Testo 760 Category IV Multimeter I was standing at a booth at the HVAC Excellence Educators conference, and an instructor walks up, grabs a meter, and asks me, “What's the difference between a category 3 and a category 4 meter?” Well, I really wasn't sure, but I knew that the category 4 meter is rated […]

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 […]

  Flowing nitrogen while brazing and pressurizing with nitrogen are great practices. Putting nitrogen in with the refrigerant? Not so much. Nitrogen is a “non-condensable” gas because it cannot be condensed (under normal conditions). However, nitrogen is just one of the non-condensables. First, let's talk about what a non-condensable gas is. Any gas that does […]