Should a gas system be "completely" air-tight?

[J2W2]

Hi,

I typically carb new beers for several days in my fermentation chamber before I move them into my keezer. Mainly because I don't like dealing with all the cleanup (fermenter, old keg, beer lines, etc) all at once. But it also gives me a chance to watch for leaks before the new keg goes into the keezer.

I moved my latest beer into the keezer on Monday, and turned off the gas to my spare regulator (the one I carb with in the fermentation chamber) at the same time. Three days later, the regulator still shows the 16 psi I carbed at, but the volume gauge has dropped from mid-green to halfway toward red. I'd guess my next Monday both gauges will show zero.

So, is a tiny "leak" like this normal, or should I expect the regulator gauges to remain where they were when I shut the gas off?

Thanks for your help!

 

[grampamark]

If the regulator leaks down when the gas is shut off it will leak when the gas is turned on. Those tiny leaks are the ones that leave you with an empty Co2 bottle when you least expect it.

 

[Spikybits]

you have a leak - if you had the gas shut off at the hose barb, close your tank now as well - if you have a leak it will be zero in the morning, but you wont drain your tank. you will prove if you have a leak or not in the gauge or tank connection. if the pressure holds, you do not have a leak between the tank and the regulator or from the reg body.

to check the hoses, pressurize the hose then turn off the tank valve. if the gauge drops to zero you have a leak in the line somewhere. do this after you have proved you dont have a leak from the tank connection or reg body.

i turn my gas off at the barbs when not in use. if i also turn the tank valve off, it will hold pressure on the gauge with no change.

if your tank goes from ambient temp to cold - IE stored in your ferm chamber when you go from 60-70 to cold crash, this will affect the reading

 

[J2W2]

you have a leak - if you had the gas shut off at the hose barb, close your tank now as well - if you have a leak it will be zero in the morning, but you wont drain your tank. you will prove if you have a leak or not in the gauge or tank connection. if the pressure holds, you do not have a leak between the tank and the regulator or from the reg body.

to check the hoses, pressurize the hose then turn off the tank valve. if the gauge drops to zero you have a leak in the line somewhere. do this after you have proved you dont have a leak from the tank connection or reg body.

i turn my gas off at the barbs when not in use. if i also turn the tank valve off, it will hold pressure on the gauge with no change.

if your tank goes from ambient temp to cold - IE stored in your ferm chamber when you go from 60-70 to cold crash, this will affect the reading

When I shut this tank off, I always just close the tank. But that's a good idea. I just briefly turned the tank back on, so both gauges are back to full, and then turned off the tank and the hose barb. I'll give it several days and see if there's a pressure drop from the tank or regulator.

I had wondered if gas disconnects are perfectly airtight when they are not connected to a keg?

The tank sits outside the fermentation chamber (it's a mini-fridge with an Inkbird controller), so tank temp isn't an issue.

Thanks to both of you for the quick replies!

 

[Spikybits]

When I shut this tank off, I always just close the tank. But that's a good idea. I just briefly turned the tank back on, so both gauges are back to full, and then turned off the tank and the hose barb. I'll give it several days and see if there's a pressure drop from the tank or regulator.

I had wondered if gas disconnects are perfectly airtight when they are not connected to a keg?

The tank sits outside the fermentation chamber (it's a mini-fridge with an Inkbird controller), so tank temp isn't an issue.

Thanks to both of you for the quick replies!

Gas QDs are not airtight when not connected to a keg - trust me on this

 

[Bobby_M]

Gas QDs are not airtight when not connected to a keg - trust me on this

This is only true in a poppet malfunction otherwise they are designed to be gas tight when disconnected. Everything with moving parts and gaskets will fail at some point.

 

[BrewChem]

Those tiny leaks are the ones that leave you with an empty Co2 bottle when you least expect it.

What he said…!! This has bitten me in the butt before..!

 

[day_trippr]

Yes, it should.

 

[J2W2]

Yes, it should.

I assume you mean yes, a QD should be airtight? Just checking!

 

[passedpawn]

No leaks are acceptable. Zero.
I often have 4 kegs on gas in my holding fridge. I have up to 3 kegs in my serving fridge. Believe me, no leaks. Those beers will sit in there for months attached to gas.

 

[passedpawn]

Ah, now I see (I think) the the OP is losing gas when the valve is turned off? Nope, that is not good either. Normally, if I don't have any kegs connected, I turn the tank valve off.

... and turned off the gas to my spare regulator

View attachment 745635

How do you turn off the gas? There is the tank's valve, then your regulator adjustment there (red knob in your pic), then often we have manifolds after the regulator to turn off the gas to the outputs. Which one?

 

[day_trippr]

I assume you mean yes, a QD should be airtight? Just checking!

Not just "a QD", the entire system, end to end.
As @passedpawn summarized, zero leaks are acceptable. And a leak-free system is achievable...

Cheers!

 

[doug293cz]

If you shut off the CO2 tank valve, and your gas plumbing is connected to an incompletely carbonated keg, then the pressure will drop. This is not necessarily due to a leak, but rather the beer will absorb CO2 even when the gas is shut off, causing the pressure to drop.

Brew on

 

[passedpawn]

If you shut off the CO2 tank valve, and your gas plumbing is connected to an incompletely carbonated keg, then the pressure will drop. This is not necessarily due to a leak, but rather the beer will absorb CO2 even when the gas is shut off, causing the pressure to drop.

Brew on

That's a good point, but the OP stated that the tank level shown on the primary meter on his tank changed when NOT ATTACHED to kegs. He says the "valve" was off, but not sure what valve means.

So, I'm guessing he does indeed have a leak, or something else changed. Temperature can play a big part in this too.

Lots of variables to rule out before I conclude he has a leak. But eliminate we must. When you have eliminated the impossible, whatever remains, however improbably, must be the truth. (part of that I lifted from sherlock holmes - not sure it means anything, but it seemed like a good time to quote him).

 

[J2W2]

How do you turn off the gas? There is the tank's valve, then your regulator adjustment there (red knob in your pic), then often we have manifolds after the regulator to turn off the gas to the outputs. Which one?

I always close the tank valve, unless it's in use (carbing a keg, pressurizing a growler, etc.) I only mess with the regulator adjustment when I need a different pressure; usually it stays where it is. I normally don't close the manifold (hose barb), but I have it closed now, with the line fully pressurized and the tank valve closed. At this point I'm trying to determine if the leak is in the tank/regulator or the tubing/disconnect.