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Vaillant · Heat pumps · Vaillant aroTHERM plus with uniTOWER plus

F.788Building circuit: Pump fault

Name in the manufacturer's documentation (service manual): Building circuit: Pump fault[1]

In plain words (editorial)

The high-efficiency pump of the heating circuit detected a fault (e.g. dry running, blockage, overvoltage or undervoltage) and switched itself off and locked. The manual's first step: switch the heat pump off (no current) for at least 30 seconds.

When to call a service technician: If the fault comes back after the power reset, contact a heating engineer.

✎ 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. 62 official manufacturer document quote verified F.788 Building circuit: Pump fault
  2. [2] Vaillant uniTOWER plus VIH QW 190/6 E – Operating, installation and maintenance instructions (0020291525_05) (0020291525_05) , p. 62 official manufacturer document quote verified The electronics system of the high- efficiency pump has detected a fault (e.g. dry running, blockage, overvoltage, undervoltage) and has switched off and locked the pump
  3. [3] Vaillant uniTOWER plus VIH QW 190/6 E – Operating, installation and maintenance instructions (0020291525_05) (0020291525_05) , p. 62 official manufacturer document quote verified Switch the heat pump off for at least 30 seconds (no current)
  4. [4] Vaillant uniTOWER plus VIH QW 190/6 E – Operating, installation and maintenance instructions (0020291525_05) (0020291525_05) , p. 62 official manufacturer document quote verified Check the quality of the plug contact on the PCB
  5. [5] Vaillant uniTOWER plus VIH QW 190/6 E – Operating, installation and maintenance instructions (0020291525_05) (0020291525_05) , p. 62 official manufacturer document quote verified Check that the pump functions cor- rectly
  6. [6] Vaillant uniTOWER plus VIH QW 190/6 E – Operating, installation and maintenance instructions (0020291525_05) (0020291525_05) , p. 62 official manufacturer document quote verified Purging the building circuit
  7. [7] Vaillant uniTOWER plus VIH QW 190/6 E – Operating, installation and maintenance instructions (0020291525_05) (0020291525_05) , p. 62 official manufacturer document quote verified Check that the dirt filter that is in place is permeable