[Overgrowth]

I'm about to get my 5 LB CO2 tank filled up, and I just want to make sure I don't have an accident. Here's a picture of my setup (yes, I do have a CO2 washer in between the regulator and the tank):

Here's the needle valve:

Okay, now I have a few questions:

1. Does the airline tubing just hook onto that little plug on that needle valve?
2. Do I just take the CO2 tank to the store, or do I take everything with me?
3. How do I safely open up the CO2 tank, regulator, and needle valve, letting the CO2 into the tank?

Thanks for answering my questions.

 

[kevmo911]

1. There should be a cap that comes with the needle valve. It compresses the tubing onto the barb.
2. Disconnect the regulator, then take the cylinder in.
3. Make sure the working pressure on the regulator is at zero, attach it to the cylinder, slowly open up the cylinder, make sure everything is attached to the regulator (airline, etc.), and slowly increase working pressure.
3a. Check for leaks.

By the way, because it isn't obvious in the pic, is there some type of sealant/tape/dope on the threads from the regulator to the needle valve? No need where there's a rubber washer, but, for example, from the regulator to that brass reducer?

 

[Overgrowth]

1. There should be a cap that comes with the needle valve. It compresses the tubing onto the barb.
2. Disconnect the regulator, then take the cylinder in.
3. Make sure the working pressure on the regulator is at zero, attach it to the cylinder, slowly open up the cylinder, make sure everything is attached to the regulator (airline, etc.), and slowly increase working pressure.
3a. Check for leaks.

By the way, because it isn't obvious in the pic, is there some type of sealant/tape/dope on the threads from the regulator to the needle valve? No need where there's a rubber washer, but, for example, from the regulator to that brass reducer?

Okay, thanks for your help. No, there's no sealant between the regulator and the brass reducer. Are you saying that since there's a washer between the tank and the regulator, I don't need it?

 

[kevmo911]

Okay, thanks for your help. No, there's no sealant between the regulator and the brass reducer. Are you saying that since there's a washer between the tank and the regulator, I don't need it?

Correct. Don't use any type of sealant between cylinder and regulator. Just the nylon washer or permaseal.

NPT threads are tapered. Tapered threads use sealant to create a leak-tight seal. Always use tape, dope, or some other sealant.

CGA threads are parallel. Parallel threads use a washer to create a leak-tight seal. Never use tape, dope, or other sealant.

You *will* have leaks if you don't use sealant on tapered threads. Teflon tape is most popular, and very cheap. Pipe dope works, but do not use it on high-pressure connections (for example, where the CGA nipple screws into the regulator body, or at the connection to the high pressure gauge), as it may literally get blown out of the threads.

 

[Overgrowth]

Okay, cool. Thanks.

 

[Overgrowth]

Okay, I have a problem. I got everything set up, but when I turned the valve on the CO2 tank, there was loud noise, like gas was escaping the tank. I have no idea what to do now. Here's a picture:

 

[kevmo911]

Your high pressure valve is reading 3000 psi. That's a problem. I'd remove the regulator quickly, and stick the cylinder in the garage or basement - somewhere that, if it vents, it won't damage anything. And open a window. Seriously, now. I'll expand in the next post.

 

[Overgrowth]

Okay, I set the tank outside. I tried closing the valve, but it won't close. Do i just turn with more force?

 

[kevmo911]

Okay, a CO2 cylinder is designed to hold 800 pounds per square inch of pressure. Your high pressure gauge is showing about 3 1/2 times that amount of pressure. There could be a couple reasons for this.

One, your CO2 cylinder is grossly overfilled. This will result in the relief valve blowing at some point, probably soon, as the cylinder warms up after the refill (you probably noticed it's ice cold). As the temperature rises, the pressure increases.

Two, your CO2 cylinder is fine, and your high pressure gauge is busted. This happens, and you can actually go without one.

I'd recommend you keep the cylinder somewhere else for a few hours, and keep a window open wherever it is. If the pressure really is 3000 psi, and it's still ice cold, it will definitely vent.

I don't know exactly what the "hissing" sound was. You'll have to be a little more clear about where exactly it was coming from.

