Great Plains CTA4000 Operator Manual - Manual (Page 41)

Adjustments 37
08/03/2010 160-269M-A
Sub-Frame Down-Force
Opener down pressure controls opener penetration and
press-wheel soil firming. Use only enough down pres-
sure to cut the furrow and maintain proper soil-firming
over seed. Excessive opener down force will lead to pre-
mature wear on opener components.
Some tractors with load-sensing or constant-flow hydraulics
need a bypass valve with the CTA4000. “Hydraulic Bypass
Kit” on page 53. Before adjusting opener down pressure, set
bypass valve per “Bleeding Hydraulics” on page 15.
Hydraulic Down Pressure
Refer to Figure 43 and Figure 44
Both valve block handles must be set for FIELD for down
force adjustments.
There is one pressure-control valve for wing sections
and one for center section
.
With hydraulic power to the implement, release the lock-
rings, and rotate the knobs to adjust pressure, while
watching the readings on the gauges. Rotating the knob
clockwise increases pressure.
Set opener down pressure to 800 psi as a general start-
ing point. For most field conditions, adjust the hydraulic
down pressure between 200 and 1200 psi.
For pressures at and above 1200 psi, make sure imple-
ment has enough weight available per opener. see
“Frame Weight” on page 35.
For pressures above 1200 psi, see “Opener-Subframe
Adjustment” on page 39.
Do not set opener down pressure above 1600 psi.
Refer to the chart on the next page for approximate force
at the openers for a given control-valve setting.
Figure 43
Down Force Valves
26372
Note: You can set center section pressure slightly higher
than wing pressure, to account for soil compaction
from tractor, cart and implement.
Figure 44
Adjusting Frame Down Force
26437
2 1
1 2
1
2