Which pre-calibration procedure specifies a tolerance for nozzle delivery deviations from equipment manuals?

• A. Make sure sprayer nozzle tips are appropriate for the application
• B. Thoroughly clean all nozzles, tips, and screens
• C. Check spray volume delivery of all nozzles and replace nozzle tips whose delivery deviates more than 10% from rates in equipment manuals
• D. If sprayer has a pressure gauge, check it and replace if rusty or not accurate

Answer: (C)

Before calibrating, you check that each nozzle is delivering the expected amount. This procedure compares the actual spray volume from every nozzle to the rates listed in the equipment manual and uses a tolerance to judge acceptable variation. The common tolerance is 10%; if a nozzle’s delivery differs by more than 10% from the manual’s rate, you replace the nozzle tip. This keeps the overall application rate accurate and the spray uniform across all nozzles.

Why this matters: even small differences between nozzles can cause over-application in some areas and under-application in others, reducing effectiveness and potentially increasing risk to crops, workers, and the environment.

Other steps, like ensuring nozzle tips are appropriate for the application or cleaning nozzles, are important for performance and reliability, but they do not specify the tolerance for deviations from the equipment manual rates. Checking the gauge is about pressure accuracy, not nozzle-to-manual flow variation.