Step 11.
Position purge device LEAK TEST/PURGE switch (10) to LEAK TEST and
observe that the purge device gauge (9) indicates vacuum is steady at 20 inches of
Hg. If unable to observe a steady vacuum of 20 inches of Hg, a leak is present.
Stop purge procedure and night vision seal device leak(s). If purge device gauge
(9) indicates a steady vacuum, position purge device LEAK TEST/PURGE switch
(10) to purge.
Step 12.
Position purge device PUMP/NITROGEN switch (11) to NITROGEN and
observe that the purge device gauge (9) indicates 3 1 PSI.
Step 13.
Position purge device LEAK TEST/PURGE switch (10) to LEAK TEST and
observe that the purge device (9) indicates a steady reading of 3 1 PSI. If
unable to observe a steady pressure of 3 1 PSI, a leak is present. Stop purge
procedure and seal night vision device leak(s). If purge device gauge (9) indicates
a steady pressure, position purge device LEAK TEST/PURGE switch (10) to
PURGE.
Step 14.
Slowly rotate the eyepiece lens assembly until eyepiece goes to its outermost
position.
Step 15.
Slowly rotate eyepiece lens assembly until eyepiece lens assembly goes to its
innermost position.
Step 16.
Repeat steps 10 through 15 three additional times.
Step 17.
Turn large knob of purge adapter clockwise until seated, then turn 2 full turns to
close purge valve.
Step 18.
Set purge device (8) PUMP/NITROGEN switch (11) to PUMP and LEAK
TEST/PURGE (10) switch to PURGE.
Step 19.
Grasp small knob of purge adapter. Unscrew from valve in monocular.
Step 20.
Prepare for continued purge/fill procedure or remove purging adapter (7), turn off
nitrogen tank valve (5) and remove and store fire control tool set (2) and purge
device (8).
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