INSTRUCTIONS IN ENGLISH |SPRAYER CALIBRATOR MODEL SC-2
04 SpotOn® Sprayer Calibrator Model SC-2 Item #38790
INSTRUCTIONS IN ENGLISH |SPRAYER CALIBRATOR MODEL SC-2
Measuring Application Rate
First set the travel speed, nozzle spacing as per above section, and units of measure by pressing
the SETTING button and +/- buttons as needed. Exit setting mode by pressing the ON/OFF button.
Subsequent measurements of nozzle ow will display true application rate on the display based
on these settings. % error can also be displayed correctly if 0%= target application rate is set to
the desired application rate.
Determine Required Speed or Nozzle Flow to Attain Desired Application Rate
First set nozzle spacing as per above section and units of measure by pressing the SETTING button
and +/- buttons as needed. Then adjust speed and/or 0%= target nozzle ow as needed until the
displayed application rate matches your desired application rate. Adjusting the actual sprayer
speed and nozzle ow rate to these settings will result in the desired application rate during
operation. This function works with or without measuring nozzle ow, however, only if an actual
nozzle’s ow was measured prior to adjusting these settings will the display show the % error.
Troubleshooting and Maintenance
This meter measures the ow rate by measuring the time it takes to ll a portion of the meter’s
container. The rising water level is sensed by 3 electrodes inside the meter. The meter will only
function with uids that conduct electricity, such as water. In the case of distilled water, the
conductivity may be too low for proper meter operation. All tap water will work very well with the
meter. Any substance that coats or covers the exposed metal on the electrodes will hinder their
ability to sense the water level. Care should be taken to rinse the inside of the meter with clean tap
water when contaminates are present in the measured ow. This will keep foreign material from
building up on the electrodes.
If the electrodes need to be cleaned, they can be accessed by removing the bottom red plug and/
or removing the upper diuser pad. The diuser pad can be pulled straight out of the top of the
unit once the front retaining screw is removed. When replacing this screw do not over-tighten.
Do not bend the electrodes while cleaning since this can aect the meter’s calibration. Complete
rinsing will also keep the diuser pad from becoming clogged and hindering the ow of water into
or out of the meter during operation. If foaming or bubbles are a signicant problem, a small drop
of de-foaming agent (for carpet cleaners or spas) may be added to the diuser pad prior to use.
Sprayer Calibration Instructions (verify with your chemical and equipment suppliers)
1. Determine application rate (GPA or LPM) from chemical label: Find the desired application rate
GPA(Gallons Per Acre) or LPH(Liters/ha) from the chemical manufacturer’s label. Note: GPA =
Gal/1000SqFt x 43.56
2. Select travel speed: Make sure it is appropriate for eld conditions in MPH or KPH
3. Adjust for solution density:
A. If using a water-based solution, then skip to Step 4 because the solution density factor
will be X 1.00
B. If using a fertilizer-based solution, then multiply desired GPA or LPH by the
following correction factor to determine water-based equivalent and continue with
Step 4 using this new number. Note: Nozzle manufacturers typically specify their
nozzles based on the density of water so when something other than water is used as a
base this adjustment accounts for the change in nozzle performance.
Multiply Rate from Step 1 by 1.11 for 4-10-10 liquid fertilizer base
Multiply Rate from Step 1 by 1.13 for 28-0-0 liquid fertilizer base (28% Nitrogen)
Multiply Rate from Step 1 by 1.15 for 32-0-0 liquid fertilizer base
Multiply Rate from Step 1 by 1.16 for 7-21-7 liquid fertilizer base
Multiply Rate from Step 1 by 1.18 for 10-34-0 liquid fertilizer base
4. Use the SC-2 to calculate required single nozzle GPM (Gallons Per Minute) or LPM (Liters Per
Minute). See above section about determining correct nozzle spacing to use on the SC-2.
The following equations can also be used:
GPM = (GPA x MPH x Nozzle Spacing in Inches) / 5940
LPM = (L/ha x KPH x Nozzle Spacing in cm) / 60000
5. Determine the best droplet size based on chemical manufacturers label or spray dri concerns.
(Small Droplets = Penetration & Coverage, Large Droplets = Less Dri)
6. Select proper spray nozzle by nding one that produces the desired ow (GPM or LPM) AND the
desired droplet size at that ow. Determine this by reviewing the detailed specs from the nozzle
manufacturer. Note the nozzle pressure to use from these specs as well.
7. Check for nozzle wear if you plan to use nozzles that are not new. The SC-2 can quickly check
each nozzle for wear. See previous section explaining how to check for nozzle wear with the
SC-2.
8. Use the SC-2 to test nozzle ow by placing the selected nozzles on your sprayer and running
them with water or fertilizer base at the required pressure from Step 6. Use the SC-2 to check
the nozzle ow rate from several nozzles. If the average ow rate in GPM or LPM from these
nozzles does not match the value you calculated in Step 4 then adjust your pressure until the
number matches. (See Fig. 4 to understand the eect of pressure on nozzle ow rate)
9. Check your sprayer’s speed: Use the following equations to verify the sprayer is actually
traveling at the speed selected in Step 2 above:
MPH = (Distance in Feet x 60) / (Travel Time in Seconds x 88)
KPH = (Distance in Meters x 3.6) / (Travel Time in Seconds)
05SpotOn® Sprayer Calibrator Model SC-2 Item #38790
Changing the Battery
The LCD will show an empty battery icon as shown in (8) of Fig. 1
when it is time to change the battery. Remove the screw cover (4) of
Fig. 1 by rotating counterclockwise. A screwdriver may be required
to loosen the cover. Gently pry out the old battery with a small
knife or tiny screwdriver as shown in (15) of Fig. 5, being careful not
to damage the battery holder. Replace with a new CR2032 lithium
coin cell battery and replace the screw cover. Tighten the cover
clockwise until the O-ring is slightly compressed. Fig. 5
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