Viessmann · Heat-pump or fixed-AC model
Vitocal 300-G
Vitocal 300-G is used for two current Viessmann ground source families: a domestic inverter range and a separate higher-output fixed-speed range.
Specifications
| Specification | Value |
|---|---|
| Type | ground source; inverter domestic and fixed-speed higher-output families |
| Rated output (kW) | 4.3, 5.3 or 7.5 domestic inverter; 21.2, 28.8 or 42.8 fixed-speed single-stage |
| Rated-output conditions | B0/W35 |
| SCOP (seasonal coefficient of performance) at 35°C | up to 5.6 for the domestic inverter family |
| Maximum flow temperature (°C) | 60 |
| Modulation range | 1.7-8.6, 2.4-11.4 or 3.8-15.9 kW for domestic inverter types |
| Sound power (dB) | 41 at B0/W55 for domestic inverter family |
| Warranty (years) | 2 standard; paid extension to 7 subject to terms |
| Product name warning | used for distinct domestic inverter and higher-output fixed-speed families |
| Inverter types | BWC 301.C06, BWC 301.C12 and BWC 301.C16 |
| Inverter rated output B0 W35 kW | 4.3, 5.3 and 7.5 |
| Inverter modulation ranges kW | 1.7-8.6, 2.4-11.4 and 3.8-15.9 |
| Inverter COP B0 W35 | 4.7, 4.8 and 5.0 |
| Fixed speed types | BW/BWS 301.A21, 301.A29 and 301.A45 |
| Fixed speed output B0 W35 kW | 21.2, 28.8 and 42.8 single-stage |
| Fixed speed two stage kW | 42.4-85.6 brine-to-water |
Vitocal 300-G is not one unambiguous heat pump. Viessmann’s current UK site uses the name for a domestic inverter family and a separate, substantially larger fixed-speed family. The full type code is needed to interpret a certificate, system record or service document.
Domestic inverter family
The inverter range comprises BWC 301.C06, C12 and C16. At B0/W35, their rated brine-to-water outputs are 4.3, 5.3 and 7.5 kW, with coefficients of performance of 4.7, 4.8 and 5.0.
Their modulation ranges are 1.7 to 8.6 kW, 2.4 to 11.4 kW and 3.8 to 15.9 kW respectively. These broader ranges describe variable operation, while the rated figures use the EN 14511 test point. For water-source operation, rated output spans 5.6 to 10.0 kW.
This family needs a separate hot-water cylinder. Optional equipment enables natural cooling. Its sound-power rating is 41 dB(A) at B0/W55, and its SCOP is up to 5.6 for low-temperature operation.
Higher-output family
The separate BW/BWS 301.A21, A29 and A45 family has single-stage brine-to-water ratings of 21.2, 28.8 and 42.8 kW at B0/W35. Two-stage master/slave arrangements span 42.4 to 85.6 kW. Water-source outputs are higher, from 28.1 to 58.9 kW single-stage.
This family uses fixed-speed scroll compressors and can be arranged in cascades. Its maximum flow temperature is 60°C. It is intended for larger homes, apartment buildings and commercial or public-sector sites.
Controls and warranty
Both families use Vitotronic controls, but their hydraulic arrangements, electrical supplies, source design and accessories are different. “Vitocal 300-G” without a type code is therefore not enough information for comparison.
At 23 July 2026, both the up-to-7.5 kW 300-G and the larger 300-G/350-G category had a two-year standard warranty and a paid seven-year extension, subject to the terms.
Related entries
Brand
Reference type
Heat-pump or fixed-AC model
Last reviewed
31 Jul 2026
Current status
Current in the manufacturer's UK range.