The Accumulator has a rubber bladder inside it that contains nitrogen gas under
pressure. When there is no oil in the Accumulator and the pressure gauge reads "0", the bladder still
has pressure in it. This is the pre-charge pressure. The pressure amount is indicated on the accumulator label(9).
As oil is pumped into the Accumulator, the bladder gets smaller and this increases the pressure.
To check the gas pressure, raise and lower the boom until the Pressure Gauge reads “0”. Using either the Hand Pump
or Electric Pump, start pumping oil. The Pressure Gauge will 'jump' from zero to a higher pressure and then appear
to stop moving momentarily. This is the nitrogen gas pre-charge pressure.
WARNING: Nitrogen gas
charging and discharging should only be done by an experienced professional.
To add nitrogen gas to the Accumulator, be sure the Pressure Gauge reads “0”, remove the cover plate over the Accumulator,
remove the Accumulator Gas Valve Cap(10) on the end of the Accumulator(9), then attach a Gas Charging Apparatus(38)
to the Valve Stem as shown in Figure H6 and charge to the specified psi. To check the gas pressure, see above paragraph.
To reduce the nitrogen gas pressure or remove it completely , be sure the Pressure Gauge reads “0”, remove the
cover plate over the Accumulator, remove the Accumulator Gas Valve Cap(10) on the end of the Accumulator, then
attach a Gas Charging Apparatus to the valve stem and discharge the gas slowly through the apparatus.