Injector bypass proper setup

I see that PWP states: “The chemical injector should be installed on the bypass side of the chemical injector bypass kit.” Does anyone have an example of this? All the bypass setups I’ve seen, have the bypass going through the 90’s. It makes sense to me to have the most flow when rinsing, or powerwashing, but I’ve never seen a setup this way. They say the injector should be on the bypass.

Yeah, here is a thread where Racer talked about that configuration and posted a pic.

Far better to avoid the bypass altogether. The gain in flow is minimal. Just more friction loss, more places to leak, and more nonsense sold by vendors


That’s the one! Seems like a lot of fittings and connects.

I originally wanted to mount the DSI right before the hose reel on the whip from washer and use quick disconnects to put it inline or remove it. Would need a ball valve just ahead of it on the whip, I guess. Would this be better? May be just as easy as the bypass kit? With less fittings and better flow? I am not going with a remote, so seems either way means a trip back to the trailer anyway!

Does that work okay? Thought the DSI should be no-where near any tees or 90s.

that is how mine are. Just no ball valve

Hard to see but injector plugs into swivel

Mark, Depends on what you’re doing. If you’re just washing a house and you just want to rinse you can either pull your soap tube out of the soap, use a little plastic on/off inline going to your injector and just leave injector hooked up. Also depends on size of your machine. On my 4gpm leaving the injector in doesn’t affect flow for squat. On my 8.5 it knocks a gal per min off of it, but still plenty for rinsing.

If you’re doing concrete and want or need all the flow you can get then the injector bypass is nice, you just turn the handle. Otherwise, even if you just put a ball valve, you’re still got to carry nozzle back to trailer to release pressure before you unhook injector or if you don’t have a ball valve, got to cut off machine, then release pressure before you can unhook the injector.

Your other option is to use a jrod or whatever and switch to higher pressure for rinsing to shut off your soap, but with all the vinyl we have here, higher pressure the last thing I want on rinsing. And that still doesn’t address the problem if you need more volume for concrete or whatever.

But there are plenty of people who don’t use a downstream bypass. I’d try it w/o first and then see if you feel like you need. I ran for couple of years w/o one. But now that I do, I like the easy factor and it’s not that much, think it was like $100.

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no ball valve? Do you swap under pressure or turn machine off?

I am currently saving up for an 8 gpm machine. I have an 2.5gpm homeowner machine I am not going to use on this build. I am plumbing the new trailer first (tanks, hoses, float valves, filters, supply and pressure hoses, etc) , then buying washer last. I figure I can’t put the washer into use until I do all the preliminary work first. I am committed, as the trailer, registration, title & tags and etc and tanks are purchased, and all business licenses has been filed. All accessories I am acquiring are based on an 8gpm belt drive pump end state. I am planning on vinyl siding low pressure wash with jrod, and residential concrete surfaces (driveways, porches, patios, community sidewalks, with rotary 4 nozzle surface cleaner)

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Good point, the easy factor just fell into play. Maybe I will give it a try later on, and remove inject for concrete work, thanks for the input.

Neither. I turn the soap off and the rinse water on

He’s asking about swapping the injector.

Dont need a ball valve before injector, turn the machine off and swap.

Gotcha. Yea, swapping injectors is a once a month thing or so. No need for a ball valve for that.

Do you still feel this way? I like to think it makes sense as long as it is plumbed correctly. Almost feel like there is a better way to build it… Working on that idea right now.

Yep, friction loss physics and vendors haven’t changed


If you bump everything up to half inch plumbing before your reel, friction losses through the 90’s should be much less.

I use a bypass because the remote I use (FlowPro) allows for it. And I get better fuel economy from my motor when rinsing. (I make sure and rinse the injector with water for a couple minutes at the end of the day/job)