Daewoo Solar 300LC-V, Manual

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S0702170K
Page 6 Hydraulic System Troubleshooting, Testing and
Adjustment
OPERATION OF WORKING COMPONENTS
BOOM OPERATING CIRCUIT
The boom operating circuit includes the right and left main hydraulic pumps (both halves of the main pump
assembly), both sides of the control valve and the boom cylinder. The circuit operates in boom down mode
through the first shift position and through the second shift position in boom up mode. Overload relief
valves set at 360 kg/cm
2
(5,112 psi) protect the hydraulic system from damage as a result of overloads or
shocks to the boom.
BOOM UP CIRCUIT
When you pull the boom control lever backward,
the right side pilot valve generates secondary
boom up pilot pressure that is transmitted to the
BOOM1 and BOOM2 spools of the control valve
simultaneously. When secondary pilot pressure
reaches 7 - 9 kg/cm
2
(100 - 130 psi), boom
control valve spools open and oil from both
pumps goes to the boom cylinder.
BOOM DOWN CIRCUIT
When the boom control lever is pushed forward,
the right side pilot valve generates secondary
boom down pilot pressure that is transmitted
only to the BOOM1 spool of the control valve.
When secondary pilot pressure reaches 7 - 9
kg/cm
2
(100 - 130 psi), the BOOM1 spool on the
left side of the control valve opens so that oil
from only one pump (PUMP(L)) assembly goes
to the boom cylinder for boom lowering.
BM1 BM2
PUMP(L) PUMP(R)
PL PR
BMD
TL
CONTROL
VALVE(L)
BOOM
CYLINDER
CONTROL
VALVE(R)
ARS1560L
PILOT VALVE
Figure 2
PILOT VALVE
PUMP(L)
PL
BMD
TL
CONTROL
VALVE(L)
BOOM
CYLINDER
ARS1570L
BM1
Figure 3