Skip to content
EN

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

F.865High pressure fault

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

In plain words (editorial)

High pressure fault – the refrigerant circuit switches off. The manual names air in the heating circuit, shut-off heating circuits, blocked or faulty pumps, a contaminated condenser, a faulty high pressure sensor, or set flow temperatures that are too high.

When to call a service technician: Make sure the heating circuits (valves, thermostats) are not all closed; if it repeats, contact your heating contractor.

✎ 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 High pressure fault:
  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 Air in the secondary cir-
  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 Secondary circuit/heat- ing circuit shut off
  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 Secondary pump or heating circuit pumps blocked or faulty
  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 Condenser contamina-
  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 High pressure sensor faulty
  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 Set flow temperatures for central heating/DHW heating too high
  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 Vent the secondary circuit.
  9. [9] 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 the system pressure.
  10. [10] 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 secondary pump and heating circuit pumps.
  11. [11] 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 Flush heating circuits.
  12. [12] 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 Measure voltage at connec-
  13. [13] 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 Adjust set temperatures of con-
  14. [14] 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 outdoor unit for icing up.
  15. [15] 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.865 Refrigerant circuit off