Daikin Heat Pump Error 81

⚡ Quick Answer: The Daikin heat pump error 81 indicates a compressor overload protection issue, often triggered by a faulty outlet water temperature thermistor. This ... ✅ DIY Fixable

What Does Error 81 Mean?

The Daikin heat pump error 81 indicates a compressor overload protection issue, often triggered by a faulty outlet water temperature thermistor. This error may cause the system to cease normal operation, display inaccurate temperature readings, and deliver incorrect water temperatures. Users may also notice unusual humming sounds from the unit as it struggles to operate correctly.

Common Symptoms:

  • System may cease normal operation when detecting abnormal outlet water temperature
  • Inaccurate temperature readings reported or displayed
  • Heat pump may fail to deliver correct water temperature

Possible Causes

  • Faulty or abnormal outlet water temperature thermistor (medium)

How to Fix Error 81

DIY Fix Check and restart the system

  1. Turn off the heat pump system and isolate power to ensure safety.
  2. Wait a few minutes then restore power to allow the system to reset.
  3. Observe whether the error 81 returns on restart.

Technician Only Inspect and replace outlet water temperature sensor

  1. Access the heat pump unit’s outlet water temperature thermistor location per service manual.
  2. Measure the thermistor’s resistance and compare to expected values at ambient temperature.
  3. If readings are out of specification, replace the thermistor sensor.
  4. Verify wiring harness and connector integrity between sensor and control board.
  5. Test system operation after repair.

Parts needed: Outlet water temperature thermistor, Associated wiring/connectors

🛑 When to Call a Pro:
  • Error persists after system reset
  • Repeated failures of temperature sensor or multiple error codes appear
  • Unit fails to operate normally affecting heating performance

Technical Specifications

wattage 3500W
component Compressor
resistance 5-10 ohms
part_number DAIKIN 3D080A
voltage_rating 240V AC

Common Questions

What does 81 error mean on daikin heat pump?

Error 81 indicates a compressor overload protection issue due to a faulty outlet water temperature thermistor.

Can I fix daikin heat pump 81 error myself?

Yes, you can check and restart the system by turning it off, isolating power, and waiting a few minutes before restoring power.

How much does it cost to fix 81 error?

The estimated repair cost for error 81 ranges from ¥5,000 to ¥20,000, depending on parts and labor.

When should I call a technician for 81?

Call a technician if the error persists after a reset, if there are repeated failures of the temperature sensor, or if multiple error codes appear.

Sources & References

Data last verified: 2026-07-01

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