CO2 question

[linuxelf]

I'm really new to kegging. I just got my kegging system together last weekend. After about 3 days of holding the CO2 at 20PSI in my keg, my CO2 tank was empty. I obviously had a leak somewhere, so I got a new tank (just swapped out at my LHBS) I noticed that the connection between the gas line and the QD was only hand tight, so I tighted that good and snug with a wrench. Also, I only hand tightened the connection between the gas line and the tank itself. Now, I've got it nice and tight with a wrench. I *think* I'm ok now, but here's my question. When I first hooked the tank up, the regulator read about 675 PSI in the tank and 20PSI in the keg. I left it in the refrigerator over night, and now the tank reads a little over 500PSI (This is a 5# tank, BTW) So, my question is, am I still leaking CO2? Would the change in temperature of the tank (about 70 degrees at start, now it's in the 50's or lower) account for a drop in PSI? With a new 5# tank, what should the PSI read when you first hook it up? I went ahead and turned the tank back off, but left it all hooked up to my keg. When I get home, I'm hoping to see that there is still pressure in the keg.

[bub]

CO2 is a liquid in the tank, the psi rating is based on the temperature of the tank. i.e. the same tank could have a 300 psi reading or 600 psi reading depending on it's temperature, as the temp rises more of the liquid gassifies and increases the pressure. The rule of thumb is ignore the "tank" pressure until it gets in the red zone. When in the red zone you are out of liquid and will soon be out of gas as well.
Hope that wasn't too confusing.
BUB

[Lufah]

Take a look here.... http://forum.northernbrewer.com/viewtopic.php?t=20211

Travis

[rich]

Linuxelf, I too, lost a whole 20# tank of co2 when I first got into kegging, so I feel for ya. Here's a few tips that may be helpfull. Appologies if it's something you already know/do:

-Keep a spray bottle of star san handy for checking fot co2 leaks. I don't like spraying soapy water all over the place.

-Check your system for leaks progessively. What I mean by this is hook up the regulator only to the cylinder and check for leaks (don't forget the nylon washer). Then attach your main line and check it for leaks. Move along the system like wise next to manifolds, secondary regs, ect. By doing this you have maximum pressure at each potential leak point. I also crank the primary reg up to 60 psi for leak testing.

-Lose that old school teflon tape a get a tube of Great White Pipe Joint Compound w/ teflon made by Oatley. This stuff withstands pressures up to 3000psi on gasses from -50*F to +400*F, and 10,000 psi from -50*F to +500*F on liquids. It's about $2 for a tube and lasts forever.

-On your beer side, lube EVERYTHING (all 7 o-rings; lid, body connect posts, dip tube rings, and the itty bitty ones on top of the poppets) with keg lube or similar food grade silicon grease.

-When hooking up a new keg, seal it initially at least at 35psi, then back down to your serving psi. Remember, these kegs were originally designed for soda pop, and higher pressures for sealing. Sure you can seal fine at lower beer serving pressures, but what would it hurt? Also check each new keg for leaks after sealing with your handy star-san spray bottle. You kill two birds with on stone cause your sanitizing the posts too!

[dawgfur]

I too went thru all the growing pains of kegging, mostly from the leaks. Get control of your leaks and all should be fine. I keep my 5# bottle in the keg fridge, so it always reads about 500psi, then it drops rapidly when the CO2 liquid is expended. I normally serve 2-3 corny kegs at a time, and the 5# bottle lasts for months between re-fills.
It all depends on your consumption and use. I'm sure if Brewcaster-J was around, the bottle (and kegs) would require much more frequent re-fills!

[linuxelf]

This is great information, guys. Thanks a bunch. So, I got home from work today and the keg is still sitting at 18psi. I'd say that it's definitely holding pressure. I think I got it licked. I'm definitely going to get some keg lube for my next keg.

[SunkenBier]

Great info, I especially loved the link Lufah put in. My tanks are sitting a little over 500 and I thought there was a problem. Since their at 40 degrees it sounds like its all about right.