First, a thermocouple is not a flame rectifier like a modern flame sensor. A thermocouple actually generates a millivolt potential difference when it is heated by a flame—just to get that out of the way for any of you newer techs who are used to modern flame sensors. With higher efficiency gas-fired equipment being the […]

Some techs and contractors swear that flex ducts are an evil invention and should never be used in ANY circumstance. I agree with what duct design expert Jack Rise said on the podcast when I asked him about flex ducts: “There's a lot of problems with flex duct, there really is, and it's a good product, […]

Over the years, I have heard technicians say that refrigerant can wear out or “lose its blend” by sitting in a tank. Refrigerant does not wear out or “lose its blend”… at least not like that. What can and does happen is called “fractionation.” Refrigerant blends are composed of a mix of refrigerants with different […]