Sub-Zero builds its refrigerators around dual refrigeration — a separate compressor and evaporator for the refrigerator and freezer compartments — which is why one side can fail completely while the other keeps working. It also means a warm fridge over a cold freezer is almost never a simple thermostat problem. Add a condenser that clogs quietly behind the grille and heavy panel-ready doors that wear their gaskets faster than most, and you get failure patterns a general-brand tech can easily misread.
We start with measurements, not guesses: compartment and evaporator temperatures, defrost operation on the affected circuit, condenser condition, and door seal integrity. You get a written quote before any part is ordered, and we only recommend sealed-system work when the numbers actually point to it.
Sub-Zero refrigerator warm but freezer works fine
On dual-refrigeration models, the refrigerator compartment has its own evaporator, so when the cold stops there, the freezer keeps running as if nothing happened. Most of the time the refrigerator-side coil has iced over because defrost failed, or the evaporator fan has quit moving air across it.
Sub-Zero high temperature alarm keeps coming on
Sub-Zero's condenser sits behind the grille and collects dust and pet hair for years without anyone seeing it. When airflow drops, the compressor runs hot, compartment temperatures creep up, and the control triggers the alarm — often before food actually shows it.
Sub-Zero door not sealing or sweating at the frame
Panel-ready Sub-Zero doors carry real weight — custom cabinet panels add pounds that the hinges and gaskets absorb every day. Over time the gasket compresses and tears at the corners, and a sagging hinge can hold the door slightly proud of the cabinet, enough to let warm, humid air in around the clock.
Sub-Zero refrigerator not cooling on either side
When both compartments go warm, we look at what they share: power, the control board, and airflow through the condenser. Sealed-system faults do happen on these units, but we confirm them with temperature and electrical readings before quoting that class of repair — it is the most expensive misdiagnosis in refrigeration.
Independent Sub-Zero service, tested before quoted
PV Appliance Repair is an independent, insured service company — we are not affiliated with or certified by Sub-Zero, and we never present ordinary trade experience as factory authorization. What you get instead: a technician tests the actual failure, explains the finding, and gives you a written quote before any work starts. The service call is waived when you approve and complete the repair, and if we can't fix it, you don't pay. Every completed repair carries a 90-day warranty on the documented work and installed part.