#furnace

Tech Tips:

Practical Uses of Combustion Analysis
By:Bryan OrrThis tech tip reviews the live stream by the same name aired on November 1st, 2023. You can watch the full live stream HERE. We want to give special thanks to the guests: Jim Bergmann, Jim Davis, Tony Gonzalez, Louise Kellar, Bill Spohn, and Tyler Nelson! Gas furnaces (or any combustion equipment) create a […]
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The Case for Buying a Combustion Analyzer
By:Matthew BrunerLast year, I bought my first combustion analyzer. I had just started my own company and felt the additional weight of responsibility to sit down and determine the best way to verify that the furnaces I was servicing were working safely. In the past, the most extensive testing I had done was a visual […]
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Gas Furnaces – What a Tech Needs to Know
By:Bryan OrrIt’s that time of year again—the furnace service calls are peaking. It’s a good idea to crack open Jason Obrzut’s book, Gas Heating: Furnaces, Boilers, Controls, Components, and listen to the many public podcasts and presentations by experts like Jim Bergmann. At HVAC School, we’re fortunate to have had some of the industry’s greatest […]
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Combustion Air
By:Bryan Orr To maintain combustion (burning), you need three things: fuel, heat, and oxygen. If you have all three in the proper proportion, you can maintain a continuous state of combustion. Remove one (or reduce one sufficiently), and the triangle of combustion can collapse. In a common natural gas (NG) furnace, the heat is the […]
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Furnace Air Temperature Rise
By:Bryan Orr Every gas furnace data plate/tag has a specification for the temperature rise through that furnace. It is shown in a range like 50-80° or 45-75°. Those first two numbers are the lowest recommended temperature rise; the highest allowed temperature rise through the furnace is usually a 30° difference. When possible, we want to get […]
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Combustion and Confined Spaces
By:Bryan Orr All fuel-burning appliances require oxygen to burn. They require sufficient oxygen to burn clean and safely, without soot and CO (carbon monoxide). I live and work in Florida, where most of our fuel-burning appliances are 80% efficient with open combustion. (You can learn more about the basics of combustion on a podcast with […]
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Checking Evaporators on Furnaces
By:Bryan Orr In Florida, there are not many gas furnaces—at least not as many as up north. Sometimes, we can look like real dummies compared to techs who work on them every day. One thing to know about 80% gas furnaces with cased evaporator coils is that you can often check the evaporator coil by […]
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Clocking a Gas Meter (It’s not that hard)
I've heard a lot made of clocking gas meters over the years, and honestly, in Florida, there isn't too much call for heat. There are even fewer furnaces. I was pleasantly surprised when I found out how easy it actually is. Here is how you do it, step by step: #1 – Make sure all […]
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Tech Question – Why Do ECM Motors Trip a GFCI?
This question was submitted on the site in response to the recent GFCI tip. It's a good question with several possible answers. What do you think? Hey Bryan, I have had a few instances where we are firing off a furnace in a new build with a temporary power pole outside with gfci outlets installed […]
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Podcasts:

All About 90% Furnaces
By:Matthew BrunerAdam MufichTy BranamanBryan Orr  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 […]
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