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Vaillant · Heat pumps · Vaillant aroTHERM plus with uniTOWER plus

F.752Fault: Frequency converter

Name in the manufacturer's documentation (service manual): Fault: Frequency converter[1]

In plain words (editorial)

Fault of the frequency converter (inverter) that drives the compressor – an internal electronics fault, or a mains voltage outside 70 V–282 V. The manual says the mains voltage must be between 195 V and 253 V.

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. 62 official manufacturer document quote verified F.752 Fault: Frequency converter
  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 Internal electronics fault on the in- verter PCB
  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 Mains voltage outside of 70 V–282 V
  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 integrity of the power sup- ply cables and compressor connec- tion cables The plugs must audibly click into place
  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 the cable
  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 Check the mains voltage The mains voltage must be between 195 V and 253 V
  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 the phases
  8. [8] Vaillant uniTOWER plus VIH QW 190/6 E – Operating, installation and maintenance instructions (0020291525_05) (0020291525_05) , p. 62 official manufacturer document quote verified Replace the frequency converter, if required