How to Replace a HVAC Blower Motor

Are you ready to learn more about, and how to replace, your furnace circulation blower fan motor? Our blog post will tell you all you need to know and talk to you through the replacement process.


What is the Furnace Circulation Blower Fan Motor?

The furnace circulation blower fan motor draws air through the return vent as part of the heating or cooling system, blows it past the heat exchanger, and forces it to vent through the homes. Through the return, the room air is then attracted back and the air flow cycle continues. To improve efficiency, the blower fan motor can run at multiple speeds. When the furnace is heated, lower speeds are used, and for air conditioning, high speeds are used.


It will not be possible for a malfunctioning blower fan motor to deliver heated or cooled air throughout the home. The set screw on the blower wheel may have loosened when the blower fan motor is noisy during use, causing the wheel to wobble on the motor shaft. By tightening or replacing the screw, or replacing the blower wheel all together, you can fix this issue.


The bearings in the motor may have worn out if the motor itself is noisy. While it is possible to lubricate some older furnace motors to reduce the noise, most current motors do not allow this and the motor will need to be replaced.


If the blower motor is not running at all, you should first verify that power is received by the motor. If it is, then the motor is likely to have burned out.


Typically, circulation blower fan motors are unique to each model of furnace. In order to find the specific fan engine you need, you should enter the full model number of your furnace in our website search bar.


How to Replace Your Furnace Circulation Blower Fan Motor

Turn the power to the furnace off first before you replace the fan motor.


Normally, the blower fan motor is supported on rails close to the bottom of the furnace. Two access panels may need to be removed since the motor power wires are connected to a control board that is often located in an upper compartment. If applicable, by placing a screwdriver with an insulated handle across the terminals, you should ensure that the motor-run capacitor is discharged. Avoid touching the blade of the screwdriver. Disconnect the wires, if required, from the capacitor terminals. You may have to uninstall a drain trap assembly, depending on the furnace model, and the attached hoses to access the fan motor. To move them out of the way, you may need to disconnect the thermostat wires from the control board if necessary. Note the orientation of the power cables of the blower motor, then unplug them from the control board. If required, cut any zip ties. Move out of the way any extra obstructions. If needed, note where the mounting rails of the blower assembly are positioned. Unthread the screws that secure the rails now. Slide out the blower assembly carefully. Use an adjustable wrench to release the blower wheel from the motor shaft by loosening the set screw. Disconnect the grounding wire if required. Cut any zip ties securing the wires of the motor. Unthread the bolts or screws that secure the blower motor now. Note the orientation of the old engine, then lift it off the housing of the blower.


You should verify that the motor capacitor rating matches the current run capacitor when installing a new blower motor. If not, you will need to replace the condenser with the one that is required. Insert the shaft of the fan motor into the blower wheel, as you align the motor properly with the housing. To secure the motor, thread and tighten the bolts or screws. Use zip ties to secure the wires and, if required, reconnect the grounding wire. Center the blower wheel in the housing and tighten the set screw with the flat side of the motor shaft facing the set screw. Realign the mounting rails for the blower assembly with the slots on the support, and slide the assembly into position. To secure the rails, replace the screws. Reinstall any components you’ve previously removed. Attach the power wires of the blower motor to the suitable terminals on the control board. As required, connect the capacitor wires. Reconnect the thermostat wires if applicable as well. To delete any slack from the wiring, use zip ties.


Replace the access panel or panels when the new blower motor is installed. Turn the power supply back on and you should be ready to use your furnace.


If you feel overwhelmed and need help with your Repair HVAC Baltimore, give us a call.


Smart Living Home Repair Services

244 Madison Avenue , #1019

New York, NY 10016

(888) 758-9103

Comments are closed.