Lull 944E-42 Service Manual - Manual (Page 460)

Hydraulic System
8.208 Model 644E-42/944E-42 Rev. 6/04
8.13.2 Pre-Charging Accumulator
Note: Replacement accumulators are not pre-charged
when shipped.
Pre-charge accumulators with nitrogen gas only.
Nitrogen gas is free of water vapor and oxygen which
makes it harmless to internal parts and will not react if
mixed with oil under pressure.
NEVER charge an accumulator to a pressure more than
specified. The proper pressure for these accumulators is
450 ±35 psi (3103 ±241 kPa).
IMPORTANT: 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 the Parts Manual for correct
part number or contact JLG Parts Department at
(717)-485-6472 for ordering information.
Use the following steps to properly pre-charge each
accumulator:
1. Remove the floor plate (1) to gain access to the two
accumulators.
.
2. Thoroughly clean the top of each accumulator (2).
3. Make sure the nitrogen supply is shut off.
4. Attach the accumulator fill kit (3) to the nitrogen
bottle.
5. Remove the protective cap from the gas valve on the
accumulator.
6. Back the “T” handle (4) on the accumulator fill kit all
the way out (counter-clockwise). Attach the schrader
adapter (5) to the gas valve on the accumulator.
Tighten securely.
7. Turn the gas valve/bleed valve (6) on the
accumulator fill kit all the way in.
8. Turn the “T” handle (4) all the way in to open the
valve core on the accumulator.
9. Open the valve (7) on the nitrogen bottle.
10. Slowly adjust the regulator (8) on the nitrogen bottle
to read 450 ±35 psi (3103 ±241 kPa).
11. Close the main valve (7) on the nitrogen bottle.
12. Back the “T” handle (4) on the accumulator fill kit all
the way out (counter-clockwise).
WARNING:
NEVER fill an accumulator
with oxygen! An explosion could result if oil
and oxygen mix under pressure. This can
result in death or serious personal injury. Only
fill accumulator with dry nitrogen.
CAUTION:
Never fill an accumulator with
air. When air is compressed, water vapor
condenses and can cause corrosion. This
corrosion may damage seals and ruin the
accumulator.
MU3770
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