Regulator says CO2 tank is empty but it's still pushing beer

[Turkeyfoot Jr.]

Last night I went downstairs to draw off a pint and I noticed that the regulator showed my CO2 tank as being empty. I've only been using the tank for 3-4 weeks. It's had 3 kegs hooked to it pretty much that entire time. I haven't paid real close attention to the regulator but I don't recall ever seeing it below 600 pounds, full its 800.

With the reg telling me it’s empty I pulled 3 pints off of one keg without a problem. I also bled all three kegs and then re-pressurized them with no problems. The CO2 tank does sit in the fridge with the kegs. Tonight I was planning on disconnecting the CO2 tank, pulling it out of the fridge, letting it warm up and then seeing if it starts to register correctly.

Any other ideas on how to troubleshoot this if warming it up doesn’t help?

 

[Bobby_M]

Put the tank on a scale and weigh it. Subtract the tare weight that is stamped on the tank and you'll know how much liquid CO2 is still in there.

 

[Chriso]

Yep. The general consensus seems to be to ignore the hi-side gauge, especially when chilled, on the grounds that "they lie" on a home-level CO2 system.

Now if it no longer pushes gas... then ya got a problem to troubleshoot.

 

[BigKahuna]

This is why I don't like the High Pressure gauge on a C02 tank. You will be able to push beer with the pressure in the tank until it hits 0. The thing is, you don't have any liquid C02 left in the tank, and it will drop FAST!! I'll bet you can get another nights worth of beer out, but Get a refill ASAP!

 

[Turkeyfoot Jr.]

So from the sounds of it there's really no telling when the CO2 tank is going to just quit dispensing. Hmmm... Looks like it's time to go pick up a back-up CO2 tank so I can have a full one at the ready.

 

[Chriso]

I like the way you think!!!! I still need to buy a backup propane cyl first. But after that, you know I'm gettin' a 2nd CO2 tank too!!!!

 

[Liquidicem]

The best way is really to weigh the tank on a scale and subtract the tare weight. This should give you a pretty accurate indication of the amount left in the tank.

 

[ohiobrewtus]

If you can't get a backup then just make sure that you fill it before the weekend comes. It really sucks running out of co2 on Saturday at noon when all of the places that can fill your tank are closed until Monday,

 

[digunderground]

I picked up a paintball tank and co2 adapter just for this reason. I have a 20# co2 tank and barely ever check it because I only serve and carbonate 2 kegs at any given time(lasts FOREVER). Once or twice that paintball tank setup has saved my rear!

Since then I have assembled a regulator just for the paintball tank so I dont have to un screw anything to switch my setup (except the main gas line from the regulator to my distribution block). Plus its just nice if you want to bring a keg somewhere, you can just bring the paintball rig.

-DIG

 

[user 4295]

Yep. The general consensus seems to be to ignore the hi-side gauge, especially when chilled, on the grounds that "they lie" on a home-level CO2 system.

Now if it no longer pushes gas... then ya got a problem to troubleshoot.

It's not that the high side gauges "lie", chilled or otherwise, but that CO2 in a liquid/vapor state has a direct pressure/temperature relationship, as can be seen in the chart below. The pressure will stay exactly the same, at a given temperature, until all the liquid has been vaporized. Once only vapor exists, the pressure in the tank will drop rapidly.

So, knowing that, you can see that the high side gauge doesn't really tell you anything until all the liquid CO2 has been vaporized and you are now just using up the remaining vapor, which will happen quickly. As others have stated, the only accurate way to determine how much liquid CO2 remains in your cylinder is to weigh it and subtract the tare weight from that.

 

[Turkeyfoot Jr.]

Last night I tried to pull another pint and she was dead. This tank was just filled ~3 weeks ago so either I have a leak somewhere or I just used up a helluva lot of CO2. Would a CO2 leak be really obvious? As in a hissing sound that could not be missed. I've never heard so much as a whisper from my setup.

I think there's a good chance I actually used up the tank. With this being my first time kegging I blew off a lot of CO2 fiddling with things. I pushed Oxyclean and StarSan through all my kegs to clean and sanitize and make sure they worked. I had issues initially connecting the CO2 tank to the reg which resulted in a fair amount of wasted CO2. I pressurized and bled my kegs several times as I was getting the pressure right for the temperature in my beer fridge. There are probably a few more examples of times I wasted CO2 that I'm just not recalling right now. At this point I hope I can just chalk this up to being a noob at kegging. That would be far easier than trying to track down a very slow/quiet leak.

I'm getting my CO2 tank refilled and reconnected at lunch. I'm hoping to buy a backup tank here shortly.

 

[Chriso]

@ CO2 leak, no, it won't necessarily be obvious. I leaked a tank overnight without knowing - it was just a mis-seated poppet in a QD.

Now, pretty much once a week, I go through with a wrench and check my flare fittings, just for minds' sake... would'nt have helped that one day though. It was a fluke, and it emptied my tank.

 

[Yooper]

Last night I tried to pull another pint and she was dead. This tank was just filled ~3 weeks ago so either I have a leak somewhere or I just used up a helluva lot of CO2. Would a CO2 leak be really obvious? As in a hissing sound that could not be missed. I've never heard so much as a whisper from my setup.

