Pilot's And Copilot's Gyro Installation With Deicer Boots - Piper Navajo Chieftain PA-31-350 Service Manual

NAVAJO CHIEFTAIN SERVICE MANUAL
NOTE
Ensure engines are up to operating temperature prior to checking
or adjusting the pneumatic system.
WARNING
Do not make adjustments of the pressure control valves that are
within the engine nacelles while engines are running.
10-18. PILOT'S AND COPILOT'S GYRO INSTALLATION WITH DEICER BOOTS. (Serial Nos. 31-5001
to 31-7652123) (Refer to Figure 10-3.)
a.
Install a test pressure gauge to the pneumatic system test gauge tap point by removing the access
cover on the forward right side of the pedestal.
b.
At the test gauge tap point remove the cap from the tap fitting and install the test pressure gauge.
NOTE
An accurate gauge with a range from 0 to 20 psi with a hose long
enough to allow the face of the gauge to be easily observed is
desired. The tap fitting is three-sixteenth straight thread flared.
c.
Operate left engine at 2200 RPM (right engine OFF) and check if the test pressure gauge reads
4.3
+
.25 psi (8.8 ± .5 in. Hg). Should the reading not be within the tolerance, shutdown the engine and
remove the forward access panel at the top of the nacelle.
d.
The pressure control valves (3) are located in the forward, center portion of the nacelle. Loosen
the locknut on the pressure control valve (3) with an attached solenoid and rotate the knurled screw
clockwise (IN) to increase pressure or counterclockwise (OUT) to decrease pressure, until the desired
pressure setting is obtained. Tighten the locknut.
e.
Repeat Steps c and d for the right engine (left engine OFF).
f.
Operate both engines at 2200 RPM. The test gauge pressure should read 5.5 ± .5 psi (11.2 ± 1 in.
Hg).
g.
To check the deicer system operation pressure, operate left engine at 2200 RPM (right engine
OFF). Actuate the deicer system. The test gauge should read 18.0± .5 psi (37
I in. Hg).
NOTE
The pressure will build steadily with a fluctuation between wing
and tail boot inflation. Therefore, the pressure should be read just
prior to completion of the cycle.
NOTE
Should the test gauge reading not be within tolerance, first ascertain
that the deicer boots have been pressure tested. (Refer to Paragraph
10-24 for test procedure.)
Reissued: 9/23/80
INSTRUMENTS
3A18