Samsung Air Conditioner Error Code 425

Error code 425 on a Samsung air conditioner signals a 3-phase power problem at the outdoor unit. Specifically, it means the unit has detected that the three power phases are connected in the wrong rotational order, or that one of the three phases has no voltage present. The system locks out the compressor automatically to prevent mechanical damage.

No. Error 425 indicates the compressor is not receiving correct 3-phase power, and operating the system under these conditions risks serious compressor damage, motor winding failure, or electrical hazards. The unit will typically lock out the compressor automatically, but the underlying electrical fault should be resolved before attempting to restart the system.

Repair costs depend on the specific cause. If the fix is simply re-sequencing the phase wiring at the terminal block, labor costs from an electrician or HVAC technician may range from $75 to $200. If the outdoor control board's 3-phase detection circuit has failed and the board requires replacement, total parts and labor costs typically fall in the range of $300 to $700 or more depending on the unit model and regional labor rates.

Some causes of error 425, such as swapped phase wiring at the terminal block, can be corrected by a qualified electrician without specialized HVAC tools. However, diagnosing the fault properly requires a 3-phase rotation tester, and any work on the high-voltage outdoor terminal block should only be performed by someone qualified to work on 3-phase electrical systems. If the outdoor control board's detection circuit has failed, board replacement is required.

A power reset will clear the active error code display, but the code will return immediately if the root cause has not been corrected. Because 425 is tied to a hard electrical fault, such as reversed phases or a missing phase, the error will reappear on the next startup attempt until the wiring issue or faulty detection circuit is properly repaired.