Thanks for the reply.
I rang Vaillant tech helpline and they said it might have been fitted with just one screw valve underneath. I have looked all over and can't find a second one.
I could email you a photo if you send me your email address. (not sure how
to do that otherwise). Or if...
HI and HELP!
I have an eight year old Vaillant Turbomax plus 824E combi boiler. I am trying to re-fill the boiler and I have been told there should be two slotted screw valves underneath the boiler which control the inlet.
(as shown on this you tube video...