Lull 944E-42 Service Manual - Manual (Page 151)

8-35 944E-42
Hydraulic System
NEVER charge an accumulator to a pressure more than
specified. The proper pressure for these accumulators is
450 ± 35 psi (3103 ± 241 kPa).
Note: Make sure the nitrogen bottle, as well as the
charging and gauging assembly used is compatible with
the gas valve assembly on the accumulator. The
nitrogen source and all components must be rated for a
pressure at least as high as the nitrogen source. It is
strongly recommended that the nitrogen bottle has a
high pressure regulator. Nitrogen gas bottles for water-
pumped nitrogen have right-hand valve threads and are
used with accumulators up to 3000 psi (207 bar).
You will require an accumulator fill kit to properly charge
the accumulators. Refer to Parts Manual for the correct
part number or contact JLG Parts Department.
Use the following steps to properly pre-charge each
accumulator:
1. Remove the floor plate to gain access to the
accumulators.
2. Thoroughly clean the top of each accumulator.
3. Make sure the nitrogen supply is shut off.
4. Attach the accumulator fill kit (4) to the nitrogen
bottle.
5. Remove the protective cap from the gas valve on the
accumulator.
6. Back the “T” handle (5) on the accumulator fill kit all
the way out (counter-clockwise). Attach the schrader
adaptor (6) to the gas valve on the accumulator.
Tighten securely.
7. Turn the gas valve/bleed valve (7) on the
accumulator fill kit all the way in.
8. Turn the “T” handle (5) all the way in to open the
valve core on the accumulator.
9. Open the valve (8) on the nitrogen bottle.
10. Slowly adjust the regulator (9) on the nitrogen bottle
to read 450 ± 35 psi (3103 ± 241 kPa).
11. Close the main valve (8) on the nitrogen bottle.
12. Back the “T” handle (5) on the accumulator fill kit all
the way out (counter-clockwise).
13. Let the pre-charge on the accumulator set for 10-15
minutes. This will allow the gas temperature to
stabilize. If the desired pre-charged range is
exceeded, turn the “T” handle (5) all the way in. With
the main valve (8) closed on the nitrogen bottle, turn
the gas valve/bleeder valve (7) out to bleed pressure
off the accumulator. Turn the valve all the way in and
check the pressure reading on the regulator gauge.
14. When the correct pressure is reached, back the “T”
handle (5) on the accumulator fill kit all the way out
(counter-clockwise). Bleed the pressure from the
hose by turning the gas valve/bleed valve out to
relieve the pressure.
15. Turn the gas valve/bleed valve (7) all the way in and
remove the schrader adapter (6) from the valve on
the accumulator.
16. Reassemble the protective cap onto the gas valve
on the accumulator.
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