Daikin · Heat pumps · Daikin Altherma 3 R F (split heat pump, R32)
FA-00OU: Abnormal high pressure, actuation of HPS
Name in the manufacturer's documentation (service manual): OU: Abnormal high pressure, actuation of HPS
[1]
In plain words (editorial)
Abnormally high pressure – the high pressure switch tripped. The manual names a dirty outdoor heat exchanger, too little air flow because the required space around the outdoor unit is not met, an outdoor temperature outside the operation range, refrigerant circuit problems or faulty components.
When to call a service technician: Keep the outdoor unit clean and unobstructed; if the code repeats, contact your installer.
✎ editorial – written from the cited sources, not a manufacturer statement. Status: draft.
For technicians
Possible causes (source text)
- Dirty outdoor heat exchanger[2]
- Closed stop valve in the refrigerant circuit[3]
- Outdoor temperature is out of operation range[4]
- Insufficient air flow or air by‑pass due to required space specifications not met[5]
- Faulty heat exchanger thermistor[6]
- Faulty expansion valve[7]
- Faulty main pcb[8]
- Non‑condensables and/or humidity in the refrigerant circuit[9]
- Clogged refrigerant circuit[10]
- Faulty outdoor unit fan motor[11]
Steps given by the manufacturer (source text)
- Clean the outdoor heat exchanger[12]
- Check that all stop valves of the refrigerant circuit are open[13]
- Check the outdoor temperature[14]
- Check the required space around the outdoor unit heat exchanger[15]
- Perform a check of the heat exchanger thermistor[16]
- Perform a check of the expansion valve[17]
- Perform a check of the main pcb[18]
- Check for the presence of non‑condensables and/or humidity in the refrigerant circuit[19]
- Check if the refrigerant circuit is clogged[20]
- Perform a check of the outdoor unit fan motor[21]
⚠ Work on refrigerant circuits, mains electricity and PV DC wiring is for qualified technicians only.
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] Daikin Altherma 3 R F – ERGA04~08E + EHVH/X04+08S18+23E – Installer reference guide (4P629086-1D (2024.04)) , p. 254 official manufacturer document quote verified
FA-00 OU: Abnormal high pressure, actuation of HPS
- [2] Daikin – Service manual Daikin Altherma 3 R F + W, ESIE20-13C – 2022.09 (PDF copy on installer site cncpompyciepla.pl) (ESIE20-13C) , p. 46 manufacturer document – copy from a distributor quote verified
dirty outdoor heat exchanger.
- [3] Daikin – Service manual Daikin Altherma 3 R F + W, ESIE20-13C – 2022.09 (PDF copy on installer site cncpompyciepla.pl) (ESIE20-13C) , p. 46 manufacturer document – copy from a distributor quote verified
closed stop valve in the refrigerant circuit.
- [4] Daikin – Service manual Daikin Altherma 3 R F + W, ESIE20-13C – 2022.09 (PDF copy on installer site cncpompyciepla.pl) (ESIE20-13C) , p. 46 manufacturer document – copy from a distributor quote verified
outdoor temperature is out of operation range.
- [5] Daikin – Service manual Daikin Altherma 3 R F + W, ESIE20-13C – 2022.09 (PDF copy on installer site cncpompyciepla.pl) (ESIE20-13C) , p. 46 manufacturer document – copy from a distributor quote verified
insufficient air flow or air by‑pass due to required space specifications not met.
- [6] Daikin – Service manual Daikin Altherma 3 R F + W, ESIE20-13C – 2022.09 (PDF copy on installer site cncpompyciepla.pl) (ESIE20-13C) , p. 46 manufacturer document – copy from a distributor quote verified
faulty heat exchanger thermistor.
- [7] Daikin – Service manual Daikin Altherma 3 R F + W, ESIE20-13C – 2022.09 (PDF copy on installer site cncpompyciepla.pl) (ESIE20-13C) , p. 46 manufacturer document – copy from a distributor quote verified
faulty expansion valve.
