Polar Refrigerator Error Code Flash 4

Flash 4 indicates that the AC heater relay on the main control board (power board) is stuck in the closed position and cannot open. This relay controls power to the defrost heater circuit, and when it welds shut, the control system detects the fault and triggers this error code. The refrigerator cannot properly manage its defrost cycle while this fault is active. Replacement of the main control board assembly is the specified corrective action.

A power cycle reset will not clear Flash 4 because the fault is caused by a physically damaged relay with welded contacts on the control board. The stuck relay condition persists regardless of whether the unit is power cycled. The error will return immediately upon restart until the faulty main control board is replaced.

The cost to repair Flash 4 primarily involves the price of the main control board assembly plus labor for installation. Parts costs for control boards on commercial-grade refrigerators typically range from $80 to $300 or more depending on the specific model. Total repair costs including a qualified technician's labor generally range from $150 to $450, though prices vary by region and parts availability.

Resolving Flash 4 requires replacing the main control board assembly, which involves working with mains voltage components. Technicians with experience in appliance board replacement can perform this repair, but it is not recommended for those unfamiliar with electrical safety procedures. Before installing a new board, it is also worth testing the defrost heater for a short circuit to avoid damaging the replacement part.

Continued operation with a stuck-closed heater relay is not recommended. The defrost heater may remain energized continuously, which could lead to excessive heat buildup in the defrost circuit and potential damage to surrounding components including the evaporator or liner. The refrigerator's cooling performance is also likely to be compromised while this fault is active.