Great Plains P16229C Operator Manual - 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
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