Advice on a malfunctioning keg system

[lydonmp]

I’m looking for some advice on a frustratingly faulty keg system

I’m using a standard 2.6 kg CO2 bottle with a new regulator (theorised the old one might be the problem) feeding into several hoses with gas disconnects. Without being connected to any kegs the system holds at 40 psi - left it for 48 hours and no drop in pressure. So, the tubing and connectors seem to be sound.

The issue is that the system has now totally lost all pressure and gas a few times now. here is a similar pattern. It’s all good holding at 8psi connected to three kegs for a week or so. Then it all goes flat literally overnight. Empty gas bottle and seemingly 3 flat kegs. this has happened with several different gas bottle so I think I can rule out gas bottles being the problem


The one constant is that this happens shortly after I start pouring full pint glasses rather than little tasters to test carbonation levels.

The whole system worked well worked well with 2 10 litre kegs. The only variable I introduced was a 20 litre keg. This keg seems to take pressure and dispense fine however, as I say, all was good before it was introduced into the chain.

I have thought of getting yet another CO2 bottle and testing one keg at a time until it’s empty until I find the culprit assuming the problem is one of the kegs.

Any suggestions on what may be going wrong or how to set up some sort of testing system that doesn’t involve wasting several bottles of CO2 would be appreciated.

 

[philrob]

Sorry to read of your issues.
I have never kegged, so can't personally help you, but I'm sure there are others on here who will be able to come up with suggestions.

 

[MHB]

You have a leak.
Odds on is the O-Ring on the gas post of one of your kegs, that’s the most common place.
If you get a spray bottle and put some detergent (dish washing liquid) and water in it.
Connect everything up. Pressurise.
Spray everywhere where things join up and look for bubbles.

Very good idea to keep a couple of post O-Rings in stock and to use a good food grade lube on them (just a smidge).
Mark

 

[lydonmp]

You have a leak.
Odds on is the O-Ring on the gas post of one of your kegs, that’s the most common place.
If you get a spray bottle and put some detergent (dish washing liquid) and water in it.
Connect everything up. Pressurise.
Spray everywhere where things join up and look for bubbles.

Very good idea to keep a couple of post O-Rings in stock and to use a good food grade lube on them (just a smidge).
Mark

Hi Mark

Thanks for that. It does seem the most likely cause. I've got some spare O-Rings so will get to diagnosing once I've get my act together and replace the keg.

Can't figure out why all three kegs de-pressurise if only one is leaking (bit of an assumption there) but I've only got a beginners level idea of how all these things work.

Mike

 

[dkril]

Can't figure out why all three kegs de-pressurise if only one is leaking (bit of an assumption there) but I've only got a beginners level idea of how all these things work.

Because all three kegs are connected to the same gas line.

Leaky keg leaks, the gas cylinder tops it up. Repeat until the gas cylinder is empty.

Once that happens, the leaky keg will keep leaking, but as the gas cylinder is empty, the gas pressure will drop. Because the leaky keg is connected to the other kegs via the gas lines (effectively sharing a common head space) they will all lose pressure equally. As the head pressure decreases, dissolved co2 will come out of solution to match the head pressure. Again, all the kegs are connected, so they are all affected.

Eventually, all the co2 has leaked out and you are left with an empty gas cylinder and several equally flat kegs.

 

[lydonmp]

You have a leak.
Odds on is the O-Ring on the gas post of one of your kegs, that’s the most common place.
If you get a spray bottle and put some detergent (dish washing liquid) and water in it.
Connect everything up. Pressurise.
Spray everywhere where things join up and look for bubbles.

Very good idea to keep a couple of post O-Rings in stock and to use a good food grade lube on them (just a smidge).
Mark

Hi Mark

Thanks for that. It does seem the most likely cause. I've got some spare O-Rings so will get to diagnosing once I've get my act together and replace the keg.

Can't figure out why all three kegs de-pressurise if only one is leaking (bit of an assumption there) but I've only got a beginners level idea of how all these things work.

Mike

Because all three kegs are connected to the same gas line.

Leaky keg leaks, the gas cylinder tops it up. Repeat until the gas cylinder is empty.

Once that happens, the leaky keg will keep leaking, but as the gas cylinder is empty, the gas pressure will drop. Because the leaky keg is connected to the other kegs via the gas lines (effectively sharing a common head space) they will all lose pressure equally. As the head pressure decreases, dissolved co2 will come out of solution to match the head pressure. Again, all the kegs are connected, so they are all affected.

Eventually, all the co2 has leaked out and you are left with an empty gas cylinder and several equally flat kegs.

That makes perfect sense. Thanks for the explanation

 

[Ballaratguy]

You could put inline one way valves on all kegs (allows the gas in but won’t let the gas to go back)

 

[lydonmp]

Thanks for everybody's input. I finally figured out the issue. As well as my 3 metal kegs I was also pressurising a brew my son had made and put in a PET keg. Typical student choosing the cheapest alternatives. Long story short his PET keg developed a hairline fracture on the neck which I found after covering everything in soapy water from a spray.

When I think back to it I'm almost sure that I've done the initial carbonation for him on what I think are all of the occasions my system flatlined.

With that out of the chain all seems to be good so far.

 

[squidley]

Another thing to have with the keg systems is the Food Grade Silicone Grease, always lubricate all rubber seals with a small layer, including the disconnects. will greatly increase the life and effectiveness of your seals.