# CO2 Check Valve



## psych (Jan 7, 2013)

I appreciate you sharing this. I purchased the drop checker from this company recently and saw the check valve as well. I didn't purchase it at the time because it wasn't needed, but I understand check valves should be replaced every few months so this was definitely on my shopping list for the future. They seem relatively low cost and since I do most of my shopping at Amazon anyway it's a natural fit.

The Rhinox name seems to be on quite a few CO2 supplies including a drop checker, bubble counter, airline tubing, and a few diffusers. The drop checker I purchased seems to be doing the trick. Certainly not as nice looking or fancy as others that are made, but at slightly more than half the price I'm not complaining.


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## latchdan (Sep 7, 2007)

I purchase 2 of those off Amazon. I couldn't get any flow. Im not sure what the break pressure is but i tried 40psi and got nothing. I usually run 20.
I was going to return them but seller was going t make me pay shipping. Instead he sent 2 replacements, i never tried them however.

Edit: Just read your edit.


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## psych (Jan 7, 2013)

latchdan said:


> I purchase 2 of those off Amazon. I couldn't get any flow. Im not sure what the break pressure is but i tried 40psi and got nothing. I usually run 20.
> I was going to return them but seller was going t make me pay shipping. Instead he sent 2 replacements, i never tried them however.
> 
> Edit: Just read your edit.


Weird that 40 PSI wouldn't get things moving. Certainly not worth paying shipping back at that price. Perhaps just a bad batch.


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## The Big Buddha (Jul 30, 2012)

Did you try them turned around? Maybe the sticker was backwards.

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## latchdan (Sep 7, 2007)

The Big Buddha said:


> Did you try them turned around? Maybe the sticker was backwards.
> 
> .


Yup


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## PlantedRich (Jul 21, 2010)

Since check valves are a pretty simple item, I might try to break the stuck valves. A quick shot of high pressure might jar a stuck mechanism? Not much to lose by doing a quick hit with high air pressure like like 100+ if you are holding the valve in your hand as it won't explode before you lose your grip. Maybe even worth the try using CO2? I can see something small like some type of sealer getting into the works that might be broken loose so that the valve is good to go.


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## latchdan (Sep 7, 2007)

PlantedRich said:


> Since check valves are a pretty simple item, I might try to break the stuck valves. A quick shot of high pressure might jar a stuck mechanism? Not much to lose by doing a quick hit with high air pressure like like 100+ if you are holding the valve in your hand as it won't explode before you lose your grip. Maybe even worth the try using CO2? I can see something small like some type of sealer getting into the works that might be broken loose so that the valve is good to go.


Ha I was just going to post. I tried my other check valves. Still no co2 would go through. I then shot some air though with an air compressor. They now work.


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## kevmo911 (Sep 24, 2010)

This is the same type that's been offered by a number of online retailers and has been selling on Evilbay for years. It also appears to be the same type that comes in JBJ-style bubble counters. I've had nothing but bad luck with these - several, both in and out of bc's, have failed within a year. I'd rate them as worse than any other type I've used except for the plastic LFS ones, and only just barely better than those.


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## latchdan (Sep 7, 2007)

I run 3 check valves in line just in case.


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## PlantedRich (Jul 21, 2010)

Since these appear to be the same old version, I do not recommend them. One has to be a bit of a skeptic on these things.
It has been my experience that we are far from what we are taught in school when it comes to business practices. We are told products are priced by what it costs to make them plus a small profit. Do you see that happen or do you more often see the profit boosted as high as possible without regard for how the profit comes in? 
So I looked at these and tried them but it soon failed and I did the teardown to see why. What I found was more of the same that my skeptical side thought. 
The outer material is brass and that sells really well. But inside where the work is done is what counts and that is where they cheap out on the design! Brass is a really good item to use if you don't want corrosion. Faucets were often made of brass in the old days. Brass springs of the correct tension are a bit more expensive to make but last far better. Corrosion is almost a given when you get moisture and CO2 together. Remember the carbonic acid thing when we put CO2 in the tank? 
Carbonic acid eats the cheap steel springs in the ones I've torn down!


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## Hoppy (Dec 24, 2005)

The only problem I have seen is that mine doesn't stop water from working its way back past the check valve. When the CO2 shuts off the conditions are right for siphoning to start. The water moves back through the CO2, and last night it made it past the check valve to at least a foot down the tubing. That delays the start of CO2 flow when the solenoid valve opens in the morning. Now that I know my check valve problem was not due to the check valve, but due to the location of the check valve (under the tank instead of at the top of the tank), I suspect I will soon put the US Plastics plastic one back.


