How to Troubleshoot Noises in the Central Air & Heat
- 1). Go outside to the condenser unit and peer through the grille on top to see if any blades have been damaged by foreign objects falling through. Remove the grille if you cannot adequately inspect the state of the blades. Bend a slightly malformed fan blade back to normal, but always replace a badly bent blade to optimize function.
- 2). Inspect the condenser unit's housing if you see no blade obstruction. The noise may be caused by a loose fit. Tighten the access panel screws to solve this problem.
- 3). Turn off the power so you can check the fan motor to the condenser unit with a multi-tester. Set the device to test for continuity and place a probe to each fan wire. The tester should show that there is continuity. Touch one probe to the motor housing and the other probe to the each of the fan's wires and see if there is continuity. If the test fails either way, the motor needs replacement.
- 4). Lubricate the fan's motor if it passes the multi-testing procedure. The noise may be due to dry motor bearings. Lubricating the motor should solve this noise problem.
- 5). Check that the blower motor belt has the proper tension. A motor belt that's either too tight or too loose can cause excessive noise. Press down on the motor belt with your hand, between the motor and blower pulleys. The tension should allow you to deflect the belt roughly 3/4 inch up or down. If the belt shows fraying or damage, you should replace it before running the unit.