Lull 944E-42 Service Manual - Manual (Page 332)

Hydraulic System
8.80 Model 644E-42/944E-42 Rev. 6/04
8.8.13 Boom Retract Circuit & Troubleshooting (Single Joystick)
(Refer to Section 8.8.52, “Boom Extend/Retract Circuit Description (Single Joystick),” for a more detailed
explanation of this circuit.)
ATTACH
TILT
FRAME
EXT/RET LFT/LWR
AU
X
TRANS
INLET
OUTLET
RETURN
FILTER
25 PSI
(1,7 BAR)
BYPASS
CHECK
VALVE
SINGLE
JOYSTICK
PILOT
SELECT
VALVE
P1 TB
TA
AUX2
AUX1
EB
EA
HB
HA
CTB
CTA
T P
P2 P3 P4
SINGLE
JOYSTICK
HYDRAULIC OIL
COOLER
CHECK VALVE
85 PSI (5,9 bar)
HYDRAULIC
RESERVOIR
Suction
Return
Load Sense
Pressure
Pilot Pressure
1
3
T
P
4
2
PUMP
ACCUMULATOR
CHARGE/SECONDARY
FUNCTION VALVE
LS
DRAIN P1
LSG ACR
SW P
ACF EF CF PIL PB
PBG
PPG
SW
EXTEND/RETRACT
CYLINDER
R E
MAIN
CONTROL
VALVE
MU5290
Implement
Pump
Pressure
Tap
Main
Relief
Valve
Pressure
Reducing
Cartridge
“PPG”
Pressure
Tap
Pilot Supply
Line
Unloader
Cartridge