Great Plains 3P300 Operator Manual - Manual (Page 18)

16
Section 3 Adjustments
3/6/06 3P200 and 3P300 Three-Point Sprayer 500-103M
Great Plains Mfg., Inc.
Section 3
Adjustments
General Field Adjustments
Boom Height
After calibrating the sprayer for the specific nozzle that will
be used at a desired pressure and tractor speed, the main
field adjustment is the boom height. Refer to Hydraulic El-
evator Option in the “Operating Instructions” section on
page 13. Depending on which type of nozzle is being
used, set the boom height so that the correct overlap for
that specific nozzle is achieved. If the crop canopy is taller
in some fields than others adjust the boom height accord-
ingly. Refer to the Nozzle Charts in the Application Guide
located in this manual to determine the height of the boom
needed.
EXAMPLE: A 2.5 MeterCone nozzle at 20 inch spacing is
being used. From the Nozzle Chart (refer to the Applica-
tion Guide), a height of 19 to 21 inches above the top of the
crop is required. If the crop is 6 inches off the ground, the
boom height should be set to 25 to 27 inches off the
ground.
Nozzle Pressure
Another area that will need some field adjustments is the
nozzle pressure. As the tank level decreases the boom
pressure may need to be adjusted to keep the pressure at
the same magnitude for what the sprayer was calibrated
for if the sprayer is not equipped with a monitor. Watch the
pressure gauge and be aware of changes in the pressure.
Tank Straps
The tank straps that wrap around the sprayer tank may be-
come loose after the first few hours of operation. This oc-
curs when the tank settles in the saddle. Polyethylene
tanks are especially susceptible to this. Retighten the tank
straps to secure the tank.
Throttling Valve Adjustment
(Manual Control System Only)
The boom valves used to turn on the individual boom sec-
tions are three way valves. These valves route the flow to
the boom sections or back into the tank, depending on
whether the boom section switches on the control box are
turned on or off.
When a boom section switch is turned to the off position,
the boom valve for that switch diverts the flow back into the
inlet of the pump. To insure that the flow going to the boom
section and the flow going back to the inlet of the pump are
the same, a throttling valve is used to adjust the flow going
to the inlet of the pump. If these flows were not equal, ev-
ery time the boom section switch if flipped, the pressure
will either rise or decrease in the other boom sections,
causing the sprayer to over or under apply chemical in
those boom sections.
To set the three throttling valves, complete the following:
1. Adjust all three of the throttling valves until they are
closed, Figure 3-1.
2. Turn all the boom section switches on with the tank
filled with water (no chemical added) and the pump
running. Adjust the boom pressure until the boom
pressure gauge reaches the selected calibration pres-
sure.
3. Turn the left boom section switch off and keep the cen-
ter and right section switches on. Unscrew the throt-
tling valve for the left boom section until the pressure
on the boom pressure gauge reaches the calibration
pressure. Flip the left boom section switch a few times
and adjust the throttling valve so that the pressure re-
mains at the selected calibration pressure.
4. Turn the left boom section switch on. With the left and
right boom sections on, turn the center boom section
off and adjust the throttling valve as described in step
#3.
5. Adjust the throttling valve for the right boom section
with the left and center boom sections on as described
in step #3.
6. With all throttling valves adjusted, it should be possi-
ble to flip any combination of boom section switches
with the pressure remaining constant.
Pressure Adjustments
(Manual Control System Only)
One of the most important areas of controlling the sprayer
accuracy is to have the proper pressure when spraying.
The pressure is determined when the sprayer is calibrat-
15774
Throttling Valve
Figure 3-1