Use our guide to walk you through a blower motor installation on your furnace. Our do-it-yourself guide will take the mystery of the repair process and provide you with helpful tips to maximize the longevity of your heating equipment.
You will need:
- Blower Motor
- Capacitor (for PSC motors. We always recommend replacement when installing a new motor)
- Screwdriver
- Socket Wrench
- Hub Puller (if blower wheel won't easily detach from the shaft)
- Blower Wheel (if not reusing existing)
- Cut-resistant Gloves
- Camera (to take pictures of wire leads for reassembly later)
1. Disconnect the Furnace
Shut off power at the power switch and close gas valve.
2. Remove Blower Compartment Door
Remove the panel. There will be twist locks on the blower door, or screws securing the panel. Other furnaces, you may simply have to lift up on the door, and pull the bottom outwards to remove the blower door.
3. Disconnect Leads Going to the Motor
Disconnect the wire leads from the control board or fan center relay to blower motor. Before disconnecting any wire leads from the control board, take a picture of the wires and connections so you will know how it reconnects.
4. Remove Blower Assembly
Next, remove the mounting screws on the blower assembly. The removal of the control board or other components may be necessary before pulling the blower assembly out. Slide the blower assembly out. We recommend using cut-resistant gloves as the sheet metal can be quite sharp. Be mindful of the wires as sharp edges can cut those as well.
5. Disconnect Ground Wire and Capacitor
Disconnect the ground wire. It is usually green and runs from the motor and attaches to the blower housing. Disconnect the capacitor. Take pictures of the wire leads. They will typically be brown and can connect to either terminal.
Furnaces with ECM motors do not have a capacitor.
6. Loosen Blower Wheel Set Screw
After removing the blower assembly, loosen the screw(s) that attach the blower wheel to the motor.
7. Unbolt Blower Motor from Housing
Next, remove the screws that connect the motor to the housing. Take a picture of the motor orientation. You don’t want to get everything back together to find your wire leads aren’t in the right place.
8. Remove Blower Motor From Wheel
Remove the motor. Sometimes this is easier said than done. If you find yourself having a hard time, use a hub puller to avoid any damage to the blower wheel and housing.
9. Inspect, Clean or Replace Blower Wheel
After removal of the blower motor, inspect the blower wheel for warping and missing fins. If you notice any of these issues, replace the blower wheel too.
An imbalanced blower wheel can overwork the motor bearings and cause premature motor failure.
Remove the blower wheel. This will likely require you remove a couple screws from the housing for it to slide out. If you are reusing the same blower wheel, right now is good time to clean it. This is also a good time to clean housing and blower compartment.
10. Install Blower Wheel
Install the blower wheel back into the housing and secure housing screws
11. Attach Blower Wheel to Motor
If your motor has a separate bracket, use a permanent marker to mark the position of the blower motor on the bracket. Install new motor on the bracket and align with the existing marks.
Slide the motor into the blower wheel. Tighten the bracket screws on to the housing.
Align the flat side of the blower motor shaft with the set screw on the blower wheel and tighten the screws. Spin the blower wheel to make sure it is not making contact with the housing or warped.
12. Attach Ground Wire and Install Capacitor
If your furnace has a capacitor, install the capacitor and attach the leads. The capacitor wires are typically brown.
If your blower motor has a capacitor, we recommend you ALWAYS replace the capacitor as well. You don’t want to install a new motor only for it to fail shortly after due to a capacitor that is out of tolerance. Capacitors are typically less than $20 and we recommend they be replaced to protect your investment- You wouldn’t change your cars oil and not change the filter!
13. Install Blower Assembly
Make sure the assembly is firmly secured in the rails and slide into place. Tighten mounting screws.
If you had to remove the control board, reinstall it and tighten screws.
14. Attach Leads
Reconnect the blower motor leads.
If you have an ECM blower motor, it likely failed because of a power surge or outage. To protect it, we recommend you install the Zebra VZPRO or X13PR to protect it from power surges.
15. Install Furnace Doors
Reinstall the blower door. Most furnaces have a door safety switch that won’t allow the blower to run without the door secured.
16. Turn on Breaker and Furnace Switch
Open the gas valve and turn on power to the furnace. Observe for proper operation.
If you have any further questions on the repair process, or need help selecting the parts you need for this repair, contact us!
About the Author
James Clark is the HVAC Controls Specialist and Ecommerce Manager for Technical Hot & Cold. He has been with the company since 2014 and enjoys helping homeowners save money by providing help articles that walk them through various DIY HVAC repairs. In his spare time, he's playing music with his children and spending too much time working on his lawn.