I own a 1924 Conway which was restored in 1994, at which time a vacuum
motor box was added that is very similar (if not identical) to the one
pictured here:  http://playerpiano.yolasite.com/resources/pump-pix.jpg
 

I recently removed the evacuator assembly from my piano, with
reservoir intact, and blocked off all ports, and the system held vacuum
for approximately 15 seconds before the reservoir was depleted.  When
reinstalled with all hoses reconnected, the reservoir vacuum only lasts
4 to 5 seconds.

With all hose ports still connected, I removed the vacuum motor box
flex hose from the reservoir and taped off the gooseneck connection
on the reservoir and foot pumped the piano.  The pedals were much more
solid and would actually play a roll with a modest amount of effort
(a distinct difference than when the vacuum motor hose was connected).

As a final check I put my mouth over the vacuum hose coming from
the motor box and suck hard, only to discover that I could feel the
internal check assembly flapper shift and partially seal off, but not
completely.  This test confirms to me that I have a problem with the
internal check valve in the vacuum motor box.

So, here is the question: Has anyone had experience with this problem
before and if so, were they successful in repairing the check assembly?
My motor box is located in the lower right side of the piano cabinet.
I tried lifting the box and when I do I can see a felt pad which seems
to be glued to between the motor box and the bottom of the piano.
I need to lift the box to gain access to the lower side screws and when
I do so it seems as if I am ripping the felt, so I stop.

Am I missing something or is a typical installation method of the box
is to glue the box in the piano using the felt pad?  Eventually I need
to lift the motor box to remove one of the motor box sides in order to
gain access to the check valve assembly.

All help and advice is appreciated.

Kind regards,
Stan Morton
Chino Valley, Arizona
aznomad450@aol.com.geentroep [delete ".geentroep" to reply]