Not Cooling · sign 6 of 6
A Temperature Alarm After Every Defrost
A temperature alarm that follows each defrost means the cabinet is not recovering from a warm spell it is designed to absorb, and that narrows the causes.
Sub-Zero Repair Sammamish · (425) 610-8986 · $89 service call, credited
- Compiled by
- Marta Fennimore
- Holds
- EPA 608 certified
- Dated
- Years at the work
- 12
What you notice
The alarm keeps a schedule of its own
Depending on the series, a temperature warning shows on the display or the service indicator lights, and it happens at what look like regular intervals rather than after a long door opening or a load of warm groceries. Sometimes the soft crackle of the freezer defrosting comes shortly before it.
The alarm clears, the cabinet cools again, and later the same thing repeats. That steady rhythm is the most useful clue an owner can bring to the diagnosis.
Sub-Zero Repair Sammamish · (425) 610-8986
What it points to
Defrost warms the coil on purpose, and the cabinet should absorb it
A freezer clears frost from its evaporator by warming it briefly. Sub-Zero's service material for the 600 series describes a defrost heater and a thermostat that ends the heating. A healthy cabinet barely notices; its temperature rises a little and recovers.
An alarm after every defrost says that recovery is failing. The usual directions are weak air across the coil, from a slow evaporator fan or ice around it; a coil that never clears fully, so frost builds between cycles; or a sealed system that can no longer pull the cabinet back down.
Defrost timing and alarm points vary by model, so the pattern counts for more than any single reading.
Sub-Zero Repair Sammamish · (425) 610-8986
Safe checks
Owner checks before the next defrost comes around
Keep to the doors, the display and the grille; the coil and its heater sit behind panels.
- Log the alarm times
Write down when each alarm starts and clears for two or three days; a steady interval is what points toward defrost.
- Check the doors and gaskets
Each door should close fully, with no torn or flattened gasket and no packaging pushed against the fan inside.
- Look for ice bridging the coil cover
After an alarm clears, note whether ice still bridges the fan cover at the back of the freezer.
- Reset a lit service indicator
On Classic units Sub-Zero says to switch off with POWER, make sure the condenser area is clean, then switch back on.
That is where an owner's part ends. Panels, wiring and refrigerant are a technician's work — Sub-Zero Repair Sammamish, (425) 610-8986.
When to call
Call when the alarm returns after the reset
If the service indicator lights again after that reset, if it flashes, which the Classic guide treats as a reason for service right away, or if the alarm keeps pace with the defrost for more than a couple of days, the next steps are behind panels. Fan, heater, thermostat and the refrigerant charge are all tested there.
Bring the list of alarm times to Sub-Zero Repair Sammamish. The $89 service call is credited to the repair.
Sub-Zero Repair Sammamish · (425) 610-8986
