Daikin Chiller Error Code 71

Full Diagnosis

System No. 2 compressor has drawn current beyond the overcurrent protection setpoint, and the control locks out that circuit's compressor while System No. 1 keeps running unaffected. This differs from the neighboring 70 code, which trips on compressor overheat (a thermal condition) rather than electrical current draw, and from E6, which is the equivalent overcurrent lockout on System No. 1. Manual reset is typically required once the electrical fault is cleared, since a locked or shorted compressor motor is a common root cause.

All Recorded Causes

Compressor motor winding short or ground fault. Mechanical lockup or seized compressor. Low refrigerant charge driving an abnormal compression ratio. Restricted discharge line or a closed service valve. Failing or miswired overcurrent relay or contactor. Loose or corroded power wiring at the compressor terminal box. Single-phasing or voltage imbalance feeding System No. 2.

Verify Before Replacing Parts

1. Confirm the exact Daikin model family and chiller context before acting on a generic code description.
2. Verify airflow first, then confirm operating pressures and temperature relationship before adjusting charge, since compressor motor winding short or ground fault.
3. Look for restrictions, iced coils, or dirty heat-transfer surfaces that can mimic a charge problem, and separately confirm mechanical lockup or seized compressor.
4. After the correction, run the system long enough to confirm the chiller fault does not return under normal load.