Do I have a gas leak?

Do I have a leak?

I have my C02 tank in the fridge along with the kegs. When I open the lid to my fridge, I am smelling (or feeling) that sensation you get when you open your primary fermenter for the first time. The burning sensation - which I asusme is C02. The keg has been hooked up to the C02 for 14 days. If I turn the C02 valve off, then turn it back on in the morning, I hear the gas rushing into the keg for about 15 seconds. Is this normal?

How tight should I screw the poppets on? I tried to test it with spraying starsan on all the contact points put I didn't see any bubbles. Any ideas? Thanks!

Hi

Indeed you probably have some CO2 leaking somewhere.

On most kegs, the poppets / posts are screwed down *very* tight. How tight? - you need an impact wrench to get them off tight. I don't think they have any need to be that tight, but that's how it's commonly done. You certailly can't over tighten them with a normal little wrench.

Things to check:

1) Tubing to barbs - do you have tight seals on all of them? You should not be able to twist the tube if the hose clamp is tight enough.

2) MFL's to manafolds (if you have them) - same thing with a twist check. You should not be able to rotate the barb portion.

3) Beer nuts to fittings (if you have them) - again same test.

4) Posts and washers on corny's- usually easyest to check with soapy water. CO2 side will blow bubbles, liquid out problems will leave a puddle before you will notice the CO2.

5) Main fitting on the CO2 tank to the regulator - more soapy water.

Past that, you get into things like - do the kegs hold pressure? Pressure relief valves on Corny's are a prime suspect - soapy water time for that. Corny lids can leak if not seated (more soapy water).

There are lots more posibilites, but I'd bet you'll find the problem somewhere on the list above.

A real quick and dirty system test:

Shut off the main valve to the CO2 tank, leaving everything else on. Watch the high pressure gauge (the one that's reading 800 to 1,000 psi). It should stay at that pressure for quite a while. If it drops quickly (minutes) you indeed have a leak or the beer is soaking up CO2.

Lots of fun.

Bob

Well, I only hand tightened the poppets/post so I imagine that could be part of the problem but I will go through the checklist as well.

Alright, so I sprayed all connections with starsan and didn't see any bubbles. I then got a soapy rag with dish detergent and found a little bubble on the air post where is connects to the keg. I will try tightening that down tonight. Because the leak is very small, I wouldn't necessarily hear the has going into the keg from the tank, correct?

If you close the CO2 tank valve, but leave the regulator open to the kegs, that should keep the low pressure reading right? and the High/Tank pressure reading will slowly drop as the little CO2 in the regulator flows through to the kegs.

scottvin said:

Alright, so I sprayed all connections with starsan and didn't see any bubbles. I then got a soapy rag with dish detergent and found a little bubble on the air post where is connects to the keg. I will try tightening that down tonight. Because the leak is very small, I wouldn't necessarily hear the has going into the keg from the tank, correct?

Click to expand...

Hi

A small leak is probably what you are looking for. If you have a leak at a post it could either be from tightness or from a bad o-ring. Post o-rings are cheap if you get them from McMaster Carr.

Bob

SnidelyWhiplash said:

If you close the CO2 tank valve, but leave the regulator open to the kegs, that should keep the low pressure reading right? and the High/Tank pressure reading will slowly drop as the little CO2 in the regulator flows through to the kegs.

Click to expand...

Hi

Right.

Bob

well, I found the leak (hopefully the only one)... I have an MFL valve coming off the regulator. This picture doesn't show an MFL valve but the arrow points to the spot of the leak.

The nut wasn't tight enough - is it alright to use teflon tape at this connection?

scottvin said:

[...]The nut wasn't tight enough - is it alright to use teflon tape at this connection?

Click to expand...

Never use tape on a flare fitting...

Cheers!

If you don't already have one, get a spray bottle and fill it with diluted starsan. Use this for bubble testing a gas leak. The spray bottle is also a great way to sanitize.

teflon tape is fine, but start the wrap of tape one thread back from the end. You don't want any tape pieces breaking off and clogging your regulator.

