Samsung Air Conditioner Error Code P426

P426 indicates an outdoor unit reverse phase detection error, specifically a second reverse phase fault. The outdoor unit's control board has detected that the incoming three-phase power supply is connected in an incorrect phase sequence. This is a protective shutdown designed to prevent the compressor and fan motors from running in reverse rotation, which would cause serious mechanical damage.

No. The unit will not operate while P426 is active because the control board has shut it down as a protective measure. Attempting to bypass or ignore this fault and force the system to run could result in the compressor operating in reverse, which causes rapid and potentially irreversible internal damage. The fault should be resolved before restarting the system.

If the fix is simply correcting swapped wiring at the terminal block or disconnect, costs are primarily for a service call and labor, typically ranging from $75 to $200 depending on the technician and region. If the outdoor unit's main control board has failed and requires replacement, parts and labor combined can range from $300 to $700 or more depending on the specific unit model. An electrician's fee may apply separately if utility or panel wiring is involved.

Diagnosing and correcting a phase sequence issue requires working directly with three-phase high-voltage electrical wiring, which is dangerous without proper training and equipment. A licensed electrician or certified HVAC technician should inspect the power wiring at the outdoor unit's terminal block and upstream connections. If the issue is simply swapped wires at a terminal, the fix itself is straightforward for a professional.

A power reset may temporarily clear the fault code, but if the underlying phase sequence issue has not been corrected, the error will return as soon as the unit attempts to operate and the control board re-checks the incoming phase rotation. The root cause must be identified and corrected for the unit to run normally.