Slow CO2 leak or pressure-change due to temp.

Yeah, I realize it's probably a slow leak... but I have to ask.

I drained a co2 tank last week due to a bad pressure-release valve. No problem, taken care of.

Got it refilled, up to 1000 PSI, plugged everything back in, fixed the valve, and everything was good.

I just took a couple of kegs out to wash it, looked at the master pressure valve, and it's down to 500 PSI. I realize pressure drops when you chill something. If I'd filled this 4 kegs ago, I might think it was normal usage, but I've really drained only one keg, maybe one and a half. Do I still have a slow leak somewhere, or is the difference in pressure due to temps and usage combined?

thx.

kvh

When I filled my tank last time, it read about 900psi @ 75F. After being in the fridge @ 42F it dropped to about 500psi. Take it out in the warmer air if you can and see if it pops back up near 1000psi...

Awesome! Exactly what I wanted to hear.

thx.
kvh.

When it dropped in the fridge I was like "man keggings definitely more money than bottling". Then I realized it was the cold temp dropping the pressure and I didn't need to already refill my tank. Seriously though, bring your tank back up to room temp and see if it heads back towards 1000psi

Remember, pressure is not a true indication of how much gas you have left (that's why it is sold by weight). This past weekend I took the tank out of the fridge while installing my draft tower, pressure almost doubled as the tank came up to room temp, soon as it was back in the fridge it dropped back down.

I wouldn't take it out of the fridge yet. See if the pressure stabilizes now at the lower level. If so you have nothing to worry about. If it continues to drop do the following:

Turn off the valve and manifold after the regulator and see if the pressure drops over a day or two. If it is still dropping then your regulator or tank valve are leaking. If it holds pressure for a couple days the tank/regulator connection and the regulator are fine.

Once this is all gas tight turn the valve back on to pressurize the gas lines but don't hook up the gas connectors to the kegs. If it holds pressure for a couple days you're golden up to the keg. If it leaks then you have a leak in your hose/fitting connections, new clamps should fix.

Once you have that taken care of you can check your kegs. It is best to check them by connecting the gas to them empty because if they are full of beer that isn't fully carbed the pressure will drop a little as the beer absorbs CO2.

pressure is no indication of how much co2 you have left. that psi will stay consistent until every drop of CO2 inside the cylinder is gone. then your psi plummets because you have nothing creating CO2 gas anymore.

malkore said:

pressure is no indication of how much co2 you have left. that psi will stay consistent until every drop of CO2 inside the cylinder is gone. then your psi plummets because you have nothing creating CO2 gas anymore.

Click to expand...

Close. Real close.

Pressure is an indication of how much LIQUID C02 you have left in the Co2 bottle. As you use gaseous Co2, the liquid Co2 in the bottle will boil off. The pressure is determined by the temperature of that liquid Co2, and will remain constant at a set temperature, as long as liquid Co2 is there.

Once the liquid Co2 has boiled off, your pressure will drop. Your pressure, with liquid Co2 still in the bottle, is determined by the temperature. (Yes, with the right chart, you can read, indirectly, the temps in your kegerator, from the Co2 high pressure gauge.)

steve