Tech Tips

First, here’s a quick summary of the role of oil in the refrigerant circuit: The compressor requires oil for the lubrication of the moving parts in the compressor. We would keep 100% of the oil in the compressor if we could. However, that is generally unrealistic. So, we need to utilize oils and oil strategies […]

It was an awkward conversation, bringing a technician nearly twice my age into my office for a talk. “I’m good at fixing units. I’m not some fancy-talking sales tech,” the technician half-mumbled as I sat looking at him. “The customer complained that you made them feel uncomfortable, you were unfriendly, and you tracked dirt in […]

Photo by Ulises Palacios Refrigerant circuit restrictions can be common things like a plugged filter drier or a restricted metering device. They can also be more difficult to diagnose and stem from exotic issues like a kinked liquid line, blocked evaporator feeder tube, or a compressor connected improperly with a discharge line full of solder […]

In many cases when a low-voltage or control circuit blows a fuse, it’s because one of the circuits is shorted to ground or common. That may happen because of rubbed-out wires, shorted components or boards, etc. Routing wires sensibly and using proper grommets to avoid rubouts and shorts will help prevent those problems. Less commonly, […]

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 […]

Electronic leak detection is a critical part of any HVAC technician’s common practice. Unfortunately, it is also one of the most common sources of misdiagnosis. Here are my tips to make your leak detection more successful: Use Your Senses First and Your Detector Second  Before starting to use your detector, STOP! Look for signs of […]

The photo above is from a video one of my techs took of proper condenser cleaning. I must say, he did a GREAT job of cleaning the coil, and he was very careful with the top. However, I STILL would have liked to see him pull the condenser top completely during a full maintenance procedure. […]

My grandfather is a really interesting guy. He grew up working in the Pennsylvania coal mines starting at the age of 7 or 8. Then, he worked as a well driller, was a plumber, went to HVAC school, did some gas work, worked a while as an electrician, became a welder, was a diver, and […]

I was talking about dry contacts with one of my techs, and he looked at me like I had three heads—and one of them was on fire. So, I figured it would be good to cover the difference between wet and dry contacts in a tech tip. Basically, “dry” contacts are switches with no shared […]