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Viessmann Vitocal 350-A (indoor installation)
Model code: AWHI 351.A20
✓ BUS eligible✓ MCS listedAir Source (ASHP)ResidentialHeating only
Heating capacity
18.5 kW
SCOP
3.24
W35
COP
3.2
A2/W35
Max flow temp
65°C
Sound power
56 dB(A)
Refrigerant
R407C
Boiler Upgrade Scheme
✓ BUS eligible
Listed on the Ofgem BUS Product Eligibility List (24 Sep 2026).
PEL certificate: BSI KM 554512/04/3
Grant also needs an MCS-certified installer and a qualifying system design.
MCS certification
✓ MCS listed
Certificate: BSI KM 554512/04/3
| General | |
|---|---|
| Heat pump type | Air Source (ASHP) |
| Application | Residential |
| Refrigerant | R407C |
| Mode | Heating only |
| Heating performance | |
| Heating capacity | 18.5 kW |
| Max heating output (low temp) | 18.5 kW at A2/W35 |
| COP (heating) | 3.2 at A2/W35 |
| SCOP (heating) | 3.24 at W35 |
| Operating range (air) | -20 to 35 °C |
| Heating flow temperature | up to 65 °C |
| Electrical, acoustic and physical | |
| Electrical supply | 380-415V (Three Phase) |
| Sound power level | 56 dB(A) (Sound Power LW(A)) |
| Dimensions (H×W×D) | 1870 × 1200 × 946 mm |
| Operational Weight | 361 kg |
Test conditions: A = outdoor air °C, W = flow water °C (e.g. A7/W35 = 7°C air, 35°C flow). Compare COP and SCOP only at the same conditions.