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How to Safely and Accurately Replace a Condenser Fan Motor

Sep 02, 2023

Replacing a condenser fan motor on HVAC equipment is a relatively simple job for technicians, but it’s always good practice to review the steps to make sure it’s done properly and safely.

The most important thing to know is how to avoid electrical issues that could have serious consequences to your technician’s safety during installation or cause a short out later.


• Fan Motors

• Service & Maintenance

Contractors can be thrown off by the fact that OEM motors have three wires while aftermarket motors have four wires. The leads are different colors as well. The advice offered in this article includes how to safely wire the motors and what to know about the wire colors.

After troubleshooting the system and diagnosing that the motor needs to be replaced, follow these steps.

CHECK FOR DAMAGE: When removing the old motor, inspect the fan blade for any damage. (Courtesy of NIDEC)

The most common type of mounting is four through-bolts to the condenser cover grate. Verify the replacement motor you are installing has the correct mounting for the system you are working on.

Single-speed condenser motors have one speed lead, making them simple to wire. The high-voltage (typically black) lead will go to the L1 high side of the contactor or defrost control board on a heat pump. The white (sometimes yellow) lead goes to the L2 side of the contactor or the common terminal on the dual capacitor.

Best practice is to always use a new capacitor when you replace a motor.


RATE THE RATING: Before wiring the new motor, verify that the rating matches the required rating for both the motor and compressor. Most OEM’s have 3-wire installation while aftermarket motors have 4 wires. (Courtesy of NIDEC)

Following these steps with an eye to safety will ensure a successful fan motor replacement while also keeping technicians safe and providing optimal motor performance.

Watch this video that shows each installation step.