I have a pedal pumped Franklin Ampico.  It didn't normally have
crescendo valves and had some extra valves to approximate them.
It is missing the primary valves.  This makes repetition and the
"zero" threshold not as good -- all this to make it use less air.

I added an electric pump to mine and added back the two crescendo
valves.  It still lacks the primary valves but it works okay.
I like mine because it has a switch to play normal pedal pumped 88-note
rolls.  When I had room for only one piano that was an advantage.

Barry Kasindorf