Ideal 173953 Hydroblock Complete
This part is based around the diverter valve section. The diverter valve is a part that only appears in combi boilers. It allows the hot water to be directed to the central heating system (radiators, etc.) or to the hot water system (taps, etc.). This feature is what seperates a normal boiler from a combi boiler due to the boiler being able to provide heating and hot water without requiring a cylinder.