Air Conditioner Capacitor Wiring

Air Conditioner Capacitors

• According to the Boston University Department of Physics, a capacitor is simply a device that stores an electrical charge. Capacitors are located in a variety of appliances other than air conditioners, such as freezers and microwaves. The capacitor in your air conditioner directs its charge to the condenser fan and the compressor via electrical wires. The extra boost of electricity the compressor receives is necessary for it to begin spinning and power the entire system.

Capacitor Wiring

• There are two varieties of air conditioner capacitor: the “start” capacitor and the “run” capacitor. Regardless of the type of capacitor your system uses, it will be connected to the fan and the compressor via three wires. The wires are labeled Herm, Fan and “C.” The Herm wire is generally yellow and connects the capacitor to the compressor. The Fan wire connects to the fan and is typically black or brown. The “C” wire is the ground wire. It is generally brown with either a white or yellow stripe.

Disconnecting the Wiring

• Before you disconnect the wiring on your air conditioner capacitor, you must discharge any stored electricity the capacitor holds. Because a capacitor stores electricity without a live power source, turning off the main power switch to the system isn't enough to protect you from an electric shock.

  After disconnecting the power and opening the electrical access panel on your outdoor condenser, lay the metal end of a screwdriver over the two raised prongs on top of the capacitor unit. The screwdriver must touch both prongs simultaneously for the capacitor to release any stored electricity. If you attempt to disconnect the capacitor's wiring before discharging the electricity you risk an electric shock.

Connecting the Wiring

• Whether you are installing a new capacitor or re-connecting the wires after testing your existing capacitor, ensuring that each wire connects to the proper terminal on your capacitor is crucial. If you wire your capacitor incorrectly it will not properly direct electricity to the fan and compressor.

  If you are not confidant that you can remember which wire connects to which terminal, sketch out a rough wiring diagram noting the location of each wire before disconnecting them. If you already disconnected the wires, refer to your air conditioner's service manual for instructions. Service manuals typically contain wiring diagrams to help homeowners and professionals alike diagnose problems and make repairs.