Hydraulic down pressure 1800-3000 – Great Plains 4000TM Operator Manual User Manual
Page 27
Great Plains Manufacturing, Inc.
Preparation and Setup
23
10/30/2012
586-288M
Hydraulic Down Pressure 1800-3000
Refer to Figure 21
Note: This setup procedure is for tractors with closed-center
or pressure compensated flow hydraulic systems.
Open center hydraulics not supported. Adjust down
pressure valve as shown on decal (located on front of
left truss) Refer to Figure 1.
33. Adjust the bypass/pressure reducing valve by turning
knob
, clockwise all the way in and then backing out 1
full turn.
34. On tractor, adjust flow-control valve to low side of flow
rate.
Note: The faster the flow of oil through the system the greater
potential for oil heating, premature wear or tractor dam-
age.
35. Lock the fold hydraulic lever for continuous downward oil
flow.
36. Adjust bypass/pressure reducing valve knob
on imple-
ment so the pressure gauge reads 1200 psi. Never
exceed 1400 psi.
37. While watching pressure gauge, slowly open valve knob
until gauge reads 1100 psi. Pressure might rise and
then fall off as knob is opened. If pressure exceeds 1400
psi during this step, the tractor flow is too high, reduce
tractor flow. Lock valve knob
at 1100 psi.
38. Finally adjust valve
to the desired wing down pressure
setting of 300 to 400 psi. Never exceed 700 psi.
39. In field operation, Lock the fold hydraulic lever for contin-
uous downward oil flow. If wings are running too high,
increase pressure setting, knob
, to level machine. If
center is too high, decrease pressure setting with knob
on valve.
Notice: When operating machine with the blades in angled
position it is generally unnecessary to apply wing down pres-
sure. Only in very hard ground will wing down pressure be
necessary.
Caution: When not operating with live down pressure the fold
system must be in “FLOAT“position. Failure to operate in
either float or active down pressure will damage the fold sys-
tem. see your tractor operator’s manual to set system to
“FLOAT” position if necessary.
Caution: This machine is designed for continuous hydraulic
flow to the wing fold cylinders during field operations. It is for
use on tractors having CLOSED CENTER hydraulics only.
Figure 21
Down Pressure 1800-3000
42255
2
1
1
2
1
1
2
2
2
Figure 1
Down Pressure Decal 1800-3000
848-829C