Author Topic: How much CO2 leak is normal?  (Read 366 times)

Offline jdwags78

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How much CO2 leak is normal?
« on: July 30, 2022, 01:08:21 pm »
Hi all!  I had been thinking of homebrewing for some time and decided to take the leap when we moved into our new house.  The new house had a bar in the basement and in an adjacent storage room the old owner left a working chest freezer the perfect size for 4 kegs!  It was a sign!   ;D  Anyway, I installed a temp controller, collar, lines, etc.  Everything worked great!  I needed to refill a keg and shut off my main co2 tank knob (I wanted to move some things around).  The regulator read 12 psi.  The next day, the regulator read 0.  I unhooked all of the keg gas qd's and turned on the main flow.  The pressure when back to 12 psi.  I turned it off at the tank and waited a day.  Back to 0.  For the next test, I cut the flow using the on/off knob attached to the output of the regulator leading to the manifold.  I pressurized back to 12, turned off the tank,  and the needle has remained at 12 psi for 4 days which makes it seem like the regulator is fine.

I took the manifold and all qds and submerged them in a large pan of water.  I pressurized the system and saw no bubbling.  I am stumped.  Is this type of slow seep normal?  Being new, I just am not sure as to what is normal loss and what isn't. 

Thank you to everyone for any help you might be able to offer!  Once I get everything set back into place I will have to take some pics of my finished build!

Offline Bob357

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Re: How much CO2 leak is normal?
« Reply #1 on: July 30, 2022, 04:29:03 pm »
CO2 leaks are not normal. Try spraying soapy water over all of the connections and the valves on your gas distributor. You should see bubbles where the leak is. If not, submerge everything you can in a sink while pressurized.
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Offline Richard

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Re: How much CO2 leak is normal?
« Reply #2 on: July 30, 2022, 05:20:31 pm »
My experience with bicycle tires is that a slow leak may cause no more than a tiny bubble every now and then, which is hard to see in a sink of water. Try dividing the system into smaller parts and test each part separately to see if it holds pressure. Don't jump to conclusions if you find a leak and assume it is "the" leak because there may be more than one. Keep going until you have tested everything.
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Offline tommymorris

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Re: How much CO2 leak is normal?
« Reply #3 on: July 30, 2022, 05:40:31 pm »
I had to submerge my keg system in the bathtub once to find a leak.

I have also had success spraying starsan on the junctions and watch for bubbles to form.

Offline KellerBrauer

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Re: How much CO2 leak is normal?
« Reply #4 on: July 31, 2022, 06:39:21 am »
Your regulator is doing its job if it’s maintaining your set point.  So your leak is definitely downstream from the regulator.

Using a spray bottle with very soapy water is the easiest way to check for leaks.  Don’t forget to also check the seal on the top of the keg.
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Offline Kevin

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Re: How much CO2 leak is normal?
« Reply #5 on: July 31, 2022, 09:16:44 am »
Keep in mind that even if you test all the seals... around the lid, the PRV, poppet seals and O-rings... and find nothing there could be a small pin prick piercing the body of the keg itself. Remember most all used Cornelius kegs came from the soft drink industry when they adopted plastic bags and the kegs became obsolete. Corny kegs were dumped on the market by the truckload and homebrewers snapped them up just as fast. They were used and abused way back then and can easily have damage you can't obviously see. Fill it with a shot of gas and submerge it in a bath tub. This will tell the tale.
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Offline denny

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Re: How much CO2 leak is normal?
« Reply #6 on: July 31, 2022, 10:06:22 am »
Keep in mind that even if you test all the seals... around the lid, the PRV, poppet seals and O-rings... and find nothing there could be a small pin prick piercing the body of the keg itself. Remember most all used Cornelius kegs came from the soft drink industry when they adopted plastic bags and the kegs became obsolete. Corny kegs were dumped on the market by the truckload and homebrewers snapped them up just as fast. They were used and abused way back then and can easily have damage you can't obviously see. Fill it with a shot of gas and submerge it in a bath tub. This will tell the tale.

Have you ever seen that happen?
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Offline reverseapachemaster

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Re: How much CO2 leak is normal?
« Reply #7 on: July 31, 2022, 10:47:05 am »
To OP--is it possible you didn't firmly turn off the knob on the tank which caused it to lose a little pressure? Like, are you seeing a loss of pressure other than that one time? I've had some CO2 tank swaps that needed a little more work to get the tank to seal completely open and closed. Is it possible you dislodged a QD when moving things around? That could also cause a leak in the system which I've also done by accident.


