Great Plains 3P300 Operator Manual - Manual (Page 45)

09/14/2009 500-103M-A
Great Plains Manufacturing, Inc. Adjustments 41
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. See “Hydrau-
lic Elevator Option” on page 37. 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 accordingly. Refer to the Nozzle Charts
in the Application Guide located in this manual to deter-
mine 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 Application 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
The SCS 440 auto control system regulates pressure
automatically. With manual control (SCS 313, 2007-
sprayers only), nozzle pressure may require some field
adjustment. As the tank level decreases, boom pressure
may need to be adjusted to keep the pressure at the cal-
ibrated level. Watch the SCS 313 pressure gauge and be
aware of changes in the pressure.
Tank Straps
The tank straps that wrap around the sprayer tank may
become loose after the first few hours of operation. This
occurs when the tank settles in the saddle. Polyethylene
tanks are especially susceptible to this. Retighten the
tank straps to secure the tank.
Pressure Adjustments
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 calibrated. Refer to Calibration Procedures in the
Application Guide.
The electric butterfly valve is used to adjust the pressure
to the booms. It is controlled automatically by the SCS
440, and manually by a switch on the SCS 313. The
boom pressure is displayed by the boom pressure mode
of the SCS 440, and by the gauge on the SCS 313.
To adjust the pressure on SCS 313, hold the pressure
adjust toggle switch up for more pressure, down for less
pressure.
As the tank level decreases, the boom pressure may
change. SCS 440 compensates automatically. On SCS
313, check boom pressure gauge frequently and make
sure that the pressure doesn’t change. Generally, the
boom pressure will need to be adjusted up slightly when
the tank level decreases.
Refer to Figure 24
When the manual pressure adjustment valve is wide
open, the pressure adjust switch is very sensitive. To
decrease the sensitivity of the pressure adjust, set the
manual pressure adjustment valve. See “Manual Pres-
sure Valve” on page 21.
Figure 24
Pressure Valves
15783