Samsung Air Conditioner Error Code P427

P427 is an outdoor unit reverse phase detection type 3 error. It means the control board has detected that the three-phase electrical power supply is arriving in the wrong sequence. The system locks out to protect the compressor from rotating in the wrong direction, which can cause serious mechanical damage. Correcting the phase wiring at the supply or terminal block is required to clear this fault.

No. The P427 error causes the outdoor unit to shut down as a protective measure. Attempting to bypass this protection and run the compressor with reversed phase rotation can cause immediate and severe compressor damage. The system should remain off until the phase wiring is inspected and corrected by a qualified technician.

If the cause is a wiring correction, costs typically cover a service call and labor only, generally in the range of $75 to $200 depending on your location and the technician's rate. If the outdoor unit main PCB requires replacement due to a faulty phase detection circuit, parts and labor combined can range from $300 to $700 or more. Getting a diagnostic assessment from a licensed technician will clarify which repair applies to your situation.

Diagnosing and correcting a reverse phase error involves working with high-voltage three-phase electrical supply, which is dangerous without proper training and equipment. A licensed electrician or certified HVAC technician should perform this repair. The fix itself, swapping two of the three phase conductors, is straightforward once the problem is confirmed with a phase rotation meter.

A simple reset will not permanently clear P427 because the control board will detect the phase reversal again as soon as the unit attempts to restart. The underlying wiring issue must be corrected first. After the phase rotation is confirmed correct, the error should clear and normal operation can resume.