Recently a friend of mine told me that he paid $500 to have his A/C repaired. I asked him what was wrong with the unit. He said the AC guy replaced the capacitor. Having been a builder for 30 plus years I knew that was an outlandish price. It takes 15 minutes to removing 4 or 5 screws and install a $30.00 part. Bad capacitors account for a large percentage of A/C repairs and anyone can install it.
It is easy to spot a bad capacitor. Turn you’re A/C on and go to the outside unit (the compressor). Listen for a humming noise like the compressor is trying to start, but the fan is not running. Take a long screw driver or other similar object and try to move the fan blade. If the fan starts, then the problem is a bad capacitor. Even though you have the fan running the unit will still not cool because the compressor is not running, so turn the thermostat off.
To replace the capacitor, turn the A/C breaker off and go back outside to the compressor. As an extra safety precaution, disconnect the power from the unit by pulling the disconnect bar from the wall mounted disconnect box located within arm’s length of the compressor. FOR SAFETY REASONS DO NOT WORK ON A/C UNLESS YOU HAVE DISCONNECTED THE POWER!! Follow the wires from the disconnect box to a small access panel. Remove the access panel screws. Inside your will see a large silver canister. This is the capacitor. Look closely at the top of capacitor. If the top of the capacitor is not perfectly flat meaning that it has a round appearance like a soda can under pressure, the capacitor is bad. LEAVE THE OLD CAPACITOR IN PLACE to make it easier to identify where each wire goes on the new capacitor.
Write down the capacitor's manufacture and part number or take a picture of its label with your cell phone. Use this information for a Google search and you will find numerous places that will sell you part on line. If you’re not sure about whether you’re buying the right part most online dealers will be glad to help you find the right part.
Once you have the new capacitor, notice that a letter or letters are stamped in the top of the lid under each of the terminals. To avoid connecting a wire to a wrong terminal remove and connect one wire at a time making sure that the letters for the terminals are the same for both the old and new capacitor.
Capacitors can go bad anytime, but my experience is that they normally go bad at 7+ years. Good practice is to keep a spare on hand. I hope this saves you some aggravation and money.