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Viessmann · Heat pumps · Viessmann Vitocal 250-A (One Base, monobloc)

F.866Low pressure fault

Name in the manufacturer's documentation (service manual): Low pressure fault[1]

In plain words (editorial)

Low pressure fault – the refrigerant circuit switches off. The manual lists checking the refrigerant amount, cleaning the evaporator and checking the fans for blockages.

When to call a service technician: Contact your heating contractor or Viessmann technical 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] Viessmann – Service instructions: System configuration and diagnosis for heat pumps with Viessmann One Base (6194799 GB, 3/2022) (6194799 GB (3/2022)) , p. 64 manufacturer document – copy from a distributor quote verified F.866
  2. [2] Viessmann – Service instructions: System configuration and diagnosis for heat pumps with Viessmann One Base (6194799 GB, 3/2022) (6194799 GB (3/2022)) , p. 64 manufacturer document – copy from a distributor quote verified Check amount of refrigerant
  3. [3] Viessmann – Service instructions: System configuration and diagnosis for heat pumps with Viessmann One Base (6194799 GB, 3/2022) (6194799 GB (3/2022)) , p. 64 manufacturer document – copy from a distributor quote verified Top up refrigerant if required
  4. [4] Viessmann – Service instructions: System configuration and diagnosis for heat pumps with Viessmann One Base (6194799 GB, 3/2022) (6194799 GB (3/2022)) , p. 64 manufacturer document – copy from a distributor quote verified Clean the evaporator
  5. [5] Viessmann – Service instructions: System configuration and diagnosis for heat pumps with Viessmann One Base (6194799 GB, 3/2022) (6194799 GB (3/2022)) , p. 64 manufacturer document – copy from a distributor quote verified Check fans
  6. [6] Viessmann – Service instructions: System configuration and diagnosis for heat pumps with Viessmann One Base (6194799 GB, 3/2022) (6194799 GB (3/2022)) , p. 64 manufacturer document – copy from a distributor quote verified Remove blockages
  7. [7] Viessmann – Service instructions: System configuration and diagnosis for heat pumps with Viessmann One Base (6194799 GB, 3/2022) (6194799 GB (3/2022)) , p. 64 manufacturer document – copy from a distributor quote verified Replace fans if required
  8. [8] Viessmann – Service instructions: System configuration and diagnosis for heat pumps with Viessmann One Base (6194799 GB, 3/2022) (6194799 GB (3/2022)) , p. 64 manufacturer document – copy from a distributor quote verified Refrigerant circuit off