Hydraulic System - Z Model - Hardi COMMANDER TWIN FORCE Series Instruction Book

7 - Fault finding

Hydraulic system - Z model

FAULT
No boom movements when activated.
Boom lift raises to max. pos. when trac-
tor hydraulics are engaged.
Oil heats up in Closed Centre systems.
Individual ram does not move.
7.4
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 a or b 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 for power supply.
Check relays, diodes and soldering at PCB in junction box.
Remove and clean restrictors a and b in bypass 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 hydraulic oil reser-
voir.
Divide return line in two and lead return oil back to reservoir
via two spool valves.
Check / close (screw in) by-pass valve 0.
Replace flow regulator O-rings and back-up rings. Replace
flow regulator.
Dismantle and clean restrictor.