Leaky System

[Petho]

Hi Guys. I have a new keg system in a chest freezer with a Ranco controller. I have a 3 gallon keg with new O Rings and a 5 pound tank.
I checked the system for air leaks using a bucket full of water so I know the keg is pretty tight. I tightened up the connection to the bottle however after 24 hours in a 35deg cooler, the dials say that I losing air in my tank. The needle is almost into the red area.
My question is, do I still have a leak or is the temperature differential causing the tank to read low? Seems that cold temps would cause the pressure to decrease.

Thoughts?

 

[runningweird]

as the co2 tank cools the reading on the gauge will go down. My 20lb tank is nearly full but reads empty if i put it in a cooler. part of the reason mine is outside my fridge, the other part is so I oculd jam 6 kegs in there.

someone more awake than me right now can explain the hithertos and why fors. but its fine.

 

[shortyjacobs]

IGNORE the high pressure gauge, (the "full/empty" one). It's USELESS with CO2.

CO2 is mostly liquid, with a bit of gas at the top of the tank. The pressure in the tank is the same whether it's almost full or almost empty, because the pressure is the equilibrium pressure required to keep the liquid CO2 liquid. As you use gaseous CO2 from the tank, liquid boils to replace it.

The equilibrium pressure, as runningweird states, is a function of temperature. So a cold tank will read 300-500 PSI, and a room temperature tank will read ~800 PSI. The tank will continue to read this until its almost empty, (all the liquid boils to gas as you use CO2), at which point it will very rapidly drop to 0.

So ignore it. It's normal for it to drop as the tank changes temp.

 

[Petho]

Thanks for the info, guys. I kinda figured it was a temperature thing but I had battled a leak earlier in the day so it made me second guess. I'm new to kegging but things seem to be going well.