May 15, 2013
By Dr. Jason S.T. Deveau
OMAFRA application technology specialist

You should plan for half-a-day per sprayer for your start-up routine. It may not take that long, but pressure gauges snap off, fittings crack, and bearings seize, so have a plan for getting replacement parts. Here are a few tips to consider as you get your sprayers rolling for the 2013 season.

Perform a visual inspection, general cleaning and lubrication. Do an operational check of the sight gauge (it should not be opaque), regulator and valves. Inspect the frame for corrosion or broken welds. Test the hitch integrity, safety chains and the tank mount, too. Clean and inspect the fan blades, housing, screen and trash guard. Be sure to clean and lubricate the power take-off telescoping shafts and the shields. Wheel bearings and tire pressure should be inspected.

One of the most common causes for faulty pump performance is gumming or corrosion inside the pump. You should get into the habit of flushing the pump and the entire system with a solution that will chemically neutralize what you sprayed that day. This will dissolve most residues remaining in the pump and leave the inside of the pump clean for the next use.

Pump manufacturer, Hypro recommends changing oil after 40 hours of break-in operation and every 500 hours after that. Diaphragms should be replaced every 500 hours and check valves should be replaced every 1,000 hours. Generally speaking, EPDM (black diaphragms) are a better choice for airblast sprayers while the Desmopan (amber diaphragms) are a better choice for lawn care sprayers.

Corrosion is the biggest concern. When you winterized your sprayer, you should have cleaned it and flushed it with a 50 per cent solution of permanent-type automobile antifreeze (Prestone, Zerex, etc.) containing a rust inhibitor. Alternately, you could have filled the pump with Fluid Film and then drained and saved the excess for the next application. The ports should be plugged to keep out air during storage.

Flush the lines. If they aren’t already off, remove the nozzles, strainers and filters. Run a few tanks of clean water through the system with the agitation running. This is when rust, scale, anti-freeze and who-knows-what breaks free of the sprayer tank and lines. Run them until the discharge is clear, then clean and replace the nozzles, strainers and filters.

Search for leaks. With the tank full, check it for leaks. If the agitator shaft is leaking a little, tighten the packing. If it has bottomed-out, re-pack it. Get the sprayer up to pressure and look for wet areas on all hoses and connections.

Check your strainers and filters. If you don’t already have three levels of filtration (including the tank-opening basket) then consider slotted (not mesh) strainers behind the nozzles in the nozzle body. If you don’t use them because they plug up, then look to your agitation system. If there is sludge at the bottom of your tank when it’s empty, then your pesticide is not mixed or staying suspended properly. That leads to clogged strainers and nozzles. It may also be your sprayer hygiene. You should wash nozzles and strainers after each spray day.

Are you sure your pressure gauges are accurate? The relief valve should always be in the by-pass position during sprayer start up. If you get a pressure spike during start-up and the needle buries, then the gauge will always read high and must be replaced. An opaque, leaking, or otherwise old gauge should be replaced. Consider purchasing a really good gauge rather than a $20 dollar version. New or old, test your gauge for accuracy. A tool to do this can be found at  

Always consult your sprayer manufacturer’s manual. There’s also a checklist at the end of Factsheet 10-047 Calibrating Airblast Sprayers at  Consider printing and laminating a copy for use with a dry-erase marker again and again.