Furnace Blower Motor Capacitor Test

Check the capacitor rating on the side of the unit.

Furnace blower motor capacitor test. A faulty capacitor will not be able to hold the charge necessary to run the blower motor properly. For example if your capacitor says 50 5 the acceptable capacitance range is 47 5 to 52 5 f. Inspect the capacitor visually for signs of damage. A capacitor helps the motor run and gives it more torque.

If you notice your furnace s motor cycling frequently you should test the capacitor. Check the capacitor rating on the side of the unit. If the capacitance number went up infinitely to the limit of your multimeter the capacitor has shorted out and should be replaced. First the power supply should be shut off then the two terminals on the capacitor should.

If it not you probably have a failed capacitor. Set your voltmeter to the capacitor. Some capacitors will have a set capacitance with an acceptable percentage of variance. I dont know how savy you are.

Faulty capacitors lead to overheating intermittent motor operation humming noises or even outright blower motor failure. When the motor generally goes south the motor itself it will trip the breaker. How to test start capacitors on furnace blowers. Buy when you get up there there are a couple of wires coming off the blower motor.

Using a capacitor tester to test the capacitor. Remove the wires that are connected to the terminals. Look at the wiring digram on the back of the furnace. This will cause the motor to run slowly causing excess heat.

Remove the wires that are connected to the terminals. Although only pros should test or repair capacitors you can examine your. Set your voltmeter to the capacitor setting and connect the meter to the terminals on the capacitor. If you re concerned that your furnace capacitor isn t operating properly you can test it by following a few simple steps.

Failed capacitor would be my guess if no blower. A furnace usually uses a run capacitor to maintain a relatively constant voltage supply to the blower motor. Locate the capacitor inside your appliance capacitors are metal tubes that store an electric charge usually found near a motor in the appliance. If a motor doesn t have the torque to turn the blower wheel or the fan belt it won t start.

The capacitors on most of residential blower motors are very small so technicians tend to overlook them. Excessive heat in the motor can cause the motor to malfunction.