Safe checks before service
Confirm the unit has power, the door is closing fully and the controls have not been changed accidentally. If a temperature setting was recently adjusted, Sub-Zero advises allowing time for the appliance to stabilize.
Check whether one compartment or both compartments are warm. Listen for unusual fan noise and note whether the unit appears to run continuously.
Possible causes
Sub-Zero’s support information lists possibilities such as fan problems, temperature-sensor or thermostat faults, compressor/evaporator/condenser issues and door-seal problems. These symptoms overlap, so testing is needed before a repair decision.
Food safety matters
If food temperatures are unsafe, move perishable items to reliable refrigeration. Do not rely on a displayed set point if the actual compartment is warm.
Frequently asked questions
Why is my Sub-Zero running but not getting cold?
Possible causes include airflow, fan, sensor, door-seal or refrigeration-system problems. The exact cause requires diagnosis.
Should I keep resetting the refrigerator?
Repeated resets can hide a symptom temporarily without correcting the underlying problem. Record the symptom and model number for service.