Great Plains 3N-4025P Operator Manual - Manual (Page 33)

4/23/2010 196-286M
31 Adjustments
Second, the press wheels provide opener depth
control on 10 series openers (on 15, 20 and 25 se-
ries side wheels control depth).The higher the
press wheels run relative to the double disks, the
deeper seed will be placed. To maintain a consis-
tent depth, upward press-wheel movement is
restricted by an independently adjustable stop on
each opener. Refer to “Opener Seeding Depth,”
page 35, for information on how to make this
adjustment.
10 Series & 20 Series Coulter
Adjustments
The drill is assembled so that when the coulters
are at two inches deep, the seeding depth is about
one inch. This is a good baseline setting for most
seeding operations. As field conditions warrant,
you can change settings on the entire drill or indi-
vidual coulters. Unit mount 15 series are set equal
to opener depth.
To prevent uneven seeding depth and excess opener
wear, run coulters at least 1 inch below seeding
depth.
Hydraulic Depth Control
Refer to Figure 20
The field-lift cylinders are equipped with a hydrau-
lic valve that regulates coulter depth. Use the
valve to adjust coulter depth.
Loosen the bolt on the side of the depth stop and
slide the depth stop up to raise coulters or down to
lower coulters. Retighten bolt after setting the
depth stop.
Make depth adjustments with the implement
slightly raised. After adjusting the valve, raise and
lower the implement several times and recheck
coulter depth.
The depth stop regulates depth on all coulters. If
the ends of either box run higher or lower than the
center, the field-lift system may be out of phase or
have air in it, or the frame sections may not be lev-
el. Refer to “Rephasing Lift System,” page 24,
“Bleeding Lift Hydraulics,” page 17, or “Leveling
Frame Side-to-Side,” page 19.
Depth Stop
Bolt
Raise Coulters
Lower Coulters
20274
Figure 20
Depth Control Adjustment
Note: It is important that all of the tires remain
in contact with the ground to maintain level-
ness of machine from front to rear. Setting the
depth control too deep combined with high
opener spring force can cause the drill to tip
forward when planting, which may cause plug-
ging.
Running with the front tires floating or skimming on
the ground will cause uneven coulter depth and
may cause uneven seed depth.