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 […]

This article was inspired by a podcast episode featuring Jeremy Smith. Jeremy is a refrigeration mechanic and has contributed a lot of good material to HVAC School. You can listen to that podcast on floating suction and head HERE. Those of you who drive your own vans are probably all too familiar with the following […]

Educators love lockout relays, and we also love pretending you will still see them out in the field all the time. Sometimes, I have to look myself in the mirror in the morning and sadly repeat, “Lockout relays are dead.” I have to say it several times before the reality sinks in. Before I get […]