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 714 of 828

TM 9–2350–311–20–2
19–6
Change 2
19–2 RECUPERATOR ASSEMBLY — CONTINUED
b.
Servicing with High Pressure Nitrogen – Method One
WARNING
Dry nitrogen tanks are marked with one or two black bands at the top of the tank. Do not use tanks
without black band. In charging recuperator, use dry nitrogen. Certain other gases will cause
recuperator cylinder to explode, resulting in possible death or serious injury.
CAUTION
Open and close nitrogen cylinder shut off valve to clear valve seat of any dust or dirt. Repeat opera-
tion after installation of pressure regulator to clear hose.
NOTE
Recuperator assembly must be serviced with hydraulic fluid before it is charged with dry nitrogen.
1
Attach nitrogen charging assembly (10) to nitrogen cylinder (11) as shown.
2
Remove nitrogen valve cap (12). Attach angle valve (13) of nitrogen charging assembly (10) to nitrogen
valve (14), but do not tighten angle valve.
3
Close stop-check valve (15) and angle valve (16) of nitrogen charging assembly (10).
4
Open nitrogen cylinder (11) shutoff valve (17).
5
Open pressure regulator valve (18) slowly until 3000 psi gage (19) shows 15–20 psi (103–138 kPa), then
close pressure regulator valve.
6
Open stop-check valve (15) on nitrogen charging assembly (10). Tighten angle valve (13) just before 3000
psi gage (19) registers 0 psi (0 kPa).
NOTE
Gage used in step 7, must be at least a 1000 psi gage.
7
Open nitrogen valve (14) and observe pressure on gage (20). Pressure should read 700
±
25 psi (4827
±
172 kPa) at 70
°
F (21
°
C). If not, go to step 8.
NOTE
If recuperator cylinder is charged to 700
±
25 psi (4827
±
172 kPa), go to step 11.
8
Open nitrogen cylinder (11) shutoff valve (17). Observe nitrogen cylinder 4000 psi gage (21). Pressure
should be at least 800
±
50 psi (5516
±
345 kPa).
9
Open pressure regulator valve (18) until 3000 psi gage (19) registers 700
±
25 psi (4827
±
172 kPa) at 70
°
F
(21
°
C).
10
Loosen nut on nitrogen valve (14) about 1 turn (2–1/4 turns provide maximum opening).


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