Viessmann boiler has separate circuits for heating and hot water
Viessmann’s Vitodens 100-W gas condensing boiler has two pairs of flow and return pipes for separate space-heating and DHW circuits at different temperatures. The efficiency of both circuits is maximised, especially if weather compensation is also fitted, as the heating side can condense effectively too.
Another benefit is that motorised valves are not required to separate circuits as this capability is built in, saving up to £250 in parts and half a day of installation work.