Sprayer Troubles!

[Glenn9643]

Please pardon that it's not an attachment, but I do haul it in the FEL bucket to spray...
Thought the post would be seen better here.
It's a 26 gallon 12v sprayer from Northern Tools that I use for herbicides. I'm not familiar with other small electric sprayers, but the pump runs on this one to build up pressure, and then comes on as the pressure drops. I had a tank mixed and sprayed about 8 gallons with no problems. Suddenly I noticed that I didn't have much spray pressure after my initial "burst" with the wand. It starts as a normal spray, but the pump kicks in and the pressure drops and the spray becomes a dribble. I stop spraying and the next spray lasts only a second or so and the pressure drops. Pump comes on immediately when I start to spray.
I've got about 5 gallons left in the tank and would like to get it fixed without draining it out if possible.
It seems to me as if it's "waterlogged", or all air in the pressure chamber has been displaced by liquid. Any input on how this might be resolved short of draining the tank and taking it apart?

 

[bczoom]

Glenn,

I have the same (or similar) sprayer. Is yours set up for (or with a boom type sprayer) as well?

I recall having the same trouble a couple years back. Mine was in the valve(s) that control the flow to the wand, boom or return. I believe I sucked in some debris from the bottom of the tank and it caused a 90% clog. Some would get by the clog and build pressure to the wand but once the pressure dropped, it was back to trickle.

I would start at the wand tip and start removing each component one at a time (and re-test) until you get back to the pump. If it was debris, you'll then know where it's stuck. If no debris, you may have a pump issue and then... I don't know.

Do exercise caution as you do still have a mix in there and don't want it to spray in non-intended areas (mainly yourself).

Brian

 

[Glenn9643]

Thanks Brian.
As usual, I was sitting in the house thinking about a problem out at the shed! I assumed that the sprayer had a "pressurizing" cylinder similar to a backpack but after looking there's a pickup tube in the tank that goes directly to the pump and from there through the hose to the wand. I'll follow your suggestions and hope it's not the pump.

 

[TonyV]

Hi Glen. I've got a similar sprayer that I tote around in the FEL as well. On mine, there's a small alan screw in the pump assembly that adjusts the pressure....in other words it controls the set point at which the motor will switch on. If you've determined that the screen in the pick up tube isn't blocked, or perhaps something blocking the hose at the exit port, you may want to try an adjustment...perhaps the screw has backed out over time.

....Tony

 

[Glenn9643]

The only problem was the screen on the pickup tube. I've never had it happen before, but the screen was covered with a film of some sort. I cleaned it and everything worked fine, but it was blocked again before I finished spraying the remaining four gallons.
I wasn't aware of a pressure adjustment screw, and I'll look tomorrow to see if I can find one. That doesn't seem to be a problem, but it'll be good to know it's there!
Anyhow, thanks again guys. At least I was able to finish my spraying and maybe won't have to do it again this year.

 

[Panache]

I put a RV water filter in the inlet line of my sprayer. It has no screen on the line in the tank. That stopped most of my problems.

 

[RonMar]

Had the sprayer set a while since you last used it? If there was old mix residue or standing water in the tank, it might have formed a film that was washed into the solution when you mixed this latest batch. How old was the herbicide you were using. I had something similar happen this spring mixing up a batch of roundup with concentrate that had been on the shelf in my garage since last summer(both heated and frozen in my garage). It didn't fully disolve in the water and near the end of the spray, it started to clog the pickup tube with little particles of crystalized concentrate.

 

[Glenn9643]

I had mixed 25 gallons several days ago and sprayed all but about 4 gallons when I had to quit. My wife is having a pretty tough time with cancer and its treatments and my attentions were required there at the time. Then it was too windy for three or four days. When I got back to the spray project I mixed some additional on top of what was left.
I'm using a generic roundup that has surfactant already added. Don't remember the name exactly. Bought it about two months ago at the local ag chemical dealer. I believe it's 48% or so.
My clogging material didn't appear to be crystalized. It reminded me of a coat of wet paint. Couldn't really rinse it off the screen, but it came off readily with a paper towel.

 

[TonyV]

So sorry to hear about your wife, Glen. May her recovery proceed quickly and God bless both of you.

...Tony