Piper Navajo PA-31 Service Manual page 650

PIPER NAVAJO SERVICE MANUAL
(d) Clamp hose connections to prevent leakage.
(e) Run engines at 2200 RPM and adjust co-pilot side of relay valve to obtain
5.5 + .2 inches of mercury on the test gauge.
(f) Lock adjustment on relay valve and remove test gauge.
(g) Reinstall gyro pressure line to relay valve.
(h) Run engines 2200 RPM and adjust pilot side of relay valve to obtain 5.5 .2
inches of mercury on the instrument panel gauge.
(i) Run engines at 2200 RPM and adjust orifice to obtain 5.5 .2 inches of
mercury for pilot's gyros (indication on panel guage) during boot inflation.
NOTE
There will be a momentary fluctuation of pressure when the
de-icer boots are first turned on. Therefore, the orifice
adjustment should be set to obtain 5.5 .2 inches of mercury
just prior to completion of the boot inflation cycle. After the
orifice adjustment is completed, recheck for 5.5 .2 inches
of mercury gyro pressure with the de-icer boots off.
NOTE
When only 2 or 3 gyros are installed, delete the requirements
a thru g, as the co-pilot's side of the relay valve will be closed
off.
3. To adjust the electrically controlled relay valve for serial numbers 31-855 and up
(refer to Figure 10-7), use the following procedure:
(a) Install a test gauge in co-pilot gyro pressure line. A hypo needle inserted in
the hose from the right side of the gyro control, located under the co-pilot
instrument panel. and connected to a accurate gauge with a range of 0 to 20
psi.
(b) Operate engines at 2200 rpm. Test gauge pressure should read 5.5 + .2 inches
of mercury. (2.7 ± .1 psi.)
(c) To raise the pressure setting, adjust the co-pilot side of the gyro control by
loosening the locknut on the right side of the control and, with an Allen
wrench, turn the set screw counterclockwise (out of the control) until the
desired setting is obtained. To lower the pressure setting, turn the set screw
clockwise (into the control). Tighten the locknut.
(d) With the engines operating at 2200 rpm, the pressure gauge for pilot gyros,
located on the right instrument panel, should read 5.5 ± .2 inches of
mercury. (2.7 .1 psi.)
(e) To raise the pressure setting, loosen the locknut on the bottom of the gyro
control and, with an Allen wrench, turn the set screw clockwise (into the
control) until the desired setting is obtained. To lower the pressure setting,
turn the set screw counterclockwise (out of the control). Tighten the
locknut.
Reissued: 10/12/79
INSTRUMENTS
3D12