Tank Leak Question

[Dermochelys]

Ok, I'm still new to diving, so I'm sorry if this is a simple question....

I was diving with a rented tank this past weekend. The first day the tank was fine and I had it refilled later in the day at the local dive shop (not the shop I rented from). Anyway, I was setting up the tank for my dive on Day 2, and there was a MAJOR leak when I turned on the air with my regulator attached. So this is what I tried...

1) Thinking something must be wrong with the O-ring, I inspected it and it looked fine. Tried again, and the leak was still there.

2) Replaced the o-ring with kit I happened to buy for this trip. The leak was still there.

3) Put my reg. on another tank...no leak...so figured the issue was with the tank.

4) My buddy put his regulator on my tank, and the leak was WAY worse, so again, it's the tank valve.

5) Called over another dive team to see if they could anything, they agreed the o-ring and valve looked fine and clean but they happened to have some grease. So I greased the ring as a last resort. Well, after doing that I opened the tank and there was the leak for about 1 second, and then a loud "POP" noise. The seal then held and I had no issues on my dive.

So my question is, what would have caused this condition? Was the O-ring not seated right? What should I look for in the future to make sure it is seated correctly? Again, it worked fine the first day and was filled fine at the dive shop. My only thought is maybe they did something while filling the tank that did something to the ring or valve. Looking at the ring now, it looks the same as it did the first day, so I'm not exactly sure what changed to make it work.

Any tips / advice would be great, again, sorry for such a newbie question.

 

[Scared Silly]

Rental cylinders get lots of use and abuse. As you found sometimes it takes a couple of tries to get an o-ring to seal. With our regs we have found that sometimes no mater what we do the reg will not seal yet another reg seals just fine.

That said sometimes just using a bit of lubricant will help. Do not be afraid to use some O2 Compatible spit for lube.

 

[guruboy]

Did you take the oring out to grease it?

 

[Dermochelys]

Did you take the oring out to grease it?

Yes, with a new ring. The old one looked fine and worked fine the day before, but to be safe I replaced it with a new one. Still had the bad leak, like the regulator wasn't on tight enough, but it was (we tried about 10 times) making sure. Only once we greased the new ring and put it in there was a leak for a second, then the "pop" noise, and all was well.

 

[guruboy]

Just guessing randomly, but maybe the groove is dirty/damaged and the oring was getting stuck somehow.

 

[Caveeagle]

Did you see where the bubbles were coming from? Bubble check etc?

There is a copper washer and at least one o-ring inside the valve, behind the handle. You might have had a leak from there that would blow bubbles from behind the knob. It could also reseal/seat after being worked around a bit. **I would not have dove that tank without determining the source of the leak.

 

[Dermochelys]

We could feel the leak coming from the bottom between the regulator and the tank opening, basically the 6:00 position if you're looking directly at the tank opening o-ring, so we knew it was in the O-ring area, not coming from the handle for sure.

 

[Bob DBF]

Had a similar problem with an older MP ScubaPro Faber tank. It uses a different size o-ring than the "standard" o-ring, and if you get the wrong one in that exact problem happens. Including the pop.

Drove me nuts for a while because it can be intermittent on a one reg, ok on another, and always bad on a third, possibly on how well the metal seat on the reg seats on the metal seat on the valve. Had one reg that only seated when mated upside down. The grease will work for a while, but eventually it will fail.


Bob

 

[Dermochelys]

Had a similar problem with an older MP ScubaPro Faber tank. It uses a different size o-ring than the "standard" o-ring, and if you get the wrong one in that exact problem happens. Including the pop.

Drove me nuts for a while because it can be intermittent on a one reg, ok on another, and always bad on a third, possibly on how well the metal seat on the reg seats on the metal seat on the valve. Had one reg that only seated when mated upside down. The grease will work for a while, but eventually it will fail.


Bob

Good to know! Luckily it was a rental and when I returned it to the shop today I told them about the issue and that they should double check that tank so that it hopefully doesn't happen to someone else. Glad to know that I tried the only remedies that seemed available to me at the time and that one worked and I was still able to dive!

 

[Bob DBF]

Glad to know that I tried the only remedies that seemed available to me at the time and that one worked and I was still able to dive!

As long as you understood that the problem could have reoccurred while you were diving.

I now carry both types of o-rings in my save-a-dive kit. Separated because they look the same visually.


Bob