This part is based around the diverter valve section. The diverter valve is directional water device that only appears in combi boilers. It allows the hot water to be directed to the heating system (radiators, etc.) or to the DHW system (taps, etc.). This feature is what seperates a normal boiler from a combi boiler due to the fact that a combi boiler wouldn't require a cylinder to provide heating and hot water.
This part is present in 17 different boilers in the Ideal range including the Ideal LOGIC COMBI , LOGIC COMBI , LOGIC COMBI , LOGIC + COMBI , LOGIC + COMBI