Pre-Charging Accumulator - JLG sky trak mmv Service Manual

9.13.2

Pre-Charging Accumulator

Note: Replacement accumulators are not pre-charged
when shipped.
WARNING:
lator 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.
Pre-charge accumulators with nitrogen gas only. Nitro-
gen 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.
CAUTION:
with air. When air is compressed, water vapor
condenses and can cause corrosion. This cor-
rosion may damage seals and ruin the accu-
mulator.
NEVER charge an accumulator to a pressure more than
specified. The proper pressure for these accumulators is
700 +50/-0 psi (4826 +345/-0 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. Contact JLG Inc. at (717) 485-5161
domestically or (877) 554-5438 internationally for order-
ing information.
Use the following steps to properly pre-charge each ac-
cumulator:
1. Thoroughly clean the top of each accumulator (5).
2. Make sure the nitrogen supply is shut off.
3. Attach the accumulator fill kit (6) to the nitrogen
bottle.
4. Remove the protective cap (4) from the gas valve (3)
on the accumulator.
Model MMV Rev. 12/04
NEVER fill an accumu-
Never fill an accumulator
5. Back the "T" handle (7) on the accumulator fill kit all
the way out (counter-clockwise). Attach the schrader
adapter (8) to the gas valve on the accumulator.
Tighten securely.
6. Turn the gas valve/bleed valve (9) on the
accumulator fill kit all the way in.
7. Turn the "T" handle (7) all the way in to open the
valve core on the accumulator.
8. Open the valve (10) on the nitrogen bottle.
9. Slowly adjust the regulator (11) on the nitrogen
bottle to read 700 +50/-0 psi (4826 +345/-0 kPa).
10. Close the main valve (10) on the nitrogen bottle.
11. Back the "T" handle (7) on the accumulator fill kit all
the way out (counter-clockwise).
12. Let the pre-charge on the accumulator set for 10-15
minutes. This will allow the gas temperature to
stabilize. If the desired pre-charge range is
exceeded, turn the "T" handle (7) all the way in. With
the main valve (10) closed on the nitrogen bottle,
turn the gas valve/bleed valve (9) out to bleed
pressure off the accumulator. Turn the valve all the
way in and check the pressure reading on the
regulator gauge.
13. When the correct pressure is reached, back the "T"
handle (7) 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.
14. Turn the gas valve/bleed valve all the way in and
remove the schrader adapter (8) from the valve on
the accumulator.
15. Reassemble the protective cap on to the gas valve
on the accumulator.
11
9
7
8
5
Hydraulic System
6
MM4530
10
9.137