Great Plains 1625AHL Operator Manual - Manual (Page 56)

52 1625AH Table of Contents Index Great Plains Manufacturing, Inc.
411-020M Table of Contents Index 2014-04-21
Air Systems General Operating Information
Air system setup differs for liquid and dry fertilizer
planters.
Refer to Figure 35 on page 48 and Figure 41
Two Magnehelic
®
meter pressurization gauges
(one each wing, bearing Air-Pro
®
decals) have scales of
0-to-6 inches of water pressure. Normal readings are in
the range 0.8 to 4.0, and vary considerably with crop
(see Seed Rate Manual).
Refer to Figure 35 on page 48 and Figure 40
On dry fertilizer configurations (models 1625AHD), there
is a third Magnehelic
®
gauge (right wing, inboard of the
Air-Pro
®
gauge, and bearing a fan system decal). This
gauge has a scale of 0-to-50 inches of water pressure.
Typical readings are in the range 35-to-45.
• The objectives are to:
obtain recommended meter pressurization, maintain it
during end-of-pass marker fold, lift and turn, and
prevent seeding skips, and dry fertilizer blockage
when planting and applying.
• For any setup adjustment while parked, operate the
tractor engine at typical field rpms, and not at idle.
• Preset the butterfly valves. See planter-specific advice
in the following pages for setting butterfly valves.
• Seed meters must be full (to inlet shutters) for valid
gauge readings. Air escaping up an empty seed tube
results in low readings. With a full meter, readings may
vary slightly when seed disk pockets are also full.
• Set the fan circuit flow to bring the Air-Pro
®
gauge
reading to near the recommended value.
• If needed, fine tune the meter pressurization with the
butterfly valves.
• If the tractor has marginal flow available, or the lift
circuit has priority, you may need to experiment with
combinations of fan flow and butterfly valve settings.
Note: Fan speed can change as oil heats to operating
temperature. Re-check pressure gauges more
often during early operations.
Note: Fan speed can change between planting and
no-seed-in-disks states. Monitor meter
pressurization when planting with full seed disks.
Note: You may find that different crop, seed disk and rate
range combinations need different valve settings. If
so, make a note of the valve angle on the chart in
the Seed Rate manual.
Figure 39
Magnehelic
®
Air-Pro
®
Gauge
29842
858-208C
A3
858-193C
Low Population Risk at Turns:
The fan requires up to 20 gpm. This figure does not include oil
for lift or oil for marker operation. Aggressive lift/lower
operations, and simultaneous lift/marker operations, can
reduce fan rpm below that needed to pressurize meter disks. If
seed falls out of pockets, low population bands occur shortly
after turns.
Unless the tractor has generous oil flow capacity, raise/fold
markers before lift, and lift slowly. Watch meter pressurization
and tune operations to keep it at planting levels in turns.
Figure 40
Magnehelic
®
Dry Fertilizer Gauge
31187
858-193C
0
10
30 20
40
50