Air and seeding system overview – Great Plains YP825A3P Operator Manual User Manual
Great Plains Manufacturing, Inc.
Air and Seeding System Overview
Refer to Figure 20, on page 27, and Figure 21.
The hydraulic fan
supplies air exclusively for meter
operation. Fan rpm is operator-adjusted (page 31),
normally via the tractor circuit’s hydraulic flow control.
A manually-adjusted butterfly valve
is provided at the
fan outlet. See page 31 for valve adjustment.
The manifold system
delivers fan air across the
planter. It includes passive internal design features to
balance pressure across the planter.
Separate pressurization tubes
route manifold air to
each row unit.
Seed is delivered from the seed box
through the sliding seed tubes
A manually adjusted inlet shutter
controls the size of
the seed pool
at the base of the meter. The shutter
also minimizes air loss back up the seed inlet tube, and
is also used during row shut off. See page 55 for shutter
At the meter, pressurization air exits the meter through
the seed pockets
of the disk, and holds seed in the
pockets until released above the seed tube
In the seed tube, the seed sensor
detects passage of
seeds. Medium size and large seeds are counted
individually. With smaller seeds, most are detected,
allowing the monitor to detect stoppages.
Several rows have a pressure sensor port
meter pressurization system. A line
from each of
these rows is connected to a chamber
to average the
The averaged pressure is reported by a Magnehelic
visible to the tractor operator. See page 43 for
use of the gauge in making fan adjustments.
in each seed tube reports seed passage to
the seed monitor. Larger seeds are counted individually.
For smaller seeds, the system acts as a blockage
Note: Use of the special blank disk (page 59), and closing
the seed inlet shutter (page 55), are particularly
important when a sensor row is shut off.
Note: On any row, running a normal disk with no seed, or
with an open empty inlet, unbalances the air
system. Doing either at a sensor row causes the
gauge to mis-report as well.
Note: Do not operate in the ground with the fan shut off, or
with insufficient manifold pressure. The meters will
completely fill with seed. Meter clean-out may be
required to resume normal operation.
Meter, Disk Side