Because the name of the website is HVAC School, I get a lot of people who assume we either: A) Have a physical location B) Sell online courses You are probably aware by now that we do neither of those things. We are a free learning resource for anyone looking to improve their professional skills […]

Every gas furnace data plate/tag has a specification for the temperature rise through that furnace. It is shown in a range, like 50-80° or 45-75°. Those two numbers are the lowest recommended temperature rise, and the highest allowed temperature rise through the furnace is usually a 30° difference. When possible, we want to get the rise […]

There are many great diagnostic tools available to the service technician today, but I haven't found a tool as versatile as the simple isolation diagnosis. There are many ways this concept can be applied, but let's start with some examples so that you get what I mean. Low Voltage Short Circuit Isolation Diagnosis You arrive […]