# CO2 Tank Pressure Relief Valve



## SpaceBug (Jan 10, 2007)

Anyone know about how the pressure relief valve works on a CO2 tank? I believe my tank was overfilled back in February but since there didn't seem to be any problems I didn't worry about it. I still have not ordered plants for my new aquarium so the CO2 tank has been sitting there for about 5 months not being used. Well, on Tuesday it decided it needed to undergo an explosive decompression and release all of the CO2. Other than scaring the kids pretty bad, no damage done.

So the last two days I've been calling welding supply shops in the Austin, TX area to see what I need to do. One place said that the relief valve will reseat itself so the tank should be good to go for a refill. Another place said they would exchange my tank for another but would charge $18 for a relief valve replacement. Anyone have knowledge about this stuff?

Thanks!


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## HoustonFishFanatic (Feb 26, 2007)

Probably what happened is the CO2 in the tank expanded due to rise in the surrounding temperature. This increased volume of the CO2 would have caused it to relieve. The relief valves on the tank can be either 
1.Re-seating type ( means it will stop relieving the CO2 once the pressure in the valve goes Below the set pressure)
If you still have CO2 in tank then that valve is the re-seating type. No need to worry about it. It just prevented your tank from exploding.

2. Pop action. This means the valve pops open once the set pressure is reached and does not re-seat until it drains all the CO2 out of the tank.

If u still have CO2 in the tank don't worry about the tank. You can just refill it when it empties.


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## SpaceBug (Jan 10, 2007)

No CO2 left in tank. The one guy said that sometimes when they pop they will freeze up and release all the gas. But after a lot of reading on the internet I do not believe my tank has a re-seatable relief valve. A quick check with a wrench tonight should tell me. Thanks.


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## HoustonFishFanatic (Feb 26, 2007)

You will have to replace that valve or get it reseated. Or just swap the tank for another one.


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## SpaceBug (Jan 10, 2007)

Finally got around to pulling the relief valve off. It is definitely a unit containing a copper burst disk. Anybody know where to get a replacement? I googled but the hits all seem to pertain to paintball tanks. Called local shops but they either don't know what I'm talking about or don't have the part.


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## HoustonFishFanatic (Feb 26, 2007)

Dude i am not sure weather you or any one not aware of the valves construction should try to replace that. Its a safety issue and the relief valve is a very crucial component. better let the professionals handle it.


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## Muirner (Jan 9, 2007)

I'm with Huston here. If you were an expert in the field ok, do it up. But dont risk screwing something up and having a pressurized tank blow up on you. It's 18$ for the pros to do it, you mind as well. 

I'm only saying this because i had a friend with a 20oz paintball tank the burst disk broke because the tank got to hot, and it shot the full tank across his room. Needless to say after it went through the wall it was ok.


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## requenym (Jul 23, 2007)

I've replaced the burst disks on paintball valves all the time, the kids that work at the shops around here love to overfill and once the tank heats up on the drive home the disk bursts--the tank does not go flying across the room, if anything it simply rolls around and sprays co2. They sell the disks sometimes at walmart, it's hit or miss though because people need them so often. Of course this only applies if you have a paintball co2 tank. Larger co2 tanks over 48oz have the resealing relief valves like 90% of the time though, so I assume your using a paintball tank. If you goto a paintball shop with the tank they will usually replace it for you for a couple of bucks. A pack of disks at walmart is like 5 and change I think.


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## Jonesy (Jul 8, 2005)

SpaceBug said:


> Finally got around to pulling the relief valve off. It is definitely a unit containing a copper burst disk. Anybody know where to get a replacement? I googled but the hits all seem to pertain to paintball tanks. Called local shops but they either don't know what I'm talking about or don't have the part.


If the local shops don't have it they should at least be able to order it. I'm assuming you have a tank with a CGA320 valve? The disk needs to be replaced with the correct pressure rated disk (they come in different burst ratings for different gases). If the local shops are no help you might give the local industrial suppliers a try - Airgas, Air Liquide, Matheson Tri-Gas (you're in Round Rock, TX right? - there's an airgas store doing industrial welder repair, equipment rental etc on N.Lamar Blvd) - their local numbers should be in the phone book or on their web pages. These are national suppliers of tanks and gas and they might be able to help with the disk or finding someone who will help.

Good luck -


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## SpaceBug (Jan 10, 2007)

For those of you not comfortable with replacing one of these burst disk units, then by all means don't. But the only real safety concern is that you don't try to remove the thing when there is CO2 in the tank! Beyond that, it consists of unscrewing the old one followed by screwing in the new one. I don't need to pay a professional to do that.

For the most part, the local welding supply shops did not know much about replacement burst disks. They just wanted to exchange my tank for another. Which if I had to do, I would, but I'm not exactly excited about trading in my brand new shiny aluminum tank for a beat up one.

I took the unit into the local Airgas (the one on Lamar Jonesy  ) where I previously had the tank filled. They searched catalogs of parts, made phone calls, and came up empty handed. But in the end they pulled one off of another tank and swapped it for mine. No charge! I now have the new one installed and ready to fill the tank again.


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