That video is with the idle low when I crank up the throttle it will kinda go away but it always kicks the same way after I let go of the trigger
Sorry to resurrect such an old thread, but is there a consensus on how to plumb the bypass? Should I plumb with 1/4 hose or nah?
I’ve got two on the way, one with #2 orifices fir a 5gpm machine and one with #3s for an 8.5 gpm machine.
Also, does anyone have a line on where I can buy just the orifices (if the thing to do is choke back on the bypass at the unloader instead on in the hose)?
You have it backwards. The #2 is for the 8gpm. Also 1/4 won’t last 1 day with a #3 on an 8gpm. I went through it this summer and blew hoses everyday while using 1/4". You should be using 3/8 bypass hose for most machines.
I bought just the orifice from Southside. Russ Johnson and Envirospec told me it’s a #2 orifice for the 8gpm.
You sure about the backwards thing? GP has the 7.3 (number 3 orifices) listed for 6.6-10.8. They also have a number 3 with a number 2 orifice listed for the same flow ranges.
They have the 7.2 listed for 4.2 - 6.6. They also have the 7.2 with the number 1 orifice listed for the same flow range.
But to be clear, you are choking the bypass by under sizing the bypass orifice by a factor of 1 and using 3/8" hose, correct?
And southwest…not familiar with that vender. Do you have a link?
I don’t know what flow ranges you have but Russ Johnson from South Side Equipment and the owner from Envirospec says it’s a #2. I used the #3 with 3/8" hose and my 8gpm would pulsate in bypass. I had to down size to a 1/4 hose to stop it but it would bust the hose. #3 with 3/8 hose and I have no pulsating and no buster hoses.
Southside: https://www.pressurewasherky.us/
Right on, man. I found them already, but I appreciate your response. I’ll reach out to Russ durring business hours tomorrow.
And for the record, I have one machine at 8.5 gpm and one at 5 gpm. I see that downsizing the orifice is pretty commonplace, so that’s where I’ll be adding the back pressure. I sort of figured choking it back at the hose would be a no go, but I had to ask after reading this thread lol
It’s definitely better to do with the right orifice versus hose size. Smaller hose is more an emergency fix. The other option is just to go with the zk1 unloader and then that eliminates most of those problems. Good from 2.3 - 10.8 gpm and can use just about any hose on your bypass
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Why don’t more guys use them? Is there a downside? It appears they’re competitively priced, have a broad operating range, and work out of the box without fiddling. What am I missing? 
@Infinity I’ve wondered the same thing. I recently built a 2nd washer and was all ready to buy a K7 until I watched @Racer’s video on his truck build. He briefly mentions the K1 and flexibility in choosing bypass hose size and no need for an orifice. Bought one for ~$100 shipped and love it. I had 5/8” heater hose already so that’s the bypass. Super easy to set and pulls soap fine through 250’ of hose
My mistake. I was thinking the K1 was a pressure trapped unloader. I see now it is flow actuated. Looks like the down side is cost.
@Sasquatch ???
Just adding my 2 cents in here… my k7 came with British pipe threads; the difference being that FPT and MPT are tapered, but British threads are straight. So when attaching my hoses, they would only seat about 2.5 threads.
I reached out to PressureTek and they did a little digging for me; this was their response:
“I have dug around on this and found that the unloader does in fact use British parallel thread while the parts (whips, etc) use national. The fit will be tight and I was told you need to crank it in. I was told by our supplier that all of the cost of converting these to national would add $38 per part and that is why it isn’t done.”
Still freaks me out every time I’m by those whip lines, picturing the tiny amount of metal holding back 3000psi!
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@Jake_Lambert: At the following webpage are adapters for joining bspp with npt:
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Thank you! That’s good info to have. If I start to notice any leaks I’ll probably run a tap and die… Or get a zk1
Speaking of K7 unloaders. I just ordered one last week. Now that I have one it seems like people are having issues with them so went ahead and ordered a zk1. If anybody wants a deal on a brand new never installed K7 for a reasonable price let me know.
I think a lot of people just don’t know about them. I had heard about but didn’t really know much about it till I got one. I think everyone just hears K7 and goes and get’s one w/o ever realizing they make the other.
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