Pressure Washer Surges with Foam Cannon

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bgray

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Hi everyone,

More of a follower than a poster. However I have a AG Foam Cannon, I tried using it on my friends Karcher HD3600, 3600 max psi gas pressure washer. The fitting snad everything are the same, but no matter what I did with pressure the cannon surges - pressure, no pressure, pressure no pressue, in about 2 second incriments.

whats going on? Need a different fitting for his pressure washer? pressure wash not foam cannon compatiable?

plz any incite would help

Brandon
 
A4 1.8tqm said:
"Prime" the pump before starting the PW.

Post #7 http://www.autogeekonline.net/forum...ries/31230-foam-cannon-surges.html#post395677
Click to expand...

I second this, probably had air in the line.

I always run the water through the pw before attaching the pw hose, then connect the hose and hold the trigger until water comes out. This pushes the air out of the line.

Always release the pressure on the compressor when staring by holding the trigger. Also, when not using the pw, say while washing in between rinses, turn it off (gas models only)-this will save your seals. I know it's a pain but it will save the machine.
 
I did that already guys. Even after that I switched to pressure washer spray fittings and back to the cannon it still happens
 
You might want to take it apart and make sure is clean and no debris is blocking the way.
 
I jsut used the cannon with my pressure washer today, works perfectly fine. Its gotta be somethign with this karcher causing it to surge/ Karcher works great until you click the cannon on then once you pull the trigger it starts surging
 
48983abb-04da-8302.jpg

I just received mine today and I am already loving it. I can't wait to try it. I still got to do a couple of fittings to my electric PW gun to make my foam lance fit.


"You can help create your own luck, you can make things happen through hard work and intelligence."- Donald J. Trump
 
Your problem is likely that your friend's pressure washer valving is designed for higher flow (less backpressure) nozzles/wands/attachments than your foam cannon. This creates a cyclic feedback loop in the system which is manifested as surging. Can you adjust the foam cannon nozzle for more flow?

You might try to modify the foam cannon to have less resistance to flow, but you’re probably better off getting a higher volume foam gun instead. I don’t know anything specific about your friend's pressure washer model; hopefully somebody can offer you a better solution. (you could probably drive two foam cannons at the same time without this happening!)

Basically when you pull the trigger the machine senses the pressure drop and a valve sends the recirculating pump water to the hose. However, the pressure washer is powerful enough that the pressure at the foam cannon continues to build for a few seconds until it reaches a threshold level that the pressure washer reads as a "no load" state and goes back into recirc mode. When the pressure falls again it all starts over.
 
does it have a pressure regulater on it with gage?if so try to bring it down to 2000 lbs.
 
jbgrant said:
Your problem is likely that your friend's pressure washer valving is designed for higher flow (less backpressure) nozzles/wands/attachments than your foam cannon. This creates a cyclic feedback loop in the system which is manifested as surging. Can you adjust the foam cannon nozzle for more flow?

You might try to modify the foam cannon to have less resistance to flow, but you’re probably better off getting a higher volume foam gun instead. I don’t know anything specific about your friend's pressure washer model; hopefully somebody can offer you a better solution. (you could probably drive two foam cannons at the same time without this happening!)

Basically when you pull the trigger the machine senses the pressure drop and a valve sends the recirculating pump water to the hose. However, the pressure washer is powerful enough that the pressure at the foam cannon continues to build for a few seconds until it reaches a threshold level that the pressure washer reads as a "no load" state and goes back into recirc mode. When the pressure falls again it all starts over.
Click to expand...
Very nice description of how the unloader valve works, I absolutely agree.

To the OP...Is the unloader valve adjustable on your friend's karcher? If it is it should have a plastic knob with a screw and lock nut on top of it. If it's adjustable try a few different pressure adjustments while using the foam cannon to see if the surging stops. If the unloader does not have a plastic adjusting knob and only has a brass screw and lock nut on top of it DO NOT tamper with it. Trust me here because if you do you'll likely be buying a new unloader for your buddies Karcher to get it working right again.
 
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