Has your central air conditioner recently started making a racket outside while the unit is running? The noise could be coming from a loose or bent condenser fan, which blows on the condenser coils. The fan draws outside air over the condenser coils, which convert gas refrigerant to liquid to send the refrigerant into your home. Problems with the fan can cause more problems than noise, since the condensing unit can become overheated and shut down your system.
Checking and fixing a noisy fan in the condensing unit is a fairly straightforward process. If you feel nervous or uncertain about any step, it is better to call an air conditioning maintenance tech than to accidentally damage the fan or another nearby part.
To get started, assemble the following tools:
- New fan (optional)
- Small hammer
Step 1: Access the Fan
Turn off all power to your central air conditioner using the nearby fuse box and/or the appropriate fuse inside your home.
Examine the case of your condensing unit to figure out how it comes off. Some units have a grated top that simply pulls off while others require you to remove the entire outer casing. Both types will have either screws or bolts holding the unit together. Unscrew the fasteners and lift off the lid or casing.
Step 2: Examine the Fan
The fan blades are attached to a motor shaft, but the way these items are positioned varies between units. You might look inside and automatically spot the fan on top of the shaft, or the shaft could be on top and the fan underneath. Either way, there should be a visible nut that connects those two together.
If the fan is already on top, spin it gently with your hand to check for a wobble while also checking the blades for any damage. If the motor shaft is on top, remove the fastener and then flip the shaft over to examine the fan blades.
Are any of the blades broken or significantly bent? Call an air conditioner repair technician to ask for a new fan. You can gently straighten minor bends with your hand or a small hammer, but only if you feel very confident about the task. Causing more damage to the blades isn't going to help.
Step 3: Tighten and Reassemble
If the fan blades pass inspection but the fan wobbles as it spins, you simply need to tighten the fastener between the fan and motor shaft. Check that the fastener isn't worn or stripped and replace it if necessary. Make sure to firmly tighten the nut with a wrench.
Reassemble your condensing unit case and its fasteners. Restore power to the unit and turn down the thermostat to check for noise. Still noisy? Call in an HVAC tech at a company like Burks Service Company for further diagnosis.