SERV1851 02/08
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311D / 312D / 314D HYDRAULIC SYSTEM
Swing Motor
Left Travel Motor
Right Travel Motor
MAIN CONTROL VALVE GROUP
BR2
AR1 BL1
Text Reference Main Control Valve
bR3
AR2
BL1
BR2
BL1 AL1
BR3
AR3
bR3
AR2 BR1
AR1
bR1
AL1
bL1
AL2
BL2
bL2
bL4
BL4
aL4
Main Control Valve Group Medium Pressure Circuit (If Equipped)
aR3
aR1
PR
aL1
PL
aL4
aL2
aR2
bL1
bR1
Travel Levers aR1
aL1
Pilot Manifold Pilot Filter Main Hydraulic Pumps
aR2
Left Joystick
Pilot Pump
aL2
bR3
bR2
bL4
Right Joystick
Medium Pressure Pump (If equipped)
aL4
Tank aR3
bL2
89
MAIN CONTROL VALVE GROUP AND RETURN SYSTEM The main hydraulic system is a Negative Flow Controlled system that supplies hydraulic power at high pressures and high flow rates to perform work. Two main hydraulic pumps supply oil to the main control valve group. The individual hydraulic circuits are controlled by valves in the the main control valve group. The main hydraulic system supplies the following circuits: - swing - stick - left and right travel - bucket - auxiliary - boom Oil returning from these circuits flows back through the return system to the hydraulic tank.
