When I first started in the trade, we used to run into shielded control wires on the Carrier Comfort Zone 1 zoning systems and also on a Carrier VVT system I used to maintain at a bank. I knew it has something to do with electrical “noise” and that communicating systems often called for it, […]

This topic came up because I was testing out the new MR45 digital recovery machine. That machine goes off by itself when it hits a 20″ Hg vacuum. It's a cool feature, but it is good to know when that level of vacuum is overkill and when it's not enough according to EPA requirements. You […]

This article was inspired by a podcast episode featuring Jeremy Smith. Jeremy is a refrigeration mechanic and has contributed a lot of good material to HVAC School. You can listen to that podcast on floating suction and head HERE. Those of you who drive your own vans are probably all too familiar with the following […]