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NexStar Troubleshooting
HC-10 NEXSTAR
Hydraulic Troubleshooting Table
ERROR
CAUSE
DIAGNOSTIC
SOLUTION
Crane moves
unexpectedly
Jammed valve cartridge
Try to manually override
valve. If unable to
move stem, cartridge is
jammed.
Replace valve cartridge.
Counterbalance valve set
too low (boom up and
boom down)
Adjust the
counterbalance out to
see if movement stops.
Contact Auto Crane
for proper adjustment
and setting of
counterbalance valve.
Valve may need to be
replaced.
Contaminant in cartridge Valve sticks in certain
positions.
Clean valve to remove
debris. Reference
Maintenance section
for valve cleaning
procedure.
No Function Operates On
Crane
Hydraulic tank is low or
empty
Visually inspect the
hydraulic oil level in the
tank.
Fill tank to proper level.
Vehicle is not running
Verify engine is running. Start vehicle.
PTO is not engaged
Verify PTO is engaged.
Engage PTO.
All functions operate
slowly
Contamination in
cartridges
Visually inspect the
cartridges for clogged
ports.
Clean valves to remove
debris. Reference
Maintenance section
for valve cleaning
procedure.
Relief valve set too low
Install pressure gauge
in control valve block.
Fully extend boom to
induce full pressure.
Verify relief pressure.
Adjust relief valve to
proper pressure.
Excessive heat during
operation
Crane operated too long Crane operation is
generally designed for
intermittent duty (15
minutes loaded / 30
minutes cooldown)
Reduce use of crane
to allow oil to cool. If
problem persists, add
hydraulic oil cooler to
system.