Perhaps you’ve noticed that the air conditioning vents in your home are no longer blowing cold air, or maybe you’ve visited your outdoor unit and discovered that the fan motor is no longer spinning. As you might have suspected, these two issues are related. The question is, what’s the problem? And perhaps more importantly, how can you resolve the issue to get cold air flowing once more?
AC Fan Motors: The Role They Play and What to Expect from a Functional Unit
Your AC fan plays several essential roles in the cooling of your home. In simple terms, it is the part of the air conditioning unit that is responsible for pumping air through the system. Without the airflow that comes from the fan, your unit can’t distribute any air—cold or otherwise—throughout the home. The fan blows air across a cooling medium—usually condenser coils filled with refrigerant—to cool the air. It then propels the air through your vents and throughout your home. At the same time, the fan helps keep the condenser from overheating, which can prevent bigger problems with your AC unit in the future.
When your unit is properly functional, you will know. A working AC unit is connected to the thermostat in your home and will start up when the interior temperature rises about the thermostat-set level. You can hear this action audibly, as the fan inside your air conditioning will begin to spin when the AC unit is running. So, if it feels oddly warm in your home, or if you haven’t heard the AC unit start-up lately, then there is probably a problem with your AC fan motor. To double-check, switch your thermostat from “Cool” or “Auto” over to “Fan.” When set to “Fan” mode, the fan motor on your AC unit will continue to run continuously—even when the condenser is not activated and what we typically think of as true “air conditioning” is not occurring. The “Fan” mode is meant to maintain airflow and continuous distribution of air throughout the house. However, it’s also a useful way of determining whether your fan motor is still working properly. If you turn on “Fan” mode and don’t hear the fan spinning, go outside to check your unit. If the fan isn’t spinning, you probably have a problem with your AC fan motor.
What’s Wrong? Potential Causes for ‘AC Fan Motor Not Spinning’ Situations
Several internal problems with your air conditioning unit could be causing the fan to fail (and thereby causing the loss of cold air indoors) These issues include:
A Dead Motor
The simplest explanation for an AC fan that isn’t spinning anymore is a dead fan motor. The fact is that fan motors work hard—especially during the summer months—which results in a significant level of wear and tear. If you are someone who tends to run your AC unit on “Fan” mode even when it isn’t actively cooling your home, you are adding extra use and strain to the equation. A fan motor placed under too much strain will eventually sputter and die. This problem is far more likely to occur in a system that has not been consistently or adequately maintained.
A Power Issue
If your unit isn’t receiving power, it stands to reason that the fan and fan motor won’t be spinning. You can typically solve this problem by restarting the relevant circuit on your home’s circuit breaker. There’s a possibility that your unit somehow tripped the circuit breaker (something that happens primarily when an AC unit is overheating), in which case you need to reset the circuit to restart the fan. If you switch off the circuit for your AC unit during the winter, you’ll also need to remember to switch it back on come the spring. With all that said, if your AC unit repeatedly trips the breaker, you should call for professional assistance. There is some deeper issue at work that needs to be resolved, perhaps with the help of an electrical expert.
An Air Filter Blockage
A clogged or dirty air filter can leave your air conditioner unable to do its job and can result in issues with the fans. Again, this is a problem that typically only arises when an AC unit has not been appropriately maintained.
A Problem With the Compressor Contactor:
The job of the compressor contactor is to deliver power to both the compressor and the fan motor. If the contractor fails, then your unit is going to stop blowing cool air. Contactors tend to go bad over time, but air conditioning professionals can easily replace them.
A Broken Belt
Modern air conditioning systems don’t use belt-powered fans, which means if you have a problem with a broken belt, it’s probably time for a new AC unit. However, if you do have an older unit, then a belt problem could be the culprit behind a dormant fan. Belts can break or come loose, which results in problems with the fan. You can get the belt repaired or replaced, but expect your AC maintenance technician to recommend a full system replacement.
A Problem With the Capacitor
The job of the capacitor is to store energy that will power the fans in your air conditioning unit. When the AC unit needs to start cooling your home, the capacitor provides the quick but potent burst of electricity necessary to start the fan motor and get the fan blades spinning. Essentially, the capacitor plays the same role for your AC unit as your car battery plays in starting the engine. Just as a car battery can lose charge over time, so too can your capacitor become less reliable in its ability to get your AC fan motor spinning. Needless to say, if the capacitor fails, that energy isn’t being stored or delivered to the fans. The natural result is a stalled fan motor. If your capacitor dies, you will need to call a professional to replace it. To test, find a long, thin wooden dowel or stick and insert it through the metal grate on the top of your AC unit. Using the stick, give the blades of the fan a gentle nudge. If the fan begins to spin (and keeps spinning), then the problem is the capacitor. Essentially, you’ve just done the capacitor’s job, of kick-starting the fan so that it can run properly. You can’t rely on this manual process every time your AC unit runs, so you will need to call for repairs. Still, this simple step is an excellent way to troubleshoot an AC fan motor not a spinning problem.
CAUTION: Never attempt to turn the blades of your AC unit with your fingers. If the capacitor is the problem, the fan will start spinning very fast almost immediately after you nudge it, which can pose a major safety hazard. Also, never use a metal tool (or anything conductive) to nudge your fan, as doing so can result in an electric shock.
A Jam of Some Sort
AC units can become jammed or impeded from time to time, which in turn can leave the AC fan motor (or the fan itself) unable to operate properly. If you attempt nudging the fan blades to kick-start the fan motor, only to find the blades themselves are difficult to move at all, there is likely some kind of debris clogging the fan. In some cases, there may be leaves or other debris wrapped around the axle of the fan, preventing it from turning properly. Fixing the problem is as simple as freeing the axle of its impediment. More commonly, you’ll find that the bearings of the fan motor itself are dirty or jammed with sludge. Depending on the condition of the fan motor, you might be able to rectify the problem by cleaning the motor bearings thoroughly—though a replacement may also be necessary.
It’s difficult for the average person to determine which of these issues is causing an AC unit to fail. If you want to try to arrive at a diagnosis by yourself, the best step is to figure out if both the fan and the compressor are failing, or if the compressor is still running even though the fan has stopped. You can typically make this judgment call with your ears. A unit with a working compressor is still going to be making a sound, even though the fan isn’t spinning. A unit with a failed compressor and a failed fan will be both dead silent and dead still.
If the compressor still works, then the issue probably has to do with the capacitor or the fan motor itself (or the belt, on an older system). Something is preventing power from getting to the fan motor or spinning the fans. If the compressor is also dead, then either the contactor is failing, or your unit just isn’t getting power.
Figuring out where the problem is can help you point an air conditioning technician in the right direction for a repair. In any case, you will still want to call a professional to look at your system, isolate the problem, and perform the necessary repairs. Going forward, try to be vigilant about performing routine, preventative maintenance on your unit. Just like a car, your AC system will last longer and perform more efficiently and reliably if you make a point of giving it annual checkups and tune-ups.