If its a flare nut teflon tape is not used.

jarrodaden said:

If you don't already have one, get a spray bottle and fill it with diluted starsan. Use this for bubble testing a gas leak. The spray bottle is also a great way to sanitize.

Click to expand...

That's the way I found the leak! Next time I will test BEFORE I put the keg on the tank. Unfortunately, my three or so week co2 tank is nearly empty.

scottvin said:

That's the way I found the leak! Next time I will test BEFORE I put the keg on the tank. Unfortunately, my three or so week co2 tank is nearly empty.

Click to expand...

don't feel bad, we all have had that happen to us, it sucks. when ever I tap a new keg I always spray the connections and o-ring lid seal with star san, saved my butt a couple of times.

Question -

1) Tubing to barbs - do you have tight seals on all of them? You should not be able to twist the tube if the hose clamp is tight enough.

Click to expand...

should this connection not swivel? right where the hose meets the nut?


If so, I found another connection that wasn't good.

Also, should these MFL connections come with a washer like this one? the four I bought did not.

The barb should not swivel once the nut is tightened down, but in any case the sealing of a flare joint is done at the face of the barb, which seals against its side of the plastic washer, which in turn seals against the face of the male end. This is why using teflon tape is a useless proposition, as that can only seal the parts of the coupling that don't actually require a seal.

female flare fittings may not come with the plastic washers because if they're to be used with quick disconnects those usually come with an integrated washer at the tip of the male flare fitting...

Cheers!

well, I don't think something is correct because the nut will not swivel now. that seems to defeat the purpose of using an mfl connection over just a barb.. however air doesn't leak out.
I think that I was supposed to get a washer, but didn't because the air was escaping right where the barb met the nut. so confusing to me...

scottvin said:

well, I don't think something is correct because the nut will not swivel now. that seems to defeat the purpose of using an mfl connection over just a barb.. however air doesn't leak out.
I think that I was supposed to get a washer, but didn't because the air was escaping right where the barb met the nut. so confusing to me...

Click to expand...

It doesn't have to be confusing! The washers are for metal-to-metal MFL connections. Quick disconnects with MFL fittings usually have plastic tips so the washer isn't required. If you have a Sankey coupler with MFL fittings, or your regulator has MFL fittings those generally are all-metal so you want to have the washer in there. You can buy them at any homebrew shop for 20 cents or so a pop.

With an MFL you don't want to use PTFE tape on the threads. It's not the threads that make the seal, it's the male part of the flare pressing against the female part of the flare. Any tape will prevent it from closing all the way and could actually cause a leak. You should tighten the swivel nuts/MFLs hand tight, then snug it up 1/8 or 1/4 of a turn with a wrench. Overtighten it and it'll leak! Once it's tight nothing should swivel; not the nut, and especially not the tubing that's slipped over the barb. You are using hose clamps, correct? If you're just using worm drives you could switch to Oetikers, which provide a much better seal.

MFL connections do provide a tremendous advantage compared to plain barbs. They're very quick to connect/disconnect, the same can't be said if you have to cut your tubing off the barb (and lose an inch of tubing each time), remove a hose clamp (especially if you're using Oetikers), then struggle to get the tubing back on the barb when you're done. If you're swapping between a Sanke coupler and regular ball lock disconnects it makes it so much easier.

EDIT: I realized I somehow missed day_trippr's post where he already said most of this! sorry

well, the arrow points to where I am getting the leak.. the hose is all the way one the barb. The MFL was hand tightened and then 1/4 turned with a wrench.
I am using the clamp almost touching the nut. Could it be a bad MFL fitting?

I think you mentioned this was at the regulator? If the MFL piece is all metal then the leak is because you didn't have the washer.

zachattack said:

I think you mentioned this was at the regulator? If the MFL piece is all metal then the leak is because you didn't have the washer.