Keep in mind that even if you test all the seals... around the lid, the PRV, poppet seals and O-rings... and find nothing there could be a small pin prick piercing the body of the keg itself. Remember most all used Cornelius kegs came from the soft drink industry when they adopted plastic bags and the kegs became obsolete. Corny kegs were dumped on the market by the truckload and homebrewers snapped them up just as fast. They were used and abused way back then and can easily have damage you can't obviously see. Fill it with a shot of gas and submerge it in a bath tub. This will tell the tale.

Reputable sellers pressure test corny kegs before selling. If they don't hold pressure, they are repaired if possible and retested. We don't know where OP bought the kegs but unless these kegs came from a questionable source they should have been pressure tested. I'm not saying this is an impossible cause, just extremely improbable.
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Offline brewthru

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Re: How much CO2 leak is normal?
« Reply #8 on: July 31, 2022, 02:36:21 pm »
Um... we keep the CO2 tank valve open to carb our beer.

How old is the regulator?

Has there ever been a backflow (beer) into the regularor?

If yes, then perhaps time for a rebuilt.

If no, then a leak somewhere. I'd suspect the QDs on the keg.


Offline kramerog

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Re: How much CO2 leak is normal?
« Reply #9 on: August 04, 2022, 11:34:20 am »
I have had a leak in the CO2 bottle that I fixed by tightening the screw in the middle of the handle.

Offline Kevin

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Re: How much CO2 leak is normal?
« Reply #10 on: August 05, 2022, 06:04:46 am »
Yes Denny I have seen pin prick holes in corny kegs. As to reverseapachemaster point no, not all kegs in peoples hands today were pressure tested before being sold. Back in the day you could buy kegs direct from the local soft drink distributor. One such distributor was located just a few blocks from my workplace and I bought several there. They were stacked like cord wood in a storage garage area. They didn't bother pressure testing them, they just wanted to get rid of them and free up that space. Entrepreneurs would buy these by the semi truck load and sell them on eBay where I also bought several from there too.

I wouldn't say there could be pin holes if I hadn't seen it happen and to think that all corny kegs have been tested prior to being put in use is just plain wrong. The OP is asking about why he has leaks. I offered my thoughts and experience.
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Online hopfenundmalz

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Re: How much CO2 leak is normal?
« Reply #11 on: August 05, 2022, 07:58:53 am »
I've had a leak on a shot off valve on a manifold. Found it by immersing the assembly under water. Thought it was at the threads, but it broke when tightening. Inspection showed there was porosity in metal body of the valve.

What works for me is working from the cylinder out. Make sure the gasket at the cylinder valve has a good seal. Tin the regulator up to 30 PSI and shut the valve on the out side off the regulator, turn off the cylinder valve, it should hold pressure over night.

Then work your way out to the keg. Immersing in water if need be. 30 PSI will help you find the leak faster.

My kegs need new o-rings and poppets sometimes, they were used to begin with, and have had a lot of use.

Hope this helps.
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Offline jdwags78

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Re: How much CO2 leak is normal?
« Reply #12 on: Today at 08:15:26 am »
Sorry for not getting back.  In the middle of a possible job change and things have been busy!  I have been doing some more testing.  The regulator is new.  I have tested it a few times and it holds pressure with the output turned off for 4+ days (I stopped the test after 4). I tightened all of my hose clamps (some were loose somehow) and found that the lines help pressure now for 4+days.  I hooked 4 of them up to kegs, pressurized the system, turned off the tank and let it sit.  After 1 day, the system lost about 3-4lb. 

I'll also mention that my kegs had been pressurized to about 10 psi when I unhooked them to start upgrading the keezer.  After more than a week, they all had pressure in them (didn't measure the exact amount). 

Two nights ago I unhooked 2 tanks to see if I could narrow down which tank or connection might be the culprit.  After 2 days, the system is still at 10 psi.  That leads me to believe that there is something up with one or both of the tanks I disconnected.  I'll start replacing some o rings and seals first since I have those. 

Thanks again everyone!

Offline Bob357

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Re: How much CO2 leak is normal?
« Reply #13 on: Today at 08:52:38 am »
Only losing 3 to 4 psi in a day may well have been your beer absorbing CO2. At this point, you may be chasing a ghost.
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Offline jdwags78

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Re: How much CO2 leak is normal?
« Reply #14 on: Today at 10:27:23 am »
Thanks Bob!  I am hoping that the loose clamps might have been the culprit from my orig. post.  Thanks all for helping!  I learned a lot!