Capacitor and contactor replacement is the most common repair we make in Port Charlotte in summer. These two small parts in the outdoor unit handle starting and switching for the compressor and fan motor, and both take a beating in our heat.
The run capacitor stores a charge that gives the compressor and fan motor their kick at start-up and keeps them running efficiently. Heat inside a sun-baked condenser cabinet wears capacitors down. So do voltage spikes. Florida sees a lot of lightning, and a nearby strike can take a capacitor out in one afternoon storm.
Signs of a bad capacitor: the outdoor unit hums but does not start, the fan does not spin, or the fan starts only after a push with a stick. We test the capacitor with a meter against the microfarad rating and tolerance printed on its label. One that reads outside that tolerance is on its way out.
The contactor is a relay that closes when the thermostat calls for cooling. Over time the contact points pit and burn, and ants love to nest between them. A contactor stuck closed can keep the outdoor unit running when the thermostat is off.
We carry a range of capacitor sizes and contactors on the truck. We also recommend a surge protector at the disconnect to help shield the compressor and control boards from the next storm. See also AC blowing warm air and emergency AC repair.
