How Many Corny Kegs Should a CO2 Tank Carbonate?

[TonyS]

Hi All!

First time post/thread and appreciate any feedback.
I've suspected an airflow leak but have done soapy water tests on all of my valve connections without any bubbles or hissing. To be on the safe side I even double sealed all connections yet I'm only able to force-carbonate 3 corny kegs before I run out of air. That seems super low! Especially cause I just finished carbing the 3rd keg and have only served 5 beers before this tank just ran out. I force carb each keg at 40 PSI for 2 days, then bring it down to 8 for serving but I also shut the entire tank off unless I'm serving. So what's going on here?? Shouldn't I be able to get more than 15 gallons of beer for each CO2 tank??
System is a 3-tap Kegco, which I've heard is a good supplier. Figured I'd ask here first before bringing in a technician. Again, thank you for any/all feedback!

 

[IslandLizard]

Hi TonyS, welcome to our forums!

Obviously, you have a leak, or even a few leaks. Probably small enough so you can't hear the hiss, but large enough to deplete your tank in a short time.

What "size" tank do you have (capacity in lbs)?

Can you perhaps post a picture of the gas side of your setup, regulator, manifold, valves, lines, QDs and such? Just so we can see what you have and easier to point to possible issues and fixes/solutions.

 

[day_trippr]

If I have it right it takes 46 grams of CO2 to carbonate one gallon of beer to 2.5 volumes of CO2, so ~230 grams for 5 gallons.
One pound of CO2 is 454 grams, so one should be able to carbonate two five gallon kegs of beer per pound of CO2, or ten kegs from a full five pound cylinder.

Definitely there's a leak extant...

Cheers!

 

[TonyS]

Hi TonyS, welcome to our forums!

Obviously, you have a leak, or even a few leaks. Probably small enough so you can't hear the hiss, but large enough to deplete your tank in a short time.

What "size" tank do you have (capacity in lbs)?

Can you perhaps post a picture of the gas side of your setup, regulator, manifold, valves, lines, QDs and such? Just so we can see what you have and easier to point to possible issues and fixes/solutions.

Thank you for the quick reply! Yes, here are some pics, including the receipt for my last CO2 refill that should indicate tank specs.

 

[IslandLizard]

That's a brand new 5 lb tank!
Actually, everything looks brand new, congrats!

What is the size of the barbs used with the swivel nuts? 1/4" or 5/16"?
Your red and blue "gas lines" are typically 5/16" ID, so the barbs should match that. If the barbs are 1/4" you can probably tighten the clamps enough to get a positive seal.

You could spray a Starsan working solution* (if you use that for sanitizing) around all gas connection areas and look for bubbles. Gas tank and valves open, regulator set at 12 psi or so, and keg connected, of course.

* Perhaps better or easier to spot leaks would be using some liquid dish wash soap mixed with some water, it should be a fairly thick solution, that can be sprayed or brushed on coating the connection areas. Or use "bubble juice" if you have it.

Are you using some sort of "keg lube" on all your o-rings, including the big ring under the keg lid? That's essential to help make a good seal, as it makes the rubber surface slippery so the rings can conform to the given space more easily.

 

[TonyS]

That's a brand new 5 lb tank!
Actually, everything looks brand new, congrats!

What is the size of the barbs used with the swivel nuts? 1/4" or 5/16"?
Your red and blue "gas lines" are typically 5/16" ID, so the barbs should match that. If the barbs are 1/4" you can probably tighten the clamps enough to get a positive seal.

You could spray a Starsan working solution* (if you use that for sanitizing) around all gas connection areas and look for bubbles. Gas tank and valves open, regulator set at 12 psi or so, and keg connected, of course.

* Perhaps better or easier to spot leaks would be using some liquid dish wash soap mixed with some water, it should be a fairly thick solution, that can be sprayed or brushed on coating the connection areas. Or use "bubble juice" if you have it.

Are you using some sort of "keg lube" on all your o-rings, including the big ring under the keg lid? That's essential to help make a good seal, as it makes the rubber surface slippery so the rings can conform to the given space more easily.

Hola! I'm actually not sure what the barb sizes are but I'll confirm with my homebrew store (who installed everything) what size they are. I've tightened them as much as I can squeeze though and have already double sealed + done the soapy water tests with a dish soap/water solution and nothing comes up. Considering that I only turn on the tank when either force carbing or serving and it's STILL running out after just 2 kegs....shouldn't that be a substantial and easily detectable leak?? I shouldn't have to look through a magnifying glass.
I'm not using keg lub but will certainly look into it if I should. What would you recommend for that?
Thank you again for the help!

