The steps to take in repairing a kitchen exhaust fan vary based on why it is not operating properly. Common problems with kitchen exhaust fans include clogged parts, damaged wiring and broken motors.
To repair a kitchen fan with clogged parts, first turn off the electricity supply to the kitchen or the entire home. Verify that the exhaust fan power switch is in the Off position and that the blades are not moving. Remove the vent to access the fan and remove it from the exhaust system. Clean each part of the exhaust fan, making sure to remove any dirt from gears that may prevent the fan from spinning.
If cleaning the kitchen exhaust fan does not resolve the problem, check the wires for corrosion or other damage. Use a voltmeter to ensure that each wire is conducting electricity properly. Replace any wires that conduct less voltage than required to operate the fan.
A kitchen exhaust fan can also be repaired by replacing the motor. Purchase a new motor that is made specifically for the model of exhaust fan in your kitchen. Turn off the electricity supply to the unit, and remove the grill or vent to expose the motor. Disconnect the existing motor assembly from the fan, and remove the motor plate. Remove the motor from the motor shaft, and replace it with the new motor. Cover the new motor with the motor plate, and connect it to the exhaust fan.