What should the delta T (ΔT) be? What do you mean!? 20 degrees, of course! We are referring to the air temperature drop across an air handling unit or evaporator coil in cooling mode. Actually, depending on who you ask, the answer will range between 18-22 degrees Fahrenheit. Heck, I’ve heard some insist that […]

This article was written by Christopher Stephens. He is a commercial HVAC/R service manager in the greater Los Angeles area. Thanks, Chris. Let’s start by covering the three elements needed for a fire: fuel, air, and heat (spark). With those three elements in the right condition, you can start a fire. So, if we reduce […]

Before the fighting starts about term definitions, let's just settle on using “adjustable drive pulley” and “sheave” interchangeably to describe the belt-driven power transmission device shown above. Second, for the newer tech, you shouldn't be altering these sheaves so that the belt rides lower or higher in them unless you know EXACTLY what you are […]