Daikin VRV Error Code P1

Full Diagnosis

P1 is triggered by the outdoor unit's main circuit detecting an unbalanced or out-of-range supply voltage across phases, or a related fault in the inverter PCB's main circuit components that regulate incoming power — the affected outdoor module shuts down to protect the inverter and compressor from running on unstable power. On a multi-module VRV system supplied by a shared or separately-fed electrical service, this typically isolates to the module experiencing the bad supply. Distinguish from U1 (reverse phase/open phase, a wiring-sequence fault) and from U2 (instantaneous power failure/voltage sag) — P1 specifically points to a sustained interphase imbalance or a failed main-circuit component like the capacitor rather than a momentary interruption or swapped phase wiring.

All Recorded Causes

Open phase in the incoming power supply, interphase voltage imbalance exceeding acceptable tolerance, defective capacitor in the main circuit, loose or damaged wiring in the main circuit terminal block, defective inverter PCB main circuit component, undersized or shared electrical service causing voltage sag under load.

Verify Before Replacing Parts

1. Confirm the exact Daikin model family and vrv 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 in the incoming power supply, interphase voltage imbalance exceeding acceptable….
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 vrv fault does not return under normal load.