I think there's a good chance I actually used up the tank. With this being my first time kegging I blew off a lot of CO2 fiddling with things. I pushed Oxyclean and StarSan through all my kegs to clean and sanitize and make sure they worked. I had issues initially connecting the CO2 tank to the reg which resulted in a fair amount of wasted CO2. I pressurized and bled my kegs several times as I was getting the pressure right for the temperature in my beer fridge. There are probably a few more examples of times I wasted CO2 that I'm just not recalling right now. At this point I hope I can just chalk this up to being a noob at kegging. That would be far easier than trying to track down a very slow/quiet leak.

I'm getting my CO2 tank refilled and reconnected at lunch. I'm hoping to buy a backup tank here shortly.

I really think you have a leak. I had a slow leak once, and I ran out of co2 in about 3 weeks. The other times, the co2 tank just kept going and going. ( I have a 5# tank). Even with all the "wasted" co2 by pushing sanitizer and purging tanks, and releasing pressure to fill bottles, and setting the psi higher to carb, I can usually get 8 kegs out of one fill.

 

[brewpal]

I lost a 20 lb tank last week due to a leak in my DIY kegerator manifold. Spraying water on it did show where it was. I had to pull it out of the fridge and immerse it in a bucket of water before the leaking joints could be found.

Dunking your entire CO2 distribution system under water might be the best way to spot any leaks.

 

[Free_Eagle]

Not to beat a dead horse but I would suggest the following to anyone using CO2, including my customers at their site:

1) Every time you charge the system with gas, leak check, hoses shrink, fittings come loose, sh*t changes with the pressure and temp variances. Like already stated, a gas leak can be so small you wouldn't notice, until you start blowing through tanks. Leak Detector, or a small amount of soap and water in a spray bottle can save you the $35 fill.

2) Scale. It is the only effective way to tell how much CO2 you actually have left. Believe it or not most colleges, i.e. Boston University, uses scales. These people will someday save my life with the all their rat testing and such, and they rely on the simplest way to tell a CO2 tanks status, whether a 75# or 5# tank. There is always a TW stamped into the tank, as we use this just the same to fill the tank. Example, typical 50# tank with TW of 106# gets filled till it weighs 156#.

On a side note, another guy I work with uses a 50% Nitrogen/50% CO2 mix for his kegerator. This is the trend amongst all of the good bars as well.

 

[Turkeyfoot Jr.]

I've got good news and I've got bad news. Bad news is I have a leak and it's on a nearly full keg of beer. Good news is that at least I know, in general, where the leak is.

Yesterday at lunch I got my CO2 tank refilled, $14 here in Toledo. ($35! Hope that's for something bigger than 5#.) I came home, connected everything back up and left it sit till I got home at the end of the day. Sure enough, I lost a fair bit of pressure. I was fairly certain I was losing it at a keg but to be absolutely certain I turned off the gas to all three kegs and let everything sit overnight.

This morning pressure was still the same. Woo hoo!

Turned the gas on to keg #1. I didn't realize the importance at the time but there was a noticeable lack of gas "whoosh" when I turned the gas on. Went to work and came home for lunch, roughly 4 hours later. Pressure's still the same. Woo hoo!

Turned on the gas for keg #2, no "whoosh" again. Went back to work, came home at the end of the day and pressure is still fine. Woo hoo!

At this point, I'm really hoping keg #3 is failing, otherwise, I must be out of my mind. Turn the gas on for keg #3 and hear a VERY noticeable "whoosh". Ah ha! Last night, before shutting off the gas to everything, I pressurized all three kegs. Kegs 1 and 2 held their pressure therefore no "whoosh" because they didn't need the gas. Keg 3, not so much.

So, here I am with a keg that I've had maybe 6 pints off of and it's leaking. My ideas so far to resolve this are:

1. I know the keg holds pressure to some extent, the 6 pints I've had have all been well carbed. I could leave the gas off except when I'm going to pull a pint and just be sure to drink off of that keg and that keg only until it's done.

2. I don't have a spare keg and seeing as I want to drop $80 to buy and fill a second 5# CO2 tank I really don't want to buy another. The other 2 kegs are both significantly lighter than the leaker. I could leave the gas turned off to the leaker, (turn it on maybe every 3-4 days just to charge it up) finish off one of the other two as quickly as possible and then transfer the beer and fix the leaker.

3. I could transfer the beer to a carboy, fix the leaker as quickly as possible and then transfer it back. I'm not too found of this one as it doesn't give me much time to thoroughly pressure test the leaker.

This is all I've come up with so far. Any other ideas?

 

[Chriso]

I like #2. See which of the other two kicks first, then just transfer from the leaking corny to a non-leaking corny. After all, the leak seems slow, and the keg seems like it holds pressure long enough to push liquid.

Do you have a liquid jumper line and/or a hose with two flare fittings, and two liquid QDs you can "borrow" from the other kegs? That's all ya need, one on Out of the leaking one and one on the Out of the good one. Apply pressure, then pull the relief valve on the good keg.