The air conditioner (AC) can only cool your house by blowing cool air into different parts of the house. The AC fan is responsible for getting the cool air moving. Thus, a malfunctioning AC fan easily leads to inefficient cooling. Below are some of the reasons an AC fan might malfunction.
Power Supply Interruption
Your AC needs electricity to run the motor, which in turn runs the fan. Thus, a power interruption will result in the fan not running at all. An example is if the circuit breaker has tripped.
The fan blades are tough but destructible. For example, a hard object can get trapped inside the assembly and damage the fans. Damaged fan blades might lose the aerodynamic shapes that allow them to rotate efficiently. Damaged blades cannot rotate efficiently if they keep hitting the fan casing.
Even if the fan blades don't suffer damage, foreign objects inside the fan casing can still interfere with their rotations. The fan blades will keep hitting the foreign object as they try to rotate.
Start Capacitor Failure
A capacitor is an electronic device that stores and releases electrical charge. The start capacitor provides the electrical burst that enables the fan motor to start running. A failed capacitor might not provide adequate electricity for the motor.
Damaged or Worn Bearing
The fan motor uses bearing for easy rotation. Damaged or worn bearings, due to poor lubrication, will interfere with the operation of the motor.
In some AC models, especially older models, a belt connects the motor to the fan. Damage to the fan belt, for example, due to wear and tear, can snap the belt. The fan won't rotate at all if the belt breaks, but it might run erratically if the belt is only loose.
The AC fan only runs if it gets the right signals from the thermostat. That is why you can set the fan to run even if the AC is not actively cooling. Thus, a disconnect between the thermostat and the fan motor can prevent the fan from running when you need it.
Overheating can damage the fan motor. The motor typically comes with a safety switch to disconnect it if the motor starts to heat. However, the motor can burn out if the safety switch fails, and it overheats.
Luckily, most of the reasons for AC fan malfunction are things you can correct. Consult air conditioning repair service to diagnose and fix the problem so that you can get your house comfort back.