⚠️ WARNING / ELECTRICAL HAZARD. This appliance operates with High Voltage or residual charges. Physical intervention is highly dangerous and it is strongly recommended to rely on a qualified specialized technician to avoid electrocution. ReeFix provides this diagnosis EXCLUSIVELY for educational and informational purposes.
Your Liebherr CBNef 4815 has a refrigerator compartment that is too warm, while the freezer works but with unstable temperatures. This scenario suggests a specific problem with the fridge circuit or its management, with a possible indirect impact on the freezer or a secondary fault. The most probable cause (65-75%) is related to the defrost system or cold air distribution.
Quick checks (to be performed with the appliance off and disconnected from the mains, if you intend to open doors or compartments):
Freezer ice inspection: Empty the freezer and remove the rear internal panels (if accessible without specific tools and with caution). Look for excessive ice buildup on the evaporator coils. A thick ice block is the most common sign.
Evaporator fan and air damper check: Listen carefully if you hear the freezer fan running when the compressor is active. Check for obstructions (food, ice) around the fan or the air passage openings towards the fridge.
Door gaskets: Visually check the gaskets of both compartments. They must adhere perfectly. Insert a sheet of paper and close the door; if the paper slides out easily, the gasket is not sealing.
Immediate decision: If you find a massive ice block (more than 1-2 cm thick) on the evaporator, or the freezer fan is clearly blocked by ice, you can attempt a complete manual defrost (turn off the fridge for 24-48 hours with the doors open). If after defrosting the problem reappears within a few days/weeks, a fault in the defrost system or the fan is almost certain. In both cases, it is advisable to call a technician.
If the checks in PHASE 1 did not reveal obvious problems or did not resolve them, the problem is more complex and requires professional intervention.
Temperature sensors (Medium-High Probability): The technician will check the resistance of the refrigerator and freezer compartment temperature sensors. A faulty fridge sensor could send incorrect readings to the control board, making it believe the temperature is correct and not activating the necessary cooling. Inaccurate freezer sensors can cause the observed fluctuations.
Main control board (Medium Probability): The board manages all components: compressor, fans, defrost, dampers. A fault on this board can manifest with complex and seemingly disconnected symptoms, like yours. It might not correctly activate the defrost heater, misinterpret sensors, or fail to control the fan/damper.
Refrigerant circuit or compressor (Low-Medium Probability): If the compressor is weak, or there is a partial refrigerant leak or a partial blockage in the circuit, cooling efficiency decreases. The freezer might still work, but with difficulty and fluctuations, while the fridge, receiving "less cold" air, is more affected.
Estimated costs for professional repair (including labor):
If after a manual defrost the ice problem quickly reappears (within 1-2 weeks) and the fridge remains warm, or if the fan is blocked, the cause is almost certainly a component of the defrost system or the fan itself. Contact a technician.
If the technician diagnoses a problem with the control board or the refrigerant circuit/compressor, and repair costs exceed 50-60% of the value of a similar new refrigerator (considering the age of your Liebherr), it might be more cost-effective to replace the appliance.
Operational decision: If you find excessive ice or a blocked fan, attempt manual defrost; if the problem persists -> contact a technician; if the technician's diagnosis indicates a control board or refrigerant circuit issue with high costs -> consider replacement.