The Vokera Linea Service Kit, the diverter valve is a part that only appears in combi boilers; it allows the hot water to be sent to the central heating system, like radiators, etc., or to the hot water system, like taps, etc. A feature is what distinguishes a normal boiler from a combination boiler due to the fact that a combi boiler wouldn't require a cylinder to provide heating and hot water. No matter if it's a condensing or non-condensing combi boiler, the diverter valve functions are the same. Combi is short for combination, and you can have a condensing combination boiler or a standard-efficiency combination boiler.