Great Plains P17897B Operator Manual - Manual (Page 34)

X-Press
Operating Instructions
34
5.7 To Adjust the System
Pressure
A low oil flow should be used,
i.e., tractor tickover or low flow
selected.
The wing circuit is controlled by an
overcentre valve contained within
the manifold block which positively
locks oil flow until pressurised by
the tractor. System pressure can
be retained in the circuit even
after depressurisation of the
tractor quick release couplings.
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.
It is normal to operate at 10-20 bar. This can
be increased to 40-50 bar max, or reduced
to 5 bar as conditions determine. Higher
pressure will cause the wing tips to dig in
causing the centre of the machine to lift it
out. Too little pressure will cause the wing
tips to lift out & the centre of the machine
to dig in. When towing another implement
behind the X-Press, the pressure may need
increasing to compensate.
In all cases the normal adjustment method
is to minimise system pressure and then
increase by adjusting the pressure valve
until the desired pressure is achieved.
In all cases, regardless of tractor make,
adjustment should start from zero (minimum
pressure) and gradually increase up to
desired pressure value.
With the machine off the ground,
1. Pressurise the wings to unfold. As the
unfolding begins the pressure reading
on the gauge will drop. When the
wings have fully unfolded the pressure
reading will start to climb. Keep
pressurising the wings until the gauge
has stabilised at the pre-set pressure.
The standard factory setting is 15 bar.
2. If the system needs adjusting:- Partially
fold the wings & hold them in this
position. To adjust the pressure utilise
valve 3 (shown in Fig. 5.03). Unscrew
the adjusting screw until no resistance
can be felt (almost fully unscrewed
position). Unfold the wings fully as
before, checking the gauge reading.
Maintain hydraulic pressure unfolding
wings & adjust the screw whilst
pressurising.
• Turning adjuster clockwise increases
pressure.
• Turning adjuster anti-clockwise
decreases pressure.
Once the desired pressure is achieved lock
the valve. As a check, partially fold the wings,
stop, and then unfold again maintaining
pressure until the gauge stabilises at your
desired setting.
Fig. 5.03: Manifold Block
5. Servicing and Maintenance