Hearing great comments about ZK1 unloader LINK from you guys, but its rated to only 3600psi.
My setup is rated to 4350psi, but can achieve about 5000psi if I put the rpm on full on engine.
My plan was to buy a K9 unloader at 434$ LINK
But my question to you guys, would it asking too much to use a ZK1 unloader on my setup?
Would it just reduce the psi and send return water to the tank with that is over 4350/5000psi?
Any recommendations?
My pump is 8.5 gpm 4000 psi and when talking to Randy at BCE systems about switching out the K7 unloader for the ZK1 during the build, he said it would be set at 3500 psi since it’s the max it could or should go. Something like that. I said go for it. There’s no reason anyone should need to even go near 3500 psi when cleaning anyways so it doesn’t hurt anything. Most washers that you buy from vendors anyways are usually 3500 rated anyways
What engine are you running?
I don’t know about the K1 but the K7 is good to 3500. I tried one on my 4 gpm, 4k psi and the machine would only put out 2 or 3 gpm. Killed it’s output.
ECH749 Kohler
I realized doing the math 8.5 x 4000 then \ by 1100 is 30.9 HP required to run that size pump.
Kohler pushes 26.5 hp.
A 8.5 3500 psi pump would require 27 HP which I’m closer on target for. Either way 3500 is plenty
Thank you for your reply, that solves my question then…
Have to go with K9 then… I do not want to lose the pressure, then I could have just bought a cheaper engine if I wanted. Sometimes there is a need for special cleaning of items with higher pressure.
Like what
Paint/rust removal, maritime equipment cleaning, industrial cleaning (oil&gas industry), boat hull cleaning etc.
I know well someone with 2x7250psi machines, but they each cost as much as an expensive car.
He tells me that you really need that power for some projects.
But I dont know, Im no expert… I also do not know if I will get much of these kind of projects.
One supplier strongly advised not to buy 1750rpm pumps, but rather 1450rpm - they last much longer he said. I first requested a GP 8gpm 4000 psi pump 1750rpm, but supplier said much better with 6.6gpm 4350psi pump 1450rpm. Engine is a bit stronger than rated pump, so it can reach higher.
Its a Honda IGX700 22hp, you mean I go the wrong route with my selection of pump and unloader?
Hello again, just a question, there is a “bolt” on the top, and these are usually for adjusting pressure?
Would it then perhaps be possible to adjust it a bit over 3500 psi you think? Or 3500 psi is really really max?
Don’t adjust for pressure, adjust for max gpm. Let pressure be an after thought.
Sorry, but you mean the top bolt on this ZK1 Unloader is for GPM?
Or you mean that make/plan your setup with gpm more important then psi?
Im just thinking perhaps to rather go for a 8gpm 4000psi pump instead… But I dont want to lose the 500 psi on the ZK1 
I need to order the rest today, just need to get done with it…
So I talked to the supplier now, the bolt on the top of ZK1 you can adjust the psi.
He said it most likely will be adjustable until 4350 psi, so that answers my question…
So will go for General Pump 8gpm / 4000psi and the ZK1…
Thank you guys for the assistance 
Wrong. Don’t let one dude working at whatever store you called trick your mind. Look up the ZK1 unloader yourself. It’s rated up to a max of 3600 psi and 10.8 GPM
The gentleman I talked to at the supplier are no kind of rookie. Who is right about this matter between you two I can not say.
As far as my knowledge many items within high pressure parts, do have specifications, but often they can be adjusted more than the specifications is rated at.
Is not this the same with the K7 that many use, this is rated to only 3000psi, but many with 3500psi use this without any issues?
@DJPWS Have you measured, that your 100% sure in your system that 3600psi is the max you can get out of ZK1 Unloader?
If the manufacturer built it to handle a max psi of 3600, then its 3600.
The ZK1 isn’t for you if you need higher psi then that.
What engine are you using? You don’t have a grasp on what is happening and the benefit you are talking to is unimpressive.
Honda IGX700 22HP.
English is not my mother tongue, so Im not sure if I completely understand your last sentence.
It is impossible to get 8gpm at 4k psi with that engine. Set your unloader for max gpm, don’t worry about what the pressure is. Your telephone contact is an idiot. I only know English so that’s the best I can do. Clear as mud?
You need at minimum a 30 hp engine to get 8 gpm 4000 psi.
