Freezer Compressor Noise

Thermostat Malfunction

• If your compressor emits a constant hum, this is usually because it is running non-stop. The thermostat in your freezer switches the compressor on and off. When the thermostat senses the internal temperature is lower than the temperature at which it is set, it will shut the compressor off. If the thermostat does not do this, it may be malfunctioning. Adjust the thermostat to a lower temperature to see if the compressor shuts off. If it does, it may have been set too high originally. If this does not shut the compressor off, you may need to replace the freezer’s thermostat.

Door Gasket

• The gasket around your freezer door seals the cool air inside. If the gasket is damaged, causing a leak of the cold air, your compressor must run more frequently to maintain the interior temperature since this loss will cause the interior to become warmer. Put a piece of paper between the gasket and the freezer frame and close the door. If you can easily pull the paper out, the door gasket needs to be replaced.

Freezer Position

• Freezers with compressors on the outside back require enough clearance to prevent the unit from touching walls or cabinets. If the compressor is touching another surface, it can cause vibrations and loud noises as it switches on. Move your freezer so that the compressor is not touching any other surface. If the noise continues, adjust the leveling feet at the bottom of the freezer unit until it is level.

Refrigerant Leak

• Compressor noise can sometimes result if you have refrigerant leaking into the sealed system of your freezer. If the noise is not caused by any other component and the thermostat is working properly, contact an EPA-certified technician to inspect your freezer for a refrigerant leak. In the United States, only an EPA-certified technician can legally repair a sealed system, and doing so yourself may void the warranty on your freezer.

Other Components

• The freezer’s evaporator fan is located on the back of your freezer, and may be positioned at the top, bottom or center. When the fan makes noise, it can sound like it is coming from the compressor. Open the freezer door and press the door switch. If the noise is louder when you hold the switch while the door is open, the noise may be coming from your evaporator fan, not your compressor. The fan may make noise if the blades are dirty. If cleaning the blades does not stop the noise, the fan needs to be replaced.