Daikin SkyAir Error Code P1

Full Diagnosis

P1 indicates a power supply phase imbalance or an inverter PCB fault on three-phase SkyAir outdoor units — the control detects an open phase, excessive interphase voltage imbalance, or a failure in the inverter's main circuit components, and shuts the compressor down to prevent motor and inverter damage. It differs from U1 (reverse phase/open phase detected at unit startup on the power supply itself) in that P1 is triggered by imbalance or component failure during running operation rather than an incoming wiring/phase-rotation error at power-up.

All Recorded Causes

Open phase on the incoming power supply, significant interphase voltage imbalance between the three legs, defective capacitor in the inverter main circuit, loose or damaged wiring in the main power circuit, defective inverter PCB, upstream electrical service or breaker issue.

Verify Before Replacing Parts

1. Confirm the exact Daikin model family and skyair context before acting on a generic code description.
2. Confirm board LEDs, wiring polarity, and model compatibility before replacing control boards — this Daikin fault points at open phase on the incoming power supply, significant interphase voltage imbalance between….
3. Check for intermittent communication faults caused by connectors, moisture, or damaged harnesses, and rule out the next candidate on the list.
4. After the correction, run the system long enough to confirm the skyair fault does not return under normal load.