K7 Unloader Adjustment

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So after all of the problems I've been having with the pressure on my machine, I've come to the last component I can change out...the unloader. So far I've re-plumbed the water lines and tightened all of my connections to ensure there are no air leaks, changed the check valves in the pump, and now the unloader.

Check out the video and see if you can tell me what's going on.

On installation I backed the bolt out to about mid-way so I wouldn't cause any damage to the pump. When I turned the machine on, it pulses in bypass. I screwed the knob in but the problem didn't get better so I backed it out. When the bolt is backed out almost completely the pulsing stops but when the trigger is engaged, the pressure is very low. Then I worked the bolt back in to raise the pressure but of course, it starts to pulse again.
 
I think the pulsing on a flow unloader can be from not enough back pressure in the bypass line, so a smaller diameter hose or a restriction could be the fix.
 
hmm. It was working fine with an identical unloader.The one I took off was the same.
 
What gpm are you running? Mine did the exact same thing until I put the smaller bypass orifice on the new unloader. Then it was perfect.
 
I took the oriface off of the old unloader and low and behold, it was WAY smaller. I think I got it figured out now. Thanks for the help. I'm going to work on a few more things in hte morning. I ran out of sunlight and I hate working by candlelight.
 
Just to cap off this thread I also wanted to mention that there is also an orifice on the outlet of the unloader that should match the orifice on the bypass outlet. They have numbers on them.
So, I'm still having issues with pressure so I'm moving on to the pump seals.
 
To prevent that surging the bypass port should be one size smaller than the pressure port, Ie. the pressure port has a #2 stamped on it and the bypass will have a #1....Or you can reduce the bypass line to 1/4" and that should correct the issue. You may also want to check for leaks, leaks on the oulet side of the system can cause the cycling on and off as well.
 
I LOVE my K7 but had to learn about it's eccentricities. About every 6 weeks or so I take the bottom off and using my finger grease that cylinder and oring on that piston with silicone grease. Only takes a couple minutes and it always solves any issues. ....now that I think about I haven't had to do it in a long time. Maybe mine is just breaking in good now.
 
Thanks for the info. Search feature still works. Enjoy the day as now I can get to washing again! Yahoo!
 
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