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Vaillant · Heat pumps · Vaillant aroTHERM plus with uniTOWER plus

F.1117Compressor: Phase failure

Name in the manufacturer's documentation (service manual): Compressor: Phase failure[1]

In plain words (editorial)

Phase failure on the compressor power supply. The manual names a defective fuse, incorrect electrical connections, too low mains voltage, the compressor/low-tariff supply not connected, or an energy supply company lockout lasting over three hours.

When to call a service technician: Check that the heat pump fuses are not tripped; otherwise contact a heating engineer or electrician.

✎ 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. 63 official manufacturer document quote verified F.1117 Compressor: Phase failure
  2. [2] Vaillant uniTOWER plus VIH QW 190/6 E – Operating, installation and maintenance instructions (0020291525_05) (0020291525_05) , p. 63 official manufacturer document quote verified Defective fuse
  3. [3] Vaillant uniTOWER plus VIH QW 190/6 E – Operating, installation and maintenance instructions (0020291525_05) (0020291525_05) , p. 63 official manufacturer document quote verified Incorrect electrical connections
  4. [4] Vaillant uniTOWER plus VIH QW 190/6 E – Operating, installation and maintenance instructions (0020291525_05) (0020291525_05) , p. 63 official manufacturer document quote verified Mains voltage too low
  5. [5] Vaillant uniTOWER plus VIH QW 190/6 E – Operating, installation and maintenance instructions (0020291525_05) (0020291525_05) , p. 63 official manufacturer document quote verified Compressor/low tariff power supply not connected
  6. [6] Vaillant uniTOWER plus VIH QW 190/6 E – Operating, installation and maintenance instructions (0020291525_05) (0020291525_05) , p. 63 official manufacturer document quote verified Energy supply company lockout for over three hours
  7. [7] Vaillant uniTOWER plus VIH QW 190/6 E – Operating, installation and maintenance instructions (0020291525_05) (0020291525_05) , p. 63 official manufacturer document quote verified Check the fuse
  8. [8] Vaillant uniTOWER plus VIH QW 190/6 E – Operating, installation and maintenance instructions (0020291525_05) (0020291525_05) , p. 63 official manufacturer document quote verified Checking the electrical connections
  9. [9] Vaillant uniTOWER plus VIH QW 190/6 E – Operating, installation and maintenance instructions (0020291525_05) (0020291525_05) , p. 63 official manufacturer document quote verified Check the voltage at the heat pump electrical connection
  10. [10] Vaillant uniTOWER plus VIH QW 190/6 E – Operating, installation and maintenance instructions (0020291525_05) (0020291525_05) , p. 63 official manufacturer document quote verified Set the max. duration of the ESCO anti-cycling time to at least three or more hours