Advice needed about a rental tank leak.

[DivemasterDennis]

I learned the hard way to check all rental tanks when we go diving locally. It's 40 miles from the dive shop to where we dive, and last fall we got a tank with a faulty tank valve . It bled more than a trickle, it bled alot, but we used the opportunity for an experiment, as we in calm, controlled conditions and not too deep. My buddy Charlie dove the leaky valve tank, and I dove the good one (I am the divemaster, after all). We stayed at 40 feet or shallower, and the tank lasted about 30 minutes. ( Normal for Cgharile at tthose depths would have been well over an hour. We learned that when Charlie's computer said zero air he still had 12 breaths at 30 feet. We learned that Charlie could breathe off my alternate air source but when I made a left turn he got quite a pull on the regulator. So now we hook up a regulator to each tank we rent and listen closeley for leaks before we load the tank. Live and learn.
DivemasterDennis

 

[DevonDiver]

Between the tank and the valve folks. How are all the "carry spare o-rings" people planning to put the air back in the tank after they empty the tank to unscrew the valve and replace the o-ring?

+1

I think some people contributing to this thread either haven't properly read the OPs question and/or seem to be assuming that other contributors are talking about the o-ring that fits into the regulator valve.

We are talking about the cylinder o-ring.... the one that fits between the cylinder and the valve. Not the one that fits between the valve and the regulator. Doh!

i.e. THIS ONE...

Not this one....

 

[James R]

0-24 dives...I think you made the right call. Swap the tank out.

All: why, as he's (or she?) is a new diver, would you advise the OP to dive it anyway? I think that's a bad call, as there's enough to think about and worry about without adding something like a leaking tank o-ring to the dive. Task loading happens fast for newer divers.

 

[spectrum]

The cylinder o-ring isn't a common leak point so I don't think anyone has enough experience to blow it off. Off the top of my head it could be:
1) Damaged o-ring
2) Loose valve. Due to thread loading from the internal pressure this would only become arrent at redused pressure.
3) Damaged cylinder seal surface or crack.

Logistics may make this a little less than black and white. I would only dive this in the most benign situations.

Pete

 

[Codiak]

Any one can call a dive at any time....

If a leak bothers you, then calling the dive is the right call.

In this case: taking the tank back to the shop, tell them the problem and getting a new tank is a reasonable course of action.