How to Replace a Central Air Conditioning Capacitor
For most homeowners, the first time they know anything about a faulty capacitor on their air conditioner unit is when the house gets hot and the A/C unit will no longer turn on. Having a professional replace a bad capacitor can be costly, in some cases exceeding $300. The capacitor itself is not terribly expensive. With a few tools and a proper replacement, learn to change a dual capacitor that operates both the fan and the compressor. Does this Spark an idea?
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Instructions
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Turn off the power to the unit. Open the breaker box, usually a separate box specifically installed on the outside of the house near the unit, and flip the breaker to the off position. Always cut the main power before attempting any repairs on this high-voltage appliance. Also, turn the A/C unit off at the thermostat inside your home.
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Open the access panel to your A/C unit with the nut driver. Remove all screws as necessary and place them with the cover of the unit in a safe area. Keep the screws and cover close by where they won't get lost, but out of the way so you can work on the unit.
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3
Inspect the old capacitor and note where each of the three wires -- fan, common and compressor -- is attached. The top of the old capacitor should have markings that tell where each wire goes. These markings should read "Fan" for fan, "C" for common, "Herm" for compressor. Mark pieces of tape and wrap them around each wire as a label if needed. Remove the spade wire connectors and wires from the old capacitor. Remove the capacitor by unscrewing the mounting strap and pulling the capacitor out of the unit.
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Place the new capacitor into the same spot as the old one. Attach the new capacitor to the unit with the strap. Use the old strap or a new one as necessary. Slide the ends of the spade wire connectors onto the appropriate posts on the new capacitor, ensuring you pay attention and place the fan wire with the fan (Fan) post, the common wire with the common (C) post and the compressor wire with the compressor (Herm) post.
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Turn the power to the A/C unit back on at the breaker box and on the indoor thermostat. Verify the unit is working properly and replace the access cover.
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Tips & Warnings
A turbo capacitor is more expensive, but fits most units and has different power settings that can be used as necessary.
Pull the spade wire connectors off the posts and crimp them if they fit loosely on the new capacitor.
Working on an A/C unit with the power on is hazardous and can cause injury.
References
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