Freestanding Freezer: Frost inside
Some frost inside the freezer is normal, because each time you open the freezer door or lid, warm, moist air enters the freezer and forms frost. But if excessive frost forms quickly inside the freezer, it could be that a damaged lid or door seal is constantly allowing warm, moist air into the cabinet, resulting in excessive frost. Check the door or lid seal and replace the seal if damaged.
A crack in the plastic liner inside the freezer cabinet can also allow warm air into the freezer and cause frost. Check the inner liner and repair any cracks using a liner repair kit.
If you see frost on the evaporator cover in the back of the freezer and the freezer isn't cooling well, then a failure in the automatic defrost system could be causing the frost. If the defrost heating element that melts frost off the evaporator fins fails, frost will cake up on the evaporator and interfere with airflow and cooling in the freezer. A failed defrost bi-metal won't allow current to reach the heater so a failed defrost bi-metal will also cause frost on the evaporator and inhibit cooling in the freezer. A failed defrost timer won't advance into the automatic defrost mode so the defrost heating element would never turn on to melt frost off the evaporator. Check the defrost system if you see frost only on the evaporator cover.
Replace the freezer door or lid gasket
The door seal attaches to the door panel of an upright freezer and the lid seal mounts to the lid of a chest freezer. The seal prevents air from entering or escaping the freezer when the door or lid is shut. A damaged seal lets warm, moist air into the freezer when the door or lid is closed, causing excessive frost and cooling problems. Replace the door seal if it's damaged or torn.
Replace the freezer defrost bi-metal
The freezer defrost sensor-also known as the defrost bi-metal or defrost termination thermostat-is next to the evaporator. It trips when the evaporator temperature gets too high, to protect the evaporator from overheating. When it trips, the defrost bi-metal shuts off the defrost heater. A defective defrost bi-metal prevents the defrost heater from working, causing frost to build up on the evaporator, causing a warmer freezer interior. Replace the defrost sensor if it prevents the defrost heater from working.
Replace the freezer defrost heating element
The defrost heating element melts frost from the evaporator fins to improve cooling. If the defrost heating element fails, excessive frost covers the evaporator fins. Replace the defrost heating element if it's damaged or not heating.
Replace the freezer electronic control board
The electronic control board-also called the main control board or the power control board (PCB)-manages the compressor and the defrost cycle. The control board activates the compressor to keep the freezer cold and runs the fans. The electronic control board monitors temperature sensors to control freezer temperature and the defrost cycle. Replace the electronic control board if it's not working properly.
Replace the freezer defrost timer
The defrost timer controls the intervals between defrost cycles and limits the length of the cycle. During the defrost session, the timer activates the defrost heating element and prevents the compressor from running, so frost melts from the evaporator fins. Replace the defrost timer if it doesn't control the defrost heater and compressor properly.
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