3PYPA
Table of Contents
Index
Adjustments
Great Plains
| 401-647M | 2019-06-11
Table of Contents
Index
63
Hydraulic Down Pressure
Refer to Figure 74
If desired opener depth cannot be consistently achieved
using cam adjustment (page 72), or gauge wheels are
slipping at the force required, the optional hydraulic down
pressure system may remedy the problem. Cylinders
transfer some center section weight to wings, controlled
by valves at the front of the center section.
Oil Heating / Tractor Wear Risks:
The current hydraulic down pressure option is compatible only
with “closed center” tractor hydraulics.
1. Before making depth adjustments with valve
,
make sure the system (valve
) has been calibrated
(page 171), and review how the system behaves as
hydraulics are cycled.
To adjust hydraulic down pressure:
2. At all rows, set the cam (mechanical spring) down
pressure to notch 3 (page 72).
3. The lever for the down pressure circuit remote must
be LOCKED OPEN to provide constant
pressure/flow to the down-pressure cylinders. See
operations tips in sidebar for specific tractor models.
4. With the tractor hydraulic lever locked forward,
release the lock disk
, turn the knob
on the
pressure control valve
.
5. Watch the pressure gauge
and set the desired
pressure. Clockwise increases the pressure and
counterclockwise decreases pressure. The
recommended pressure range for planting is
between 400 psi and 600 psi.
6. Once the pressure is set, lock the knob
with the
lock disk
.
The row down-force setting controls the soil firming
pressure on the press wheel as well as the disk
penetrating force. DO NOT use more down-force than
necessary to obtain the desired opener penetration and
to maintain the proper firming action over the seed.
Excessive opener force leads to excessive wear and
damage of the opener components.
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 lift assist to circuit #2 and
the markers to circuit #3.
Figure 74
Hydraulic Down Pressure System
29194
John Deere 8000 Series tractors:
Set timer to continuous.
Push lever forward until detent clicks.
Case-IH Magnum tractors:
Lock lever forward in detent position. You may need to
turn up detent pressure to its maximum setting. Do not
tie hydraulic lever past detent position with a strap. See
your tractor dealer for hydraulic-system details.
Other tractors:
Lock lever forward in detent position. You may need to
turn up detent pressure to maximum or use a
mechanical detent holder to hold lever forward. See
your tractor dealer for providing constant flow to
openers.
On some tractors with very positive remote hydraulic
checks, a slight increase in the reading on the pressure
gauges may occur after the tractor remote lever is
returned to neutral. This is caused by back pressure on
the opener cylinders and may be ignored.
The NET OPERATING PRESSURE on the opener
cylinders is maintained at the pressure you selected
while the tractor remote lever was held forward–not at
the “apparently increased” pressure. Reactivating the
tractor lever forward confirms this
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