Daikin Heat Reclaim Ventilator

Daikin Heat Reclaim Ventilator Error Code C4

Troubleshooting guide for the Daikin Heat Reclaim Ventilator system fault C4.

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What It Means

Malfunction of liquid pipe thermistor for heat exchanger.

Possible Causes

  • Defective thermistor for liquid pipe.
  • Defective indoor unit PCB.
  • Defective connector contact.

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 liquid pipe thermistor for heat exchanger

All Recorded Causes

Defective thermistor for liquid pipe Defective indoor unit PCB Defective connector contact

Verify Before Replacing Parts

  1. Confirm the exact Daikin model family and heat reclaim ventilator context before acting on a generic code description.
  2. Verify the sensor or thermistor reading against the expected range for the current operating condition, keeping in mind that defective thermistor for liquid pipe.
  3. Check the sensor harness and board connection before condemning the sensor itself; on Daikin units this is also where you'd confirm defective indoor unit PCB.
  4. After the correction, run the system long enough to confirm the heat reclaim ventilator fault does not return under normal load.

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