How to Test a Chest Freezer Compressor

A chest freezer.
  • 2 hours
  • Intermediate

A chest freezer compressor is part of a system designed to freeze food to keep it from spoilage. The compressor circulates the refrigerant gas to raise its pressure and temperature. The heat is then dissipated inside the Condenser coil, then cools down some through the expansion valve before reaching the evaporator coil which absorbs the warm humid ambient air while releasing cool dry air to cool the freezer.

The compressor is the component needed to compress and circulate the refrigerant in order to maintain the action that actually "freezes" food and keeps it frozen. Because of the importance of this component, it is expensive both to buy and to repair. If your freezer is not working the way it should or food is not kept at the temperature you had set, the first thing you should do is to have your compressor checked out and tested. Follow the steps below to test your chest freezer compressor to determine whether or not it needs to be replaced.

Step 1 - Take Readings

Read the instruction manual of your chest freezer as not all appliances are the same. Consult the troubleshooting section to take the first steps in identifying the problem and solution.

Step 2 - Turn on Your Freezer

Plug your freezer in and check if its light functions or there is a sound coming from the fan or motor. If everything functions well, but your freezer is still having trouble, try to plug in any appliance that needs the use of electricity to function. If it works, examine your circuit breakers or fuse.

Step 3 - Check the Evaporator Coil

Remove the panel and take a look at the chest freezer’s evaporator coil to see if heavy frost has formed. If it has, this may be the reason why it is not cooling well. This is applicable for self-defrosting chest freezers. If your chest freezer is not of this kind and it’s not cooling well, then you must defrost it. Confirm if the temperature is in the right setting.

Step 4 - Identify the Noise Generated Inside Your Chest Freezer

Activate your chest freezer, and listen carefully to the sound it is making. If there are noises coming from it, identify the source. If the sounds are coming from inside, it may be caused by a fan when the freezer door is opened and closed. If it’s noisier when open, then there is something wrong with your evaporator fan motor. This is an indication that it needs replacement.

If the noise is coming from the outside back of the appliance, then it’s either the compressor or the condenser fan. If it’s the compressor, you must change it. If it’s the condenser fan, a thorough cleaning may fix the problem.