Sprayer Troubleshooting

I'm spraying my corn and beans but I think the application rate is maybe a little light.

I was taught 5mph, 30psi equals 10gal/acre, now go dump in the chemical and go. Easy.

Except I misplaced my monitor book so I know my speedometer isnt set right. So I just did timed runs with a stopwatch and determined for 5mph I want to the speedo to read 5.7 or 5.8, but that is about 2100RPM in 2nd gear and for some reason my pump has only been achieving 23-28psi in that range. 1st gear doesn't get to 5mph, 2nd has too low an engine speed to get the pump to pump enough pressure.
I bought a new belt because I thought if it was running closer to the outside on the crankshaft pulley that would make the pump pulley spin faster for more volume/pressure.

So--if I can't make the 5/30 formula work, how do I adjust for proper rate? I have a 4 speed manual transmission in my spray coupe, a pressure-adjust switch, 8003VS TeeJet nozzles. I tested the nozzles and found that in the 30 seconds it takes me to go 220 feet (5mph), each of my 36 nozzles is putting out 17-19 (18 average) fluid ounces.

So I'm estimating, I'm putting on 16.67gallons of water / acre, and that out of my 200gallon tank comes to about 12 acres.

Is there a nozzle chart somehwer so I can adjust my speed and pressure to get my exact rate? Thanks!

Does that rig have a flow controler or is it all manual?

If it has a flow controler you need to enter a flow calibration number as well as the speed calibration number and boom widths.

Yes there are charts to set up speed and pressure.
click here.

Dan-IA,
Most sprayer I've been around have a "T handle" control valve that one screws in for more psi & out for less psi.

It is a Spra Coupe. It has a flow controller, but I don't know if it works. I had to have the speed sensor replaced and monitor fixed so I can check ground speed. There are other things to the monitor but I don't use them. There is a flow sensor, a flow control. I leave them be. Previous owner installed a pressure gauge on a bracket on the hood so I just read that. Pressure is adjusted using an up/down switch on the dash. I hold the switch up for more pressure, down for less.

Problem is I still don't get the proper pressure. I am wondering if I have a blockage somewhere or plugged screens, since if the pump can't get it it can't push it, and likewise if the flow can't get to the gauge it can't read as high.

So my next choice was to see if I could calculate for a different water flow rate at a lower pressure or different ground speed, and just adjust my mix accordingly.

That pressure gauge needs to be plumbed into the boom hoses.

Who cares what the presure is everywhere else.

Boom pressure is what you need to know.

Yes there could be obsturtions about anywhere. The filter is a good place to start.

Gary

The pressure gauge is plumbed in on the boom hoses, just before the solenoids that turn the individual booms on or off.

My key issue is how to get just a little extra pressure? Is it a belt tightness issue? I put a new belt on and thought I don't want to tighten it excessively because that would make its radius smaller on the crankshaft pulley and therefore reduce the RPMs at the pump. But if the belt is slipping that might be a problem. I know a belt squeals when I start the sprayer, but I am under the impression that's the alternator belt.