Mitsubishi Electric · Heat pumps · Mitsubishi Electric Ecodan PUZ-WM outdoor unit (R32)
U2High discharge temperature / high compressor surface temperature
Name in the manufacturer's documentation (service manual): High discharge temperature / high compressor surface temperature
[1]
In plain words (editorial)
High discharge temperature or high compressor surface temperature. The service manual lists refrigerant shortage, a stop valve problem, a thermistor, the expansion valve or a clogged circuit.
When to call a service technician: Call a technician with F-gas certification.
✎ editorial – written from the cited sources, not a manufacturer statement. Status: draft.
For technicians
Possible causes (source text)
Steps given by the manufacturer (source text)
- Check intake superheat. Check leakage of refrigerant. Charge additional refrigerant.[7]
- Check if stop valve is fully open.[8]
- Turn the power off and check if U3 is displayed when the power is turned on again.[9]
- Check linear expansion valve.[10]
- After recovering refrigerant, remove water from entire refrigerant circuit under vacuum more than 1 hour.[11]
⚠ 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 discharge temperature
- [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
Overheated compressor
- [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
Defective operation of stop
- [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
Defective thermistor
- [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
Defective action of linear
- [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
Clogging with foreign objects in
- [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
Check intake superheat.
- [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
Check if stop valve is fully open.
- [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
Turn the power off and check if U3 is
- [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 linear expansion valve.
- [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
After recovering refrigerant, remove water