Fan motor failure is the most common problem with ceiling fans. This calls for a motor replacement which indeed is a quicker and easy task than installing an entire new ventilator fan. The steps below will help you replace your Broan 688k motor.
Remove the Old Bathroom Fan
Step 1: Turn off the electric power supply
Wear safety glasses and switch off the electric power to the fan at the circuit breaker. Mostly, disconnecting the old bathroom fan may not expose you to contact with live wires, but switching off the power will protect you in case of faulty wiring. If the fan is a bit high such that you need a ladder to access it, ensure the ladder is strong and stable enough before you climb.
Step 2: Remove the grille
If you can disconnect the grille with your hands, check around the edge for a pair of flexible metal rods. Squeeze these rods together to get them out of their slots and release the grille. Else, locate the screws holding the grille in place. They are usually hidden beneath the grille and can be reached through the vent slots.
For a fan and light fixtures combination, let the bulb cool, and then remove it to access the screw or mounting nut holding the motor assembly in place.
Step 3: Remove the fan
Disconnect the wire on the fan housing. Most fans have a visible power cord and outlet that can be seen once you remove the grille. It looks like a normal electrical cable or a few wires connected to a plastic clip. Whichever way, you can pull it out of the unit to remove the fan from the power supply.
Step 4: Remove the mounting bracket
If your fan and motor are fixed into a metal bracket connected to the other housing parts, you are lucky. You only need to unscrew this bracket on any side of the housing and pull it out of the housing with the fan motor and attached impeller.
Step 5: Remove the plate
Remove the whole plate if your fan is not connected to a bracket. Usually, the motor sits on a plate joined by one or more screws. Remove these screws first.
You will see a large plastic unit fixed with several screws if you have a big fan. Unscrew them, and then disconnect the whole unit from the housing. If you cannot access the fan motor inside, check for its model number written on the device and request the entire unit.
Step 6: Lower the unit
Remove the tabs using a flathead screw to free the plate. After removing the screws, you will see several tabs holding your unit in place. Check for these tabs and use a flathead screwdriver to pry them out. Pull out the entire plate together with the fan blades and motor.
If this information cannot work for your fan model, then you are having a less common device. Check for more screws, clips, and other pins holding the motor in place. Some models require you to twist the motor by hand before pulling them out.
Testing the Fan for Easy Fixes
Step 1: Clean the grille and the fan blades
If your fan was running but producing a lot of noise or not providing enough air, it needs cleaning. Clean any dust build-up on the fan blades using compressed air or the brush attached to your vacuum cleaner. Use soapy water to wash any dirt on the grille vents.
Step 2: Check the movement of the fan blades
While the blower is on the motor shaft and disconnected from the power supply, rotate the blower wheel or fan blades with your finger and check for any problems. You can repair your fan by clearing the small pieces of debris, lubricating any stuck piece, or reinstalling it if it is not well aligned on the motor shaft.
This may not fix your problem, but you should know it is a crucial maintenance tip. If your fan blades are bent or broken, you should replace them with the motor.
If the unit has a normal power cable connected to it, plug it into the wall socket and switch it on to test the unit thoroughly.
Step 3: Tighten all the screws
Tightening all the screws stops vibration noises from the fan. If the fan was producing a buzzing noise, you need to replace the motor. Check the fan and motor unit, the grille cover, and the housing where the motor is fixed for bolts and screws. Tighten each of them well and turn on the fan to check if the noise is gone.
If your fan was previously fixed using nails, replace them with screws as nails can easily loosen due to vibrations, causing the noise.
Installing a New Motor
Step 1: Confirm the motor model number
Check if the model delivered is the same as the old one. The motor has a model written on it. Most models are easy as they have a single motor and blower connected alone inside the housing. The motor should be connected to a shaft that rotates the blower, with electric wires running out through the side or back. If you can’t locate the product code, pull out the blower from the shaft to expose more of the motor.
Step 2: Look up your motor ratings
Check the specifications of your motor airflow and noise level. If you realize that your motor is making a lot of noise even with a new motor, use the model number to check its specifications online. If your doubts are cleared, look at the home improvement store or online for a new motor that matches the old housing or a whole new fan unit. There are two crucial ratings you should check:
- Fan’s airflow: It is indicated in Cubic feet per minute (CFM). A bathroom fan should have at least 50CFM or 1CFM per square foot. In the countries outside the US, the airflow is measured in liters per second (l/s).
- The measure of noise level: It is measured in sones. If you need a quiet fan, order a replacement with a rating of 1.0 sones or less (the same as the volume of a fridge).
Step 3: Connect the new motor to the fan
Slide the blower onto the shaft to connect it. Connect your new motor to the fan housing by reconnecting the bracket and screws that were fixing the old motor in place.
If the motor came with a normal power cable connected, plug it into the socket and switch to check if it’s working. If the blower is shaking or you notice any buzzing or rattling, disconnect it from the power source and cross-check if all parts and screws fit well and tightly.
Step 4: Reinstall the fan assembly
Since you had removed the fan housing from the wall or ceiling, it is now time to lift it back to the vent. If the plate was fixed using metal tabs, lift one side higher to insert the tab into its slot. Push up the other side of the plate until it clicks into place. Insert the screws and tighten them to connect the plate to its housing and connect the power cable. Pinch the metal rods together and insert them into their slots to reinsert the grille cover or tighten the screws holding it in place. Once you are done with the installation, turn on the power and test if the fan is running smoothly.
Broan is the leader in residential ventilation products, customized climate, and indoor air quality solutions. Find more Broan products here!
Robert Syengo is an experienced web writer with a home improvement history that includes toilet remodeling and appliance installation. He enjoys writing and learning about electronics, gardens, design, remodeling and repair.