Viessmann · Heat pumps · Viessmann Vitocal 250-A (One Base, monobloc)
A.96Air in the secondary circuit
Name in the manufacturer's documentation (service manual): Air in the secondary circuit
[1]
In plain words (editorial)
There is air in the heating (secondary) circuit – you may hear unusual noise and see unusual start-up behaviour. The manual says to vent the system and top up with water if required.
When to call a service technician: If you cannot vent the system yourself, contact your heating contractor.
✎ editorial – written from the cited sources, not a manufacturer statement. Status: draft.
For technicians
Steps given by the manufacturer (source text)
- Vent the system. Top up with water if required[2]
What the device does (source text)
- Unusual operating noise · Unusual starting and operational characteristics[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] Viessmann – Service instructions: System configuration and diagnosis for heat pumps with Viessmann One Base (6194799 GB, 3/2022) (6194799 GB (3/2022)) , p. 70 manufacturer document – copy from a distributor quote verified
A.96
- [2] Viessmann – Service instructions: System configuration and diagnosis for heat pumps with Viessmann One Base (6194799 GB, 3/2022) (6194799 GB (3/2022)) , p. 70 manufacturer document – copy from a distributor quote verified
vent the system. top up with water
- [3] Viessmann – Service instructions: System configuration and diagnosis for heat pumps with Viessmann One Base (6194799 GB, 3/2022) (6194799 GB (3/2022)) , p. 70 manufacturer document – copy from a distributor quote verified
unusual operating noise