Tech Tips

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 […]

First off, the correct acronym for a GFI (ground fault interrupter) is “GFCI” (ground fault circuit interrupter). The purpose is to act as a safety device to protect from electrical shock. GFCIs are important components of electrical safety. GFCIs can be built into outlets, circuit breakers, and even extension cords. We generally use them for […]

In a series circuit (loads connected in a row end to end), it's easy to calculate total circuit resistance because you simply add up all the resistances to get the total. In a parallel circuit, the voltage is the same across all the loads; the amperage is simply added up, but the resistance is a […]

That picture above is a WW2 poster reminding soldiers of informed self-interest, which is something we ought to consider when making decisions. We live in a world where we often make decisions quickly and expect to see quick results. That works whenever I buy from Amazon. I order a new belt, and it shows up […]

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 […]

This article is not a full lesson on making a flare, but it will give you some best practices to make a flare that doesn't leak. First off, we need to clarify that very few unitary manufacturers use flares anymore. You will most often find flares on ductless and VRF/VRV systems and in refrigeration. A […]

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 […]