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Our range of gas open vent boilers

An ideal replacement for older boiler systems, our range of open vent boilers are designed to be installed on an open vented system.

Often referred to as regular, conventional or heat only boilers, an open vent boiler system will usually comprise of two tanks in the loft, a hot water storage cylinder and a separate pump.

All of the open vent boilers in our range are built around our long established reputation for producing high quality heating systems.

Offering the latest in heating technology, our open vent boiler range defines the quality benchmark for other brands and is focused on using energy efficiently, cutting costs, saving natural resources and protecting the environment.

Benefits of a Viessmann open vent boiler

  • An ideal replacement for traditional heating systems without having to make pipework changes
  • Ideal for installation into homes with older radiator systems
  • Ideal for delivering hot water to two or more bathrooms in a property
  • Ideal for homes where large volumes of hot water will be used at the same time
  • Depth of only 285 mm (340 mm for 35 kW model) for installation into standard kitchen wall units
  • No pump overrun required 
  • Comprehensive warranty on the entire range, as standard  

Which gas boiler is the best for you?

Popular products

Vitodens 100-W Open Vent

A compact and efficient open vent gas boiler

An open vent, wall mounted gas fired condensing boiler which is compact enough to fit in a standard kitchen cupboard. Also suitable for use in other applications where there is only limited space available.

Discover the Vitodens 100-W
  • Designed for


  • Powered by


  • Up to

    35 kW

  • Energy efficiency


Discover the Vitodens 100-W
  • EfficiencyLabel

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