How Many PSI in a 5# CO2 bottle??

I just got my CO2 bottle filled... Supposedly 5#.. I didn't weigh the bottle.... dang it!
So how many PSI is a full tank??

I'm used to 2K PSI on an O2 bottle.

So why is CO2 lower?

Cheers

Takes less pressure to make it liquid, I guess.

I think at room temp they're about 800? I could be wrong about that. The pressure won't drop until the tank is nearly spent, once all the liquid has been used and only gas remains in the tank.

Moonshae said:

Takes less pressure to make it liquid, I guess.

I think at room temp they're about 800? I could be wrong about that. The pressure won't drop until the tank is nearly spent, once all the liquid has been used and only gas remains in the tank.

Click to expand...

Exactly. Pressure can range a little bit but will average 800 psi at room temperature.

Yup, it's the liquifying pressure/temp. When the tank is full of liquid and you're only concerned with a secondary pressure in the range of 10-20psi, it really doesnt matter what the tank pressure is.

Just refilled my 5lb tank and it read 700PSI after warming to 65 - 68 degrees. Room temperature will have an effect on what gauge pressure you read in the tank, so keep that in mind.

Salute!

FxdGrMind said:

I just got my CO2 bottle filled... Supposedly 5#.. I didn't weigh the bottle.... dang it!
So how many PSI is a full tank??

I'm used to 2K PSI on an O2 bottle.

So why is CO2 lower?

Cheers

Click to expand...

It compresses to a liquid at a lower pressure than O2. I normally see about 1200 psi unless its cold then you can see as little as 800. Next time its empty weigh it and write the weight on the bottle. I have always weighed mine but would forget what the empty weight was. Now I know at a glance. Some tanks have the empty weight stamped on them, but trying to decipher the code can lead to excessive alcohol consumption which only compounds the problem.

Yep, varies slightly from between 800-1000 at room temp. The difference between O2 and CO2 is that the CO2 is in the tank as a liquid which boils off to a gas as you use it so there is *much* more gas in that tank than the equivalent volume of an O2 bottle. That 5# (slightly less actually) is equivalent to ~43 cu. ft. of gas.

Thanks!!

Never had CO2 so the explanations make it very clear!
Cheers!

If you want to know if you actually have 5 lbs of CO2, there should be a tare weight stamped into the side of the tank somewhere. That's the weight of the metal and gauge of the tank. So weigh the tank, subtract the tare weight, and that's how much CO2 you have in it. It should look something like TWxxx lb.s

I don't think it was stated explicitly, but it will be 800-1000 psi from 100% full to just before completely empty. The pressure will never drop as long as there is liquid CO2, assuming the temperature remains the same.

If you see it get below 800, your tank is on it's last leg, again, assuming you see 800-1000 psi at the gauge normally.

keithd said:

I don't think it was stated explicitly, but it will be 800-1000 psi from 100% full to just before completely empty. The pressure will never drop as long as there is liquid CO2, assuming the temperature remains the same.

If you see it get below 800, your tank is on it's last leg, again, assuming you see 800-1000 psi at the gauge normally.

Click to expand...

+1! Or, if it's cold, it will read lower. As soon as there is enough space for the liquid to turn gas, it drops and you are very soon going to be cursing at it. I highly recommend having a spare tank filled (especially with the hours of my local fill place, and getting lucky if they can fill my nice aluminum and not try and swap me due to turning off pump etc).

I rarely get over 1k psi fills, and when it's cold it usually reads around 400-500 (in the red). At about 100 or so is when it get it refilled.