What It Means
Reports an open, shorted, or out-of-range reading from the thermistor monitoring hot water temperature on units equipped with a heat-recovery or hot water production circuit, used for heating/hot-water setpoint control logic.
Daikin Chiller
Daikin Chiller Error Code HC
Troubleshooting guide for the Daikin Chiller system fault HC.
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Possible Causes
- Hot water thermistor lead damaged or disconnected.
- Thermistor not properly immersed or clamped to the water line.
- Thermistor resistance out of tolerance or drifted.
- Corroded or wet connector.
- Defective outdoor unit PCB thermistor input.
Not sure which one it is — or if it's none of these? Try ACLogics today.
Disclaimer: This information is for general reference. Error codes can vary by model and production year. Always refer to your machine's specific manual and the information printed on the unit itself.
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Full Diagnosis
Reports an open, shorted, or out-of-range reading from the thermistor monitoring hot water temperature on units equipped with a heat-recovery or hot water production circuit, used for heating/hot-water setpoint control logic. It differs from 80 and 81, which monitor the chilled-water entering and leaving temperatures on the main water loop rather than the hot water/heat-recovery circuit tracked by HC. Hot water production (or the heating function tied to it) is disabled until the thermistor fault clears, though the primary chilled-water circuit may continue operating.
All Recorded Causes
Hot water thermistor lead damaged or disconnected. Thermistor not properly immersed or clamped to the water line. Thermistor resistance out of tolerance or drifted. Corroded or wet connector. Defective outdoor unit PCB thermistor input. Wrong thermistor substituted during a prior repair.
Verify Before Replacing Parts
- Confirm the exact Daikin model family and chiller context before acting on a generic code description.
- Confirm filter condition, blower operation, and coil cleanliness before replacing any controls — start by ruling out whether hot water thermistor lead damaged or disconnected.
- Measure airflow-related readings that match the symptom, such as temperature split or static pressure, and check whether thermistor not properly immersed or clamped to the water line.
- After the correction, run the system long enough to confirm the chiller fault does not return under normal load.
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