Capacitor Failures

Why do capacitors fail?

Capacitor failures are very common. A bad capacitor can go unnoticed for a long time or at least until it dies completely. If they are not properly checked or an observant technician sees the signs of a capacitor on the verge of failing, a typical capacitor failure will cause a motor to not have the extra kick to get to start spinning. A weak capacitor will also cause a motor or compressor to run higher amps aka use more electricity. This causes them to run hotter and shortens their life expectancy. If you are lucky you have a dual run capacitor and both the compressor and fan motor will not start. If the fan motor capacitor is the only capacitor to fail, it will cause the compresser to go out on high pressure. If you have high pressure protection it will shut the compressor off before it goes into by-pass. If you don't the compressor will go into bypass and run until it over heats. Now I have seen many compressors go through this process and survive but common sense says it shortens the life of the system every time it happens!

What does a repair like this cost:

This is a tough question to answer accurately. A lot depends on the area you live in, the company, flat rate vs. time and material and many other factors. I have seen prices as low as $120 and as high as $300. Capacitors for this repair are pretty inexpensive. It is a great candidate for a do it yourself person or someone just looking to save a little cash.

Replacing the capacitor

If you didn't already, now you must shut down the power to the air conditioning unit. You can do this at the disconnect or the breaker panel.
WARNING: A capacitor stores power. That has not changed because you've shut off the power. The capacitor is still ready to fire. Touching two of the terminals at the same time with your hand will discharge this power and make for a shocking experience. Do not throw away a capacitor that has not been discharged as it could cause a fire in your garbage. Discharge your capacitor by placing an insulated handle screwdriver across the terminals before you continue.
Now remove the old capacitor. This is very simple. The capacitor is likely mounted to the unit by a metal band that has only one screw to remove. Remove that screw and the capacitor should come loose from the unit itself.
Now, be sure to label or draw a small picture of what wire goes to which terminal before you begin to remove them. Once you're sure where the wires will connect to the new capacitor, you can remove them using a simple pair of needle nosed pliers. If they are tight, try not to just yank on them. Use a rocking motion while pulling slowly. This will help keep you from touching another terminal or possibly having the pliers slip and hit yourself in the face. Don't laugh, I've watched it happen.
That's it. Now all you need to do is obtain the right replacement part and re-install it just as you removed this one.