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 […]

Dielectric grease is an often misused and misunderstood product that could easily benefit HVAC/R technicians in various ways. From food service to electrical connections, dielectric grease can help lubricate mechanical components and prevent corrosion on electrical connections. But we need to understand what it is in the first place before we can properly apply it […]