Electrical Fundamentals & Troubleshooting

I'd like to give special thanks to Steve Rogers from TEC for helping write this tech tip about ECM blower fan watt draw and sharing some helpful visuals. Thanks, Steve! ACCA Standard 310 introduced a grading protocol for HVAC systems. While HVAC practitioners won’t be the ones carrying out the tasks laid out in Standard […]

When reading ANY article about electrical theory or application, keep in mind that it will only scratch the topic's surface. You can dedicate years of your life to understanding electrical theory and design the way many engineers do and still know just enough to be dangerous. In HVAC, we rarely need to have a DEEP […]

Suppose you have two extension cords. One is a nice, thick #10 50′ cord with good ends, and the other is a crappy #14 25′ cord. Unfortunately, you need to connect them both to get to your drill 75′ away. Which do you connect to the plug, and which to the drill? Come up with […]

Assessing the Situation It is fairly common for a service technician to come across a failed condenser fan motor in the field. It doesn’t matter if we are talking about really old or fairly new equipment—condenser fan motors sometimes fail. The issue is deciding whether to use an OEM (Original Equipment Manufacturer) or a universal […]

It can be useful to think of a multimeter as a “voltage drop” tool. Bryan covers the concept here in an excellent class that I highly recommend. This concept was a big help to me as I began to truly learn how to use a multimeter.  A meter reads the voltage differential between two points. […]

  How do HVAC surge protectors work? What sorts of electrical events do they protect HVAC systems from? Does every HVAC system need one? What is undervoltage protection? In this article, we will cover the basics of surge protection and help you determine the best use cases for the various options available in residential applications. […]

The point of this article is to give you a full understanding of the role fuses, overloads, and circuit breakers play in the protection of HVAC/R equipment. If you skim-read or jump to conclusions, you will be tempted to argue. Be patient; if you want to understand, you will need to read all the way […]

On an energized, intact circuit, you will read voltage across an OPEN switch when testing with a voltmeter. However, you probably won't read significant voltage across a CLOSED switch. Both sides of a closed switch are electrically identical (or at least very close). Therefore, there should be no movement of electrons between the leads of […]

The definition of a transformer is a device that changes the voltages in an alternating current circuit. You may have heard of an autotransformer or a buck-boost transformer, and these terms are usually used for the same type of device; they just highlight different aspects. A transformer does not need to be a buck-boost to […]