The AC fan motor is a rather simple yet vital component of your air conditioning unit. The air through the system gets pumped from the fan motor, which makes your home cool. The fan motor works hard and, as a result, will be subject to wear and tear.
If the fan motor develops a snag, the cool air will stop blowing from your AC and you would not want that to happen on a particularly Bay Area warm day. Here are a few signs that will indicate that you are having a failing fan motor in your AC unit:
The Fan Fails to Start When the AC is On
When you turn on the AC and the fan refuses to start, it is a direct sign that the fan motor may have developed a fault. If you continue to run the AC without the fan working, the evaporator coils could eventually freeze over. This will lead to more damage to your air conditioning unit. Therefore, call a trained HVAC technician right away.
The Fan does not Stop When the AC is Switched Off
This is the reverse of the previous problem. Even after you have shut off the air conditioner, the fan might continue to run. If this problem has occurred because of a defect in thermostat, you may need thermostat replacement. But if that issue is ruled out, chances are that the relay switch is stuck. When this happens, the circuit remains closed. Consequently, the fan will continue to run because the electric supply to the fan motor will not stop.
The Fan is Operational but Runs Slowly
Your AC fan may be operating, but the blades could be rotating a slow speed. As a result, very weak airflow will be produced by a slow moving fan. If your AC unit has multiple fan settings, first check if it has been set at a low speed. But if you find that is not the issue, it might indicate that the bearings of your fan motor require oiling or the capacitor is failing.
Intermittently Operating Fan
An intermittently running fan may indicate one of two issues. There could be a loose connection or wire or a short in the fan motor winding. Or, overheating may be occurring in the motor, which could cause it to cut out. For your own safety, do not attempt to repair an electrical fault on your own, and contact a reliable HVAC technician for this job.
Condenser Unit Makes Noise When the Fan is On
Noise in your AC unit could occur for a variety of reasons. A loud buzzing or rattling noise could indicate a minor problem, such as debris or loose stones which are caught in the condenser unit. However, this noise may also occur because of unbalanced or loose fan blades that are hitting the side of the fan housing unit.
But if you do not find anything stuck in the condenser unit and the fan blades are moving smoothly and freely, it could indicate a problem with the fan motor. A buzzing sound from your AC may, in fact, indicate that the fan motor is nearing the end of its life. Consult with an HVAC expert to fix this problem.