DIY Softwash Metering System


i figured that would be your answer lol. i will just go with the diaphram check valves and take your advice on the PVC and VITON Seals. I will go with 3/4 on sh and water. 1/2 on soap.

these are the 3/4 metering ball valves i’ll be going with for the SH and Water side. I’ll go with 1/2 on the soap side. Maybe these were the ones you said are on back order? regardless if they are or aren’t, i’m personally in no rush to get this thing built. It is on my list of things to do this winter though.


Just so I understand, the check valve is for stopping backflow right?


I agree with needing a soap line. Since I do mainly stucco, a lot of the time ok I won’t need soap, or at least very little soap. It would be nice to be able to have more control with that.


Yes chemline is the right brand. If you want to hold off though, I have great access to all these parts and get a really big discount on parts. I’m going to put together a completed package that I might offer to people, and it likely won’t cost much more than you doing it all yourself. For example, I get 40% off the chemline valves.


Yes, check valves prevent backflow which will prevent getting your water and SH mixed up in their source tanks.


Yeah i would for sure be interested in that for sure, keep me (us all) posted.

I haven’t done any research for a replacement to their fancy stainless steel box. Do companies make them for 3 metering ball valves ? Or is this something we would have to build from scratch


In all honesty, you don’t need it. The stainless still corrodes, and I don’t think it looks nice when it does. The PVC components may discolor from UV exposure over time, but that’s the only side effect of not having your components in a box.

Benefits to not having the system in a box?

You can see any leaks that could develop. You can replace components yourself if something gets broken. You can see all the “extremely complicated and top secret plumbing.” I think this is better.

If you wanted to still put it in a box, go ahead. Or mount it in a truck tool box like @Racer does with his softwash pumps. Just put it all in there. Or mount it on a plate or anything else you want.

I think the stainless steel box you are referring to is a custom made box. I believe it adds a lot of costs that isn’t necessary, when that money could be put towards enabling high flow capacity and higher quality components.

The setup I’m putting together will be field serviceable by whoever owns it. Metering valves and check valves can be replaced or serviced right there by you. Though the idea though is that with the right setup and diaphragm check valves, this should never really need to be done. I mean, it’s not like the design is complicated or secret or patent worthy. It just takes a lot of time to pick out the right components, located and source everything, and put together the right bill of materials. And of course assembly is an issue too. Using all threaded joints instead of using pvc cement really increases chances of leaking, then the need to service, then the need to mail a system in to keep any warranty, which means downtime with no metering system, unless you have 2, which defeats the purpose of having a quality one in the first place.

If you really wanted a box, I’d go with something like these below.


Brought home an extra flowmeter from work today for testing different metering system setups. Range of 1-17 GPM. Once the parts arrive for the 1/2" setup, I should be able to run some tests to see actual GPM out of the pump with different valves open at different percentages. I’ll also be able to compare the 1/2" metering valves to standard 1/2" ball valves hopefully to set a benchmark. Then when I build a large 1" or 3/4" system, I’ll be able to compare those figures to the previous measurements.


Awesome… i’m looking forward to the results. Please keep us posted as much as you can. And for sure do the 3/4" test compared to the 1/2" setup.


I may not do the 3/4" unless someone wants to order a 3/4" system. I already have the 1/2" GF valves, and someone is planning to purchase a 1" system as well, so those I can test. After that, if someone wanted 3/4" setup, I’d order the parts, build it, test the flow, then mail it out to them. But at this point the only ones on the schedule are 1/2" and 1".


No problem… and based on the results of the 1/2" and the 1" test we will be able to figure out what 3/4" would be with some quick math.


BTW if no one has said this. @jzbreeland This is some of the best content going in this message board. I appreciate your scientific method and your ability to document as you go. Truly quality content.
If I can make one request. Can you make a video at the end of your process to summarize all your choices and final solution?


I want 5/8 or 3/4" No interest in 1" I" line is big and not real flexible. Look at your feed line on a larger pw. You can club someone to death with a 1" line.

