Hi All,  The suction boxes in the modern Aeolian players were designed

to operate at a maximum of 34" of water vacuum.  Most of them topped

out at around 32".  In all my years working on Aeolian players, I've

only encountered two pumps that were actually worn out or 'burned out'.

Most often, performance problem are related to the player system, not

the vacuum pump.  Also, occasionally the brushes get a little stuck,

causing a dramatic decrease in the vacuum level, overheating, and

possible damage to the motor.



If you examine the inside of the suction box, you find that one of the

auxiliary vacuum supply fittings on the pump has a one-way flap valve

which prevents vacuum from leaking back through the pump during

foot-pump operation (see pictures at the link below).



  http://www.player-care.com/pump-box.html 



One can only presume that Aeolian felt it was important to use

unregulated vacuum to power the reroll device when the electric vacuum

pump was being used.



Musically,

John A Tuttle

Player-Care.com

Brick, New Jersey, USA