If the cooling plate (evaporator) in the lower compartment of your fridge is covered with ice on half side only, and the cooling efficiency is lower than usual, it is likely due to a problem with the automatic defrost system. Modern refrigerators are designed with an automatic defrost system to prevent excessive ice buildup on the evaporator, which can lead to cooling issues. Here are the probable causes and what you can do to address the problem:
1. Defrost Timer or Control Board:
- The defrost system in your fridge relies on a timer or control board to activate the defrost cycle at regular intervals. If the timer or control board is faulty, it may not initiate the defrost cycle as needed, leading to ice buildup on the evaporator.
- Check the defrost timer or control board for any signs of malfunction. If it's defective, you may need to replace it.
2. Defrost Heater:
- The defrost heater is responsible for melting the ice that forms on the evaporator during the defrost cycle. If the defrost heater is faulty, it may not adequately melt the ice, causing it to accumulate on the evaporator.
- Inspect the defrost heater for any signs of damage or malfunction. If it's defective, it will need to be replaced.
3. Defrost Thermostat:
- The defrost thermostat is a temperature-sensitive device that monitors the temperature of the evaporator. It signals the defrost heater to turn on and off during the defrost cycle.
- A faulty defrost thermostat may not signal the heater to activate, resulting in excessive ice buildup on the evaporator.
- Check the defrost thermostat's continuity with a multimeter. If it's faulty, replace it.
4. Airflow Issues:
- If there are obstructions or problems with the fans or vents that circulate air in the refrigerator, it can lead to uneven cooling and ice buildup on the evaporator.
- Check for any blockages or malfunctions in the fans and vents. Clear any obstructions and ensure proper airflow within the refrigerator compartment.
It's essential to address this issue promptly, as excessive ice buildup can reduce the cooling efficiency of your fridge and lead to further problems. If you are unsure about diagnosing or fixing the problem yourself, it's best to seek the assistance of a professional appliance repair technician. They can accurately diagnose the issue and perform the necessary repairs to get your refrigerator back to its optimal functioning.