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Vaillant · Heat pumps · Vaillant aroTHERM plus with uniTOWER plus

F.818Freq. converter fault: Mains voltage

Name in the manufacturer's documentation (service manual): Freq. converter fault: Mains voltage[1]

In plain words (editorial)

The mains voltage is wrong for the frequency converter, or the energy supply company has shut the unit down. The manual says the mains voltage must be between 195 V and 253 V.

When to call a service technician: If there is no utility (tariff) lockout, contact an electrician or 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.818 Freq. converter fault: Mains voltage
  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 Incorrect mains voltage for operating the frequency converter
  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 Shutdown via the energy supply company
  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 Measure and, if required, correct the mains voltage The mains voltage must be between 195 V and 253 V