Great Plains NTA3007HD Operator Manual - Manual (Page 92)

88 NTA907HD or NTA3007HD
166-207M 04/04/2011
Refer to Figure 94
4.
Release locking disks on transfer , center and
wing down-pressure valves.
5. Adjust knobs on pressure-control valves , for
opener down pressure until gauges , are at
9.7 bar (1400 psi).
The recommended down-pressure ranges for drilling are:
Note: Rotate knob clockwise to increase pressure and
counterclockwise to decrease pressure.
6. In some applications, pressure on center section is
set slightly higher than the wings to account for addi-
tional compaction due to tractor and drill transport
tires. Do not operate at pressures so high that the
wing gauge wheels loose traction, or are off the
ground, causing loss of seed depth control.
Setting the Bypass Valve
• LS Closed:
Tractors with load-sensing, Closed-Center hydraulics
require the bypass valve
to protect the tractor
hydraulic system. Continue at “Bypass with LS or
PFC Closed Systems” on page 89.
• PFC Closed:
Pressure Flow Compensating - same adjustment as
LS Closed. Continue at “Bypass with LS or PFC
Closed Systems” on page 89.
• PC Closed:
Pressure Compensating - no bypass is required.
Release locking disk. Close bypass valve
for no oil
flow by turning knob clockwise completely. Tighten
locking disk. Always operate the drill with the bypass
valve locked closed.
• Open Center (OC):
The NTA907HD and NTA3007HD drills are not pres-
ently compatible with tractors that have Open-Center
hydraulics.
If you are unsure what type of hydraulic system is on
your tractor, contact your tractor manufacturer.
Center 4.8 to 14.5 bar (700 to 2100 psi)
Wings 5.5 to 15.2 bar (800 to 2200 psi)
Null4:
Figure 94
Down-Pressure Adjustment
29422
W
C
T
B
k
r
w
c
t T C
W
C W
c w
c
w
B
B