Viessmann Vitodens 050-W 25kW B0KA Combi Boiler | 7098601

Description

The Viessmann Vitodens 050-W 25kW combi is an attractively priced wall-mounted gas condensing boiler, built around the Inox-Radial stainless steel heat exchanger and modulating MatriX cylinder burner used across the Vitodens range.

At 700mm high and just 300mm deep, it's compact enough to fit inside a standard kitchen cupboard while still delivering up to 97% gross seasonal efficiency, making it a strong value choice for smaller households.

25kW

Combi output

97%

Gross seasonal efficiency

Class A

Energy efficiency

1:4

Modulation range

12.2 l/min

DHW flow rate

35kg

Weight

🛈

Please Note: This boiler must be connected using the Viessmann 60/100mm concentric flue system, tested and CE-designated as one structural unit with the boiler in accordance with DVGW-VP 113. Only this flue system may be used.

ℹ

Good to Know: Approved for a hydrogen admixture of up to 20% by volume and tested to EN 15502, this Vitodens 050-W requires no conversion kit for LPG — switching gas type is done entirely from the control unit.

Inox-Radial stainless steel heat exchanger

Delivers high operational reliability and a long service life on a very small footprint.

Modulating MatriX cylinder burner

Consumes relatively little natural gas with lower CO2 emissions across a wide 1:4 modulation range.

Integral WiFi control unit

Built-in wireless interface supports the ViCare app for remote heating and hot water control, with no separate modem required.

Compact 700 x 400 x 300mm footprint

Small enough to be fitted inside a kitchen cupboard, ideal for flats and space-constrained properties.

Integral instantaneous DHW heating

A plate heat exchanger provides direct hot water on demand with a diverter valve, up to 12.2 l/min flow.

Variable speed circulation pump

The integral high-efficiency pump adjusts its speed automatically, reducing electricity consumption compared with fixed-speed pumps.

Specification

Performance

Boiler type

Gas condensing combi (Type BPJD)

Rated heat output (50/30°C)

3.2 – 19.0 kW

Rated heat output (80/60°C)

2.9 – 17.1 kW

DHW output

25.4 kW

DHW flow rate

10.2 l/min

Standard seasonal efficiency (Hs)

Up to 97%

Energy efficiency class

A

Modulation range

1:4

Gas & Electrical

Gas types

Natural gas and LPG (no conversion kit required)

Hydrogen compatibility

Up to 20% H2 blend

Natural gas supply pressure

20 mbar

LPG supply pressure

50 mbar

Electrical supply

230V~, 50Hz

Dimensions & Connections

Height

707mm

Width

400mm

Depth

300mm

Weight

35kg

Flue gas connection

60mm

Ventilation air connection

100mm

Gas connection

G 3/4"

Heating flow/return

G 3/4"

DHW/cold water connections

G 1/2"

ℹ

Good to Know: Fill and top-up water must meet Viessmann's water quality requirements (see VDI 2035 or local equivalent). From a water hardness of 20°dH and above, a water treatment system in the cold water supply is recommended to protect the plate heat exchanger from limescale build-up.

What size property suits the 25kW Vitodens 050-W combi?

A 25kW combi typically suits a 2-3 bedroom home with one bathroom, depending on radiator count and insulation standard — a heat loss calculation is the reliable way to confirm sizing.

Does this boiler need a conversion kit for LPG?

No, the Vitodens 050-W runs on natural gas or LPG with the fuel type simply reconfigured at the control unit — no physical conversion kit is required.

Can this boiler run on a hydrogen gas blend?

Yes, it's approved for operation with a hydrogen admixture of up to 20% by volume.

What flue system is required?

Only the Viessmann 60/100mm concentric flue system, CE-designated as one structural unit with the boiler, may be used.

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Room Dimensions

Length (in m):

Width (in m):

Height (in m):

Room Type

Living Room

Bedroom

Kitchen

Bathroom

Conservatory

Hallway

Glazing Type

Single Glazed

Double Glazed

Triple Glazed

External Walls

0 Wall

1 Wall

2 Walls

3 Walls

4 Walls

Insulation Level

Poor

Average

Good (New Build)

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Required Heating

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Watts

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