Massive leak

[AlexKay]

Ok, this is driving me nuts.

I’m checking for obvious leaks by closing the stem valve on my main tank and seeing if the second stage pressure drops on the regulator. Gas goes right from the regulator to a four port manifold, to which two ball-lock disconnects are hooked up. Everything is EVABarrier and Duotight. There are no leaks at this point.

Then, when I put one specific ball lock connecter onto a keg, at that moment, all the gas runs out instantly. This is not just filling the headspace; I can repeat it several times with no change. I tried replacing this connector — same thing.

Here’s the thing: the keg seems to hold pressure. After I’ve done this, the keg is and remains pressurized.

Where is the leak? What on Earth is going on? Thanks in advance for help or commiseration.

 

[day_trippr]

There isn't much gas involved here, right? Just what it takes to fill the tubing and the disconnect?
You write "one specific ball lock connector" like it matters. So, what happens when you plug another QD on a keg?

Cheers!

 

[Spikybits]

i have found that a majority of the gas ball lock QD i have actually leak when not connected to a keg. they can leak from the small o-ring on the screw down cap or from the pin in the center that pushes down the poppit. best practice is to have a shut off valve on the secondary reg/manifold/primary reg/in line to prevent gas leaking from the QD

i tested my QDs in a bucket of star san and most have a slow leak - i shut off the line from the secondary i have in the kegerators when not in use.

 

[AlexKay]

There isn't much gas involved here, right? Just what it takes to fill the tubing and the disconnect?
You write "one specific ball lock connector" like it matters. So, what happens when you plug another QD on a keg?

Cheers!

Nice idea! So it’s the keg, not the disconnect. Whatever disconnect I put on one particular keg, all the gas runs out right away. But … that keg holds pressure.

 

[Golddiggie]

Have you checked all the o-rings/seals on that keg? Is it brand new or did you get an used keg? IMO, if a seal is not holding, it won't matter if it's when the gas is connected or not. Might be worth inspecting the poppet in the post to see if it's 100% good or not.

This is why many of us have 'spare' parts for most fittings. Especially the ball lock posts. I also have a couple of o-ring replacement sets, which include the large o-ring. Most of the time I just need to replace the smaller o-rings, which I have plenty of.

 

[balrog]

I agree with @Golddiggie - sounds most like the o-ring on the out post, possibly undersized/aged/dried/recalcitrant/ornery/whatever.

Replace the o-rong on the out post.

Then lube it.

 

[AlexKay]

I bought the keg new, but it’s been in (continuous) service for a couple of years. I’ll check both posts. I do have some spare poppet assemblies sitting around somewhere.

 

[marc1]

I bought the keg new, but it’s been in (continuous) service for a couple of years. I’ll check both posts. I do have some spare poppet assemblies sitting around somewhere.

Have you changed the o-ring on the post?

 

[bracconiere]

i know obvious, but is the post tight on the keg? i've had some get loose...

edit: i forgot you said the keg holds pressure, disregard....

now, does the gauge drop if you hook the keg up but not turn on the manifold? could be a bad ball valve on the manifold?

 

[day_trippr]

If the now-suspect keg is empty, charge it up, remove the gas QD, invert the keg in a sink full of water and look for the bubble-stream...

Cheers!

 

[AlexKay]

The keg is almost completely full, alas. It makes sense to me that it’s the outer o-ring on the ball lock post—there’s a leak when there’s a connector on it, but pressure holds when there isn’t. It looks ok, though. However, I’ll replace and lube it. Spare o-rings coming in the mail just as soon as they can get here.

 

[Miraculix]

Massive leak:

 

[dwhite60]

I love bottling. Haven't had a gas leak in thirty years. Never had a beer fail to dispense either.

 

[Misplaced_Canuck]

Use a spray bottle of Star-San. Go to town and find that leak.

 

[IslandLizard]

Spare o-rings coming in the mail just as soon as they can get here.

Hope you ordered Buna-N (Nitrile rubber) ones. Not silicone! Although with some water-based lube (?) silicone can work fine. You definitely need to reduce friction/stickiness when pushing or pulling the QD on and off, that can tear them.

There is a simple way to check your gas poppet for small leaks too, in case you pull the QD off and let the keg sit without gas connected. Put a few drops of Starsan (or water) on top of the post, and look for (small) bubbles.

 

[AlexKay]

Ok, I think I found it! The top lip of the gas in tube was bent:

the o-ring underneath it was a bit chewed, as well. I’m not 100% sure why this would cause a leak with the quick disconnect in place, but hold pressure without it. But I replaced the tube and the problem seems to be fixed.