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When Your First CO2 Bottle Runs Out

I’ve had a 4-keg system for about 2.5 years. I got a 10-gallon bottle from the local Praxair. A couple of weeks ago, I accidentally put the CO2 post on the liquid hole and vice versa and had a hard time getting the quick connects to take on a fresh keg of Blonde Ale. But I finally got them on. As I was trying to get them off (using a rubber hammer) I ended up cracking the CO2 quick connect (Yeah, I know, but I couldn’t figure out any other way, and the liquid quick connect popped right off).

I was sharing another CO2 connection from another keg until I got a new quick connect. Got it in the mail on the 16th, tightened it on the nut, and hooked all the kegs up to gas. I actually drank off the kegs that night.

I didn’t pull another beer until Friday evening. I got a full glass of lager and made dinner. After dinner, I went down and pulled from a honey lager. Nothing. Blonde ale - nothing. I knew my CO2 was getting low and sure enough - Flatlined.

I was kind of worried about it, since I was able to get a beer out of the lager keg, but not out of the blonde ale keg (with the new CO2 quick connect). I wondered if it was on correctly.

After I got a refilled CO2 bottle, I kept checking the PSI, and it has been above 800 for the past 3 days, so I figure that once the bottle goes dead, then the pressure will equalize if the manifold valves are kept open.

Is this similar for everyone? Do you normally leave your manifold valves open as long as there’s beer in the kegs, or do you let them get pressurized to the carbonation level you want and then turn the valves off until the pour slows - and then you open them up again?

Do you know how many kegs were dispensed and carbonated through that tank before it ran out? It could just be coincidence that it blew shortly after replacing something in your air lines. You should be getting >10 kegs carbonated and served out of a 10 lb bottle (I assume you meant pound, since that is how CO2 is sold).

It doesn’t sound like you have check valves between the manifold and the kegs, so when you run out of gas and open one keg line the gas from all the kegs and lines will go to the lower pressure. Was there anything unusual about that first pour, like extra slow? Did you check the high pressure gauge before your first pour on Friday?

Whenever you break an air line you should check for leaks using something like gas leak detector. You can also pressurize the system and shut off the tank, looking for a pressure drop in the gauge (this can be affected by ambient temp and the pressure in the kegs). It’s best to do this with no kegs connected to eliminate that variable, then connect the kegs. Also each keg should be leak tested at both poppets and the PRV every time it is taken apart.

Thanks, Nyakvat,

Yes, I do the leak checks after pressurizing every keg. You’re right, I meant 10-POUND not 10-gallon. And over 2.5 years, I probably had close to 20 kegs on that one bottle. I’d actually have to go back and look. I’m on batch #40 or so starting this weekend, and I didn’t start kegging until somewhere like batch #10. I still bottle some batches.

Basically, what I have is:

Gas Bottle → Gauge → 4-valve manifold → 4 kegs

Since I don’t usually have a beer during the week, the first beer from each line is just a short or small beer so I can get the old beer out of the line, so it’s like a sip or 2. Then I pull a full glass. The full glass DID pour slower.

It’s possible to have an empty tank and still pour beer. The pressure in the keg will push beer out. With 4 kegs hooked up to a manifold without check valves, the entire system equalizes. Which means, the pressure in all the kegs and lines is the same. So when you pour from Keg#1 and there is no new gas flowing in, gas from kegs #2-#4 will add pressure over to keg #1 since it is lower and the whole system drops a little. You may have had an empty tank for a while before you lost the ability to pour.

I have the same setup as you and I leave all my valves open. Even without a keg hooked up to the disconnect. I’ve accidentally gotten beer in my gas lines because I opened a lower pressure line’s valve causing gas/beer to flow into it. I’ve considered adding check valves to prevent this. I believe I’ll also be able to carbonate at different pressures this way.

It does sound like the last slow pour was just getting pressure from all the kegs in the system. If it was pouring strong then on the next pour all the kegs were out, that would be more indicative of a leak.

20 sounds in the neighborhood of what you should get, maybe a few short. I don’t know the exact number because I never take good enough notes. Sean (a10t2) has posted that you can carb (to 2.4 vol) and serve 3.6 kegs/lb of CO2 with no losses, so if you had close to 30 then you could be pretty confident about not having leaks. Plus you have things like keg-keg transfers (which I do a lot for taking beer on the road) which hose up the numbers.

Many people swear by star-san as their gas leak detector. I’ve always used something similar to NB item#K224, which is used for natural gas plumbing setups to detect leaks. Just daub it on, wait about 10 min, and check it. Big leaks show up right away as huge bubbles and are obvious, but the tiniest of leaks will take a while and will slowly accumulate tiny bubbles around the leak site. Star san may do the same, just never tried.

The system pressurization test is also a very good way to see if you have tiny leaks, provided you are willing to disconnect everything for 3 days or so. I would do both a local check with gas leak detector and a pressurization test just to be sure you are leak free. Then if you do have an issue in the future you can pretty much just look to the kegs, which are much less reliable and prone to degredation. I leave my CO2 on all the time too, BTW.

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