months, and those shiny coils now resemble something pulled […]
Read more![](https://hvacrschool.com/wp-content/uploads/2025/01/ahri-ratings-fi-300x300.jpg)
I’ve been designing a system for a home here in Dallas and noticed a couple of interesting (and disturbing!) things about the equipment’s advertised capacity vs. the actual capacity at design conditions. Equipment is rated at AHRI conditions (95 degrees outside and 80-degree dry bulb, 67-degree wet bulb inside). These conditions make equipment performance LOOK […]
Read more![](https://hvacrschool.com/wp-content/uploads/2025/01/VCRT-300x300.jpg)
Valve core removal tools were originally developed to remove damaged valve cores without the need to pump the system down. This technology was a major leap forward in work efficiency, as pumping down a system can be a tedious and time-consuming task. Eventually, technicians discovered that removing valve cores led to faster evacuation, recovery, and […]
Read more![](https://hvacrschool.com/wp-content/uploads/2025/01/wst-manifesto-in-practice-300x300.jpg)
I wanted to offer some practical advice from Bryan’s last podcast, “White Shirt Techs- Manifesto.” The link can be found here. In this episode, Bryan strongly (and rightfully) critiques sales tactics that are divorced from technical skills and meaningful benefits for homeowners. As a one man HVAC company, I wanted to offer a suggestion for […]
Read more![](https://hvacrschool.com/wp-content/uploads/2025/01/Solving-Subcool-01-4-300x300.jpg)
I teamed up with Ty Branaman to design an intuitive way for techs to solve some of the “what should it be?” questions in the HVAC field. The topic for this sheet is subcooling. Subcooling is a measurement of the temperature DECREASE of a liquid below its saturation (mixed liquid/vapor) temperature at a given pressure. […]
Read more![](https://hvacrschool.com/wp-content/uploads/2025/01/Contactor-Alternatives-and-Upgrades-01-300x300.jpg)
Our HVAC equipment can’t run without the contactor coil, but contactors can develop problems with age and during high-voltage electrical events. Contact pitting is unmistakable, and it’s unfortunately all too common in areas where bugs can get into the coil and fry on the contacts. Factor in problems with the utility, such as brownouts and […]
Read more![](https://hvacrschool.com/wp-content/uploads/2024/12/The_Chemistry_of_Combustion_In_the_Wild-01-300x300.jpg)
If you’ve been following my writing for the last couple of years, you know that I like to blather on and on about combustion analysis. Now, I am by no means an expert on the subject, as I live in North Texas (which is not known for its intense heating season), but I love using […]
Read more![](https://hvacrschool.com/wp-content/uploads/2024/12/01_2-300x300.jpg)
I’d like to give special thanks to Roman Baugh for the section about compressor superheat. It’s not something we talk about very often outside of chiller and commercial refrigeration applications, but it definitely has value in the HVAC world as well. Thanks, Roman! Since I started in the trade, we would take discharge line temperature […]
Read more![](https://hvacrschool.com/wp-content/uploads/2024/11/Heat_Pump_Defrost_Troubleshooting_Tips-01-300x300.jpg)
We’ve entered that season of service calls for “smoking heat pumps,” and I figured now is as good a time as any to share a few quick tips for troubleshooting defrost. Of course, the “smoking heat pump” calls can be solved over the phone with a quick explanation of normal defrost conditions—as can the service […]
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Podcasts:
![](https://hvacrschool.com/wp-content/uploads/2025/02/Featured-Image-Templates-2025-01-28T143037.010-300x300.png)
In this podcast episode, Bryan, Jacob, and JD provide an in-depth look at a significant HVAC project that tested their team's ability to adapt, learn, and improve. The discussion centers on a large-scale apartment building project that presented numerous challenges in project management, team dynamics, and installation processes. What began as a chaotic and […]
Read more![](https://hvacrschool.com/wp-content/uploads/2025/02/circuit-board-troubleshooting-fi-300x300.jpg)
In this short Q&A podcast episode, Bryan answers a listener-submitted question about circuit board troubleshooting: is there a quick way to learn how to check circuit boards, and if so, where are those resources? A circuit board is a bunch of components put together on a printed circuit board (PCB). There isn't a lot […]
Read more![](https://hvacrschool.com/wp-content/uploads/2025/02/ai-troubleshoot-fi2-300x300.jpg)
In this episode of the HVAC School Podcast, Trevor Matthews and Bryan dive deep into the transformative potential of artificial intelligence (AI) in the refrigeration and HVAC industries. They explore how AI is not a new concept in their field, discussing how manufacturers like Copeland, Sporlan, and Danfoss have long incorporated AI-driven tools and […]
Read more![](https://hvacrschool.com/wp-content/uploads/2025/02/Featured-Image-Templates-99-300x300.png)
In this short episode of the HVAC School podcast, Bryan and Tom Lorenz from Copeland talk about the new Sensi equipment interface. This product has been in field trials for months and will be launching in February. It will also be featured at the 2025 AHR Expo in Orlando. You can learn more about […]
Read more![](https://hvacrschool.com/wp-content/uploads/2025/01/The-Buyout-Epidemic-Manifesto-Podcast-01-300x300.jpg)
In this episode of the HVAC School Podcast, Bryan shares his perspective on the growing trend of private equity buyouts and investments in the trades, particularly in home services businesses. He addresses the “buyout epidemic” with a balanced view, acknowledging the significant financial opportunities these deals present while expressing concerns about their long-term impact […]
Read more![](https://hvacrschool.com/wp-content/uploads/2025/01/Standing-Pilot-Short-228-Podcast-01-4-300x300.jpg)
In this short podcast episode, Bryan talks about the standing pilot gas systems and the ignition strategy in gas-fired appliances. Standing pilots are very simple devices that are common in fuel logs, water heaters, and some pool heaters. These devices have a thermocouple or thermopile; in a thermocouple, two dissimilar metals are connected at […]
Read more![](https://hvacrschool.com/wp-content/uploads/2025/01/Featured-image-History-of-Gas-Furnaces-01-1-300x300.jpg)
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 […]
Read more![](https://hvacrschool.com/wp-content/themes/hvacrschool/assets/img/default-image.png)
In this short podcast episode, Bryan talks about heat exchangers and temperature rise in gas furnaces, especially 80% open-combustion gas furnaces. Temperature rise is the difference between the return air temperature and supply air temperature; in cooling, we usually refer to this difference as a delta T or temperature split. The manufacturer sets a […]
Read more![](https://hvacrschool.com/wp-content/uploads/2025/01/Manufacturer-Responsibility-Manifesto-Podcast-01-300x300.jpg)
In this episode of the HVAC School podcast, Bryan shares his “Manufacturer Responsibility Manifesto,” a document he wrote over two years ago but held back from publishing until now. The manifesto addresses growing concerns about the burden being placed on HVAC contractors, particularly smaller businesses, due to manufacturing quality issues and warranty policies. The […]
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