 

[TonyS]

What's extra frustrating is that the dude at our local homebrew store said that air leaks should be extremely rare, especially with new setups like mine. I have no problem cooking up great batches but just can't get around this apparatus issue

 

[tracer bullet]

Agreed there's a leak. Maybe charge the system, turn off the CO2 tank, and then get creative and shut off various parts of the tubing and see if the pressure drops or not. Start close to the regulator and go out from there.

 

[IslandLizard]

I'm not using keg lub but will certainly look into it if I should.

You definitely need to use keg lube.
It comes in small (1 oz) black plastic tubs with golden lettering, named keg lube. That's what I have always used. It's pretty thick, the consistency of vaseline. Also comes in small (squeeze) tubes. Your LHBS (Local Home-Brew Store) should have at least one of the other.

You just rub the keg lube onto the o-rings, between thumb and forefinger.

Your (corny) kegs have 7 o-rings:
The large one, around the lid
One around the top of each of the 2 posts. They make the seal with the quick disconnects (QD).
One under the flange of each of the 2 dip tubes. They seal the top of the dip tubes and bottom of the posts.
The poppets (one inside each of the 2 posts) have a (small) o-ring, sealing the posts on top.

• "Universal poppets" have a pyramidal (conical) spring underneath each poppet with a small o-ring around it. Those poppets are truly universal and the o-rings are easily replaceable. All new kegs use those. Looks like that's what you have.
• Older model poppets come in different shapes and sizes, depending on the posts they fit into, specific to the manufacturer of the kegs. The poppets are not interchangeable among different keg brands, and the (poppet) o-rings are not replaceable.

 

[TonyS]

Agreed there's a leak. Maybe charge the system, turn off the CO2 tank, and then get creative and shut off various parts of the tubing and see if the pressure drops or not. Start close to the regulator and go out from there.

But that’s exactly what I’m doing. I only have it turned on when serving or carbing and can’t find any leaks

 

[IslandLizard]

What's extra frustrating is that the dude at our local homebrew store said that air leaks should be extremely rare, especially with new setups like mine.

My emphasis^ they're gas leaks, CO2, not air.

Right, everything is brand new, so leaks should be rare!
However, something is being overlooked...

Definitely start with using keg lube on all your keg's o-rings. They'll love you for it!

 

[tracer bullet]

But that’s exactly what I’m doing. I only have it turned on when serving or carbing and can’t find any leaks

I think you misunderstood. You'll want to disconnect and plug at the first joint / junction / union / connection / adapter / whatever downstream of the regulator and plug it up. Turn the tank on long enough to pressurize your now very short line to 12 or something like that psi. Then turn the tank back off. Give it a while, overnight or however long needed, to see if the regulator holds pressure. If it doesn't, then you know your issue is around the regulator (gauge, PRV, connection to the tank, etc.) and can focus there. If it holds pressure overnight, then your issue is downstream of it. You repeat this idea to find out the location of where the leak must be based on when things do or do not hold pressure.

It's not a quick thing, you have to devise a test and let it go for a while, until the regulator shows an obvious pressure drop or overnight perhaps, whichever comes first. Might take a week to get it done.

 

[Graham H]

Picture #1–there looks like a small white plastic piece tied to the regulator beside the nut used to screw it onto the tank. Is that a gasket meant to seal the tank-regulator connection?

 

[hottpeper13]

I agree with everything tracer bullet says and can add one more thought. All gas cylinders have valve stem sealing "O" rings and must be opened all the way.

 

[hottpeper13]

I also have better luck with the fiber washers for the tank to regulator.

 

[day_trippr]

^good catch^ Could be an extra but it's a valid question...

Also...always fully open a CO2 tank valve to the stop and don't depend on the gland packing...

Cheers!

 

[Broken Crow]

^ yes to all and the part I'm wondering about is why there's both a plastic clamp and an oversized worm-clamp on the output.
With respect, while your pictures tell us that everything (probably including the corny keg) is a new Kegco that was made for commercial kegs and adapted for cornys, the angles are bad and things that we'd look for such as off-centered and oversized hose-clamps or hose wrinkling on too small a barb aren't really observable. Could you take a few more pics directly from the side of each connection? ..including the cheap non-CMB disconnect that looks vaguely like the hose clamp might be too far out.
A note on those cheap disconnects: While most of them are reasonably OK as long as you use keg lube, I did have a flawed one whose center was not entirely round...trashed it and replaced everything with genuine CMB disconnects... I just don't trust the cheap ones.

