Viessmann · Heat pumps · Viessmann Vitocal 250-A (One Base, monobloc)
A.81Insufficient heat transfer in evaporator
Name in the manufacturer's documentation (service manual): Insufficient heat transfer in evaporator
[1]
In plain words (editorial)
Poor heat transfer in the evaporator of the outdoor unit – efficiency (COP) and output drop, and the refrigerant circuit may switch off. The manual says to check the evaporator and clean it if necessary.
When to call a service technician: Keep the outdoor unit free of leaves and dirt; if it repeats, 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)
- Check evaporator. Clean if necessary[2]
What the device does (source text)
- Performance factor (COP) too low · Compressor output too low · Refrigerant circuit off[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. 69 manufacturer document – copy from a distributor quote verified
A.81
- [2] Viessmann – Service instructions: System configuration and diagnosis for heat pumps with Viessmann One Base (6194799 GB, 3/2022) (6194799 GB (3/2022)) , p. 69 manufacturer document – copy from a distributor quote verified
check evaporator. clean if neces-
- [3] Viessmann – Service instructions: System configuration and diagnosis for heat pumps with Viessmann One Base (6194799 GB, 3/2022) (6194799 GB (3/2022)) , p. 69 manufacturer document – copy from a distributor quote verified
performance factor (cop)