Testing An Attic Fan

Step 1 test the fan motor.

Testing an attic fan.

Turn the attic fan off and unplug the motor from the thermostat. Look for movement of the needle on the meter toward infinite ohms. Place the black probe on the white wire. Sometimes you face an issue where the attic fan s motor comes on but the fan blades don t move.

Step 2 test the thermostat. You ll need to take out the outer casing of the fan and look to see if the belt is cracked sagging worn out or broken. Fan motor runs but not the blades if the motor is working but the fan blades are not moving the problem may be the belt. Once done test that the motor still works by plugging the motor into an extension cord that is connected to an outlet.

Also note down the power rating and the fan capacity in cubic feet per minute. Reverse the leads on the capacitor. Note down the temperature settings for later reference. Note down the wiring before proceeding to remove it.

The cause of the problem could be the belt. If there s a problem with the belt replace it with a new one. If the fan turns on the motor is still good. Place the leads of the ohm meter on the wires that run from the capacitor to the motor.

It is preferable to do this test without the moving blade. Switch off the power of the attic fan and remove the power cord. Inspect the attic if your attic is not sufficiently vented you probably won t have to look very hard to find signs. Count to three while the leads on the meter charge the capacitor.

They include rafters and ceiling joists that are damp or blackened with mold. You may need to replace a circuit breaker an electrical outlet or one of the wire connections.