TM 1-1520-238-T-7
10–191
10–67. NITROGEN INERTING SYSTEM – MAINTENANCE OPERATIONAL CHECK (cont)
10–67
WARNING
To prevent bodily injury, nitrogen inerting system pressure must be
relieved prior to opening fuel service port covers.
Task
Result
a. On utility receptacle circuit breaker box
(fig. 10–71), check that NITROGEN INERT
circuit breaker is closed.
If NITROGEN INERT circuit breaker does not stay
closed, go to paragraph 10–69.
b. Verify that unit is operating by listening for
chugging sound.
If NIU is not operating (absence of chugging sound),
remove ammo storage magazine
(TM 9-1090-208-23-1).
Perform visual inspection of all visible components. If
components exhibit physical damage that affects NIU
operation, replace damaged components
(TM 1-1520-238-23). If no components exhibit
physical damage, go to paragraph 10–69.
c. In aft avionics bay, check that NITROGEN
INERT MONITOR indicator is all black (OK).
If NITROGEN INERT MONITOR indicator is not black
(OK), go to paragraph 10–70.
d. Depress NITROGEN INERT MONITOR
PRESS TO TEST switch for 10 seconds.
Check that indicator trips to black and white
(FAIL).
If NITROGEN INERT MONITOR indicator is not black
and white (FAIL) with PRESS TO TEST switch
depressed for 10 seconds, go to paragraph 10–71.
NOTE
PRESS TO TEST simulates a fault in the NIU. Resetting the NITROGEN
INERT MONITOR indicator does not reset the NIU indicator.
A FAIL condition on the indicator of the NIU has no effect on the
operation of the NIU system. Resetting the indicator is not necessary.
e. Reset NITROGEN INERT MONITOR
indicator by manually rotating knurled ring
clockwise 90 and release.
f. Remove external pressurized air, if applied
(TM 1-1520-238-23).
