80
GB 16 02
Fault-finding
FAULT
No boom movements
when activated
Boom lift raises to max.
pos. when tractor
hydraulics are engaged
Oil heats up in Closed
Centre systems
Individual ram does not
move
PROBABLE CAUSE
nsufficient oil pressure
Insufficient oil supply.
Blown fuse.
Bad / corroded electrical
connections
Insufficient power supply.
Defect relay / diodes in junction
box.
Clogged restrictors
B
or
C
in
by-pass block.
Wrong polarity.
Wrong oil inlet to by-pass
block.
Back pressure in return line
exceeds 20 bar
By-pass valve
0
does not close
properly
Internal leaks in flow regulator
Clogged restrictor
CONTROL/REMEDY
Check oil pressure - min. 130 bar, max. 160
bar.
Check tractor hydraulic oil level
Oil flow must be min. 10 l/min. and max. 90 l/
min.
Check tractor hydraulic oil level.
Check / replace fuse in junction box.
Check / clean connections, multi plugs etc.
Voltage on activated solenoid valve must be
more than 8 Volts. Use wires of at least 4 mm
2
for power supply.
Check relays, diodes and soldering at PCB in
junction box
Remove and clean restrictors
B
and
C
in by-
pass block (See hydraulic diagram) Change
hydraulic oil + filter
Check polarity. White pos. (
+
) Blue neg. (
-
).
Connect hydraulic snap couplers opposite in
tractor outlets, or engage spool valve lever in
opposite direction
Connect the return line with free flow to hydrau-
lic oil reservoir.
Divide return line in two and lead return oil
back to reservoir via two spool valves.
Check / replace locking clip on by-pass valve
0
.
Replace flow regulator O-rings and back-up
rings. Replace flow regulator.
Dismantle and clean restrictor
Hy
Hy
Hy
Hy
Hydr
dr
dr
dr
draulic sy
aulic sy
aulic sy
aulic sy
aulic system (Dir
stem (Dir
stem (Dir
stem (Dir
stem (Direct Acting Hy
ect Acting Hy
ect Acting Hy
ect Acting Hy
ect Acting Hydr
dr
dr
dr
draulic Sy
aulic Sy
aulic Sy
aulic Sy
aulic System)
stem)
stem)
stem)
stem)