Bertazzoni Wine Refrigeration / Wine Cellars E4 Error: Cabinet frost sensor failure
What Does E4 Mean on a Bertazzoni Wine Cellar? E4 on a Bertazzoni wine column indicates a failure of the refrigerator (cabinet) frost sensor — the defrost termination thermistor on the evaporator. This sensor tells the control board when to end the automatic defrost cycle by detecting that the evaporator has reached the target defrost […]
Quick Assessment
Answer to continue safely
Is it safe to keep using?
No. Unchecked frost accumulation will progressively degrade cooling performance and compromise wine storage temperatures; the sensor must be replaced.
Can I reset the code?
No. E4 reflects a physical sensor failure; a power-cycle does not restore sensor function and the fault will recur after the next defrost cycle.
When to stop immediately?
Stop if you notice: Frost accumulation is visible and growing on the evaporator area., Wine zone temperature is rising above the set point with the compressor running..
Symptoms You May Notice
Frost visible on wine column evaporator or rear wall
More frost than usual accumulates on the rear interior surface or evaporator fins because the defrost cycle cannot terminate at the correct temperature.
Wine storage zones gradually warm above the set temperature
As frost insulates the evaporator coils over days, the unit's ability to absorb heat declines and the internal temperature drifts upward, affecting wine preservation.
Possible Causes
Failed evaporator defrost thermistor
The thermistor that signals the end of the defrost cycle at the target evaporator temperature has failed open or shorted.
Requires ProfessionalBroken or corroded sensor wiring
The wiring or connector to the frost sensor has deteriorated in the cold, damp evaporator environment, breaking the signal.
Requires ProfessionalSafe Checks You Can Do
-
1
Check the rear interior for heavy frost
Open the wine column and inspect the rear panel. A thick slab of frost concentrated on or around the evaporator area confirms the defrost cycle is impaired.
A light uniform frost mist is normal; a growing solid frost layer is abnormal.
-
2
Manually defrost the unit
Remove the wine, switch off the column, and leave the door open for several hours until all frost has melted. Dry the interior thoroughly before restoring power.
Move wine to a cool dark location during defrosting — avoid large temperature swings by wrapping bottles in towels.
When to Call a Professional
Contact a qualified technician if:
- E4 returns after a complete manual defrost and power-cycle.
- Defrost thermistor resistance is outside the specified range.
- Frost re-accumulates within days despite manual defrosting.
Need Professional Help?
Find qualified technicians in your area for proper diagnostics and repair.
Wine Refrigeration / Wine Cellars Repair Service Schedule Appointment