Piper Malibu PA-46-310P Pilot Operating Handbook page 287

SECTION7
DESCR/OPERATION
PIPER AIRCRAFT CORPORATION
PA-46-310P, MALIBU
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(OPTIONAL VACUUM SYSTEM WITH STAND-BY PU.MP)
The optional vacuum system adds a second clutch-driven dry air
vacuum pump, a second regulator and a vacuum manifold/check valve.
The vacuum gauge provides the same information to the pilot regarding
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operation of the vacuum system as the standard system and additionally
incorporates two red flow buttons which indicate when the respective
vacuum pump is operating. The left flow button indicates the primary pump
and the right flow button indicates the standby pump. If the flow button is
visible the pump is not operating.
The system incorporates two vacuum regulators mounted on the
forward pressure bulkhead in the forward baggage compartment and a
vacuum manifold/check valve mounted on the forward pressure bulkhead
inside the cabin. The vacuum in the system is regulated between 4.8 and 5.2
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inches of mercury (as shown on the vacuum gauge).
The standby vacuum pump is operated by the STANDBY VAC PUMP
switch located on the main switch panel on the left side of the pilot's
instrument panel. For normal operations the standby pump is OFF and the
right side red flow button will be visible on the vacuum gauge. Should the
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left side red flow button appear the STANDBY VAC PUMP switch should
be turned ON. The vacuum gauge reading will return to normal and the right
side red flow button will disappear. The standby vacuum pump has the same
capacity as the primary pump and all vacuum systems will function normally.
If a primary pump failure has occurred, the problem should be corrected
prior to any further flights.
Cabin pressurization will not provide a back up vacuum supply in
aircraft equipped with the optional system.
REPORT: VB-1200
7-38
ISSUED:
.JANUARY
11, 1984
REVISED:
OCTOBER
14, 1991