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 […]

Imagine a glass of ice sitting on a table. Now, imagine you place a lid on the glass so that all the water and ice are contained in the glass. If the ice and water are well mixed, the water and ice will both be at 32°F because the ice is slowly changing state from […]

This article is based on HVAC School’s special video for 100k subscribers. The episode features Eric Mele, Andrew Greaves, and Sam Behncke as special guests. To celebrate HVAC School’s 100,000 YouTube subscribers milestone, we've released a video on a topic that applies to all sorts of HVAC techs. Customers don’t like making callbacks, and we […]