Daikin Chiller Error Code E5

Full Diagnosis

Signals that an inverter-driven compressor has either stalled or lost synchronism, or that its inverter module temperature has exceeded a safe limit, and the control shuts down that compressor circuit to prevent motor or driver damage — usually requiring a manual reset once the cause is corrected. Unlike E6 and 71, which cover fixed-speed compressor overcurrent lockout on Systems 1 and 2 respectively, E5 is specific to variable-frequency inverter-driven compressors and can be triggered by module overheat as well as electrical lockup. It also differs from E8, which is an inverter compressor overcurrent trip tied to the drive's power electronics rather than a motor lock or overheat condition.

All Recorded Causes

Inverter compressor mechanically locked or seized. High differential pressure at startup preventing the compressor from starting. Incorrect U/V/W phase wiring between the inverter and compressor. Inverter module overheating from inadequate cooling or a dirty heat sink. Defective inverter PCB or power module. Low refrigerant charge causing an abnormal compression ratio. Failed or miswired compressor position/current sensor feeding the inverter control.

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 inverter compressor mechanically locked or seized.
3. Check for intermittent communication faults caused by connectors, moisture, or damaged harnesses, and rule out high differential pressure at startup preventing the compressor from starting.
4. After the correction, run the system long enough to confirm the chiller fault does not return under normal load.