Five Causes Of AC Fan Failure

Posted on: 27 January 2021

If your AC fan fails, the unit won't be able to cool your home. Knowing the reasons for possible failure can help you prevent or repair them.

1. Broken Blade

Problems with the fan blade itself can cause poor operation. AC blades are made of metal, but they can still become bent or even cracked over time. Dirt and debris inside the fan housing, along with poor lubrication or an out-of-balance fan, make it more likely for the device to break. Annual maintenance can keep the fan clean, lubricated, and balanced so that it lasts the life of the AC. Replacement is necessary if it breaks.

2. Worn Bearings

Bearings in the fan assembly ensure that it rotates smoothly and doesn't suffer friction damage. Over time these bearings can wear out, which means they will actually impede fan movement rather than aid it. When this occurs, the old bearings must be removed so new ones can be installed. Lubricating the bearings can help extend their service life.

3. Stressed Motor

The motor is one of the more expensive components in your AC. It is also the heart of the blower assembly since it powers the fan and ensures the cool air can blow into your home. Motors become stressed when they are dirty, poorly lubricated, out of adjustment, or trying to power a damaged fan. Too much stress causes the motor to burn out, which will require a replacement. Annual tune-ups can prevent most of the above issues, or at least catch them early enough so extensive damage doesn't occur.

4. Failed Electrical Components

The two main components of concern with the fan are the capacitor and the contactor switch. The capacitor stores up the energy for running the fan. If it fails, the fan will no longer power on. Contactor switches control the flow of electricity to the blower motor so that the blower comes on when it should. A failed contactor switch can result in a complete failure for the motor to turn on, or the motor may run constantly, depending on the position the switch is in at the time of failure.

5. Loose Belts

The belt connects the motor to the fan in some AC units, although not all models use a belt. If your model has a belt, then it will need to be inspected annually and replaced periodically. Belts can stretch, tear, and become worn over time, so replacement is considered normal maintenance.

Contact an air conditioning contractor to prevent issues or in the event that the fan needs a repair.