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CMB gas QD leaking poppet.

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kiwipen

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I got a brand new CMB gas QD and when testing for leaks I noticed bubbles slowly leaking out of the poppet. This will only be a problem when not connected, but dang does it annoy me.

Before using it I disassembled it just for a quick look and to check if the cap was on tight. Could this have put the poppet in a slightly different position than it had been in for some time in the QD causing improper sealing on the poppet gasket? I have 2 other CMB gas QDs that are stored disassembled. These also leaked in the same spot, that made me wonder about the poppet possition, and maybe it getting better over time.

Is this normal? Is there anything I can do?
 
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day_trippr

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If by "leaking out of the poppet" you mean leaking out from around the QD cap, did you verify that there was a thin flat plastic gasket under the cap?

Cheers!
 
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kiwipen

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It's not form the cap (and yes the gasket is in there) it's from the spring loaded piece. Part #3 in the diagram, that is shown upside down there for some reason.

 

day_trippr

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How are you determining there is a leak around the QD poppet? And are you saying all three of your CMB QDs leak?
It doesn't count for much here, but I do have almost three dozen CMB QDs in service with no leaks, so I'm at a loss to understand what you're seeing, if it affects more than a single disconnect...

Cheers!
 
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kiwipen

kiwipen

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I put it in a glass of water and see bubbles forming around the poppet.



Edit:

Just to clarify

kegkegkeg.png
 
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bracconiere

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could always try and stretch the spring out a bit? what PSI do you see bubbles?

(and now i want to if my QDs are leaking. if they are, i can say it'd have to be less then 3 grams of co2 a day.)


also, tap water will have some residule co2 in it looking for, i think nucleation sites? or chlorine or, what not.

i'm just guessing at something to try being that @day_trippr is surprised, and so am i. could try boiling the water first? maybe? if you don't i might try it myself to satisfy my curiosity!

edit: day tripper! for confirmation, why not strap a ballon over the line for a couple days! ;)
 
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kiwipen

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It's about 15 PSI. I don't want to mess with the spring since it should be working fine without modifications.

I can clearly see bubbles forming around the poppet (see picture in previous post), it's happening that fast. It's not like bubbles slowly showing up in a glass of water if left alone.
 

day_trippr

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Again, this syndrome occurs with all three CMB QDs? Or just one?

Take the leaky QD apart and look down the bore of the body to the surface that mates with the plunger.
See if there is any plastic flashing or mold parting marks in there. Then inspect the plunger.
There has to be a reason for the leak. Find it.

[as for bagging a QD that clearly leaks when dunked, wth is the point?]

Cheers!
 
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kiwipen

kiwipen

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It happened to all three CMB QDs. I couldn't see anything on the inside two of the QDs or on the plungers that would explain the leaks. The o rings were intact and felt rubbery.

Temporary solution: Take a QD from my kegerator that wasn't hooked up to a keg and swap it with the leaking one. In the kegerator it's connected to a manifold with shut off valves. It's still leaking, but I can shut of the pressure to it, and I'll check it in a few days or weeks and see if it seals properly or not.
 

IslandLizard

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It's not form the cap (and yes the gasket is in there) it's from the spring loaded piece. Part #3 in the diagram, that is shown upside down there for some reason.

You realize that in those diagrams the poppet is incorrectly shown upside-down, right?
The black part, the o-ring, should point downward, to make a seal with the QD body.
 

bracconiere

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Part #3 in the diagram, that is shown upside down there for some reason.
You realize that in those diagrams the poppet is incorrectly shown upside-down, right?
The black part, the o-ring, should point downward, to make a seal with the QD body.

he said that. i think day_trippr is the equivalent of the expert on this forum about kegging, he'll get him worked out...

for what it's worth i just submerged my burst carbing QD in a bowl of water and didn't see a leak.
 

garzlok

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I think @day_trippr is very surprised by the statistical anomaly of 3 CMB quick disconnects failing for one person.

Just yesterday, I heard some hissing from a CMB QD, but alas, it was the o-ring around the gas post that needed to be replaced.
 

IslandLizard

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It happened to all three CMB QDs. I couldn't see anything on the inside two of the QDs or on the plungers that would explain the leaks. The o rings were intact and felt rubbery.
Maybe a bad batch of QDs...
Is "CMB" embossed on the top side of the QDs? There are many knockoffs, but those should be without the CMB signature.

I can clearly see bubbles forming around the poppet (see picture in previous post), it's happening that fast. It's not like bubbles slowly showing up in a glass of water if left alone.
When pushing in the poppet from underneath, with the back end of a nail set or small screwdriver, how easy is it? When comparing to older ones, that resistance should be substantial, it's compressing that pretty tight inner spring.

On a side note, once the QD is on a post, the poppet channel is wide open, while the seal is made on the post's o-ring. So you're safe while connected.
 

IslandLizard

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bracconiere

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But it won't hurt to chime in with alternative takes and perspectives.

It is more fun that way! ;) :mug:

i've never really even taken my QDs apart in 16 years.....i did notice the new pin lock one was for some reason plastic instead of stainless though. is CMB a new company? i think i bought my old ones straight from coke and pepsi, lol
 
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kiwipen

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One of the QDs was bought recently, the other two I've had for a while. So likely not the same batch. They all have CMB embossed on the side, and have been bought from reputable dealers.

