Vaillant · Heat pumps · Vaillant aroTHERM plus with uniTOWER plus
F.774Sensor fault: Air inlet temp.
Name in the manufacturer's documentation (service manual): Sensor fault: Air inlet temp.
[1]
This page only quotes the original English documentation. A plain-language explanation has not been written yet, so the page is not indexed by search engines.
For technicians
Possible causes (source text)
- The sensor is not connected or the sensor input has short-circuited[2]
Steps given by the manufacturer (source text)
⚠ Work on refrigerant circuits, mains electricity and PV DC wiring is for qualified technicians only.
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] 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.774 Sensor fault: Air inlet temp.
- [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 sensor is not connected or the sensor input has short-circuited
- [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
Check and, if required, replace the sensor
- [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
Replace the wiring harness