Pressure on new CO2 tank

levians69 · 01-13-2009, 07:10 PM

Hi folks,

I just rented a 25lb CO2 tank and attached my regulator. After warming up, my pressure regulator tells me that the tank is at 550PSI. According to the regulator, 500PSI is the "order more gas level".

Is this typical or inkeeping with other's experience? Or, did the welding shop send me an empty tank by accident or intention?

Thanks for your help!

Cheers,
Jay.

PS. I know 25lbs excessive but it was the smallest size available for rent and I didn't want to buy a tank since I move a lot and movers, for some reason, seem to hate moving pressurized tanks.

**Gussymo** · 01-13-2009, 07:18 PM

I just had my new #20 tank filled and once it warmed up it had over 700 lbs of pressure.

xumbi · 01-13-2009, 07:27 PM

My 20# tank that I just swapped out reads about 600lb of pressure in the keezer (about 40F).

I've seen the warning you're referring to, I don't think it's relevant for beer.

Displaced MassHole · 01-13-2009, 07:28 PM

My 20#er will go from over 1000psi in the warm summer months to 300psi in a 34 degree fridge over night and then back to a 1000 the next day.

**GNBrews** · 01-13-2009, 07:29 PM

If it's at room temperature, you've got an empty tank. Take the regulator back off and weigh the tank on your bathroom scale. It should weigh *at least* 25lb plus (the tank weighs a few lbs, plus the fill, which may not be the full 25lb anyway).

**jonp9576** · 01-13-2009, 08:18 PM

are you sure its a 25 lb tank. they make tanks in 5, 10, 15, 20, and 35 lb, but i've never seen a 25# tank.

**GNBrews** · 01-13-2009, 11:43 PM

Whether it's a 25# tank or a 5# tank matters very little (apart for the accuracy of the weight test I mentioned). The pressure should be the same as long as the temperature is constant and there is still liquid CO2 in the tank. If it's close to room temp, 550PSI is empty.

Edit: How long was the regulator connected before you realized the pressure was that low? Is it possible you had an overnight leak and emptied the tank?

levians69 · 01-14-2009, 12:06 AM

Thanks everyone for your quick replies. The pressure has now steadied at 600PSI at about 20C (60F). I think this is because the house has warmed up a couple of degrees for the evening.

From what you guys are saying it sounds like even 600PSI is a little low. Reported pressures at roughly room temperature should be 700 to 1000PSI or more.

I just hooked up the tank this afternoon, so I didn't empty the tank overnight. Also used a fingerfull of washing-up liquid to check for leaks on the system and I seem to be tight.

I'll need to find a bathroom scale. Thanks for the suggestion. I hadn't thought of that wonderfully obvious idea! Silly of me.

And, yup, it's a 25lb tank from a welding supply shop. I live in Newfoundland so that might be partial explanation.

Thanks again for the help. Much appreciated.

**jonp9576** · 01-14-2009, 07:26 PM

i wasnt asking because the presures are different, i was just curious. i've never seen a 25# tank.

i work in the compressed gas industry and thats weird to me. i kinda want to see it.