There are many appliances with compression refrigeration circuits that do not have ports installed for testing, recovery, charging, and evacuation.  These can include window units, PTACs, fountains, refrigerators, and much more. This fact presents a challenge any time you suspect or know there is a refrigerant circuit issue. How can you diagnose and repair when […]

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 […]

This article is based on Ross Trethewey’s energy comparison sheet for fuels at select efficiencies and costs. All tables and their respective data belong to him. Ross Trethewey is the founder and lead engineer of TE2 Engineering and has served as the Home Technology Expert on “This Old House.” You can find a PDF file […]