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A new attic fan with thermostat wired remotely

Attic Fan Replacement

Dear Mr. Electrician:  How do I determine if I need an attic fan replacement? Answer:  You may not need a full attic fan replacement.  Many times it is just a matter of replacing the fan thermostat or the attic fan motor or sometimes both.  NOTE: Text links below go to applicable products on Amazon and EBay. A simple test is to disconnect the thermostat and hard wire the fan motor directly.  If the motor works fine like that, a new thermostat is needed.  If the motor doesn't work, or hums, or makes noise, you need a new attic fan motor. I have repaired and installed a number of attic fans in my career as an electrician.  Although the work is pretty straight forward, it becomes challenging given the working conditions.  It is rare that a full attic fan replacement is needed. Replacing the roof mounted attic fan motor involves climbing up in an attic with tools, safety gear, parts, water, and lighting.  In some instances I have had to put plywood on top of the ceiling joists and bring a ladder up into the attic to reach the fan motor comfortably enough to work on it. Sometimes I had to do this twice, once to diagnose the problem with the fan and get the model number, and the second time to actually replace the attic fan motor.  Attic fan motors are proprietary and are not interchangeable even though many look alike. It is important to get the correct model number of the fan before searching for attic fan replacement parts.  The model number on the fan motor itself can be helpful in tracking down a replacement, but having the original fan manufacturer's name and fan model number is the best. The fan motor above had bad bearings and was making a loud noise when turned on.  I disconnected the thermostat and wired the motor directly to test the motor.  This fan had an accumulation of dust because the dryer vent duct up to the roof was leaking air and the fan sucked up the dust.  The dust inhibits air flow through the motor for cooling purposes.  The motor could overheat and fail prematurely. The fan model above has its thermostat mounted directly on the fan.  Other brands have the thermostat a short distance from the fan blades. EBay Has Many Types of Attic Fan Motors For Sale HOW I REPLACE AN ATTIC FAN MOTOR It begins with my work pants that have built-in kneepads and side pouches.  I also have a dust mask or a respirator to wear.  Sometimes I will wear my hard hat, but it can  be inhibiting depending on the working conditions.  Work gloves are also important to keep from getting splinters when grabbing onto wood beams.  I wear a head light and if there is no other light will bring a drop light and cord up there. Though it may be summer and hot in the attic, I always wear lightweight long sleeve work shirts.  Insulation on the skin is not pleasant.  What I do to help...