Tech Tips

Fenestration is a fancy architectural term that means “openings in the outside of the building.” You will see this word a lot when you read ACCA Manual J or when you are doing a Manual J load calculation. Fenestration loads include heat losses and gains through windows, doors, skylights, etc., and they can make up […]

Photo Courtesy of Parker/Sporlan There are many brands and styles of evaporator pressure regulating valves (EPR), but none as common as the Parker/Sporlan SORIT and ORIT valves. The diagram above clearly shows some of the common applications. An EPR or “hold back” valve maintains a set suction line pressure and, therefore, coil temperature. That is […]

I hear the following phrase a lot: It's the amperage that kills you, not the voltage. While there is truth to the statement, it is sort of like saying, “It's the size of the vehicle, not the speed that kills you when it hits you.” OK, so that's a pretty bad example, but hopefully, it […]

The term “short” has become a meaningless phrase in common culture to mean “anything wrong with an electrical device.” In reality, a short circuit is a particular fault that can mean one of two things in technical lingo: 1. Any two circuits that are connecting in an undesigned manner. This issue would be the case […]

Before I start on this one… At HVAC School, we focus on a wide range of topics. Many of them are very basic. My experience as a trainer for over 20 years has taught me that no matter what I assume others SHOULD know, it doesn't change the fact that they often do not. This […]

In this article, we’ll discuss superheat while using this diagnostic sheet to help us better understand how it is calculated and from where it is derived. I want to thank Ty Branaman for helping me develop these sheets that will hopefully aid in a better understanding of some of the basic HVAC measurements that both […]

Low pressures are often measured in inches of water column or “WC. Like most units of measure, it has a very simple origin; in a water manometer, 1″ of water column is literally the amount of force it takes to raise the column of water by 1”. While some water manometers (water tubes) are still […]

As HVAC/R techs, we don't generally do a lot of soldering—unless you are in a shop that has embraced Stay Brite® 8 from Harris. Several aluminum repair products on the market also use an indirect soldering type technique, so this is a general and generic overview of some best practices. As always, follow the manufacturer's […]

There are many examples of teaching using metaphors to help someone grasp how something works without being EXACTLY correct. Some examples are how we often use water flow to explain electrical flow or refrigerant circuit dynamics. It's enough like the way it works to get our heads wrapped around it, but there are many differences. […]