If your outdoor AC unit's fan turns too slow or not at all, you may wonder if there's something wrong with it. If a fan motor doesn't receive enough electrical power from the unit's AC capacitor, it may not operate properly. In addition, the fan's inability to spin can cause a number of issues with the outdoor unit, including a bad compressor. Here are things that might happen if your fan motor doesn't receive enough power from the capacitor and what you can do to prevent them.

Why Is the Fan Motor So Important?

Without a functional fan motor, the condenser coil can't remove heat from the outdoor unit. The fan motor consists of two parts: blades and a motor. The motor should receive enough electrical power from the AC capacitor to turn its blades at a speed of about 1725 rpm. The AC capacitor is a small, metal canister that sits securely inside the outdoor unit's housing. If the capacitor becomes too damaged, old or rusted, it may not have enough energy to power up the fan. 

Poor electrical power to the motor can make it's blades spin slower than normal, or not at all. The motor can eventually give out from the overload and stress placed on it. You should understand that a nonworking fan motor can't help the condenser coil eject heat from the unit, which can potentially cause problems with the compressor motor.

The compressor motor is the part of the outdoor unit that receives hot refrigerant gas from the indoor unit. The motor increases the refrigerant's heat load in order to transfer it to the condenser coil. You might even hear the compressor motor inside the unit hum or struggle to compress and transfer heat to the condenser coil when the fan quits. Eventually, the compressor overheats and/or fails because it can't discharge or release the heat inside it.

To avoid the issues mentioned above, check the AC capacitor now.

How Do You Check the AC Capacitor?

The first thing you should do is turn off the AC system's power at the circuit breaker. You can also pull out the fuses inside to the outdoor unit's power box. You'll encounter many electrical parts during your maintenance check and repairs. Next, allow the outdoor unit time at least 30 minutes or so to cool down. The cooling down period may vary, so use your best judgment.

After the unit cools, locate the capacitor, which is usually found at the back of the unit and hidden behind a small, removable panel. Before you do anything to the fan motor, you must discharge power to the capacitor. Even if the capacitor is damaged, it can still convey electricity.

Now, examine the condition of the capacitor's canister. If the part appears rusted, warped or bulged out anywhere on its surfaces, it's most too damaged to support the fan motor. You can try to replace the capacitor, but this may not be as simple as you think. Even if you purchase the same capacitor brand for your unit, you may still need to replace its electrical wiring and mounting bracket if they have any type of damage.

In addition, it's a good idea that you upgrade the power or voltage capacity of the capacitor to prevent future problems with the fan motor. If you select a part with too little or too much power, it may not support the fan properly. It may be in your best interest to contact a contractor to avoid these issues.

Once you have a new capacitor in place, the fan motor should operate at it's correct speed and keep the condenser coil cool. If you have any future problems with your fan motor, schedule an appointment with a heating and air conditioning contractor today.