Great Plains P16229 Serial No 18007975 2009 - Manual (Page 23)

23 Hydraulic Reset Flatliner
Operating Instructions
5.7 Specific Instructions
Relating to Trip Reset Tine
Hydraulics
Please refer to page 80 when
referring to these instructions.
The circuit allows for the tines to be
pressurised down into work, whereupon a
relief valve (REF. X) limits this applied tractor
down pressure to a value less than the main
system accumulators (80b x 2 litre). This
allows tines to trip in work, the oil being
absorbed by the main accumulator. A
secondary (rod side) accumulator ensures
this side of the cylinder is maintained full of
oil to minimise cavitation and seal damage.
A pre charge valve (REF. Z) restricts return
rod side oil flow to the tractor as the tines are
pressurised down to ensure this secondary
circuit is charged.
In operation, oil is locked in the cylinder circuit
at a pressure determined by the relief valves
90-120 bar full bore side (REF. X) and 20 to
60 bar rod side (REF. Z). This occurs at all
times, even with the circuit in float at the tractor,
provided the tines are fully down. For
extremely stony conditions, adjust the valve
(REF. X) to read 90 bar on the gauge as the
tines are pressured down. For heavy soils
with little stone where compaction is present
it is possible to increase this pressure to 120
bar.
To de- pressurise the circuit, identify and
adjust the following valves on the Tine Control
Manifold (P09078).
All valves can be identified by stamped codes
adjacent to each valve (identified on the
drawing on page 80 and the references
contained in this procedure).
• Set tractor hydraulics to neutral,
machine raised.
• Adjust pre charge valve (REF. Z) fully
clockwise. If necessary, note the number
of turns that it takes for the system to be
reset.
• Adjust relief (REF. X) fully anticlockwise.
If necessary, note the number of turns
that it takes for the system to be reset.
• Set tank return line circuit to float or down
to return oil to tractor.
• Set main system to float, or allow oil
pressure to be released in both
directions.
• Refer to pressure gauges on machine.
Ensure both read zero before
attempting any maintenance. Repeat
the above procedure until both gauges
read zero in all circumstances.
Follow detailed setting sequence on page 24
to reset the system prior to returning to work,
or alternatively revert the above valves back
to their original setting (number of turns).
5.6 Hydraulics
A low oil flow should be used, i.e.,
tractor tickover or low flow
selected.
Exercise extreme care when
checking the valve or circuits, and
under no circumstances attempt
to adjust or loosen fittings without
prior reference to your authorised
Simba dealer, and detailed
maintenance instructions.
The hydraulic circuit contains
specialised fittings which should
not be tampered with under any
circumstances. Do not attempt to
modify hose routings or hose
clamping arrangements, doing so
my cause serious damage to the
machine and/or injury.
5. Servicing and Maintenance