 

[kevmo911]

Sorry, didn't mean to be alarmist. But it's better to not have a venting cylinder in living quarters, and certainly not in a place where it might be pointed at sensitive stuff "like skin".

It's not going to explode, no worries there. But it may make a really loud hiss for a bit.

By the way, is your high pressure gauge back to zero now?

 

[Overgrowth]

I don't know exactly where the hissing came from, but I definitely heard it somewhere around the tank and the regulator.

 

[Overgrowth]

Sorry, didn't mean to be alarmist. But it's better to not have a venting cylinder in living quarters, and certainly not in a place where it might be pointed at sensitive stuff "like skin".

It's not going to explode, no worries there. But it may make a really loud hiss for a bit.

By the way, is your high pressure gauge back to zero now?

Oh, haha. My mom was worried for a minute there. Yeah, it's outside, and it's really cold too; it almost snowed a few minutes ago when it was raining. How do I remove the regulator?

 

[Overgrowth]

How exactly should I remove the regulator from the tank?

 

[kevmo911]

It should be safe to go out to it. Just don't stand in front of the nozzle or the little nut on the side of the nozzle - that's the relief valve. You can try to make sure it's turned off.

Can you walk through exactly the steps you took? I assume the cylinder was closed when you attached the regulator, and then when you opened the cylinder you heard something hissing. Well, my guess is it wasn't the cylinder that was hissing, it was the relief valve on the regulator. It's designed as a CO2 regulator, which means that the relief valve on the reg (not the one on the cylinder) has a much lower cracking pressure than 3000 psi, even though the gauge shows up to 3000 psi.

So, a couple questions - one, did you remove the regulator, and if you did, does the high pressure side now show zero?

Two, did you just get the cylinder refilled, within the last hour or so? if so, the CO2 and cylinder will still be warming up, and pressure will be increasing. I would definitely leave it outside for a while in this case.

If the high pressure gauge on your regulator is back to zero, then the gauge is *probably* working correctly, and the pressure in the cylinder is way too high, meaning the cylinder was overfilled. It's not safe to use until it's at a lower level. Unfortunately, I think your best option *in this case* is to wait for it to warm up and see if it vents, and then, if it doesn't, go outside and manually open the cylinder valve and allow the CO2 to escape. Then take the cylinder back to the refill place, give them hell for putting your safety at risk, and demand a free refill. Or a refund, and take it somewhere else to fill.

 

[kevmo911]

Okay, with the regulator still attached to the cylinder, I'd go check on the pressure first. If it's still way up around 3000 psi, just wait. If it's dropped a bunch, make sure the cylinder is turned off, then remove the regulator.

You can also call the refill place and see what they recommend.

 

[Overgrowth]

1. I still haven't removed the regulator. It still shows close to 3000 psi.
2. I got it filled within the last hour. However, it's cold outside; it's 37 degrees, so would that help?

 

[Overgrowth]

Okay, I think the best thing to do would be to release the CO2. I think the regulator is broken since the pressure hasn't dropped. How should I go about this?

 

[kevmo911]

When did it stop hissing? Did you turn the cylinder off right after it started?

Assuming it's no longer hissing, just to be on the safe side, I'd give it another couple hours to make sure that the cylinder is at ambient temperature.

After that, I'd go make sure the cylinder valve was closed and remove the regulator. Then I would very slowly open up the valve, making sure it's pointed away from you, and let it all gas out. Then I'd see about getting it refilled again. If you go to the same place, I'd bring the regulator and attach it after the refill to check pressure.

And to anybody else reading this, please chime in if you have any advice.

 

[kevmo911]

Okay, I just looked back through the thread. In the first picture, the hp gauge is reading the same as the post-refill picture. That tells me that the high pressure gauge is busted.

I'm still not sure what's going on with the hissing. But, yes, it's probably safe to remove the regulator. If you want to wait on venting the cylinder, I'd bring it to a homebrew/hydroponics place, or a good LFS, and have them test the cylinder pressure with one of their gauges. And, in the meantime, I'd order a new high pressure gauge (probably less than $20 shipped), or see if a local shop will sell one.

 

[Overgrowth]

Actually, there wasn't any hissing except for the time when I tried to open the valve. I also thought that the HP gauge was broken, because it's been several hours, and it hasn't moved.