Viessmann · Heat pumps · Viessmann Vitocal 250-A (One Base, monobloc)
F.4Short circuit, secondary circuit return temperature sensor
Name in the manufacturer's documentation (service manual): Short circuit, secondary circuit return temperature sensor
[1]
In plain words (editorial)
Short circuit of the secondary circuit return temperature sensor. According to the manual there is no room cooling while the fault is present.
When to call a service technician: The sensor is checked and replaced by the installer.
✎ 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] Viessmann – Service instructions: System configuration and diagnosis for heat pumps with Viessmann One Base (6194799 GB, 3/2022) (6194799 GB (3/2022)) , p. 50 manufacturer document – copy from a distributor quote verified
- [2] Viessmann – Service instructions: System configuration and diagnosis for heat pumps with Viessmann One Base (6194799 GB, 3/2022) (6194799 GB (3/2022)) , p. 50 manufacturer document – copy from a distributor quote verified
Check resistance value (NTC 10 kΩ) at connec
- [3] Viessmann – Service instructions: System configuration and diagnosis for heat pumps with Viessmann One Base (6194799 GB, 3/2022) (6194799 GB (3/2022)) , p. 50 manufacturer document – copy from a distributor quote verified
Replace sensor if necessary
- [4] Viessmann – Service instructions: System configuration and diagnosis for heat pumps with Viessmann One Base (6194799 GB, 3/2022) (6194799 GB (3/2022)) , p. 50 manufacturer document – copy from a distributor quote verified
No room cooling