My tank is leaking... as I type this

[S0ckm0nk3y]

All,

I purchased a couple used HP100's last week. I haven't had a chance to use them yet.

Last night I set up my rig on one tank and put it in the closet ready to go. The din regulator was screwed into the thermo valve but the valve was turned left on. I did check the pressure and it was 3500 psi even.

I came home earlier in the afternoon and it was fine. However I just walked in (from getting the other tank filled ironically) and I heard a hissing noise from the closet!

There is a tiny tongue of purple plastic sticking out between the valve and the tank and a steady stream of air is slowly hissing out where the tongue is.

Does anyone know what happened?

I emailed the guy I bought them from and hopefully he can be honest if this tank has some sort of history... its a fairly new worthington.

I'll bring it to a LDS for service in a few days but I'm annoyed enough now to want to know what happened. Maybe the hissing noise has me stressed out

I've attached a few photos of the hard purple plastic goop.

Any insight would be appreciated.

Thanks in advance,

-Eric

 

[do it easy]

That is the tank o-ring extruding from underneath the valve. It does happen, although it is fairly rare. The valve might have been a bit loose when it was assembled, which would leave a slightly larger gap for the o-ring to escape.

You'll probably have to wait until the tank is empty and then replace the o-ring. Some LDSs might want to perform a VIP if you bring in an empty tank.

Where the tanks shipped empty to you or did you buy them with gas inside?

 

[california]

Since the tank was purchased used, I would advise have the LDS take a look.

 

[DA Aquamaster]

The purple goop is your neck o-ring.

The purple ones are known to fail that way from time to time on the rare tank. They work ok on Aluminum tanks as the pressure is a bit lower and it is captured better given how the neck is machined with a square shoulder. On a steel tank where the neck is more cone shaped with no sharp shoulder, extrusion is more likely and the purple o-rings are not really up to the task 100% of the time. Its possible the valve was slightly loose as well.

The good news is that the solution is fairly simple - drain the tank, replace the o-ring, get the tank refilled.

It is probably obvious but do NOT dive the tank in that condition - the small leak can rapidly turn into a large leak and nothing will dump the contents of a tank faster than a failed neck o-ring.

 

[S0ckm0nk3y]

Where the tanks shipped empty to you or did you buy them with gas inside?

do it easy,

When I bought them (craigslist) they had gas inside. This one was full in fact... and the other I just had filled today.

It is still dumping gas... I've been home for 30 mins or so.

Thanks for the quick reply,

-Eric

 

[S0ckm0nk3y]

Thanks everyone

It is indeed obvious to not dive with a leaking tank. Even if it wasn't obvious to me, by the time i got from here to the water it would be empty.

Ok I feel better now. I'll head back to the LDS and have them re-do the o-ring.

Thanks again.

-Eric

The purple goop is your neck o-ring.

The purple ones are known to fail that way from time to time. They work ok on Aluminum tanks as the pressure is a bit lower and it is captured better given how the neck is machined with a square shoulder. On a steel tank where the neck is more cone shaped with no sharp shoulder, extrusion is more likely and the purple o-rings are not really up to the task 100% of the time.

The good news is that the solution is fairly simple - drain the tank, replace the o-ring, get the tank refilled.

It is probably obvious but do NOT dive the tank in that condition - the small leak can rapidly turn into a large leak and nothing will dump the contents of a tank faster than a failed neck o-ring.

 

[Nemrod]

This is not unusual. Most likely the valve was not screwed in all the way. When the pressure is fully relieved--0 PSI---remove the valve, I bet it is hand tight. Replace the O ring and remove any silicone grease. Hand tighten the valve and then go about another 1/3 turn, maybe a bit more. You do not need to smoke it on there. Your problem should be fixed. N

 

[SparticleBrane]

To the best of my understanding...

The purple O-rings you see were the original EPDM O-rings used by Worthington when they first started manufacturing cylinders. They have since stopped using them due to this very issue. Replace your current O-ring with a 90-durometer O-ring, don't use any lube on it, put the valve on like Nemrod suggested, and you'll be good to go.

I can't remember but I think these EPDM O-rings are 70-durometer -- a bit soft for this particular application, making the occasional extrusion a bit more common.

 

[Under Pressure]

The EPDM o-rings were 90 shore but they haven't been used as original equipment on Thermo valves for over two years. Viton is now the material of choice as it is stronger than EPDM. Going to a buna-n 90 shore o-ring (for breathing air) or viton o-ring (for nitrox) will probably fix the problem.

 

[Couv]

If you are going to do this yourself, in order to get around the LDS VIP Nazis go to a hydraulic shop and get at least two (because you should do both tanks) Viton duro 90 orings (most likely size is -214) While you are at the hydraulic shop, get a fitting that will allow you to make an equalizing whip from two spg hoses. See this thread:

http://www.scubaboard.com/forums/do-yourself-diy/228353-cheap-equalization-hose.html

Others have advised you well on removing any lubricant and proper torque to prevent this from happening again.

couv