Why Wont My Attic Fan Shut Off

If it does the problem is not likely the thermostat.

Why wont my attic fan shut off.

Turn the thermostat up to a temperature at or near the outside temperature. Replace the thermostat and its cover. The only way to get that pesky fan to stop running is to shut it off at the breaker or the emergency shut off switch. If the fan continues to run make sure the wires are secure and not touching.

Fan motor runs but not the blades. Attic fan not turning on if the attic fan isn t turning on it could be an electrical issue a problem with the. It s normal for the fan to kick on a couple of minutes before heating starts or to stay on for a couple of minutes after cooling stops but your fan shouldn t run for hours on its own. Indoor fan won t shut off unless i use the circuit breaker.

Common attic fan problems and how to fix them. Your hvac fan should turn on and off with the rest of your heating and cooling system. Read more about why attic fans are a bad idea in my post on attic ventilation. The fan switch on the thermostat is in the auto position not the on position.

If the motor is working but the fan blades are not moving the problem may be the belt. Fan motor runs but the blades don t move sometimes you face an issue where the attic fan s motor comes on but the fan. So your indoor fan never stops running. The problem is that they will pull air not only from the attic but also from your house where they ll steal air conditioned or in your case even heated air making it most costly to heat or cool your living space.

Still if it is installed properly it should turn off by itself once the air temperature cools to an acceptable temperature. If the unit continues to run it may be the thermostat. If the fan stops running the thermostat is the problem and should be replaced. Here s why attic fans are seldom the most efficient way to vent an attic.

On the off chance that someone has inadvertently mis connected or shorted fan control wires at the fan limit switch also check. Pull the cover off the thermostat then remove the mounting screws holding the thermostat to the sub plate and pull the thermostat off. Remove the outer casing of the attic fan and check to see if the belt is sagging cracked worn or broken. Remove and replace it with a new thermostat.

You ve checked the obvious. You tried turning the thermostat to the off position nothing works. Out fan limit switch installation wiring. On the chance that there is a shorted thermostat wire a problem that can also cause the a c or warm air furnace fan to run continuously.

Wait to see if the air conditioning unit fan eventually shuts off. It may be a bad thermocouple but in any case the fan does not know when to shut off.