Click to expand...

hmm, ok.. the washer goes at the top of the MFL or in between the nut and washer? this is the kit I bought - http://www.austinhomebrew.com/product_info.php?products_id=12568

That actually isn't a MFL (male flare), it's just the swivel nut (female flare if you will). But that's just semantics. You said you're using the flare side on your regulator, so does that mean you're using the plain tube over a barb on your quick disconnect? The reason this kit didnt come with the washer is because the MFL quick disconnects are plastic tipped. If you're using an MFL fitting on your regulator, chances are it's not plastic-tipped and will require a washer.

The nylon washer goes in between the MFL and the swivel nut, I find it easiest to put it in the swivel nut (pointier end down), make sure it's all the way in there and the orientation is right, then put in the MFL piece and tighten. I'm not sure what other washer you're talking about? Unless you mean the one on a beer nut.

This is a QD with a plastic-tipped MFL connection that can connect directly to the swivel nut that you posted:


And this is a metal MFL fitting (on top) that requires a washer to properly seal with your swivel nut:


Maybe post a picture of your regulator?

this is the valve I have

edit - and from what I have learned on this thread, I should be using a plastic washer, correct?

Yup, it sounds like that's your problem! A very easy one to fix. In my experience the only place to buy the washers is at a homebrew shop, hardware stores don't carry them. They should be in a little drawer near all the kegging supplies and o-rings, and like I said maybe 20-30 cents each. Buy a bunch of them and keep them in a ziplock in a drawer somewhere. They like to jump all over the place and you'll lose them before you know it.

zachattack said:

Yup, it sounds like that's your problem! A very easy one to fix. In my experience the only place to buy the washers is at a homebrew shop, hardware stores don't carry them. They should be in a little drawer near all the kegging supplies and o-rings, and like I said maybe 20-30 cents each. Buy a bunch of them and keep them in a ziplock in a drawer somewhere. They like to jump all over the place and you'll lose them before you know it.

Click to expand...

Well, I appreciate your perseverance in this matter! I could have been out another tank of co2! However, shouldn't I have received a washer when I bought the regulator (new)?

Thanks again!

You'd think so, but I didn't receive any with my kit. I think most people just use them with the plastic-tipped quick disconnect I showed above, so in that case you don't need the washer. I had to buy some for my Sanke couplers, which use all-metal MFLs like yours. Oh well. You could always try calling AHS and see if they'd comp you a few of them...

do any of the check valves for regulators come with the plastic tip or are they always all metal?

scottvin said:

do any of the check valves for regulators come with the plastic tip or are they always all metal?

Click to expand...

Not saying they don't exist - in some far-flung region of the Brewing Continuum - but I've never seen plastic-tipped MFL distributor valves...

Cheers!

scottvin said:

do any of the check valves for regulators come with the plastic tip or are they always all metal?

Click to expand...

Hi

The only thing you will see with plastic tipped flares are the quick disconnects that go to the posts on a Corny keg. You *might* see some flare nuts with washers so tightly embedded in them that they don't fall out, and are not real obvious.

Always do the twist test on all screw down fittings. None of them twist if properly tightened.

Bob

carlisle_bob said:

Hi

The only thing you will see with plastic tipped flares are the quick disconnects that go to the posts on a Corny keg. You *might* see some flare nuts with washers so tightly embedded in them that they don't fall out, and are not real obvious.

Always do the twist test on all screw down fittings. None of them twist if properly tightened.

Bob

Click to expand...

will do, but I am ordering some washers today as well

So, I just got the tank filled. Hooked up the regulator, check for leaks, and turned it on and noticed the tank was reading was the picture. Is the correct for a full tank? If it matters, the tank is in the keezer.

Thanks,
Scott

Yes, that's fine. Tank pressure is just a function of temperature, it's independent of the amount of CO2 in there.

Hi

You have liquid CO2 in the tank. It converts to gas at different pressure when warm than when cold. If your tank was sitting out on a nice warm (103F) deck, it would be nearly empty with that pressure reading.

The only real way to know how much is in there is to weigh the tank. While it's full, go ahead and see what it weighs.

Bob

thanks, I will do that next time I get it filled. I really appreciate all the help I received in this thread!