A while back, I had a tech who was having some trouble finding a 35 PSI (2.41 bar) make-on-fall pressure switch. One adjustable switch in the catalog said (SPDT), but he didn't quite understand what that meant. In that case, it means single-pole, double-throw, and the “double-throw” part means that the switch has terminals in both the […]

You probably didn’t expect to find the word “autodidact” on an HVAC education site. You’d probably expect to see it in an SAT prep book or a list of words to say five times fast. What does that word have to do with HVAC? Well, autodidacts are some of the best techs in our trade. […]

The first law of thermodynamics is an extension of the law of energy conservation. The latter states that energy can be neither created nor destroyed but converts from one form to another. Thermodynamics is the study of heat’s relationship with mechanical work, and it establishes heat as a form of energy that can be neither […]