Got my ZK1 unloader all plumbed up… Pumps rated for 5 gpm at 3000 psi… I bought a 5.5 (4.76 gpm @ 3K psi) and 6 (5.20 gpm @ 3K psi) nozzle size tip figuring I might get a little more flow with my engine then the pump was rated for. Regardless of which tip I use to set the unloader I’m able to reach 3000 psi (according to my cheapo pressure gauge) when on trigger. I’ve got the screw backed all the way out to the point that it feels like it’s going to fall out. This seems to be typical according to what I’ve read from other users with 5 gpm machines.
What I’m finding though is I have a very steady, unbroken, stream coming from the bypass line when on trigger… no drip/trickles like most recommend adjusting unloaders for. So with that happening, my research tells me this is “wasted” flow thats getting bypassed. I have a size 7 tip (6.06 gpm @ 3K psi) from my old machine, if I use this to set the unloader, could one suspect that the unloader would build enough pressure before the screw is fully backed out, therefore my bypass stream would slow down to a trickle, and I would therefore again back the additional flow that was being bypassed? Is that the correct line of thinking, or do I need to go the other way to a smaller tip size? Or does none of that matter and I should just live with how it is currently set up?
This is for a flow actuated unloader, the ZK1… It’s already turned all the way out, anymore turning it and it just spins without increasing pressure, turn it the opposite way (clockwise) the pressure decreases as it screws back in. I’m basically turned all the way out to get the most pressure I can, but still getting a lot of flow through the bypass when on trigger. Hence why I think I should be using a bigger size tip for a higher flow then the pump is rated to set the unloader.
Gotcha, didn’t know on those you back it out to raise pressure. Thats opposite of everything I know. What nozzle are you exactly using ie 2507 4007 etc
With the M5DS and 200 feet pressure hose I’m pulling 6 gpm. So throwing on a size 7 tip (which should give 3K psi @ 6.1 gpm) My gauge at the end of the 200 feet of hose but before the gun is reading 2750 psi (seems believable with friction loss and all that, I’m going to move it to right after the unloader after lunch). I’m still getting a steady stream, though it seems to be less then before… not a trickle/drip though. Unloader screw has no impact at this point if it’s unscrewed even more. Do I step up one more size to a 7.5 tip? That seems like the next logical step (I’ll know more after measuring the container to find a more accurate gpm) but maybe I’m closer to 6.5 gpm then I think.
Most of those apply to a pressure trap unloader. Of course, they all say trickle. guess you need to define ‘trickle’
With a flow unloader, should be a minimum of 5% bypass flow. To me that is more than a trickle or fast drip.
I think you were fine with that last setting you posted. You’re way over thinking this. The difference between 6 and 6.5 flow is minor. The important thing is it cleaning what you need cleaned.
If you haven’t figured it out by my other posts… I tend ti overthink a lot of things and get analysis paralysis… I guess I was just expecting less of a stream and more trickle then I was getting. 5% would be a little over a 1/4 gallon so that sounds more like a stream… regardless I used it to clean some concrete yesterday and all worked out well so I’ll leave it where it is.
I’ll bet you’re loving that ZK1. I’ve never even looked at the bypass but I have the unloader opened up all the way & the adjustment screw is barely in there. No issues yet. Send it!
So nice. Yea the screw is basically out (or at least to the point that it feels disconnected and any more spinning does nothing to raise the pressure) I’m still getting the hang of not being able to rinse with the ball valve (trying to break bad habits) but other then that everything is gravy.