I couldn't tell any difference in spring pressure on new or old poppets. Not that my fingers are a perfect way to measure that.

My main theory is that disassembly caused the poppet or plunger to land in a slightly different position, and that the o ring needs some time to adjust. I sure hope it will.

Anybody want to test that theory by disassembling their QD?

Please chime in with alternative takes and perspectives.
 

IslandLizard

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Anybody want to test that theory by disassembling their QD?
I've disassembled and reassembled (CMB) QDs for 7 years, routinely to give them a good soak, clean, and sanitation (Starsan). Never had a failure, yet.

Maybe it's a bad batch of o-rings, or as @day_trippr hinted, some unevenness in the sealing area inside the QD.
Or maybe bad springs...
 

day_trippr

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Yes, considering how many I have and never have leaks, I'm totally surprised that one person has three CMB QDs that can't hold pressure.
Verging on inconceivable.

But, again...there has to be a reason, and it should be discernible...

Cheers!
 

bracconiere

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Anybody want to test that theory by disassembling their QD?

sure, i'll do both my pin lock, and ball lock burst carb ones! going to have to wait till i'm done with afternoon coffee, and back on beer though. i'll report back, and i will try to be as clumsy with reassembly as possible, lol :mug:
 

bracconiere

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so i forgot to hit [post on the last one. but i've got a few beers in me now, just broke down both my ball lock and pin lock QDs. reassembled, sat and stared at both upside down in a pitcher of water. there was one buble after 30 seconds, and i keep staring for a couple minutes at both and that was it...


do you use universal poppets on your kegs that maybe compressed the spring in them too much, i know i had to clip mine to even get them to go on the kegs?
 

day_trippr

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The OP is dealing with a new QD and has two other QDs that "are stored disassembled".
I don't see whatever is going on having anything to do with actual use - as it appears none of these QDs have ever been used on a keg...

Cheers!
 

bracconiere

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as it appears none of these QDs have ever been used on a keg...

he said he uses the leaky ones on kegs all the time as a stop gap measure? i thought anyway? because he has a manifold to shut off the others?


damn, i'm getting lost on this one now..... :mug:

Temporary solution: Take a QD from my kegerator that wasn't hooked up to a keg and swap it with the leaking one. In the kegerator it's connected to a manifold with shut off valves. It's still leaking, but I can shut of the pressure to it, and I'll check it in a few days or weeks and see if it seals properly or not.
 

day_trippr

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I'm just relating what the OP wrote in the opening post.
Pretty clear something is hinky here. Nobody complains about CMB QDs...

Cheers!
 

day_trippr

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Consider that a leaking swivel barb literally has nothing to do with the OP's problem.
Get back to me if you're still puzzled ;)

Cheers! (as for 'serious', I don't see that happening ;))
 

bracconiere

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as for 'serious', I don't see that happening ;)

glad to hear it's my end i'll try and flush it...(and it was a joke? i have had problems with QDs before? lol)

i've had to replace PRV's, keg poppets, and those i had to clip to even get the QD to fit on, thanks to a tip from here....but after 16 years, i've never had a problem with my QD poppets?

but i do have a very slow leak in my gas lines, and now i'm wondering if maybe i should replace them..with all my kegs disconnected my LP guage goes down like 1-2 lb's over night....but my scale says to me it must be trivial, so haven't been TOO worried about it.

that's why a video of this leak would be nice to see....
 
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kiwipen

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How about a thin smear of keg lube on the poppet gaskets? CMB is the industry standard.
I tried it, but it still leaked.

The OP is dealing with a new QD and has two other QDs that "are stored disassembled".
I don't see whatever is going on having anything to do with actual use - as it appears none of these QDs have ever been used on a keg...

Cheers!
The two that are stored disassembled mostly gets used for closed transfers from fermenter to keg.


do you use universal poppets on your kegs that maybe compressed the spring in them too much, i know i had to clip mine to even get them to go on the kegs?
No universal poppets here.




I'll try to get a video of the leak if it helps.
 

bracconiere

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yes, that will help...


definatly looks like a leak that would drain a tank pretty quick. :(

your poppet looks strangely different then mine? it looks flush with the housing?

edit: when i was putting my QD back together i noticed that the top screw part, kinda was tough to go back in evenly?
 
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kiwipen

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It's not flush with the housing, it just looks that way in the videos.

I haven't noticed any problems with screwing the top part in.
 

bracconiere

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well all i can say is it's serious assuming, each bubble is a ml, and one every second. that would drain a 20lb cylinder in a month and a half, assuming you didn't even use it for anything else....each one of those is about 0.00197 of a gram, lol...

i feel your pain, but besides my sympathy, don't have much to offer.... :(
 

bracconiere

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could you have maybe mixed up the poppets old with new?

edit: and if you want to see if reseating helps as you said, grab a spoon handle or something and just just press it in out a few times...
 
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kiwipen

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I'm as sure as I can be that the new QD does not have parts from my older ones.

The older ones are stored disassembled together and the parts are mixed together. So the parts will likely get mixed up all the time.

I've pushed the poppet in a few times, but it still leaks.
 
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