When the thermostat calls, the contactor coil pulls in and closes its contacts. Contacts pit and burn over time, and a contactor that welds shut runs the outdoor unit nonstop, while one with chattering contacts damages the compressor. Ants and other insects drawn to the electrical field are a famous cause of jammed contacts in warm climates.
Contactor's pitted black and buzzing, swap it while you're up here, it's a ten dollar part that saves a compressor.
Also heard as
- compressor contactor
Related terms
Cap
Short for capacitor, the part that gives compressor and fan motors the phase shift they need to start and run.
Whip
The short length of flexible conduit and wire running from the disconnect to an outdoor unit or air handler.
Short cycling
A compressor or system turning on and off too often, with run times too short to reach steady operation.
Compressor
The pump that raises refrigerant vapor from evaporator pressure to condenser pressure and keeps it circulating.