Attic Fan Motor Not Working High Speed

Check that a whole house fan is receiving electrical power when it doesn t work at all.

Attic fan motor not working high speed.

These are the common causes. Does the speed switch look like the silver handle coming out of the plate. Remove the outer casing of the attic fan and check to see if the belt is sagging cracked worn or broken. Attic exhaust fans power ventilators we usually simply replace the entire unit.

If the attic fan isn t turning on it could be an electrical issue a problem with the thermostat or the motor of the fan that s not working. This means that the current running through the blower motor and its speed is therefore controlled by the resistor value. If this fan has a timer and or a variable speed switch repairs are sometimes possible if the fault lies in one of the switches and not the motor. Parts can come loose or erode from high amounts of fan usage while turning the speed up to high can cause a persistent loud hum.

It selects one fan winding for slow or the other for high. Little or no airflow. If the motor is working but the fan blades are not moving the problem may be the belt. The blower resistor is connected in series to the blower fan motor.

Blower resistors are made of. The user chooses a fan speed by selecting a speed which then connects one of the resistors in the blower resistor pack. If this is not your issue the next thing in line is the high speed relay mounted on the front of the hvac box behind the accumulator. Try tapping on that relay to see if it is stuck.

Attic fans can sometimes start making noise whether it s humming rattling or making some other annoying noise. Look at the circuit breaker or fuse box to see if a switch has flipped. Your attic fan may not be turning on because of an electrical problem like a tripped circuit breaker a blown fuse or a bad connection. Other possibilities include damage to the wiring or a switch best repaired by an electrician.

If there is any damage to the belt replace it with a new one. Attic fan not turning on. A two speed attic fan should just need a basic toggle switch. If it is rotating slowly or not producing a lot of air in the high speed setting you may have a problem with the exhaust or intake.

When running at a high speed setting does the attic fan run hard or sluggishly.