The Vokera diverter valve is a part that only appears in combi boilers. It allows the hot water to be redirected to the central heating (radiators, etc.) or to the domestic hot water system (taps, etc). This feature is what separates a normal boiler from a combi boiler.
Fits a number of vokera boilers
Technical specification
TypeDiverter ValveMaterialPlasticColourBlackSupplier Part Number10026508Brand NameVokera