Daikin Chiller Error Code 72

Full Diagnosis

The condenser fan motor circuit for System No. 2 has exceeded its overcurrent protection setpoint, so the control disables the fan for that circuit — which can push System No. 2 toward a high-pressure trip if airflow isn't restored. This is distinct from the No. 2 fan inter lock code (78), which trips on loss of a safety interlock or proof-of-flow signal rather than motor current, and from E7, which covers a broken wire or stalled fan on the outdoor unit generally rather than a discrete per-circuit overcurrent event. Fan operation on the affected circuit stays disabled until the overcurrent condition is cleared and the protection is reset.

All Recorded Causes

Seized or binding fan motor bearing. Fan blade obstruction or physical damage. Fan motor winding short. Failing run capacitor on single-phase motors, or a fault on the fan's drive module for EC/inverter fans. Fan motor overload relay miscalibrated or nuisance-tripping. Debris-clogged condenser coil increasing fan motor load. Loose or corroded fan motor wiring connections.

Verify Before Replacing Parts

1. Confirm the exact Daikin model family and chiller 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 seized or binding fan motor bearing.
3. Check for intermittent communication faults caused by connectors, moisture, or damaged harnesses, and rule out fan blade obstruction or physical damage.
4. After the correction, run the system long enough to confirm the chiller fault does not return under normal load.