 

[Neldog0]

Hi All!

First time post/thread and appreciate any feedback.
I've suspected an airflow leak but have done soapy water tests on all of my valve connections without any bubbles or hissing. To be on the safe side I even double sealed all connections yet I'm only able to force-carbonate 3 corny kegs before I run out of air. That seems super low! Especially cause I just finished carbing the 3rd keg and have only served 5 beers before this tank just ran out. I force carb each keg at 40 PSI for 2 days, then bring it down to 8 for serving but I also shut the entire tank off unless I'm serving. So what's going on here?? Shouldn't I be able to get more than 15 gallons of beer for each CO2 tank??
System is a 3-tap Kegco, which I've heard is a good supplier. Figured I'd ask here first before bringing in a technician. Again, thank you for any/all feedback!

I typically get 10-11 kegs before I have refill. I check for leaks about once a week I replace post o-rings every time I refill a keg & check the regulator for any leaks. If you have relieving regulator make sure it’s not relieving all the time.

 

[TonyS]

Picture #1–there looks like a small white plastic piece tied to the regulator beside the nut used to screw it onto the tank. Is that a gasket meant to seal the tank-regulator connection?

Yeah that’s the extra seal I put on. The main seal is in front of it

 

[TonyS]

^ yes to all and the part I'm wondering about is why there's both a plastic clamp and an oversized worm-clamp on the output.
With respect, while your pictures tell us that everything (probably including the corny keg) is a new Kegco that was made for commercial kegs and adapted for cornys, the angles are bad and things that we'd look for such as off-centered and oversized hose-clamps or hose wrinkling on too small a barb aren't really observable. Could you take a few more pics directly from the side of each connection? ..including the cheap non-CMB disconnect that looks vaguely like the hose clamp might be too far out.
A note on those cheap disconnects: While most of them are reasonably OK as long as you use keg lube, I did have a flawed one whose center was not entirely round...trashed it and replaced everything with genuine CMB disconnects... I just don't trust the cheap ones.

Yes, I’m on a flight right now but will be home on Monday and take additional pics then. Thank you!!

 

[Closet Fermenter]

There’s one other remote, very remote, possibility; your tank wasn’t completely filled from the vendor. It doesn’t happen often, but I have had it happen with welding gas exchanges. I actually had it happen to me twice in a row. (I don’t do business there anymore.) Next go around, weigh your tank before hooking up, and after you empty it and see what you find out. It would be good to eliminate this possibility if you don’t discover the problem otherwise.

 

[tracer bullet]

Yeah that’s the extra seal I put on. The main seal is in front of it

"Extra" seal?

Between the tank and regulator assy there should just be 1 seal total, and it should be reasonably smushed into place as well.

Mine are a plastic, a somewhat soft one that deforms to the shape of the pieces it connects including a little ridge of sorts.

 

[IslandLizard]

There’s one other remote, very remote, possibility; your tank wasn’t completely filled from the vendor. It doesn’t happen often, but I have had it happen with welding gas exchanges. I actually had it happen to me twice in a row. (I don’t do business there anymore.) Next go around, weigh your tank before hooking up, and after you empty it and see what you find out. It would be good to eliminate this possibility if you don’t discover the problem otherwise.

Although you could do that, to double check, we already know it:
The tare weight (TW) is stamped into the tank's shoulder. It's clearly visible in the 2nd picture in post #4: 7.73 LB
That number includes the weight (mass) of the valve assembly.

 

[TonyS]

There’s one other remote, very remote, possibility; your tank wasn’t completely filled from the vendor. It doesn’t happen often, but I have had it happen with welding gas exchanges. I actually had it happen to me twice in a row. (I don’t do business there anymore.) Next go around, weigh your tank before hooking up, and after you empty it and see what you find out. It would be good to eliminate this possibility if you don’t discover the problem otherwise.

I did consider that but the spot I go to is highly rated with multiple locations in town. They do huge tank refills for numerous industries so I highly doubt they're cutting corners this way but I will do a weight test next time to be on the safe side. thank you!

 

[TonyS]

"Extra" seal?

Between the tank and regulator assy there should just be 1 seal total, and it should be reasonably smushed into place as well.

