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Daikin · Heat pumps · Daikin Altherma 3 R F (split heat pump, R32)

U2-00OU: Defect of power supply voltage

Name in the manufacturer's documentation (service manual): OU: Defect of power supply voltage[1]

In plain words (editorial)

Supply voltage problem in the outdoor unit – the manual names a disturbed power supply (it must be within ±4% of nominal operating voltage), a momentary voltage drop or power failure, or component faults. After a momentary drop, the manual says to wait until the compressor restarts.

When to call a service technician: If the code persists, contact your installer or electrician.

✎ editorial – written from the cited sources, not a manufacturer statement. Status: draft.

The Polish page has more detail (plain-language explanation, safe checks, guides): Read in Polish →

Sources

Every statement has a footnote to the document and PDF page. “Quote verified” means the quote was found automatically in the text of that page.

  1. [1] Daikin Altherma 3 R F – ERGA04~08E + EHVH/X04+08S18+23E – Installer reference guide (4P629086-1D (2024.04)) , p. 255 official manufacturer document quote verified U2-00 OU: Defect of power supply voltage
  2. [2] Daikin – Service manual Daikin Altherma 3 R F + W, ESIE20-13C – 2022.09 (PDF copy on installer site cncpompyciepla.pl) (ESIE20-13C) , p. 59 manufacturer document – copy from a distributor quote verified ▪ faulty or disturbance of the power supply (power supply must be within range of nominal operating voltage ±4%), ▪ power drop, ▪ short circuit.
  3. [3] Daikin – Service manual Daikin Altherma 3 R F + W, ESIE20-13C – 2022.09 (PDF copy on installer site cncpompyciepla.pl) (ESIE20-13C) , p. 59 manufacturer document – copy from a distributor quote verified faulty compressor or miswiring of the compressor power supply cable.
  4. [4] Daikin – Service manual Daikin Altherma 3 R F + W, ESIE20-13C – 2022.09 (PDF copy on installer site cncpompyciepla.pl) (ESIE20-13C) , p. 59 manufacturer document – copy from a distributor quote verified faulty outdoor unit fan motor.
  5. [5] Daikin – Service manual Daikin Altherma 3 R F + W, ESIE20-13C – 2022.09 (PDF copy on installer site cncpompyciepla.pl) (ESIE20-13C) , p. 59 manufacturer document – copy from a distributor quote verified faulty main pcb.
  6. [6] Daikin – Service manual Daikin Altherma 3 R F + W, ESIE20-13C – 2022.09 (PDF copy on installer site cncpompyciepla.pl) (ESIE20-13C) , p. 59 manufacturer document – copy from a distributor quote verified faulty inverter pcb.
  7. [7] Daikin – Service manual Daikin Altherma 3 R F + W, ESIE20-13C – 2022.09 (PDF copy on installer site cncpompyciepla.pl) (ESIE20-13C) , p. 59 manufacturer document – copy from a distributor quote verified ▪ momentary drop of voltage, ▪ momentary power failure.
  8. [8] Daikin – Service manual Daikin Altherma 3 R F + W, ESIE20-13C – 2022.09 (PDF copy on installer site cncpompyciepla.pl) (ESIE20-13C) , p. 59 manufacturer document – copy from a distributor quote verified faulty expansion valve.
  9. [9] Daikin – Service manual Daikin Altherma 3 R F + W, ESIE20-13C – 2022.09 (PDF copy on installer site cncpompyciepla.pl) (ESIE20-13C) , p. 59 manufacturer document – copy from a distributor quote verified check if the power supply is compliant with the regulations.
  10. [10] Daikin – Service manual Daikin Altherma 3 R F + W, ESIE20-13C – 2022.09 (PDF copy on installer site cncpompyciepla.pl) (ESIE20-13C) , p. 59 manufacturer document – copy from a distributor quote verified perform a check of the compressor.
  11. [11] Daikin – Service manual Daikin Altherma 3 R F + W, ESIE20-13C – 2022.09 (PDF copy on installer site cncpompyciepla.pl) (ESIE20-13C) , p. 59 manufacturer document – copy from a distributor quote verified perform a check of the outdoor unit fan motor.
  12. [12] Daikin – Service manual Daikin Altherma 3 R F + W, ESIE20-13C – 2022.09 (PDF copy on installer site cncpompyciepla.pl) (ESIE20-13C) , p. 59 manufacturer document – copy from a distributor quote verified perform a check of the main pcb.
  13. [13] Daikin – Service manual Daikin Altherma 3 R F + W, ESIE20-13C – 2022.09 (PDF copy on installer site cncpompyciepla.pl) (ESIE20-13C) , p. 59 manufacturer document – copy from a distributor quote verified perform a check of the inverter pcb.
  14. [14] Daikin – Service manual Daikin Altherma 3 R F + W, ESIE20-13C – 2022.09 (PDF copy on installer site cncpompyciepla.pl) (ESIE20-13C) , p. 59 manufacturer document – copy from a distributor quote verified wait until the compressor restarts.
  15. [15] Daikin – Service manual Daikin Altherma 3 R F + W, ESIE20-13C – 2022.09 (PDF copy on installer site cncpompyciepla.pl) (ESIE20-13C) , p. 59 manufacturer document – copy from a distributor quote verified perform a check of the expansion valve.