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 […]

The point of this article is to give you a full understanding of the role fuses, overloads, and circuit breakers play in the protection of HVAC/R equipment. If you skim read or jump to conclusions, you will be tempted to argue. Be patient; if you want to understand, you will need to read all the […]

To maintain combustion (burning), you need three things: fuel, heat, and oxygen. If you have all three in the proper proportion, you can maintain a continuous state of combustion. Remove one (or reduce one sufficiently), and the triangle of combustion can collapse. In a common NG gas furnace, the heat is the igniter, the fuel […]