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 […]

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 […]

You likely already know a bit about radiant heating from your education and work in the HVAC industry. Science textbooks like to use the sun and campfires as classic examples of radiant heat transfer. We also have plenty of heating devices with radiation right in the name, such as water radiator heaters and radiant space […]