Quck answer
To reverse a vent fan, follow these steps:
1. Turn off the fan and unplug it from the power source.
2. Locate the switch or button on the fan that controls the direction of airflow.
3. Toggle the switch or press the button to change the direction of rotation.
4. Plug the fan back into the power source and turn it on to test the new airflow direction.
5. If the fan doesn’t have a dedicated switch, refer to the user manual for instructions on reversing the direction.
Reversing the vent fan’s direction can help improve air circulation and ventilation in a room.
While it may not be expected, there might be situations where you need to reverse the direction of a vent fan. This could be due to renovations that require a different airflow or because the fan’s motor broke and the replacement is rotating in the wrong direction. Luckily, it is usually possible to reverse the direction of a vent fan using basic tools.
Why Changing Vent Fan Direction is Important
The direction in which the blades of a vent fan rotate is crucial for its proper functioning. Clockwise rotation draws the air upwards, while counterclockwise rotation blows the air straight down. Some vent fans have a switch that allows for easy change in polarity, but most do not.
If a vent fan is rotating in the wrong direction, it might be fixable. Not all vent fans can reverse their blade direction, but certain ones that use alternating current (AC) motors can, such as a 110-volt AC motor and certain shaded pole motors.
Unfortunately, many motors cannot be reversed. Most motors are designed to operate in only one direction. Before attempting to reverse the direction, check the model number on the vent fan’s motor to determine if it is possible.
Reversing AC Motors
AC motors are induction motors that rely on wires and magnetic fields for rotation. Changing the rotation direction of these motors requires switching the wire connections. Only proceed with this project if you have experience with electrical work. Otherwise, it is best to call a professional electrician.
For this project, you will need a screwdriver or wrench, depending on the vent fan structure. Before starting, ensure that the vent has no power running to it. Unplug it and switch off the connected circuit breaker. Once you have confirmed there is no power, you can remove the vent cover.
Keep the screws organized and nearby, set the fan cover aside, and remove the blade shroud to expose the motor. Depending on the vent, there might be other components in the way. Carefully remove any necessary pieces, making sure not to lose any important hardware.
Electrical Wires and Reassembly
Once you have accessed the motor, locate the wires underneath. They will be protected by a metal covering or plastic on some models, and secured with nuts or screws. Remove the covering and set it aside.
The electrical wires will be neatly tucked beneath the covering, connected to the motor’s coils. Carefully loosen the connections and switch them to the opposite coil. This should change the fan’s polarity, allowing it to run in the desired direction.
Reattach the covering for the electrical wires, securely fasten the fasteners back in place. Attach the shroud and all other parts back to the motor and vent housing in the correct order. Once everything is back in place, reattach the vent cover and restore power to the vent.
Reversing a Shaded Pole Motor
Shaded pole motors are a specific type of AC induction motor with a pole that connects to the blades and a copper ring known as the shading coil. The direction of the fan’s rotation is determined by the direction the unshaded side of the shading coil faces. To reverse a shaded pole motor, flip the frame 180 degrees. Carefully disconnect the blade from the pole and unscrew the motor from the frame.
With carefulness, take off the motor on one side of the frame and the backing on the other side. Now that all of the components have been removed from the frame, reverse the frame by 180 degrees so that the shaded side of the copper ring is facing the opposite direction from its original position. Put the motor back together with the frame now facing its new direction.
