Time and time again we hear about replacing air conditioner capacitors. Why do air conditioner capacitors go bad? several reasons. Capacitors are similar to batteries. They hold electrical charges and discharge when the electrical current is missing like when the power goes out. Yes this is over simplification for the real technical minds but it is what a capacitor does in simplistic terms. Your power from the power company comes in waves. The peak of the wave is the most power and the valley of the wave is the least and an air conditioner capacitor charges up during the peak of the incoming wave and discharges during the valley of the incoming wave. It’s like getting an extra jolt when the power is at it’s weakest. This cycle repeats itself 60 times a second (60 Hz) in the United States. Imagine your flashlight being turned on until it burns out the batteries and then is recharged and repeated 60 times a second. After a while the battery is
going to burn out. Other factors influence the lafe of the capacitor. High temperatures will shorten the life of a capacitor, as well as shelf life. If the capacitor has been sitting in the warehouse for several years before the installation, it may not be up to the full charge when the HVAC technician installs it.
Here is an example of a capacitor that has exceeded its life and has begun to leak the internal fluids (dialectic) and indicating the capacitor may break down soon. The fluid acts as a medium for the current to flow and if leaked out, can short out the internal electrodes inside. When this happens you will usually see a deformed housing for the capacitor.
Checking for weak or dead capacitors is one of the several checks we perform in our Air Conditioning Tune-Up service.