Tech Tips

Depending on what segment of the business you are in and your location, you either work on pump-down solenoid systems all the time, or YOU HAVE NO CLUE what a liquid line solenoid is. A liquid line solenoid valve (LLSV) is just a valve that opens and closes; it has a magnetic coil. Depending on […]

Maintaining the correct vapor-liquid refrigerant balance is crucial for air conditioning and refrigeration system performance. Longer line sets hold more refrigerant, which increases the risk of liquid accumulating in the suction line or entering the compressor during off-cycles. Heat pumps are one common application that requires additional measures. Refrigerant flow reverses during heating, turning the […]

The HVAC/R industry isn’t short on tragic figures. There’s John Gorrie, whose ice machine showed a lot of promise but didn’t have enough financial backing due to the lucrative ice industry and the death of his business partner. While Gorrie may have died without seeing his vision reach the masses, he was ahead of his […]

This tech tip is based on a conversation with Nikki Krueger and David Schurk. Nikki is a longtime contributor to HVAC School and is a relatively frequent podcast guest and symposium speaker. David Schurk is the Director of Applied Engineering and National Sales Manager at Innovative Air Technologies. Nikki specializes in traditional cold-coil dehumidifiers, and […]

A while back, I had a tech who was having some trouble finding a 35 PSI (2.41 bar) make-on-fall pressure switch. One adjustable switch in the catalog said (SPDT), but he didn't quite understand what that meant. In that case, it means single-pole, double-throw, and the “double-throw” part means that the switch has terminals in both the […]

I remember it like it was yesterday. It was my first day of work as a trainee at my first technician job, just a wet-behind-the-ears kid fresh out of trade school. It was a Monday morning, and the technicians and I were standing in the dusty warehouse surrounded by stacks and stacks of brand new […]

Proper sizing and orientation of grilles, registers, and diffusers may seem like such a simple thing, but it's an area where confusion and mistakes are commonly made. First, let's define some terms. Return A return draws air into a return duct system with negative pressure compared to the space, usually via a fixed “grille” (also […]

There has been much written and many jokes made about the misdiagnosis of TXV (thermostatic expansion valves), and rightly so. This article will cut straight to the point to help those of you who may still need a bit of clarification, and hopefully, we will save the lives of a few TXVs and the pocketbooks […]

Disconnects walk the fine line of being HVAC or electrical, but the HVAC technician is allowed to repair and replace disconnects in most places. Even if you work at a place where it isn't allowed, finding problems is a diagnostic skill you will want to have. As always, work safely with proper safety gear and […]