Keg leaks when CO2 is attached

[eulipion2]

Hello,
I have a pepsi tank, not sure how old. It seals fine when nothing is attached to the input, but as soon as I attach my CO2 tank, or even just the fitting, I get a hissing sound, indicating that the tank is leaking. I also can't seem to force-carbonate my beer because of this. I'm fairly sure it's on the keg side, but how would I determine this and fix the problem?

Thanks

 

[rdwj]

I'm not quite sure I know what you mean...

Are you saying the keg holds pressure until you attach a fitting?

When you attach, you're basically opening the keg for pressure. If you're just putting the fitting on it's going to depressurize

 

[olllllo]

Baseline Diagnostic:
Black = Beer = Long tube
Grey = Gas = Short tube

Is that the case?

 

[eulipion2]

I'm not quite sure I know what you mean...

Are you saying the keg holds pressure until you attach a fitting?

When you attach, you're basically opening the keg for pressure. If you're just putting the fitting on it's going to depressurize

Yeah, I know that. What I mean is, even if I plug the "In" fitting, or if I have gas on and attach it as if to carbonate, I still get a hissing sound from the fitting, suggesting that gas is leaking, whereas if I attach my CO2 to the "Out" I get bubbling, but once pressure has equalized, no hiss.

And yes, grey-gas, black beer.

 

[rdwj]

Well, it it's only when the fitting is attached, my guess is that it's the fitting or the poppit. Also, could be the O-ring on the assembly

 

[david_42]

I suspect the small o-ring on the post is bad (about 90% chance). I had this problem once & the o-ring was completely gone (It was dark, ok?). They are about 0.50 each, but if you don't know how old the keg is, I'd buy the o-ring kit for about $4. You can replace the plug rings and the lid ring now & make a note to replace the tube rings once the keg is empty.

I spend a little extra and get red/green o-rings for the gas side.

 

[user 4295]

The subject of keg o-rings reminded me that I wanted to post this info with regard to a source for cheap o-rings when bought in bulk. They can be purchased from McMaster-Carr. The part numbers are as follows. I thought this info might be useful to add to the FAQ's, if the Admin was so inclined.

(1) Dip Tube O-Rings
5/16" ID x 1/2"OD x 3/32" width
9452K172 BunaN #109
Pkg 100/$2.24

(2) Post O-Rings
7/16" ID x 5/8" OD x 3/32" width
9452K23 BunaN #111
Pkg 100/$2.77

(3) Lid O-Rings
3 1/2" ID x 4" OD x 1/4" width
9452K218 BunaN #417
Pkg 10/$12.50

There are also some alternative o-rings available, like the quad rings for the dip tubes, and silicone o-rings for the keg fittings. While I have never used these, I have included them for your edification.

Q: What about the so-called quad-rings (a.k.a., h-rings, double-seal rings) for the dip tube seals?
A: 90025K368 - Double Seal Buna-N O-Ring As568A Dash #109
Pkg 100/$4.72

Q: Those are more expensive than the regular o-rings. What's the advantage?
A: They seal without excessive force. Tightening the posts too much can result in galling the threads.

Q: I've also heard that silicone o-rings work better than Buna-N on the posts. Is there a part number for these?
A: 9396K24 - Silicone O-Ring As568A Dash#111
Pkg 100/$13.53

 

[gnef]

just to cite the source, that is from the set of FAQ's at www.brewboard.com

 

[gonzoflick]

Do you have hose clamps tightly attached to the hose where its attached at the fitting? Crank those suckers down and make sure they are tight.

 

[G. Cretin]

Keg lube might help.

 

[Yuri_Rage]

You can get even cheaper o-rings from Harbor Freight. If you're anything like me, the assorted sizes come in handy all the time.

 

[eulipion2]

Thanks for all the tips. I think it's the o-rings. Clamps are secure. Might be the poppit, but I'm going to test the o-rings first.

And what is keg lube and what is its function?

Thanks

 

[user 4295]

And what is keg lube and what is its function?

Thanks

This is the type of Keg Lube that I use. There are many different makers and styles of food grade lubricant, but they all serve the same purpose. And that is to improve sealing and extent the life of rubber parts.

When I ordered this from Williams Brewing, they sent double of everything that I had ordered. It was a lot of stuff! I called and they refunded my credit card for the double items, but said I could keep everything. What I'm saying is that these two containers of keg lube should last me the rest of my life!

John

 

[gnef]

i believe there are a few different types of lube, generally two categories that i can recall. one type will degrade at 100C, this is so that you can remove it with boiling water if you want to clean everything up. the other kind has a much higher temperature tolerance. they should both be able to operate well for our purposes. just thought you should know so you can think of what you would want to use.

 

[user 4295]

i believe there are a few different types of lube, generally two categories that i can recall. one type will degrade at 100C, this is so that you can remove it with boiling water if you want to clean everything up. the other kind has a much higher temperature tolerance. they should both be able to operate well for our purposes. just thought you should know so you can think of what you would want to use.

Good point gnef, the keg lube I use, seen above, does not come off in hot water, well at least not at a temperature you can put your hands in. It does come off in a hot soak of PBW though.

John

 

[ajf]

Thanks for all the tips. I think it's the o-rings. Clamps are secure. Might be the poppit, but I'm going to test the o-rings first.

And what is keg lube and what is its function?

Thanks

It can't be the poppet. When you connect the gas line, it holds the poppet open so the gas can get in. The poppet only seals when you remove the gas line.

If you can hear the gas escaping, you should be able to find the source of the leak with the aid of some soapy water.

-a.

 

[eulipion2]

Thanks for all the info, and sorry it's taken me so long to respond. I'm currently without internet, and my ability to get online is limited. So I'm going to order some o-rings and some keg lube. I'm probably going to trash my current batch of ale as I'm not very pleased with its taste, so I have a little time before the next batch to work on overhauling my keg's rubber parts.

 

[Mike-H]

1. Fill your bath tub
2. Attach the pressure to the keg, bump the regulator up to 30-40 PSI
3. Disconnect and quickly go to your bathtub and put the keg in it while there is still pressure
4. Report back