Vacuum System Description - Piper Malibu Meridian PA-46-500TP Airplane Maintenance Manual

1. Vacuum System (See Figure 1.)
A. Description
The vacuum system functions by bleed air being forced through a venturi device called an ejector.
As the primary bleed air flow is forced through the ejector, a decrease in pressure develops
providing the secondary flow. The secondary flow acts as the source of air to the system.
An ambient pressure reference is located between the firewall and the forward pressure bulkhead.
The vacuum is controlled on the vacuum side of the system by a vacuum regulator and check valve.
The regulator maintains vacuum at a nominal 5.0 inches mercury, relative to ambient pressure. On
the vacuum side of the regulator, a check valve is built into the line, preventing reverse flow.
The vacuum system operates the cabin pressurization controller, safety outflow valve, and
pneumatic deice system.
The vacuum gauge has been incorporated into the Meggit Engine Instrument Display System
(EIDS) (see 77-40-00). A transducer mounted on the aft side of the forward pressure bulkhead
provides input to the EIDS Data Acquisition Unit which then transmits the data to the EIDS Engine
Display Unit. Nominal pressure is 5.0 in. hg.
See also 21-30-00 and 30-10-00.
B. Troubleshooting
See Chart 1.
6D7
PIPER AIRCRAFT, INC.
PA-46-500TP, MALIBU MERIDIAN
MAINTENANCE MANUAL
DISTRIBUTION
37-10-00
Apr 15/07
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