Operation a n d M a i n t e n a n c e I n s t r u c t i o n s w i t h
NOTE: When charging in the range of 0 to 500
Illustrated Parts Breakdown (Intermediate and
psi, observe the low-pressure gauge (13); when
Depot), Nitrogen Servicing Unit, A/M26U-4. (Refer
charging in the range of 500 to 3,500 psi, observe the
back to figures 9-5 and 9-6 to locate the components
high-pressure gauge (14).
and trace the nitrogen flow.)
c. Slowly adjust the pressure regulator (17)
until the outlet pressure gauge (13 or 14)
WARNING
reads the desired servicing pressure.
Nitrogen pressure is now available at the
Always open valves slowly. Servicing hose should
servicing hose valve (2).
be slack when under pressure and should not be
stretched to make a connection.
d. Remove the protective cap (22) from the
servicing line (1). Firmly holding the end of
the servicing line (1), open the servicing line
valve (2) slightly to expel any potential
NOTE: The number in parenthesis following the
contaminants, and then close the servicing
component name refers to figures 9-5 and/or 9-6.
line valve (2).
CHARGING AN EXTERNAL SYSTEM.--
Before using the A/M26U-4 to charge a system, you
WARNING
must perform a preoperational inspection on the
Always use an approved remote inflator assembly
servicing unit in accordance with its preoperational
when charging tires with the nitrogen servicing
inspection checklist, AG-750AO-MRC-000. The
unit to prevent possible personal injury. NAVAIR
servicing unit must be positioned sufficiently close to
17-1-123 covers the requirements for the remote
the system to be charged to avoid stretching the
inflator assembly.
servicing hose, and the parking brake must be set. At
the start of a charging operation, all valves (2, 4
through 10, and 17) should be closed.
e. Firmly connect the servicing line (1) to a
The A/M26U-4 has three modes of operation for
remote inflator assembly, and connect this
charging a system: direct servicing from cylinders G1
assembly to the system being serviced.
through G4; pump operation using nitrogen drive; and
f. Open the servicing line valve (2) and the
pump operation using air drive.
valve on the system being serviced, and
1. Direct Servicing from Cylinders G1 through
service the system to the desired pressure. If
G4:
during servicing, the pressure in the
servicing unit cylinder drops below 200 psi,
NOTE: Open only one green lever control valve at
close that cylinder lever control valve (4)
any one time to prevent equalizing cylinder pressure.
and open the valve of the next cylinder with
a. Open the green lever control valve (4) of the
lowest usable pressure.
cylinder with the lowest pressure above the
required servicing pressure. Do not use
g. When the desired servicing pressure is
cylinders with less than 200 psi.
reached, closed the valve on the system
being serviced, and then close the servicing
line valve.
WARNING
h. After gas has stop venting through the
If leaking is noticed, close the cylinder valve
servicing line valve (2), disconnect the
immediately to prevent possible injury to
remote inflator assembly from the system
personnel.
being serviced. Replace cap (22) on
servicing line (1).
i. Set the regulator for no-flow condition. If no
b. Open the manifold shutoff valve (10),
other system is to be serviced
allowing nitrogen to flow through the
immediately,shut down the unit as described
purifier (24) and filter (23) to the manifold
gauge (15) and pressure regulator (17).
in the next section.
9-12