In theory 1/2" should be enough because at 40psi less than 25’ distance a 1/2" hose should flow 24gpm. So obviously, there is something else in the Proportioner that’s restricting the flow. All I know is when I open water and SH to full on I get about 5’ more feet of distance.

What could be the cause?


@John_Martinez, I’d consider a video after it’s all done, but that’s still a ways off lol. Getting closer though. And thank you for your kind comments. I appreciate it.

@Racer, I hear you on the 1" being large. It is large. And expensive. Got new quotes today for the new generation of the Chemline valves, and their pricing went up significantly, which that alone may rule out the 1" option, at least in my opinion.

As far as 1/2" not flowing like it 1/2" should, I think this is the problem…

Metering valve linear v-groove ball:
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Metering valve fully open:

Metering valve fully closed:

As you can see, these do not look like regular ball valves. Breathing though one fully open isn’t like breathing through a 1/2" pipe. It’s restricted. There is resistance. You have to actually suck in air and blow out air. This is why I think running tests with various sized systems would be best, because it’s not simple math or pipe flow charts for these valves. For instance, I don’t think you’d get the same distance/flow with a singular ball valve fully open going into the diaphragm pump vs a single metering valve of the same diameter fully open going into the diaphragm pump. I haven’t tested this, but I’d like to.

@cleanunderpressure, show me the quick math? Lol. It’s actually not that simple, in addition to the information shared above about the v-groove ball in the metering valves, you have this to deal with: The area of a circle is A=πr^2. That means it’s an exponential relationship based on radius, or half the diameter, and that assumes a full circle (looking straight through the valves). But it doesn’t close or open perfectly with respect to all that, plus you don’t truly have that cross sectional area because of (see above photos). So there might be some math to aid or get the general idea. I did do an excel file with some math for ratios and area, but that’s just to get ratios based on valves open. Not actual area open for fluid volume to flow through, so it doesn’t really apply in terms of “where did my distance or gpm go?”


So basically looking at the cross section, they’re using the width of the channel to control the flow %?


Yes. That’s why I don’t think 1/2" is the right size to go with. Even at full open, it’s not the same kind of open as a regular ball valve. Take a look at these photos and diagrams.

I just assumed this was common knowledge about the metering valves, but that’s my fault. I’ve been looking at them in so much detail the past couple of months I probably didn’t think to point it out. I guess anyone owning a proportioner doesn’t see the inside ball in the valve lol.

This is why I’d like to actually do some performance testing. I’m not really sure how this type of ball allows flow compared to a standard ball and compared to a larger diamter v-groove type such as the 3/4" or the 1".


I have been thinking about this recently… thinking about what the optimal size would be, and whether 1" could be overkill for our purposes.

Even with booster pumps, which have 1" openings, no one runs larger than 5/8" line on the reel, and most run 1/2". With that being the case, im wondering if there is any benefit to going larger than 3/4". Testing would be the best way to determine this, i suppose. Put 3/4" and 1" plumbing side by side, and see if there is a distance increase between the two.

Whether 1" would be better for the pumps than 3/4" is another good question… but no easy way to test that, that i can think of.


Here’s a dumb question… what’s a booster pump? Or what brand/kind I guess. And what’s the difference between a booster pump and a 12v?


It’a hard to answer without actually running them, like you say. If they opened fully like regular ball valves, 1/2" would probably be fine. I think the issue comes from that v-groove that doesn’t actually full open in the same way, so those charts that say 1/2" is good for 14 GPM or 25 GPM or whatever the values are… I don’t think they apply with these metering valves. They might I guess, but I don’t think so lol.


I’m going to step out and pull a squid move here and just put up a screenshot from a google search lol.

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I don’t actually really understand them. AOD and 12V, yes, but not the boosters. I think they are popular with Power Wash Store. Paul uses them in a lot of their proportioner videos for demos. I know they are electric, 120VAC, and run off a generator or an extension cord to an outlet. When I spoke to Rex with PWProducts, he mentioned that booster pumps use a series of gears that compress the fluid and increase pressure. His point being that SH shouldn’t be run through a booster pump because of this and they should only be used for rinsing applications. Right or wrong, it’s just what he said. I think @tireshark uses a booster pump too.