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## PlantedRich (Jul 21, 2010)

I find there may be a hint in the name, even though we don't usually think of it? 
A "check" valve may check the flow but that doesn't mean it stops it! It just kind of monitors the problem. 
When I look at the small check valves and see what they are dealing with, I'm not sure there is a really good way to design what we want at a price most of us are willing to pay. We want them small to fit tiny tubing. We also want them weak so that low level pressure like under 50PSI can push them open. So what we get is a tiny little weak spring or other design that kind of pushes the valve closed. That works okay until just a tiny bit of water pushes back and gets under and around the opening. When the water stays and dries there, we get hard water deposits. So every time water reaches the valve we may get an added layer of minerals. That set up a pretty obvious death spiral where each time the valve doesn't work perfectly, the problem will get worse and the valve will be even less perfect next time. 
Check valves may not be designed to hold water, they just check it as it seeps past! Kind of like the current commercials on TV?


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## Seattle_Aquarist (Jun 15, 2008)

Hi All,

Really folks a quality check valve isn't that difficult to purchase. I have used the same check valves for 8 years....no failures - period. I used them on CO2 lines and airlines (where I need to) and although I have had multiple power failures and CO2 tanks run empty I have never, that is *n-e-v-e-r* had water back-flow behind the check valve. Water has back-flowed to the check valve several times it has never gone beyond that point. The check valves handle 300 PSI maximum pressure (well beyond the CO2 burst disc in your regulator) and cracking pressure is approx. 1/2 PSI.

If you are changing out check valves every six months that is expensive. If you are using a check valve that you don't have the confidence in to protect your expensive CO2 regulator that is just crazy.

Clippard Check Valve search Ebay using highlight phrase

Body - Clippard 10-32 Ports Female MCV-1BB = $9.99 + $4.35 shipping
10/32 to 1/8" multi barb for airline hose - CLIPPARD MINIMATIC 11752-3 = $14.99 free shipping (10 pack)
10/32 to 1/8" single barb for airline hose - CLIPPARD MINIMATIC 10-32 TO 1/8" "11752-4" = $18.99 + $12.54 shipping (10 pack)

Or you can purchase the body and fittings at: www.diyco2regulator.com/


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## LRJ (Jul 31, 2014)

Seattle_Aquarist said:


> Really folks a quality check valve isn't that difficult to purchase.


Agreed. For plug n' play, I've had a good experience with this one from GLA: Industrial aquarium check Valve | Green Leaf Aquariums


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## Seattle_Aquarist (Jun 15, 2008)

Hi LRJ,

Are there fitting for that SMC check valve for 1/8" hose; multi-barb and single-barb?


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## LRJ (Jul 31, 2014)

Hi Seattle,

Not sure I know the answer. I use CO2 resistant tubing with 1/4" OD and 1/8" ID. The tube inserts directly into the check valve and locks in place. When you want to extract the tube, you just press a quick release. No barbs involved in my setup.


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## PlantedRich (Jul 21, 2010)

If we want to move over into the "few dollars more" group, there are likely to be a number of choices that would last better. 
Depending on how many one might need, this could be an alternate that makes parts supply a bit easier to find. Using 1/4" fittings tends to make things easier for many. 
https://www.grainger.com/product/CDI-CONTROL-DEVICES-Brass-Check-Valve-6D914?s_pp=false&picUrl=//static.grainger.com/rp/s/is/image/Grainger/6D914_AS01?$smthumb$

It has a stainless spring and ball as well as a Viton seal.


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## Immortal1 (Feb 18, 2015)

Have a Grainger here in town - will have to see if they have any.


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## PlantedRich (Jul 21, 2010)

PlantedRich said:


> If we want to move over into the "few dollars more" group, there are likely to be a number of choices that would last better.
> Depending on how many one might need, this could be an alternate that makes parts supply a bit easier to find. Using 1/4" fittings tends to make things easier for many.
> https://www.grainger.com/product/CDI-CONTROL-DEVICES-Brass-Check-Valve-6D914?s_pp=false&picUrl=//static.grainger.com/rp/s/is/image/Grainger/6D914_AS01?$smthumb$
> 
> It has a stainless spring and ball as well as a Viton seal.


I should note that it APPEARS to be okay but I have NOT used it for our purpose and things can be missing in a quick look.


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## Hoppy (Dec 24, 2005)

These work very well: 1/8" Kynar® Standard Check Valve with Viton® Diaphragm | U.S. Plastic Corp. They are made of very chemical resistant materials, have a very low minimum opening pressure (0.5 psi), are very cheap, and I have had very good experience with them. They do shut off completely, too, as all "check valves" do.


