What It Means
Reverse phase, open phase.
Daikin Heat Reclaim Ventilator
Daikin Heat Reclaim Ventilator Error Code U1
Troubleshooting guide for the Daikin Heat Reclaim Ventilator system fault U1.
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Possible Causes
- Power supply reverse phase.
- T phase open phase.
- Defective outdoor unit PCB (A1P).
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
Reverse phase, open phase
All Recorded Causes
Power supply reverse phase T phase open phase Defective outdoor unit PCB (A1P)
Verify Before Replacing Parts
- Confirm the exact Daikin model family and heat reclaim ventilator context before acting on a generic code description.
- Start with the exact model documentation and verify the full operating sequence before replacing parts, particularly around power supply reverse phase.
- Use the listed causes as branches to confirm or eliminate with measurements, not assumptions — t phase open phase is a reasonable second branch.
- 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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