INTRODUCTION 2250 SERVICE/MAINTENANCE MANUAL
1-64
Published 07-19-16, Control # 249-01
When the power button or boom butt cylinder switch is
released, the PC sends a 0 V output to shift the spool of
solenoid HS-15 to the center position.
Boom Butt Handling Cylinder Retract
When the power button is pressed and the boom butt
cylinder switch is held in the DOWN (retract) position, an
input signal is sent to the PC. The PC sends a 12 V output
signal to the auxiliary system’s disable-relief valve HS-12
that adjusts system pressure to 276 bar (4,000 psi).
The boom butt handling cylinder retract solenoid HS-16 is
enabled by the PC to shift the solenoid valve in the retract
position. Hydraulic fluid enters the upper accessory valve
and flows through the variable output control valve HS-20
and the hydraulic quick disconnect assembly to the lower
accessory valve.
Hydraulic fluid exits the valve assembly and flows through
the free-flow check valve section of the counterbalance
valve. Hydraulic fluid then enters the rod end of the boom
butt handling cylinder, retracting the cylinder to lower the
boom butt.
Fluid from the piston end of the cylinder is blocked by the
opposite side free-flow check valve section of the
counterbalance valve and flows through the flow-restraining
section with a relief setting of 207 bar (3,000 psi).
The counterbalance valve acts as a deceleration control with
a 3:1 pilot ratio. Hydraulic fluid flows through the boom butt
handling cylinder valve to the tank through the hydraulic
quick disconnect.
When the power button or boom butt cylinder switch is
released, the PC sends a 0 V output to shift the spool of
solenoid HS-16 to the center position.
To Next Page
Loading...
Need help?
General
