AThe Divertor Valve is also known as a 3 way valve/three way valve, its a mechanical boiler part that pushes the hot water that's produced by the Biasi boiler either to the hot tap (if there is a demand for hot water)or around the central heating if there is a demand for central heating. Note a Biasi combi boiler can only supply heat to 1 source at any one time, either hot water or central heating but not both at the same time.
Biasi BI1141504 Diverter Valve

Part: BI1141504

Price: £131.00
Biasi BI1011504 Diverter Valve Repair Kit

Part: BI1011504

Price: £37.50
Biasi BI1131501 Return Group Kit

Part: BI1131501

Price: £98.49
Biasi BI1011503 Riva 24S Diverter Valve

Part: BI1011503

Price: £134.95