Capacitors - A Common HVAC Item to Fail

What is a capacitor and why do I need it? Well, Darryl, what we've got today is two of your typical capacitors you'll see in your residential HVAC system. They are run capacitors. One is a single run capacitor, which you would see on your motors. They are designed to operate while the motor is running. What it does is it creates a magnetic field and allows that motor to run at a good speed, at the speed it is designed to do. To make it as efficient as it can. You've got a dual capacitor as well, and a dual capacitor is simply two capacitors built into one, and they did this to kind of save room in a unit. That way you could have a capacitor for your compressor as well as your motor. It does the same thing as your single capacitor does, just operates two different devices. These capacitors are really not designed to fail, but they do over an extended period of time. After you get years and years of wear and tear and them running with the motor motor, you will typically see them start to lose their value and fail. They can fail in multiple ways. They can swell and bust or they can just lose their power and not start or let the system run like it needs to. They also can fail if that motor is running during a lightning strike or a power surge. That incoming voltage can throw these capacitors off and need to be replaced.

Is there a good way to prevent these from going out or can you?

Well, there's really not a way that you can actually prevent them, but you can help catch that problem before it turns into an issue to where you don't have air conditioning. Routine maintenance. If you have regular routine maintenance, your system checked right like it needs to be, you can catch these when they start to lose their value. You do not want to see this value go below about 5% of what it's designed to do before you start changing them out.