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Mike Williamson

Unloader partially bypassing

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I'm stumped!!

About two weeks ago I started losing pressure, though the motor and pump are running just fine. Checked my water supply, and it's fine...force fed the pump with a sufficient supply and still had the problem. It was an intermittent problem, but I finally figured out the unloader (K7) was dumping about 2gpm or so back into the tank with the trigger pulled.

I changed the unloader with a spare that came with the trailer. Worked fine for a while, then same problem. Ordered another, installed it yesterday, and guess what? Worked fine for a short time, then same problem.

What in the world could be causing all three unloaders to partially bypass?

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Mike,

It sounds like you are pulling air.We had a nylon fitting that caused a similar problem last year.It compressed over time from the pressure of the clamp make it almost flat,there was just enough air passing to give the unloader a problem.

I had gone over the machine a dozen times making sure all clamps and hoses were secure.The final time is when I noticed the fitting was smashed.

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Mike,

It sounds like you are pulling air.We had a nylon fitting that caused a similar problem last year.It compressed over time from the pressure of the clamp make it almost flat,there was just enough air passing to give the unloader a problem.

I had gone over the machine a dozen times making sure all clamps and hoses were secure.The final time is when I noticed the fitting was smashed.

Nope, not pulling air. I hooked up the water supply hose directly from the spigot to the pump inlet, and there are no leaks with it under pressure. Fired it up, and it did just fine for a couple minutes. Shut it down and checked the oil (I'd just changed the oil), topped it off and fired it up again. Lousy pressure.

Damn I'm stumped. :lgbonk:

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I had a similar prob. a few weeks ago, and it was a dirty check valve. Might want to check them. I bought some new ones and while I had the head off I found 2 of them that had debris, still not sure how it got in there, nI replaced them and worked great.

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I bypassed the coil/flow switch, running a 10' whip straight from the unloader block to a gun with a 6.5 tip...worked great. Ran it for quite a while under full pressure and no problems. No bypassing at all with the gun/hose open. It appears the problem is either in the flow switch or the burner coil.

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Mike it sounds like you might have a restriction in your coil. I thought in an earlier post you had bypassed it and had the same problem thats why I didn't mention it.The same thing happened to mine and I just clean the coils.I now have a quick connect on my coil and only run water through it when I use Hot water.Also the K-7's are very pressure sensitive if you have worn tips or the wrong ones it can affect it.

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Ok...next issue. The unloader is now constantly cycling when the trigger isn't pulled. I did some searching and found that the bypass orifice is likely the culprit (though not sure why it is now a problem, since nothing is different on the machine except bypassing the coil/flow switch). I have jury-rigged a solution for now, but I need to get a smaller orifice (mine is a #2, I assume the next size down is a #1?). Does anyone know where I can order a couple of these? The two places I usually order parts don't carry them, and I need one rather quickly.

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I can get you a #1 or #0 as quick as you want it. It can be shipped or you can pick it up here if you need it sooner.

I'll give you a call tomorrow. I saw you called earlier, but I was away from the phone and didn't check it until just a while ago. I think the way I have it rigged will be fine for a couple days, if you can get them in the mail tomorrow.

Talk to you in the AM.

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