Problems With Air Conditioner and Rattling

Debris

• The first place you can look for air conditioner noise is the fan condenser housing. Debris, such as sticks, plastic bags or leaves, can fall or get inserted into the fan housing. When the fan rotates, it can strike the object or the object can wrap around the fan gears, causing it to make a noise every time the fan rotates. With the removal of the air conditioner fan housing panels, the fan housing can be examined. All foreign objects should be removed.

Fan Installation

• If the fan isn’t installed correctly, the fan may strike the sides of the fan housing as it turns. Not only does this cause a noise, it prevents the fan from blowing properly. After the fan housing panels are removed, you can give the fan a spin and observe whether the blades strike anything. You may even see marks inside of the housing where the fan has struck. The fan should be uninstalled and reinstalled correctly, so that it swings freely.

Ball Bearings

• Non-lubricated fan ball bearings can cause a lot of noise and hinder the effectiveness of the condenser fan. With the fan housing panels removed, the state of the ball bearings can be determined when the fan is spun. If the fan doesn’t spin freely or makes a noise, the ball bearings should be lubricated with motor oil through the lubrication holes on the fan motor.

Window Frame

• Poor window installation produces rattling, if the air conditioner in question is a window unit. The window unit should be securely fastened down both in and outside of the frame for safety. Before installing the unit, you may pad the windowsill and sash with weather stripping. Not only will this prevent metal-on-metal contact of the unit to the window frame, but also it prevents cold air from escaping the room.

Duct Work

• Duct work of all makes, such as flexible ducts, small ducts and metal ducts, can cause a rattling noise as it contracts and expands, if not secured against a wall or beam. Wherever possible, you can examine the state of the duct work of the unit. If you see that it’s loose, the duct could be the cause of the rattling as the unit runs. Duct work can be secured with special straps or tape.