Great Plains CTA4000 HD Operator Manual - Manual (Page 47)

Great Plains Manufacturing, Inc. Adjustments 43
2012-11-28 160-037M
Sub-Frame Down-Force
Opener down pressure controls opener penetration and
press-wheel soil firming. Use only enough down
pressure to cut the furrow and maintain proper
soil-firming over seed. Excessive opener down force will
lead to premature wear on opener components.
Some tractors with load-sensing or constant-flow hydraulics
need a bypass valve with the CTA4000HD. See “Hydraulic
Bypass Kit” on page 59. Before adjusting opener down
pressure, set bypass valve per “Load Sensing Setup” on
page 25.
Hydraulic Down Pressure
Refer to Figure 56
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 1400 psi as a general
starting point. For most field conditions, adjust the
hydraulic down pressure between 1000 and 2200 psi.
For pressures at and above 1600 psi, make sure
implement has enough weight available per opener. see
“Frame Weight” on page 41.
For pressures above 1600 psi, see “Opener-Subframe
Adjustment” on page 45.
Do not set opener down pressure above 2200 psi.
Refer to the chart on the next page for approximate force
at the openers for a given control-valve setting.
Figure 56
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 57
Adjusting Frame Down Force
26459
2 1
1 2
1
2