how to fill my vaillant combi without a manual?

Vaillant boilers have a filling loop built in under r/h side bottom two small black handles or a screwdriver slot. only fill to one bar make shaw you turn off taps again etc.

it could have a flex hose between flow or return and the cold mains water with tap and flex.

***warning before you start look to see if a header tank is fitted in loft in which case do not use a filling loop cheak ballvalve and water level.***

John Thompson Heating
March 2007