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Vaillant · Heat pumps · Vaillant aroTHERM plus with uniTOWER plus

F.729Compressor outlet temperature too low

Name in the manufacturer's documentation (service manual): Compressor outlet temperature too low[1]

In plain words (editorial)

The compressor outlet temperature is too low (the manual gives below 0 °C for more than 10 minutes, or below -10 °C within the operating characteristics). Checks in the refrigerant circuit follow – a job for a refrigeration specialist.

When to call a service technician: Contact a competent heating engineer (installer or Vaillant customer service).

✎ 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] Vaillant uniTOWER plus VIH QW 190/6 E – Operating, installation and maintenance instructions (0020291525_05) (0020291525_05) , p. 60 official manufacturer document quote verified F.729 Compressor outlet temperature too low
  2. [2] Vaillant uniTOWER plus VIH QW 190/6 E – Operating, installation and maintenance instructions (0020291525_05) (0020291525_05) , p. 60 official manufacturer document quote verified The compressor outlet temperature is lower than 0 °C for more than 10 minutes or the compressor outlet temperature is lower than -10 °C even though the heat pump is in the operating characteristics
  3. [3] Vaillant uniTOWER plus VIH QW 190/6 E – Operating, installation and maintenance instructions (0020291525_05) (0020291525_05) , p. 60 official manufacturer document quote verified Checking the high-pressure sensor
  4. [4] Vaillant uniTOWER plus VIH QW 190/6 E – Operating, installation and maintenance instructions (0020291525_05) (0020291525_05) , p. 60 official manufacturer document quote verified Checking that the EEV is working correctly
  5. [5] Vaillant uniTOWER plus VIH QW 190/6 E – Operating, installation and maintenance instructions (0020291525_05) (0020291525_05) , p. 60 official manufacturer document quote verified Check the condenser outlet temper- ature sensor (supercooling)
  6. [6] Vaillant uniTOWER plus VIH QW 190/6 E – Operating, installation and maintenance instructions (0020291525_05) (0020291525_05) , p. 60 official manufacturer document quote verified Check whether the 4-port diverter valve is in the intermediate position
  7. [7] Vaillant uniTOWER plus VIH QW 190/6 E – Operating, installation and maintenance instructions (0020291525_05) (0020291525_05) , p. 60 official manufacturer document quote verified Checking the refrigerant volume for overfilling