On playing standard rolls the expression (accordion) pneumatic should
not react to any of the 4 lowest notes, i.e., they should be turned
off.  When tubed correctly either the level 1 or 2 (sometimes level 4)
part of the accordion is closed constantly, setting the lowest playing
level just like a normal Themodist unit would do.  It therefore acts
just like the Themodist: nothing happens when you don't move the
Themodist levers over to the left.

When you do move them over, the instrument will gradually play softer
in the bass and/or treble (depending on which lever you move) until
playing at it's softest with the levers all the way to the left.  With
the levers all the way to the right the Themodist box has no effect
as the slide valves are wide open.  This is why there is a locking
mechanism on the levers of a Pedal Duo-Art -- to set the levers in the
closed position otherwise also nothing would happen when playing the
Duo-Art roll.

If it is impossible to have the piano to sound on the 88-note setting,
it seems like the slide-valves on the levers are not opening.  Please
check the setting of those.

Kind regards from the Netherlands,
Niels Berkers