As a HVAC service company, a common problem that we find is an AC unit fan that isn’t working. In most cases the AC fan is not spinning, but the rest of the system is still running. There are numerous possible causes for this problem, but the most common cause for an AC fan not working is a bad or faulty capacitor. The capacitor is what gives the AC fan its juice to start up. If the capacitor isn’t working properly, the AC fan won’t either.
Let’s go over the other common causes of an AC fan not working and what you should do if you run into this problem.
Is Your AC Fan AND Compressor Not Running?
Before we move forward, it’s important to differentiate between an AC fan that isn’t working and an AC fan and a compressor that aren’t working. If you don’t hear your outside air conditioner unit running at all, then it’s likely a power problem. To troubleshoot this problem follow the steps below.
- Turn off your AC unit if you haven’t already. This can be done on the thermostat.
- Check your circuit breaker panel and see if the circuit breaker tripped for some reason. Look for “HVAC”, “Air Conditioner” or something similar. If the circuit breaker did trip, go ahead and reset it. If the circuit breaker didn’t trip, you can switch it off momentarily and then switch it back on.
- Turn the power back on to your air conditioner and see if the outside unit works properly.
If this doesn’t fix your problem go ahead and call your local AC repair company. The problem with your outside AC unit likely needs further troubleshooting by a professional.
If your compressor is running properly, you should hear it humming. If your compressor is running but your AC fan is not working, continue to the next paragraph.
What to Do if Your AC Fan Isn’t Working
If your AC fan, or AC compressor fan is not working, the first thing you want to do is turn off your AC unit. By turning off the AC unit, you are preventing any other problems from occurring.
Next, you can try to determine what the problem is by continuing to read below or you can call a professional. Your local AC repair company can come out and pin point the problem and repair it.
Why Your AC Fan Is Not Working
As we stated earlier, the most common cause of an AC fan not working is a bad or faulty capacitor. While this is the most common cause, it certainly isn’t the only cause. Other culprits include:
- A power supply problem
- A frozen AC unit
- A bad AC fan motor
- A bad contactor
- Belt slippage with older units
If you suspect that it could be a power issue, follow the steps that we listed previously for resetting the circuit breaker.
If the cause of your AC fan not working isn’t power related, then it is likely a bad capacitor, a frozen AC unit, or a bad AC fan motor. In rare cases, the cause can be a bad contactor, belt slippage on older units, or some other culprit.
How to Test the Capacitor
To test the capacitor, follow the steps below.
- Turn the AC unit back on if you have turned it off.
- Go outside to the outside unit and bring a large stick or some sort of safe piping.
- With the AC unit turned on, go ahead and try to spin the fan with the large stick or pipe.
- If the air conditioner fan begins spinning on its own after you gave it a kick start, then the capacitor is the problem.
- If the air conditioner fan is not spinning on its own, then it’s likely another problem other than the capacitor.
How to Tell if Your AC is Frozen Up
When an AC unit freezes up, it will usually cause the fan to shut down if it runs long enough. To determine if your air conditioner has frozen up, follow the steps below.
- Check the vents inside your home. If you don’t feel cool air coming out, your AC unit might be frozen.
- Inspect the outside unit for any ice on the unit itself or on any connected pipes.
- If you don’t find ice on the exterior of the outside air conditioner unit, open the access panel on the inside unit (typically near the furnace or air handler system) and check the evaporator coil for ice. Please follow the manufacturer’s instructions when opening any panels on your AC unit.
If you don’t find any ice, it doesn’t necessarily mean that your air conditioner isn’t frozen, but chances are it’s not. A professional can verify this and/or pin point what the actual problem is.
At this point, if you don’t think your air conditioner is frozen, the next most probable cause is a bad AC fan motor.
How Do You Know if Your AC Fan Motor Is Bad?
If you’ve followed the steps above and have found that the problem with your AC fan doesn’t seem to be power related, a bad capacitor, and your unit isn’t frozen up, then it is likely a bad AC fan motor. There are other possible causes such as a bad contactor or possible belt slippage, but they are more rare.
At this point, we recommend having a professional come out and confirm that the fan motor is the problem. From there you can move forward with the proper AC repair and have it operating properly again.
Can Your AC Work Without a Fan?
The AC fan is located in the outside portion of the air conditioner unit. This outside unit is also known as the condenser. This is where the coolant inside the AC system releases it’s heat to be dispersed to the outside air. The AC fan is what delivers this transferred heat from inside your home to the outside environment. This is why you can feel hot air coming out of the outside AC unit when the fan is spinning.
While it would be nice to be able to disregard a problem with an AC fan, it’s not recommended. A properly working AC fan is essential for the operation of an air conditioner. Without the fan operating, the heat cannot be transferred out which can result in big problems and repair costs such as replacing the AC compressor.
Wrapping It Up
I hope this has given you some understanding as to why your AC fan isn’t working properly. In most cases, the problem is a power supply issue, a bad capacitor, a frozen AC unit, or a bad fan motor. In rare cases the problem can be a bad contactor or some other culprit.
Unless the cause of the AC fan not working is a simple power issue, we recommend contacting a professional to troubleshoot the problem and to repair it properly.