The pump is usually located after the primary heat exchanger within your heating appliance and allows the heated water to be circulated within the closed heating system. In the design of most combination boilers , the pump can be found before the diverter valve to allow circulation through the DHW and central heating systems.
This part is present in 3 different boilers in the Vaillant range including the Vaillant ECOmax 646 , VU 466/4-5 , VU 466-7
Supplier Part Number: 160976
Vaillant ECOmax 646 (2006-2008)
Vaillant VU 466/4-5 (2007-2010)
Vaillant VU 466-7 (2006-2008)