Mitsubishi Electric · Heat pumps · Mitsubishi Electric Ecodan PUZ-WM outdoor unit (R32)
U1High pressure (High pressure switch 63H operated)
Name in the manufacturer's documentation (service manual): High pressure (High pressure switch 63H operated)
[1]
In plain words (editorial)
High pressure – the high-pressure switch 63H operated. The service manual lists a stop valve not fully open, a clogged or broken pipe, a locked outdoor fan, short cycling of air or a dirty outdoor heat exchanger.
When to call a service technician: Keep the outdoor unit clear; further checks need a service technician.
✎ editorial – written from the cited sources, not a manufacturer statement. Status: draft.
For technicians
Possible causes (source text)
- Defective operation of stop valve (not fully open)[2]
- Clogged or broken pipe[3]
- Locked outdoor fan motor[4]
- Short cycle of outdoor unit[5]
- Dirt of outdoor heat exchanger[6]
- Decreased airflow caused by defective inspection of outside temperature thermistor[7]
- Defective action of linear expansion valve[8]
- Malfunction of fan driving circuit[9]
Steps given by the manufacturer (source text)
- Check if stop valve is fully open.[10]
- Check piping and repair defect.[11]
- Check outdoor unit and repair defect (fan motor, short cycle, dirty heat exchanger).[12]
- Check the detected temperature of outside temperature thermistor on LED display.[13]
- Turn the power off and check F5 is displayed when the power is turned on again.[14]
- Check linear expansion valve.[15]
- Replace outdoor controller board (fan driving circuit).[16]
⚠ 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] Mitsubishi Electric – Service Manual: Air to water heat pump units, outdoor unit PUZ-WM50VHA … PUZ-WM112YAA (OCH727 REVISED EDITION-A, 12/2023) (OCH727A (12/2023)) , p. 25 official manufacturer document quote verified
High pressure (High pressure switch
- [2] Mitsubishi Electric – Service Manual: Air to water heat pump units, outdoor unit PUZ-WM50VHA … PUZ-WM112YAA (OCH727 REVISED EDITION-A, 12/2023) (OCH727A (12/2023)) , p. 25 official manufacturer document quote verified
Defective operation of stop
- [3] Mitsubishi Electric – Service Manual: Air to water heat pump units, outdoor unit PUZ-WM50VHA … PUZ-WM112YAA (OCH727 REVISED EDITION-A, 12/2023) (OCH727A (12/2023)) , p. 25 official manufacturer document quote verified
Clogged or broken pipe
- [4] Mitsubishi Electric – Service Manual: Air to water heat pump units, outdoor unit PUZ-WM50VHA … PUZ-WM112YAA (OCH727 REVISED EDITION-A, 12/2023) (OCH727A (12/2023)) , p. 25 official manufacturer document quote verified
Locked outdoor fan motor
- [5] Mitsubishi Electric – Service Manual: Air to water heat pump units, outdoor unit PUZ-WM50VHA … PUZ-WM112YAA (OCH727 REVISED EDITION-A, 12/2023) (OCH727A (12/2023)) , p. 25 official manufacturer document quote verified
Short cycle of outdoor unit
- [6] Mitsubishi Electric – Service Manual: Air to water heat pump units, outdoor unit PUZ-WM50VHA … PUZ-WM112YAA (OCH727 REVISED EDITION-A, 12/2023) (OCH727A (12/2023)) , p. 25 official manufacturer document quote verified
Dirt of outdoor heat exchanger
- [7] Mitsubishi Electric – Service Manual: Air to water heat pump units, outdoor unit PUZ-WM50VHA … PUZ-WM112YAA (OCH727 REVISED EDITION-A, 12/2023) (OCH727A (12/2023)) , p. 25 official manufacturer document quote verified
Decreased airflow caused by
- [8] Mitsubishi Electric – Service Manual: Air to water heat pump units, outdoor unit PUZ-WM50VHA … PUZ-WM112YAA (OCH727 REVISED EDITION-A, 12/2023) (OCH727A (12/2023)) , p. 25 official manufacturer document quote verified
Defective action of linear
- [9] Mitsubishi Electric – Service Manual: Air to water heat pump units, outdoor unit PUZ-WM50VHA … PUZ-WM112YAA (OCH727 REVISED EDITION-A, 12/2023) (OCH727A (12/2023)) , p. 25 official manufacturer document quote verified
Malfunction of fan driving circuit
- [10] Mitsubishi Electric – Service Manual: Air to water heat pump units, outdoor unit PUZ-WM50VHA … PUZ-WM112YAA (OCH727 REVISED EDITION-A, 12/2023) (OCH727A (12/2023)) , p. 25 official manufacturer document quote verified
Check if stop valve is fully open.
- [11] Mitsubishi Electric – Service Manual: Air to water heat pump units, outdoor unit PUZ-WM50VHA … PUZ-WM112YAA (OCH727 REVISED EDITION-A, 12/2023) (OCH727A (12/2023)) , p. 25 official manufacturer document quote verified
Check piping and repair defect.
- [12] Mitsubishi Electric – Service Manual: Air to water heat pump units, outdoor unit PUZ-WM50VHA … PUZ-WM112YAA (OCH727 REVISED EDITION-A, 12/2023) (OCH727A (12/2023)) , p. 25 official manufacturer document quote verified
Check outdoor unit and repair defect.
- [13] Mitsubishi Electric – Service Manual: Air to water heat pump units, outdoor unit PUZ-WM50VHA … PUZ-WM112YAA (OCH727 REVISED EDITION-A, 12/2023) (OCH727A (12/2023)) , p. 25 official manufacturer document quote verified
Check the detected temperature of outside
- [14] Mitsubishi Electric – Service Manual: Air to water heat pump units, outdoor unit PUZ-WM50VHA … PUZ-WM112YAA (OCH727 REVISED EDITION-A, 12/2023) (OCH727A (12/2023)) , p. 25 official manufacturer document quote verified
Turn the power off and check F5 is
- [15] Mitsubishi Electric – Service Manual: Air to water heat pump units, outdoor unit PUZ-WM50VHA … PUZ-WM112YAA (OCH727 REVISED EDITION-A, 12/2023) (OCH727A (12/2023)) , p. 25 official manufacturer document quote verified
Check linear expansion valve.
- [16] Mitsubishi Electric – Service Manual: Air to water heat pump units, outdoor unit PUZ-WM50VHA … PUZ-WM112YAA (OCH727 REVISED EDITION-A, 12/2023) (OCH727A (12/2023)) , p. 25 official manufacturer document quote verified
Replace outdoor controller board.