We keep two-pole, 40-amp 24v coil contactors on all of our vans. They are versatile and reliable, and you can replace most residential A/C contactors with them. There are a few things to watch for, though, especially when you have a crankcase heater. Many brands power the crankcase heater constantly and shut it on and […]

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 […]

The general law of perfect gas is a combination of Boyle’s and Charles’s laws. Each of those laws neglected pressure, temperature, or volume in their formulas. The law of perfect gas combines the two, clearly establishing the relationship between all three variables and giving those laws a much more practical use in our field. We […]