Piper Navajo PA-31 Service Manual page 656

PIPER NAVAJO SERVICE MANUAL
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 5.7 inches of mercury just
prior to completion of the boot inflation cycle. After the
orifice adjustment is completed, recheck for 5.7 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.
n. Tighten adjustment valve jam nuts, pneumatic relay valve lock screw, and install
access plates.
10-21a. REMOVAL OF DRY PNEUMATIC PUMP.
a. Remove engine cowling and locate the pneumatic pump at the top center aft of the
engine.
b. Remove hose clamps on inlet and outlet sides of pump.
c. Disconnect hoses from both sides of the pump.
d. Disconnect the four nuts securing the pump and remove the pump.
NOTE
Before installation of fittings on pump, check for external
damage. A pump that has been damaged or dropped should
not be installed. When a vise is used to secure pump while
installing fittings, suitable caution must be exercised to avoid
pump damage. The square mounting flange must be held
between soft wood blocks and only at right angles to the vise
jaws. Use only enough vise pressure to hold pump firmly. DO
NOT apply vise pressure to outside diameter or overall
length. The ports of the AIRBORNE dry air pump have been
treated with a dry film lubricant and the AIRBORNE fittings
are cadmium plated thus eliminating any need for thread
lubricants. If a thread lubricant is required, use a powdered
moly sulfide or graphite in dry form or in an evaporating
vehicle; or employ a silicone spray. Apply sparingly to
external threads of fittings only. DO NOT use pipe tape,
thread
dope, hydrocarbon
oil or grease, as these can
contaminate pump and cause malfunction. With pump
properly secured in vise, insert fittings in ports and hand
tighten firmly. Next, using a wrench, tighten each fitting
from one-half to two turns additional.
Reissued: 10/12/79
INSTRUMENTS
3D18