Maintenance
50
8/4/11
Operation Manual - SP 305
Check the pre- charge of accumulators
Check the accumulator gas pre-charge as shown:
• 1st check-one week after first use
• 2nd check-three months after first use
• 3rd check-one year after first use
• 4th check and beyond-annually
If the accumulator requires charging, read all of the
instructions before beginning the job. Accumulators
must be charged only with dry nitrogen. Never use
compressed air or oxygen (Figure 36), as the oxygen
molecules will combine with the hydraulic oil and
lower the flash point of the oil to below room
temperature. You will create a major explosion by
using compressed air or oxygen to charge
accumulators. People have died using compressed air
or oxygen to charge accumulators. Use dry nitrogen,
not liquid nitrogen.
Charging procedure
The following steps are required for checking and
charging the accumulator.
1. Before you begin, you will need a charging kit
(Figure 37). Do not attempt to charge the
accumulators without one. You can order the
charge valve assembly from Schwing America
using part number 30338635. There is also a kit
available directly from Hydac. Hydac Corporation
can be reached at (610) 264-9503. The Hydac part
number is FPS 250 F 2.5 G4 K.
2. You must use a high-pressure regulator with the
nitrogen bottle. If it was not supplied with the
bottle, order one before proceeding with this job.
3. Before beginning the charging procedure, stop the
engine, and remove the key.
NOTE!
The accumulator on the P305 does not serve
to shift the Rock Valve as it would on a twin
circuit system. The only function of the
accumulator on this unit is to absorb shock
from pressure spikes as the valve shifts.
Figure 36
Warning decal for accumulator charging
WARNING
EXPLOSION CAUSED BY
IMPROPER ACCUMULATOR
CHARGING CAN RESULT IN
DEATH OR SERIOUS INJURY!
* Follow the charging instructions exactly!
* Use ONLY dry nitrogen to charge the
accumulator!
* NEVER use oxygen or compressed air to
charge the accumulator!
explosion warning.eps
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