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).
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.
John A Tuttle
Brick, New Jersey, USA