Mine are a plastic, a somewhat soft one that deforms to the shape of the pieces it connects including a little ridge of sorts.

Sorry, meant clamp. Guy at my homebrew store said I can just put an extra plastic clamp alongside each of the steel hose clamps he put in place when he initially installed this. That way, if there are small leaks stemming from his clamps, these extra ones should close them off.

 

[tracer bullet]

Got it. I double mine up too, haha. Cheap insurance since I have tons of clamps.

 

[whoaru99]

Sorry, meant clamp. Guy at my homebrew store said I can just put an extra plastic clamp alongside each of the steel hose clamps he put in place when he initially installed this. That way, if there are small leaks stemming from his clamps, these extra ones should close them off.

Ok, but what about where the regulator attaches to the tank?

Is there a seal between the tank outlet and the regulator inlet?

Along the lines of something like shown below just for example.

 

[beren]

also make sure to not use thread tape on the threads. These are straight, not tapered threads and the orings do the sealing.

 

[beren]

the angles are bad

What do you mean?

 

[sbro]

I had setup a 3 keg gas supply for a temporary setup and it was not holding pressure. Various checks did not point to any easy fix. I then took the manifold and all lines and fittings (removed from kegs) and submerged them in a plastic bin with 4 inches of water. turned on the air and immediately found a one way check valve bad, a gas quick connect leaking on the back of where it would connect to the keg and 2 duotight to MFF connections that were not tight enough. Tightened the connectors, replaced the QD and removed the check valve and all was good.
I found that submerging the components was way quicker than troubleshooting individual lines or spraying with starsan or bubble mix. It might be a quick way to check your entire gas side.

 

[day_trippr]

I had a rough experience many years ago when outfitting a fridge with a 4 way CO2 manifold, so when I did the second fridge I dunked the works - and
found no fewer than four leaks, including iirc a cracked fisheye washer, less than tight swivel nut, less than tight band clamp, and a poorly taped end plug. Those would have been a nightmare to debug in place, so it was totally worth taking the time to leak test before installing everything...

Cheers!

 

[IslandLizard]

submerged them in a plastic bin with 4 inches of water. turned on the air [...]

Although one could test for leaks using compressed air, I reckon you used CO2 from your tank.

 

[sbro]

Yes, I used the CO2 for convenience as it did not lose much during the submersion test and eliminated the need for an adapter to compressed air.

 

[Broken Crow]

What do you mean?

The angles of the pictures...they skillfully avoided all the details.

 

[Bobby_M]

Note... people are picking up that there's a gasket zip tied to the tank stem of the regulator. Many regs will have one in place and also include a spare. Yes, definitely check that there is one in place between the tank and reg but I suspect it is.

Here is how you can perform a leak down test to see if you have a leak and generally isolate it to where.

Open the valve of the tank fully open. Turn the yellow quarter turn valve on the bottom of the regulator OFF/SHUT. Set your low pressure to 30psi exactly. Turn the tank valve off and start a timer. Does the low pressure gauge hold at exactly 30psi for 10 minutes? No=your leak is probably between the tank and regulator. That nut should be tight, like a 12" adjustable wrench with half your body weight on it.

Yes=no leaks between the tank and regulator and none of the accessories threaded into the regulator have leak problems. Moving on...

Open the yellow valve on the regulator, but keep the three output valves on the distributor/splitter in the closed position. Open the tank valve again, then close it. Set a timer for 10 minutes. Is the gauge still reading 30? Yes means still no leak problems INCLUDING the distributor. If the pressure slipped below 30, your leak is somewhere between the regulator and distributor or on the threads of the distributor fittings. Dunk all that in water and look for bubbles.

Moving on...

With none of your grey QDs attached to any kegs, open valve 1 and perform the leak down process. Open the tank valve, close it, timer... 10 minutes... If valve one holds, open valve 2 and repeat, then valve 3...
If all three of the lines hold 30 psi then your leak is involving one or more kegs or the connection between the QD and keg.


My opinion is that it's somewhere in the tubing to barb connections because it looks like those clamps are squeezing the tubing smaller than the OD. To me, that indicates that the inside diameter of the tubing is slightly larger than the barbs they are connected to. Maybe not. Do the leak down test as it's the most meticulous way of finding the general area of a leak.

 

[tracer bullet]

Here is how you can perform a leak down test to see if you have a leak and generally isolate it to where.

Thanks. That's what I was also trying to suggest way above, but I don't think it made sense. You made it a lot more clear. Interested to see if they will try this.