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## PlantedRich (Jul 21, 2010)

I also use this type but I have a different result after a while. 
The water does work it's way back to the check valve. Not as a result of the check valve leaking but as the CO2 in the line is mixed into the water and takes less space. The loss of gas lets the water replace it in that space so, given time, the water does get to the valve. And If I wait long enough and give it time to get wet several times, I do find I get oozing leaks through the check valve and at some point I replace them. 
Whether to call it failure or just not working? In either case, I want to replace it before the water passing the check valve gets far enough to get into the fussy, expensive things I want to keep dry.

Placement of the check valve seems to help give me more time between changes. I use a reactor so that the line goes in below the tank level. With this placement, I find a check valve close to the reactor and water will get wet sooner than one placed in a coil of line which makes the water travel much further. 
At about a dollar each, I feel it worth my time to have two inline. When the first gets wet a time or two, I replace it and let the second inline protect me. Since everything has shipping questions involved in the decisions, I go for ordering 10-12 at a time.


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## latchdan (Sep 7, 2007)

Seattle_Aquarist said:


> Hi All,
> 
> Really folks a quality check valve isn't that difficult to purchase. I have used the same check valves for 8 years....no failures - period. I used them on CO2 lines and airlines (where I need to) and although I have had multiple power failures and CO2 tanks run empty I have never, that is *n-e-v-e-r* had water back-flow behind the check valve. Water has back-flowed to the check valve several times it has never gone beyond that point. The check valves handle 300 PSI maximum pressure (well beyond the CO2 burst disc in your regulator) and cracking pressure is approx. 1/2 PSI.
> 
> ...


Is 10/32 a common size for barb? I know I purchased a barb for my co2 reactor at OSH and could buy just one.( was 1/8) but I think thread was 1/4" Would it be a good idea to purchase the 10/32 hose barbs online even though I only need 2? Only comes in 10 pack.


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## Seattle_Aquarist (Jun 15, 2008)

latchdan said:


> Is 10/32 a common size for barb? I know I purchased a barb for my co2 reactor at OSH and could buy just one.( was 1/8) but I think thread was 1/4" Would it be a good idea to purchase the 10/32 hose barbs online even though I only need 2? Only comes in 10 pack.


Hi @latchdan,

The 10/32" is the size of the threaded end that goes into the check-valve body; the barbed end is 1/8" and fits standard aquarium airline. I use the multi-barbed end for airline and the single barb end of the more rigid CO2 tubing.


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## latchdan (Sep 7, 2007)

Seattle_Aquarist said:


> Hi @*latchdan*,
> 
> The 10/32" is the size of the threaded end that goes into the check-valve body; the barbed end is 1/8" and fits standard aquarium airline. I use the multi-barbed end for airline and the single barb end of the more rigid CO2 tubing.


Ok I just ordered everything you listed on evilbay.
close to 30 bucks for 1 check valve but If your correct it will last forever.

I was going to order 2 but I didn't get a break on shipping and so I could always order another down the road if I need a second.

I got the multi barb 10/32 barbs as well as I'm not using rigid tubing.


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## PlantedRich (Jul 21, 2010)

Anybody following the thread and looking for just a few 10-32 connectors might try the local hobby shops who do RC cars and planes. It's the pits when shipping is more than the item so sometimes local is cheaper. Look for Dubro brand fittings as they are used for fuel lines.
Dental supply is also a spot to check for local buys.


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## NotASpammer (Aug 23, 2016)

Hi ppl--I saw this thread after purchasing some check valves last week while building a CO2 reactor (rex griggs)
It's a push to connect with a .3 psi cracking pressure. Haven't installed/received them yet.
PARKER Legris A4VC4-MG








epdm seal
and rated for liquid or air, I think having a low cracking pressure is critical to prevent water from coming back into the tube.

These are one of the highest quality you can buy from my research and you can get them on ebay or walmart.com for about 10 bucks each minus shipping. Grainger has them at 16. 
I think I found the company on amazon first then looked up their catalog to research their products.


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## latchdan (Sep 7, 2007)

Seattle_Aquarist said:


> Hi All,
> 
> Really folks a quality check valve isn't that difficult to purchase. I have used the same check valves for 8 years....no failures - period. I used them on CO2 lines and airlines (where I need to) and although I have had multiple power failures and CO2 tanks run empty I have never, that is *n-e-v-e-r* had water back-flow behind the check valve. Water has back-flowed to the check valve several times it has never gone beyond that point. The check valves handle 300 PSI maximum pressure (well beyond the CO2 burst disc in your regulator) and cracking pressure is approx. 1/2 PSI.
> 
> ...


Okay parts came in and I made mine, just an FYI on the brass 10/32 nipples, don't overtighten, I just did with a wrench and slightly past snug it snapped off. Thankfully I was able to get the threaded part out of the check valve.
Snug is all that's needed.


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## The Big Buddha (Jul 30, 2012)

I Have a few of these to try on my next build.

Part# MJCV-1BA

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