TM-9-2350-311-20-2

HOWITZER, MEDIUM, SELF-PROPELLED, 155MM; M109A2, M109A3, M109A4 AND M109A5

TECHNICAL MANUAL; UNIT MAINTENANCE MANUAL FOR CAB, ARMAMENT, SIGHTING AND FIRE CONTROL, ELEVATING AND TRAVERSING SYSTEMS AND ASSOCIATED COMPONENTS

DECEMBER 1993
TM-9-2350-311-20-2

  TM-9-2350-311-20-2 - Page 728 of 828

TM 9–2350–311–20–2
19–20
19–4 ACCUMULATOR ASSEMBLY, MAIN — CONTINUED
b.
Service (Method Two)
WARNING
Accumulator contains high pressure nitrogen. Use caution when handling and working with it to
avoid injury.
1
Open and close shutoff valve (12) to clear valve seat of any dust or dirt. Repeat this operation after installa-
tion of pressure regulator to clear hose.
2
Connect and tighten nitrogen charging assembly (2) to nitrogen cylinder (3) as shown.
3
Remove air valve cap (4). Connect air pressure gage assembly (15) to valve body (5) on accumulator (6).
4
Connect nitrogen charging assembly (2) to air pressure gage assembly (15).
5
Open angle valve (7).
6
Close stop-check valve (10).
7
Close safety-relief valve (16).
8
Open angle valve (17) by turning clockwise.
9
Close pressure regulator valve (13) by turning counterclockwise until no spring pressure is felt.
10
Open shutoff valve (12) slowly until full cylinder pressure is indicated on 4000 psi gage (18) of pressure indi-
cator.
11
Open pressure regulator valve (13) slowly, turning it clockwise until pressure on 3000 psi gage (14) registers
50 psi (345 kPa).
12
Open stop-check valve (10), allowing nitrogen to enter the accumulator (6) until gage (19) on the air pres-
sure gage assembly (15) reads 50 psi (345 kPa).
13
Close stop-check valve (10).
14
Open safety-relief valve (16) until all nitrogen is bled from accumulator (6), then close safety-relief valve.
15
Repeat steps 10 and 11 to remove all traces of moisture prior to charging system to full pressure. Reopen
stop-check valve (10).
NOTE
Charging the system too fast will heat the dry nitrogen. This will give an inaccurate reading because
the pressure will decrease when the nitrogen cools. Estimated time to charge system is 30 minutes
or more. System should be charged at ambient temperature of weapon use.
16
Open pressure regulator valve (13) slowly, turning clockwise until pressure on 3000 psi gage (14) registers
550 psi (3792 kPa).


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