Vaillant · Heat pumps · Vaillant aroTHERM plus with uniTOWER plus
M.201Sensor fault: Cylinder temperature
Name in the manufacturer's documentation (service manual): Sensor fault: Cylinder temperature
[1]
In plain words (editorial)
The hot water cylinder temperature sensor is defective (sensor fault).
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.
For technicians
Possible causes (source text)
- Cylinder temperature sensor defective[2]
Steps given by the manufacturer (source text)
- Check the plug contact on the PCB and on the wiring harness; check that the sensor is working correctly and, if required, replace the sensor[3]
⚠ 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. 59 official manufacturer document quote verified
M.201 Sensor fault: Cylinder temperature
- [2] Vaillant uniTOWER plus VIH QW 190/6 E – Operating, installation and maintenance instructions (0020291525_05) (0020291525_05) , p. 59 official manufacturer document quote verified
Cylinder temperature sensor defect- ive
- [3] Vaillant uniTOWER plus VIH QW 190/6 E – Operating, installation and maintenance instructions (0020291525_05) (0020291525_05) , p. 59 official manufacturer document quote verified
Check the plug contact on the PCB and on the wiring harness; check that the sensor is working correctly and, if required, replace the sensor