Air conditioning (A/C) motors require a lot of power to start. The A/C motors use a start capacitor to give the motor an extra boost of electrical power during the starting cycle. Over time, the start capacitor will fail. When this occurs, the motor will simply give off a humming sound as electrical power is sent to the device. Of course, the motor will eventually trip an overload protection circuit built into the air conditioner system. When that happens, no electrical power will be sent to the A/C motor and the start capacitor will have to be replaced.

Instructions.Things You’ll Need:
Screwdriver
New start capacitor

1.1
Remove all electrical power from the air conditioning unit. This may entail shutting off the circuit breaker or pulling the fuses that supply electricity to the unit.

2.2
Open the electrical wiring cabinet of the A/C unit. Use the screwdriver and pull the screws that hold the metal cover in place. Various manufacturers will have different locations for the electrical wiring area. Consult the manufacturer’s specifications for your specific unit.

3.3
Identify the start capacitor. Many units will have two separate capacitors, a start and a run. The start capacitor is typically a round metal object that is 4 inches to 5 inches long and approximately 2 inches in diameter. The run capacitor will be an oblong shape. Both will have 3 or 4 wires attached to the top terminals.

4.4
Use the metal portion of the screwdriver and touch it to the two terminals simultaneously to short out the capacitor. This will remove any remaining charge left to the device.

5.5
Write down which terminals the wires are attached to. Remove the wires from the old capacitor.

6.6
Use the screwdriver and loosen the retaining strap around the capacitor. Pull the old capacitor from the unit.

7.7
Install the new replacement capacitor into the retaining strap. Tighten with the screwdriver. Attach the wires to the correct terminals as per your notes.

8.8
Reset the overload protection device by pressing the reset button. Consult your unit specifications for the location of this overload device. Each manufacturer will place it in a different location inside the electrical area.

9.9
Replace the main cover. Re-energize the power to the A/C unit. Test the new capacitor by starting the unit.
•Follow all local electrical regulations whenever servicing any type of electrical equipment..•Never service any piece of electrical equipment while it is energized. Electrical shock can occur resulting in serious burns.