Daikin Chiller Error Code H0

Full Diagnosis

Indicates the control has detected an abnormality in the compressor's general sensor/feedback wiring harness — typically a broken or disconnected lead feeding the compressor drive board — rather than a fault traced to one specific sensor type. It is a broader catch-all than H5 (which isolates the fault to the compressor motor overload thermistor), H6 (which isolates it to the position/rotor detection sensor), and H8 (which isolates it to the current transformer input), so when H0 appears alongside one of those more specific codes, treat the more specific code as the primary lead. The affected compressor circuit is typically locked out until the sensor circuit is verified and the fault reset.

All Recorded Causes

Compressor sensor harness disconnected or broken at a connector. Chafed or pinched sensor wiring near the compressor terminal box. Defective compressor drive/control PCB sensor input. Moisture or corrosion at a sensor connector. Incorrect sensor harness routing after service work. Intermittent connection from vibration-loosened terminals.

Verify Before Replacing Parts

1. Confirm the exact Daikin model family and chiller context before acting on a generic code description.
2. Verify the sensor or thermistor reading against the expected range for the current operating condition, keeping in mind that compressor sensor harness disconnected or broken at a connector.
3. Check the sensor harness and board connection before condemning the sensor itself; on Daikin units this is also where you'd confirm chafed or pinched sensor wiring near the compressor terminal box.
4. After the correction, run the system long enough to confirm the chiller fault does not return under normal load.