How do I Check my AC Fan Motor?
TechXpert verified by Ken Kontra
One of the primary ways to check if your AC fan motor is working is to see if your AC system will turn on. A faulty fan motor means pressure and temperature limit controls are keeping the unit from running. You’ll notice a problem with your fan motor if your AC system isn’t turning on, if it’s not producing cold air, or if the compressor is making louder noises than usual. The worst motor failure is in the compressor – that’s the equivalent to blowing the engine in your car.
Become Your Biggest Fan by DIY
If your mind is spinning because your fan motor isn’t, there are certain signs to check for that could explain what’s wrong with your fan motor and if it will eventually be in need of a replacement.
Keep Your Thermostat Cool
The first step is as easy as it sounds: Make sure your thermostat is set to cool.
Tripped Circuit Breaker
Checking your circuit breakers for power is a safe way to begin diagnosing the issue. Most circuit breakers have three handle positions: “on,” “off,” and “tripped,” which is located halfway between off and on. If your AC is not running, check to see if the circuit breaker is in the tripped position. Make sure to set it firmly to off before you turn it on again. Reset it only once. If it trips again, a service call is required.
Let Your Air Filters Breathe
As part of your routine maintenance checks, it’s important to see if there’s dirt or debris clogging the air filters. A blocked air filter will prevent sufficient airflow throughout the system and cause stress and strain for other parts of your AC unit.
Motor Blades of Glory
The condition of your fan motor’s blades can indicate if there’s something wrong with your system. Check to see if the blades are spinning or if anything is obstructing them from doing so. You can attempt to kickstart the blades by giving them a gentle nudge with something like a screwdriver.
Once you get the blades spinning on their own, they usually work fine. So when they’re not spinning easily, there could be an issue with your AC’s capacitor that makes the fan run, or the motor bearings could be worn or tight.
The capacitor is the most common point of failure in AC systems, since it delivers energy and power to other parts of the unit. If your capacitor is defective, it won’t be able to provide sufficient power supply to the blower wheel or fan blade motor.
Start with a closer look: does your capacitor appear to be swollen, leaking oil, or have rusty wire terminals? If this is the case, it’s time for a new one. Otherwise, you can check the capacitor by first discharging it, and then using a digital multimeter to measure the capacitance of the capacitor. The circuit breaker to the unit must be turned off when performing this test to avoid electrical shock.
One Too Many
If you find yourself checking too many things, too many times, your AC motor fan could be blowing you in the direction of a replacement. An HVAC technician can help diagnose the issues and find you the efficient and sustainable replacement your house needs.
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