Great Plains YP825A3P Operator Manual - Manual (Page 35)

Great Plains Manufacturing, Inc. Table of Contents Index Operating Instructions 31
2013-05-28 Table of Contents Index 401-652M
Fan General Operating Information
Adjust the fan to provide the meter pressurization
recommended for the seed disk, seed, and seed density.
See the tables and charts for recommended values in
the Seed Rate Manual.
Normal gauge readings are in the 0.8 inch to 4.0 inch
water pressure range, and vary considerably with crop.
Refer to Figure 25
Use tractor remote hydraulic valve flow control to set fan
speed and butterfly valve adjustment to make fine
adjustments to meter pressurization. Precise technique
depends on tractor capabilities:
• The objective is to obtain recommended meter
pressurization, and maintain it during end-of-pass
marker fold, lift and turn.
• For any setup adjustment, operate the tractor engine
at typical field rpms, and not at idle.
• Preset the butterfly valve. Use any setting that you
previously developed for the crop/disk/range (see Note
at right), otherwise:
If the tractor has fine control of remote flow rates, and
consistent flow at varying tractor engine rpm, initially
set the butterfly valve to 30
°
or less.
If the tractor has only coarse control of flow, initially set
the butterfly valve to 45
°
.
• Set the fan circuit flow to bring the gauge reading to
near the recommended value.
• Fine tune the meter pressurization with the butterfly
valve.
• If the tractor has marginal flow available, or the list
circuit has priority, you may need to experiment with
combinations of fan flow and butterfly valve settings.
Always start the fan with a low flow setting.
Gradually bring fan up to the recommended initial meter
pressurization.
At excessive rpm, too much air flow can cause:
• oil heating
• slow lift times
If desired pressure cannot be reached, or requires
unusually high oil flow at low butterfly valve settings,
chances are the fan is running backwards. Reverse the
inlet/return lines at the hitch.
Butterfly Valve Operation:
To adjust, loosen bolt
and rotate the handle .
Re-tighten bolt.
0
°
is wide open - maximum air flow.
90
°
is closed - minimum air flow.
The valve provides the most effect at settings between
20
°
and 70
°
.
Starting at 30
°
reduces the fan workload.
Starting at 45
°
provides the most adjustment range up or
down.
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 25
Fan Butterfly Valve Handle
25137
1 2
1
2
20
°
45
°
70
°
Low Population Risk at Turns:
The fan requires up to 4.5 gpm. This figure does not include oil
for lift/lower 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 will 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.