Hydraulic System - Z Model - Hardi COMMANDER 4500 Operator's Manual

Hydraulic system - Z model

FAULT
No boom movements when activated.
ParaLift lock does not lock.
Boom lift raises to max. position when tractor
hydraulics are engaged.
Oil heats up in Closed Center systems.
Individual ram does not move.
PROBABLE CAUSE
Insufficient hydraulic pressure.
Insufficient oil supply.
Blown fuse(s).
Bad / corroded electrical connections.
Insufficient power supply.
Defect relay / diodes in junction box.
Clogged restrictors in bypass block.
Wrong polarity.
Back pressure in return line exceeds 15 bar.
Bypass valve does not close properly.
Internal leaks in flow regulator.
Clogged restrictor.
7 - Fault finding
CONTROL/REMEDY
Check oil pressure.
Check tractor hydraulic oil level.
Oil flow must be min. 2550 l/min. and max. 130 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 for power supply.
Check relays, diodes and soldering at PCB in junction
box. LED diodes indicate boom functions.
Remove and clean restrictors in bypass block (See
hydraulic diagram). Change hydraulic oil + filter.
Check polarity. Red positive (+) Black negative (-).
Connect the return line with free flow to hydraulic oil
reservoir.
Divide return line in two and lead return oil back to
reservoir via two spool valves.
Check / close (screw in) by-pass valve.
Replace flow regulator O-rings and backup rings.
Replace flow regulator.
Dismantle and clean restrictor.
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