Daikin SkyAir

Daikin SkyAir Error Code P4

Troubleshooting guide for the Daikin SkyAir system fault P4.

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What It Means

Malfunction of radiation fin temperature sensor.

Possible Causes

  • Defective radiation fin temperature thermistor.
  • Defective inverter PCB.
  • Defective INV.
  • compressor.
  • Defective fan motor.

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

Malfunction of radiation fin temperature sensor

All Recorded Causes

Defective radiation fin temperature thermistor Defective inverter PCB Defective INV. compressor Defective fan motor

Verify Before Replacing Parts

  1. Confirm the exact Daikin model family and skyair context before acting on a generic code description.
  2. Confirm board LEDs, wiring polarity, and model compatibility before replacing control boards — this Daikin fault points at defective radiation fin temperature thermistor.
  3. Check for intermittent communication faults caused by connectors, moisture, or damaged harnesses, and rule out defective inverter PCB.
  4. After the correction, run the system long enough to confirm the skyair fault does not return under normal load.

Diagnosing SkyAir across a fleet?

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