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

F.1Lead break, flow temperature sensor, secondary circuit or heating/cooling circuit 1

Name in the manufacturer's documentation (service manual): Lead break, flow temperature sensor, secondary circuit or heating/cooling circuit 1[1]

In plain words (editorial)

Lead break of the flow temperature sensor (secondary circuit or heating/cooling circuit 1): the controller gets no reading, so the heat pump switches off. The manual says to check the sensor resistance and replace the sensor if necessary.

When to call a service technician: Sensor measurement and replacement are done 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. [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. [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 Lead break, flow tempera
  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. 50 manufacturer document – copy from a distributor quote verified Check resistance value (NTC 10 kΩ) at connec
  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. 50 manufacturer document – copy from a distributor quote verified Replace sensor if necessary
  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. 50 manufacturer document – copy from a distributor quote verified The heat pump is switched off