Great Plains 2525A Operator Manual - Manual (Page 27)

Great Plains Manufacturing, Inc. Table of Contents Index Operating Instructions 23
2013-06-04 Table of Contents Index 118-999M
Air and Seeding System Overview
Refer to Figure 11, on page 22, and Figure 12.
The hydraulic fan supplies air exclusively for meter
operation. Fan rpm is operator-adjusted (page 25), nor-
mally via the tractor circuit’s hydraulic flow control.
A manually-adjusted butterfly valve is provided at the
fan outlet. See page 25 for valve adjustment.
The manifold system delivers fan air across the drill. It
includes passive internal design features to balance
pressure across the drill.
Separate pressurization tubes route manifold air to
each row unit.
Seed is delivered from the seed box by gravity
through the sliding seed tubes , to the inlet of the
Air-Pro
®
seed meter .
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 46 for shutter
adjustments.
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 .
Several rows have a pressure sensor port for the
meter pressure system. A line from each of these
rows is connected to a chamber to average the pres-
sures.
The averaged pressure is reported by a Magnehelic®
gauge
visible to the tractor operator. See page 35 for
use of the gauge in making fan adjustments.
If the optional seed monitor system is installed, a sensor
in each seed tube (not shown) reports seed passage.
Larger seeds are counted individually. For smaller seeds,
the system acts as a blockage monitor.
Figure 12
Air-Pro
®
Meter, Disk Side
29825
12
11
9
4
8
7
10
1
2
3
4
5
6
7
8
9
10
11
Use of the special blank disk (page 50), and closing the
seed inlet shutter (page 46), are particularly important
when a sensor row is shut off.
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.
12
13
14
15