Daikin Chiller

Daikin Chiller Error Code 73

Troubleshooting guide for the Daikin Chiller system fault 73.

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What It Means

System No.

Possible Causes

  • Dirty heat exchanger.
  • Shortage of water volume.
  • Clogged refrigerant piping.
  • Defective connector contact.
  • Defective HPS.

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 Actuation of high pressure switch (HPS)

All Recorded Causes

Dirty heat exchanger Shortage of water volume Clogged refrigerant piping Defective connector contact Defective HPS

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 dirty heat exchanger.
  3. Look for restrictions, iced coils, or dirty heat-transfer surfaces that can mimic a charge problem, and separately confirm shortage of water volume.
  4. After the correction, run the system long enough to confirm the chiller fault does not return under normal load.

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