How to Replace an Attic Fan Thermostat

Obtain the proper specifications from the attic fan before purchasing the replacement thermostat. Most home stores or hardware stores will carry the correct replacement part. Critical information such as voltage, amperage and cubic feet per minute (CFM) should be a consideration in garnering the proper part.

Remove the electrical power from the attic fan. This should be done at the circuit breaker panel box. The attic fan should be on its own dedicated circuit and not connected with any other electrical device.

Use the screwdriver and remove the protective cover of the thermostat.

Use the pencil and paper and record the following information that is set on the two thermostats that are revealed once the cover is removed. The "on" fan temperature and the "off" fan temperature. The "off" fan temperature for the "fire" condition is a factory setting, and you should not have access to make this adjustment

Make note of the feeder power wires placement on the screw terminals as well as the fan wire terminations. Different manufacturers will have various arrangements of the wires.

Remove the wires and the thermostat using the screwdriver. Position the wires out of your way so you can remove the thermostat from the attic fan housing.

Unpack the new thermostat and remove the metal cover. Reset the temperature settings on the new thermostat so they equal the old temperature controller.

Mount the new replacement to the attic fan housing and terminate the wires in the proper location.

Replace the thermostats cover and apply power. Depending on the attic temperature for the season, you may have to wait until a warm day for a full test of the fan's operation. Some thermostats have a fan "on" bypass, and the attic fan can be tested in this way.