How to Fix a Noisy Compressor

How to fix a noisy compressor problem on the heat pump when it is making a sound such as gurgling, rattling, humming, high pitch, whistle or ...

The compressor is a mechanical pump driven by an electric motor contained in a welded or hermetic shell, and is equipped with the internal motor protection. Before troubleshooting allow compressor to cool and protector to close. Mechanical problems are very hard to check and fix while electric side is easier. Most failures on the electric side are due to an open, grounded or short circuit. Turn the power off and disconnect the lead before testing.

One of the problems with the compressor is that it runs but does not pump the refrigerant resulting in overheating.

Gurgling sound coming from the compressor indicates that the liquid refrigerant is returning to the compressor. The reasons for the gurgling noise are dirty coils, loss of evaporator blower and improper airflow.

Rattling noise is due to the loose components, which should be checked, and re-tighten or internal compressor components. Also the rattling issue happens due to the pressure differential issues and can be solve by a quiet shift, if possible.

High pitch noise during operation that can resonate through the suction line can be fixed by adding the field-fabricated suction line loop (per Carrier manufacturer for scroll compressors) or by adding the discharge muffler in a case of the reciprocating compressors.

Whistle sound on shut down may indicate a refrigerant leak and a check valve could solve this problem.

Humming noise of the compressor that also won’t start indicates a voltage or amperage issues.

Swooshing” sound is heard when the heat pump switches into or out defrost and is the result of the pressure change. The sound is made by a reversing valve as it begins or ends defrost and the pressure equalize. There is no a solution that will fix this problem, while the insulation of defrost sensing device or incorporating quiet shift might help but not eliminate the sound. The reverse valve is generally easy to troubleshoot (using the ohmmeter) and replace.

Vibration during the startup that goes away quickly after is the indication of refrigerant migration to the compressor where it changes its state from vapor to liquid. The solution for this is a proper charge, and installation of the crankcase heater.

These are just some of the sounds that can be heard during the proper and improper compressor operation.

› Fixing Compressor Noise