I. The diagthram rots. Crap component. If you get a new tap (highly recommended) which seems to happen every 20,000 mls odd or wear it´s marked on the new vacuum tap assembly. If fitted Ok up arrow is ´ON´ , 3 0´clock facing is ´RES´ and due south is ´PRIME´. ie. no vacuum. Just dropped by as a 1200 owner in the UK and S.Spain. I´ve probably f....it up........