Tech Tips

Fundamentally, three-phase, alternating current (AC) motors are about as simple as a motor gets. The power company produces three phases by spinning magnets. Then, on the other end, we produce electromagnets that spin the motor according to the same 60 cycles per second frequency (60hz). All three phases are 120 degrees out of phase from […]

When the quiz or the teacher asks what “latent” heat is, there is generally some reference to it being hidden heat, which is what the word “latent” means. We then learn that it is heat energy transferred that results in a change of state rather than a temperature change. Later on, we hear a lot […]

I teamed up with Ty Branaman to design an intuitive way for techs to solve some of the “what should it be?” questions in the HVAC field.  The topic for this sheet is subcooling. Subcooling is a measurement of the temperature DECREASE of a liquid below its saturation (mixed liquid/vapor) temperature at a given pressure. […]

Our HVAC equipment can’t run without the contactor coil, but contactors can develop problems with age and during high-voltage electrical events. Contact pitting is unmistakable, and it’s unfortunately all too common in areas where bugs can get into the coil and fry on the contacts. Factor in problems with the utility, such as brownouts and […]

Some techs and contractors swear that flex ducts are an evil invention and should never be used in ANY circumstance. I agree with what duct design legend Jack Rise said on the podcast a few years ago when I asked him about flex ducts: “There's a lot of problems with flex duct, there really is, and […]

There is a lot of misunderstanding about the HSO (hard shut-off) or “non-bleed” TXV (thermostat expansion valve) and what makes it shut off, why it exists, and how it “magically” opens. Once you understand the forces inside the valve, it is quite simple, obvious, and sadly devoid of any magic. The Three Forces  The TXV […]

WARNING: This article contains spoilers for Die Hard (1988). If you’ve never seen the film and want to avoid spoilers, I suggest skipping this one or watching the movie first before you read this Christmas tech tip.  Here’s a fun thing to do at Christmas dinner: start the debate as to whether Die Hard is […]

My goal in this tech tip is to help those who struggle to understand heat pumps get their heads around them as quickly as possible and understand some of the things a tech needs to know about them. The basic idea of a heat pump is to use the compression refrigeration cycle to move heat […]

In these tips and on the podcast, we talk a lot about the importance of deep vacuum. Pulling a deep vacuum using proper processes and tools is really the ONLY way to ensure that a system is clean, dry, and tight. Just for review, that means: Nitrogen purge, flow, and pressurize > Cores removed > […]