Great Plains P17921E Operator Manual - Manual (Page 32)

UniPress
Operating Instructions
32
Avoid sharp-edged and pointed
parts (disc blades, etc.) when
working on the machine.
Place the machine on suitable
s u p p o r t s w h e n w o r k i n g
underneath! Do not work under a
machine which is not supported!
On a new machine tighten all nuts and bolts
after 5 hours work and again after 15 hours.
This also applies to parts that have been
moved or replaced. After the initial 15 hours
of work a once a week check should be
sufficient depending on daily work rates.
5. Servicing and Maintenance
5.10 Maintenance
Intervals
Apart from daily maintenance, the
maintenance intervals are based on the
number of operating hours and time data.
Keep a record of your operating hours to
ensure that the specified maintenance
intervals are adhered to as closely as
possible.
Never use a machine that is due for
maintenance. Ensure that all deficiencies
found during regular checks are remedied
immediately.
5.11 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
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 UniPress, 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.
5.9 Brakes & Wheel Hubs
The brakes should be tested before using for
the first time and after the first laden journey.
Check that the road and parking
brakes operate and release
correctly before using the
machine.
Check for hydraulic fluid and air
leaks.
Brake and hub maintenance and
servicing should be carried out by
an authorised dealer.