When it comes to replacing or repairing anything in your house, you might opt for a DIY approach. Even with your furnace blower motor, you can easily replace it yourself if you have basic handyman knowledge. If you call for an HVAC professional, it will cost you couple hundred dollars for a standard service. But with our furnace blower replacement guide, you can save money and do the replacement yourself.
This guide is for modern furnaces with direct drive blower motors. In the case of a belt drive blower, the replacement procedure is not the same. You have to first identify your motor and proceed to select a new motor to replace.
How to diagnose a faulty blower motor
Shut off the power of your furnace, and using your hand, try to spin the blower. If it does not spin freely, examine the oil ports. If you notice the oil ports are clogged, try adding a few drops of oil to check whether it helps the motor spin properly. But if you cannot find any port or the motor does not spin freely even after putting in some oil, it means that the motor has to be replaced. Remember to check the wires of the motor connections along with the run capacitor. If you switch the power and turn the fan on, check if the blower spins freely at full speed. If not, shut it off again and continue with replacing the furnace blower.
How to remove the old motor
First, write down or take a photo of the wire colors and where they're connected before you disconnect them. There is a separate wiring control box for most furnaces that contains the wire connections and a relay. For updated models, the wires are connected by spade connectors to a control board. For the next step, remove all the nuts or bolts holding the blower in place with the furnace. Usually, you will find 2 or 3 bolts to unbolt in front of the blower assembly. Remove the remaining mounting bolts that attach the motor to the housing. Once all the nuts are removed, pull out the motor carefully. You should also remove the mounting bracket and remember how it was placed so that you know the orientation while replacing it.
6 things required for replacing a motor
You have to select the correct replacement motor. Usually, you can find a universal replacement if you cannot find the exact replacement motor.
These are the 6 things you need to know to find a replacement motor:
1. Direct or belt type of drive
2. Motor diameter in inches
3. Voltage (208-230)
4. Horsepower (1/2, 1)
5. A belly band
6. Run capacitor
Installing a new blower motor
The installation part is quite easy. It is practically the reverse of the removal procedure. After you remove the old one, secure the wheel of the new motor in place. Make sure to center the motor in the housing to ensure proper placement. Then you have to rotate carefully. Make a note of the right direction when you're removing the old motor. Once you put the new one, place the mounting bracket and start fixing the bolts in place. If any unused motor leads remain, you have to isolate them separately using electrical tape or wire nuts. It is advised to replace the old run capacitor while replacing the old motor. Once you secure all the bolts, switch on the power to check the normal operation of the furnace. If it makes no weird noise or the air comes out of the supply registers properly, you can conclude that the replacement is successfully completed.
The furnace blower motor is an important part of your system, so be careful to fix any repairs or replacements whenever you notice an issue. If you see that your furnace is malfunctioning or isn't turning on, you have to try to diagnose the problem soon. If you are unable to figure it out on your own, you better call for the technicians. Either way, be mindful of solving any issues with your furnace to avoid bigger problems in the future.
See the summary of this content here in an infographic – How to Replace Furnace Blower Motor [Infographic]