How can I fix a sub-zero refrigerator that is not cooling properly?

To fix a Sub-Zero refrigerator that is not cooling properly, follow these steps:
1. Check the temperature settings: Ensure the refrigerator and freezer temperatures are set correctly. The recommended temperatures are around 37°F (3°C) for the refrigerator and 0°F (-18°C) for the freezer.
2. Clean the condenser coils: Dust and debris can accumulate on the condenser coils, affecting cooling efficiency. Clean them using a coil brush or vacuum cleaner.
3. Inspect the door gaskets: Check the door gaskets for any damage or wear. Replace them if necessary to maintain a proper seal and prevent cold air leakage.
4. Ensure proper ventilation: Ensure enough space around the refrigerator for proper airflow and ventilation.
5. Check the evaporator fan: Make sure the evaporator fan is working correctly. If not, replace it to improve cooling performance.
7. Verify the refrigerant levels: Low refrigerant levels can hinder cooling. If you suspect a refrigerant leak, contact a professional Sub-Zero appliance repair service to diagnose and fix the issue.
If these steps don't resolve the problem, it's best to seek assistance from a certified Sub-Zero technician for a thorough diagnosis and repair.