- [8] Daikin – Service manual Daikin Altherma 3 R F + W, ESIE20-13C – 2022.09 (PDF copy on installer site cncpompyciepla.pl) (ESIE20-13C) , p. 46 manufacturer document – copy from a distributor quote verified
faulty main pcb.
- [9] Daikin – Service manual Daikin Altherma 3 R F + W, ESIE20-13C – 2022.09 (PDF copy on installer site cncpompyciepla.pl) (ESIE20-13C) , p. 46 manufacturer document – copy from a distributor quote verified
non‑condensables and/or humidity in the refrigerant circuit.
- [10] Daikin – Service manual Daikin Altherma 3 R F + W, ESIE20-13C – 2022.09 (PDF copy on installer site cncpompyciepla.pl) (ESIE20-13C) , p. 46 manufacturer document – copy from a distributor quote verified
clogged refrigerant circuit.
- [11] Daikin – Service manual Daikin Altherma 3 R F + W, ESIE20-13C – 2022.09 (PDF copy on installer site cncpompyciepla.pl) (ESIE20-13C) , p. 46 manufacturer document – copy from a distributor quote verified
faulty outdoor unit fan motor.
- [12] Daikin – Service manual Daikin Altherma 3 R F + W, ESIE20-13C – 2022.09 (PDF copy on installer site cncpompyciepla.pl) (ESIE20-13C) , p. 46 manufacturer document – copy from a distributor quote verified
clean the outdoor heat exchanger.
- [13] Daikin – Service manual Daikin Altherma 3 R F + W, ESIE20-13C – 2022.09 (PDF copy on installer site cncpompyciepla.pl) (ESIE20-13C) , p. 46 manufacturer document – copy from a distributor quote verified
check that all stop valves of the refrigerant circuit are open.
- [14] Daikin – Service manual Daikin Altherma 3 R F + W, ESIE20-13C – 2022.09 (PDF copy on installer site cncpompyciepla.pl) (ESIE20-13C) , p. 46 manufacturer document – copy from a distributor quote verified
check the outdoor temperature.
- [15] Daikin – Service manual Daikin Altherma 3 R F + W, ESIE20-13C – 2022.09 (PDF copy on installer site cncpompyciepla.pl) (ESIE20-13C) , p. 46 manufacturer document – copy from a distributor quote verified
check the required space around the outdoor unit heat exchanger.
- [16] Daikin – Service manual Daikin Altherma 3 R F + W, ESIE20-13C – 2022.09 (PDF copy on installer site cncpompyciepla.pl) (ESIE20-13C) , p. 46 manufacturer document – copy from a distributor quote verified
perform a check of the heat exchanger thermistor.
- [17] Daikin – Service manual Daikin Altherma 3 R F + W, ESIE20-13C – 2022.09 (PDF copy on installer site cncpompyciepla.pl) (ESIE20-13C) , p. 46 manufacturer document – copy from a distributor quote verified
perform a check of the expansion valve.
- [18] Daikin – Service manual Daikin Altherma 3 R F + W, ESIE20-13C – 2022.09 (PDF copy on installer site cncpompyciepla.pl) (ESIE20-13C) , p. 46 manufacturer document – copy from a distributor quote verified
perform a check of the main pcb.
- [19] Daikin – Service manual Daikin Altherma 3 R F + W, ESIE20-13C – 2022.09 (PDF copy on installer site cncpompyciepla.pl) (ESIE20-13C) , p. 46 manufacturer document – copy from a distributor quote verified
check for the presence of non‑condensables and/or humidity in the refrigerant circuit.
- [20] Daikin – Service manual Daikin Altherma 3 R F + W, ESIE20-13C – 2022.09 (PDF copy on installer site cncpompyciepla.pl) (ESIE20-13C) , p. 46 manufacturer document – copy from a distributor quote verified
check if the refrigerant circuit is clogged.
- [21] Daikin – Service manual Daikin Altherma 3 R F + W, ESIE20-13C – 2022.09 (PDF copy on installer site cncpompyciepla.pl) (ESIE20-13C) , p. 46 manufacturer document – copy from a distributor quote verified
perform a check of the outdoor unit fan motor.