Great Plains Manufacturing, Inc.
Operating Instructions
33
2019-03-12
195-068M
Priority Flow Hydraulic Systems
On some tractors with load-sensing hydraulics, the
circuit #1 is capable of taking nearly 100 percent of
available hydraulic flow. Operating the openers or
markers on circuit #1 will starve the other circuit, making
one function inoperable.
To operate markers and constant opener down pressure
at the same time, connect the openers to circuit #2 and
the markers to circuit #3.
Non-Active Hydraulic System
To run drill with open-center hydraulics or
fixed-displacement hydraulic pumps requires a Great
Plains kit, part number 194-143A. After installing the kit,
refer to the following instructions for opener operation.
1. Lower opener frames by pushing forward on tractor
hydraulic lever. Lock lever temporarily in this position
while adjusting opener down pressure.
2. With tractor hydraulic lever locked forward, release
lock disk and set down-pressure with adjustment
knob . Watch pressure gauge and dial in desired
pressure on openers. There is one pressure-control
valve for openers on center section and one for
openers on wing sections of drill.
Note: Rotate knob clockwise to increase pressure and
counterclockwise to decrease pressure.
3. Once pressure is set, set knobs with lock disks .
4. After opener down pressure is set, return tractor
hydraulic lever to neutral. This locks-in the selected
pressure, and opener frames remain fixed in this
position.
Machine Damage Risk:
Open-center tractors and tractors
with fixed-displacement pumps are not designed to provide a
continuous supply of pressurized oil to remote valves. Locking
hydraulic lever forward on these tractors can cause overheat-
ing of hydraulic oil and tractor damage. After setting opener
down pressure, always return hydraulic lever to neutral.
Note: On some tractors with very positive remote hydrau-
lic checks, a slight increase in the reading on the
pressure gauges may occur after tractor remote le-
ver is returned to neutral. This is caused by back
pressure on opener cylinders and should be ig-
nored. The net operating pressure on opener cylin-
ders is maintained at the pressure you selected
while tractor remote lever was held forward-not at
the apparently increased pressure. Reactivating
tractor lever forward will confirm this.
FigureSpacer
Figure 26 - Non-Active
Pressure Control Valves
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