A standard central air conditioning unit consists of two parts — the outdoor condensing unit and the interior air handler. The air handler houses the fan and the blower motor, which are the parts that move the cool air throughout your home. There are a few parts inside the air handler unit that can fail, but you can avoid a total breakdown by knowing the most common issues.
1. Clogged Filter Housing
Most homeowners know to regularly change the air filter in the air handler, but the housing for the filter is often overlooked. Dust and debris can build up in the housing, especially if you have pets. The dirt then can clog up a new filter more quickly or even make its way into the unit where it will lead to motor or fan damage. Each time you change the filter, use a large duster brush or the hose on your vacuum to clean out the housing.
2. Fan Belt Damage
The fan belt connects the fan to the blower motor. Over time, this belt can develop wear and tear, such as cracks or stretching. You can often hear when the belt is failing — the AC may make a whining noise when the fan first powers on. Fortunately, a failing fan belt won't require any in-depth repairs. Your AC technician simply needs to replace it. Don't ignore a failing fan belt, though, or you may find yourself abruptly without AC.
3. Motor Burn Out
The blower motor powers the fan. It can burn out from age or from dust entering the system. The best way to prolong the life of the motor is to have your air handler serviced annually. Your tech will clean the motor, check the bearings, and lubricate the moving parts so that everything works well. This prevents break down and can add years of life onto the motor, thus saving you the expense of a premature AC replacement.
4. Limit Switch Failure
One issue that can be puzzling is when the AC fan powers on as it should, but then it just keeps going and won't shut down. This problem typically means that the limit switch has failed. The job of this switch, which is attached to the motor, is to turn off the fan at the end of the cooling cycle. The good news is that limit switch failure is a minor problem. Your tech can quickly replace it so your unit is as good as new.
Contact an AC repair service in your area for more help with your air handler concerns.