Viega Multiplex Trio F Instructions For Use Manual page 24

Handling
Unscrew cover plate by hand.
Loosen the Allen screws of the inlet element with the Allen key
(size 3).
Remove inlet element.
Clean inlet element by holding it under running water.
Do not use any sharp or pointed objects when cleaning as this could
damage the material.
Loosen the Allen screw of the valve cone with an Allen key (size 3).
Multiplex Trio F drain/overflow functional unit 24 from 25