Broke Down, Only 30 Hours on New Setup

Setup: GX630 powering Gear Driven Udor 5.5/4000. K7 Unloader mounted to unloader block. 200’ of 3/8 pressure hose. Bypass hose installed back to buffer tank. Adjustable nozzle at gun for use with X-jet.

I built this setup early this spring and has been working flawlessly up until this point. As the topic is labeled, I only have 30 hours on this (I do this part-time).

I noticed on Thursday at a small residential job that every once in awhile when I would squeeze the trigger I wouldn’t get any power, so I would let go of trigger and squeeze again and it would work. Sometimes I’d have to do that a couple times for it to start spraying. It did this multiple times during this job, but got it finished. I heard the K7’s can be finicky so I attributed it to that not thinking much about it… Saturday the same thing started happening and then finally, nothing. I took off whip line from pump to unloader and then checked all of my pressure line to be sure there was no debris clogging it and there wasn’t.

Any ideas of what this could be? Anyone run into anything similar in the past?

Could something be sticking in my unloader? I don’t know much about the unloaders other than what purpose they serve.

Unloaders are something you need to keep a spare or two on hand. They do go bad, and I have a theory that some of them (perhaps flow actuated, most of all) have a “shelf life” of sorts. They seem to want to fail on you regardless of how many hours you put on them. And maybe leaving them idle is more damaging than working them a bit.

Only 30 hours for the spring sounds like the machine has been sitting more often than not?

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As I said I do this part time. Although it gets worked about every evening and every nice weather Saturday we have. Jobs are usually only about 2 hours (or less) long. I have done about 20 jobs so far this spring.

I do have a backup trapped pressure unloader in the trailer for this reason. But I didn’t know if that was even the problem…I was just trying to see if anyone else ran into something like this before I went and tore apart the whole setup.

I’m with Alex. First thing I would do is swap the unloader with a new one. Sounds like it’s staying stuck in bypass.

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Will try the unloader first and report back. Thanks guys

check the bypass line when this is happening to see If stuck in bypass, before you take it off to put other unloader on.

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How long did you wait with the trigger pulled for the pressure to kick in? I have a k7 and have seen it take up to about 7 seconds to kick in. It’s not often but if I don’t get pressure I keep on the trigger till it kicks in. Try that before replacing unloader.

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Do you have another gun you can try? Probably going to jinx myself but I’ve got over 900 hours on one of my k7s and it works like a charm.


I already had my pressure line removed from pump to unloader so I didn’t check to see if it was stuck in bypass. I just did a quick swap out of the unloader. Everything is working fine now. So I would have to assume it was stuck in bypass (should have checked this prior to switching but, lesson learned). I did notice some sand/small debris in my buffer tank (which I cleaned out thoroughly before starting back up). And yes, I do have a bowl filter from pressure tek between tank and pump. Maybe something got in the unloader causing it to stick in bypass mode? I’m just happy it isn’t the new pump and was a semi easy fix.

Any way to look at my K7 to see if I can fix? Can they be torn apart to see if some debris got in there causing it to stick in bypass?

Thank you all for the suggestions. This forum is a wealth of knowledge and appreciate any and all of you who take the time to contribute.