Leaking keg or just equalizing pressure ?

[iasquith]

Hi ,
I'm getting ready for my first keggging attempt with a second hand corny ,Iv'e checked all the valves, connections, posts and lines for leaks with lots of foam
and cured them all.
before I attributed the slowly falling pressure on the regulator when given a blast at 30psi to the actual leaks, but now having fixed them all I see that the pressure still drops ever so slowly.
What I wanted to know is, this is normal :?
is it the co2 already being dissolved and equalizing the pressure ?
should I worry ?
thanks

 

[malkore]

psi should stay steady.

however, two things:

1. I've notice brand new regulators go through a little 'break in' period. you'll screw them down to 30psi, and then due to the mechanics, they creep back down to 20psi or so. Eventually you break in the internal parts and when you set it at 30psi it stays at 30psi.

2. if you set it at 30psi and then put it in your keg fridge, the psi of the co2 tank itself will drop from about 1000psi to 600psi or so. Again that's 300-400psi less pressure pushing on the regulator. That can cause it to drop the psi. But if you let it cool the tank then set to 30psi, it shouldn't drop.

 

[Homercidal]

Until you saturate the beer with CO2 the beer will absorb what it can from the headspace, effectively lowering the pressure. So if you gas it up and then take the tank off, you will lose pressure. If you leave the gas on, then it should NOT drop (unless you change the temperature, as Malkore has described.)

 

[iasquith]

thanks homicidal and malkore,
yes, sorry I should have said - after hitting 30psi I turned the tank off ..... then it dropped . there's no beer in there yet its just water to test to see everything goes ok. and its out of the fridge. so now I'll guess I'll try leaving the tank on with the gauge set at 30 for an hour or two - if it stays the same reading then I know I'm good to go for beer right?

 

[BuzzCraft]

thanks homicidal and malkore,
yes, sorry I should have said - after hitting 30psi I turned the tank off ..... then it dropped . there's no beer in there yet its just water to test to see everything goes ok. and its out of the fridge. so now I'll guess I'll try leaving the tank on with the gauge set at 30 for an hour or two - if it stays the same reading then I know I'm good to go for beer right?

the CO2 is probably just going into the water and your pressure is dropping. if you want to see if the keg can hold 30psi for a period of time, leaving the pressure on won't tell you that...if your system is leaking slowly the tank will keep adding pressure and keep it at 30 psi. so....empty the keg of fluid and hit it with 30psi, then turn the tank off and check back later.

 

[GilaMinumBeer]

Or, go to the hardware store and get a pipe test valve. Fit that to a spare disconnect. And use a air compressor to pressure test your kegs and save the gas.

 

[david_42]

Disconnect the keg, crack the valve, shut it. Come back in 12 hours. You've now tested the entire system short of the keg. Pressure drops when connected to beer will be due to carbonation or consumption.

 

[shortyjacobs]

So many people get the bright idea of pressurizing a keg, then shutting off the gas to see if it leaks. One, if you shut off the gas, teh water will absorb CO2, so pressure will go down.

Two, your CO2 tank is a back seating valve. When you close it, CO2 in the SYSTEM will leak out past the CO2 tank valve! (side note, when you open your CO2 tank, open it all the way so the valve can seat against the top).

I made you a picture:

 

[iasquith]

thanks shortyjacobs,
the diagram was really helpful and knowing that gas can escape back out through the valve chamber\regulator when turned off makes a lot of sense ,
so I tested the corny with the tank turned on and its holding the pressure just fine and I'm a lot happier\ wiser now , thanks all.