How To Clean Your Central Air Conditioning System's Blower Fan

16 March 2015
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The all-important task of circulating cooled air in your home's central air conditioning unit is performed by a blower fan. If there is an accumulation of dust and debris inside the blower fan and its housing, then your system will fail to work as it should. Below is how you can remove the grimy buildup inside your air conditioner's blower fan:

Blower fans explained

The blower fans found in most central air conditioning systems are centrifugal-type fans; these fans are also known as squirrel cage fans due to their resemblance to hamster exercise wheels. They are mounted inside an enclosed housing that funnels air into the duct work. Small blades around the outside circumference of the fan "scoop up" the air molecules and "fling" them into the duct. The entire blower fan assembly is located inside the air handler, which serves as a central collection point for distributing cooled air.

Centrifugal fans are powerful, efficient, and quiet; this makes them ideal for the continuous work they often perform within a central air conditioning system. However, one drawback of using centrifugal fans is the ease with which they accumulate dust and tiny particles that are distributed through central air conditioning systems. This accumulated material adds weight to the fan, which decreases efficiency as the motor struggles to keep it turning. In addition, accumulated material also can penetrate bearings and other sensitive components, and that can shorten the lifespan of the fan and system itself.

How to clean blower fans

Fortunately, it's not difficult to clean your blower fan as long as you keep a few safety precautions in mind and pay attention to your work environment. Here is what you need to do:

1. Disconnect the power from the blower by turning off the appropriate switch at the circuit breaker panel. You may also have a simple on/off switch mounted near the air handler, but in all cases, be certain there is no electrical current present inside the unit before opening it up.

2. Once you are sure the unit is not energized, locate and remove the access panel that covers the blower. It may be attached with sheet metal screws or it may simply lift-up and pull out, depending on the manufacturer and model. Be careful not to pinch any wiring or damage any sensitive components.

3. With both the fan and motor exposed, inspect the internal components for dust and debris buildup. Brush the fan blades with a soft-bristled brush and use a wet/dry vacuum to remove the debris as it comes loose. Try not to allow debris to drift into any other areas such as the evaporator coil. If you are satisfied that most of the material has been removed, replace the access panel and restore power to the unit.

4. If the accumulated buildup can't be readily removed by brushing and vacuuming, you will need to remove the blower fan for a more thorough cleaning.

5. Find the screws that mount the motor to the blower fan housing. Remove these screws and set them aside in a safe location.

6. Unplug any wires leading to the blower fan motor. Before doing so, take a quick photograph of the wiring so you will know where everything is attached. 

7. After unplugging the wiring from the fan blower, pull the blower fan and motor assembly from the housing.

8. The blower fan will be attached to the motor shaft using a set screw or some other fastener. Remove this fastener so you can pull the blower fan free from the motor; remove the fan and set the motor aside.

9. Mix a solution of warm water and two tablespoons of a grease-cutting, liquid dish-washing detergent inside a washtub or other large container and immerse the blower fan. After permitting it to soak for about ten minutes, use a plastic bristled brush to scrub away the accumulated grime.

10. Rinse the blower fan with clean water and allow it to dry completely. Once dry, wipe it down with a cloth lightly moistened with an all-purpose machine oil. Reattach the blower fan to the motor, plug-in wiring and re-install the fan and motor assembly in its housing.

11. Reattach the access panel and restore electrical power to the unit.

Should you not have time to do this yourself, you can call experts from sites like http://www.capefearair.com.