Tech Tips

Here is another excellent article from Michael Housh, owner of Housh Home Energy and a regular contributor to HVAC School. Thanks, Michael! I thought I would go through a simple example of sizing a hydronic circulator for an application. This is a made-up scenario, but I sketched out a 20’ x 20’ square home with […]

This article is written by one of the smartest guys I know online, Neil Comparetto. Thanks, Neil! Recently, I posted a question in the HVAC School Group on Facebook that went like this: “When designing a residential duct system, what friction rate do you use?” As of writing this, only one answer was correct according […]

This article was written by Michael Housh, owner of Housh Home Energy and a regular contributor to HVAC School. Thanks, Michael! This is another article in trying to relate the air side of HVAC with the water side. In this article, I’m going to talk about how to determine pump flow (GPM) based on the […]

The most common diagnosis with expansion valves is failed closed or restricted, resulting in underfeeding of the evaporator. The symptoms are low suction, normal subcooling, and high superheat when a TXV fails “shut,” but there are some other issues to watch for that can actually result in overfeeding the coil. Schrader in the Port The […]

When you are checking a unit of any kind, you should be keeping your eyes open for signs of arcing and melting at all of your wire connections and contact points. We find issues with melting terminals on contactors and in disconnects regularly. Still, We rarely think about the relationship between circuit ampacity, wire size, […]

Air-to-water pool heat pumps are seeing more and more popularity in the climates that can support them over the more traditional gas and electric pool heaters we usually see. While they definitely contain some familiar operating principles to an air-to-air heat pump, there are some striking differences in how the heat is transferred and how […]

If you remember my recent article on the company that went to my friend’s house for a PM and did nothing but leave a system quote. Well, it got worse… My friend Josh left them a D-rated review on a popular review site, and the owner of the company responded with… an apology? A bottle […]

I once had an old commercial blower assembly on a 20-ton package unit, and the bearings and pulleys were seriously shot. I was 19 or 20, and as much as I tried, I just couldn’t get the rusted hunk of metal apart. I tried penetrating oil, pullers, pry bars… I knew better than to beat […]

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 […]