The diverter valve is a part that only appears in combi boilers. It allows the hot water to be redirected to the heating system (radiators, etc.) or to the domestic hot water system (taps, etc.). This feature is one of the mains reasons combi boilers are

Brand Name	Riello
Colour	N/A
Material	N/A
Manufacturer Model No	20032135
Wear Type	N/A
Type	Regulator
Certifications Met	N/A
Country of Origin	N/A
Protects From	N/A
Waterproof	N/A
Number of Pockets	N/A
Waist Size	ab59cg13gv
Toilet Cistern Capacity	FTW
Supplier Part Number	Z20032135