Enthalpy is easy. It's just a state function that depends only on the prevailing equilibrium state identified by the system's internal energy, pressure, and volume. It is an extensive quantity. Simple. Like most things, the scientific definition is as clear as mud. In HVAC/R, we use enthalpy measurement to come up with the total heat […]

This article is part 5 of a 5-part series on troubleshooting by Senior Refrigeration and HVAC tech Jeremy Smith. This step might be the most challenging part of troubleshooting. We've got a “Most Likely candidate” for the trouble, but we don't know for certain that's what is wrong. So, we have to combine our customer […]

Evaporator temperatures below 32° are common and acceptable in refrigeration; that's why there is a defrost sequence. In a heat pump running in heat mode, it's the same; freezing is a part of the process, and defrost is necessary. In comfort cooling, we can't allow the evaporator to get below 32°, or it will freeze. […]