If your freezer is defrosting instead of keeping your food cold, the first thing to check is the door. The seals may be worn, and that's an easy fix. It's also possible that people in your household are opening the door too often or not fully closing it, and that should also be easy to remedy.
Once you've eliminated the door as a cause of your freezer issues, you can move on to other possibilities. The problem may be one that causes other malfunctions in the appliance, which makes it easier to diagnose, but barring that, it's best to start with the problems that are easiest to diagnose and repair and proceed from there. Repair Clinic specifies 10 such problems.
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Check Evaporator Coils For Freezer Issues
The evaporator coils are where cooling happens as liquid refrigerant passes through them and turns into vapor, which is the process that removes heat from the surrounding air. Evaporation and heat exchange are hindered if the coils are covered with dirt, so cleaning them may restore the freezer's functionality.
The evaporator coils are located right behind the freezer and shouldn't be confused with the condenser coils, which are below them and actually radiate heat. Both sets of coils need to be cleaned periodically, but the evaporator coils are more sensitive and need it more often. Use a rag or brush to do the job.
You may also find the evaporator coils covered with a layer of ice, which is just as effective at hindering heat exchange as dirt. When the coils are iced over, you generally need to unplug the refrigerator and leave it off until all the ice has melted. If your freezer has an automatic defroster, you shouldn't encounter this problem.
Faulty Controls Can Alter the Freezing Cycle
Although electronic malfunctions can be difficult to diagnose, they're easier to repair than a fault with the refrigeration system. Any one of the following electronic components could alter the freezing cycle and be the reason why the freezer temperature keeps going up and down:
- The start relay for the compressor.
- The temperature control thermostat and sensor.
- The main control board.
Detecting a faulty component usually requires continuity tests, which you can do with a multimeter set to measure resistance. You generally have to unplug the refrigerator and disconnect the component you're testing, and during the procedure, you may find a loose or broken wire that's the source of the malfunction.
Faulty Compressor or Refrigeration System
Failing to find a simple cause for the freezer issues, it's time to turn to the heart of your refrigerator or freezer — the refrigeration system. The compressor is the engine that drives the refrigerant, and if it has weak seals or is otherwise malfunctioning, the freezer won't get cool. Suspect this problem if the compressor makes strange noises or cycles on more frequently than it should.
If you don't suspect the compressor, the last possibility is a leak in the refrigeration system. Without the proper quantity of refrigerant, the coils can't get cool enough to maintain a low temperature in the freezer. Suspect this problem if you detect a musty odor behind the refrigerator.
Malfunctions of the refrigeration system, including the compressor, must by law be repaired by a licensed service technician. So, if you've narrowed the problem down to the compressor or refrigeration system, you need to call an appliance pro. Do it as quickly as possible, especially if you suspect a leak because refrigerant vapor is harmful to your health and the environment.