What It Means
System No.
Daikin Chiller
Daikin Chiller Error Code 91
Troubleshooting guide for the Daikin Chiller system fault 91.
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Possible Causes
- Defective connector contact.
- Defective electronic expansion valve coil.
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
System No. 2 Malfunction of electronic expansion valve
All Recorded Causes
Defective connector contact Defective electronic expansion valve coil
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 defective connector contact.
- Measure airflow-related readings that match the symptom, such as temperature split or static pressure, and check whether defective electronic expansion valve coil.
- After the correction, run the system long enough to confirm the chiller fault does not return under normal load.
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