Small hole in Thermo Valve DIN

[Mitchell]

We were doing a bubble check the other day and noticed a small stream of bubbles coming from the tiny hole next to the threads. So we shut the valve, purged reg, then resrewed DIN back in. Still has leak. The Oring seem to be in perfect condition. Please help me figure this out. Is it supposed to leak or not? What is the fix?

Thanks

 

[Captain CaveMan]

install a new o-ring on to the reg and retry. There might be a small cut on the o-ring that you can not see.
The small hole on the valve is made for a Din plugs. The plug is used to safely keep fills from actidently excaping when storing the tank were the valve might be opened. The pug than is sealed in by 2642-3442psi. When you unscrew the plug the hole is made to slowly leak down the pressure at the same time of releasing the pressure away from you.

 

[spectrum]

It sounds like you are diving a DIN regulator. (Not a yoke with the DIN plug) What has probably happened is that your DIN connector has spun out. There is the regulator side and then the core that includes the valve connection O-ring. These screw together to capture the hand wheel / DIN threads. There are 3 machined pieces in all. An internal O-ring seals the two. If the regulator is twisted while connected or while being tightened the torque can go to the assembly and break it free internally. The resulting leak is on the exposed side of the valve and vents into the thread area where the vent hole you mentioned is located.

The repair probably involves tightening the connector core which may have a hex socket. It is soft brass so be careful. In many cases a dab of Locktite is part of the procedure.

Pete

 

[SparticleBrane]

install a new o-ring on to the reg and retry. There might be a small cut on the o-ring that you can not see.
The small hole on the valve is made for a Din plugs. The plug is used to safely keep fills from actidently excaping when storing the tank were the valve might be opened. The pug than is sealed in by 2642-3442psi. When you unscrew the plug the hole is made to slowly leak down the pressure at the same time of releasing the pressure away from you.

I would bet that this is incorrect, namely since these holes in valves have been around much longer than DIN plugs. I have several valves that do not have these holes, and the air escapes just fine while you release the pressure from an energized DIN plug. In fact, I prefer the ones without the holes, because the o-ring doesn't extrude anywhere when you unscrew the DIN plug...

 

[Mitchell]

What part of the Reg am I supposed to tighten? I tried to tighten the piece that has the oring and hex screw. didn't seem to move so I loosend then retightend. Wish I had the names of the parts handy so I don't sound to stupid..

Thanks

 

[Under Pressure]

Assuming that this is a 300 Bar DIN valve, most of the others are correct that this is probably an o-ring issue. The small hole is designed for air to escape in case the regulator to valve seal has not engaged properly. The first thing to check in all cases with this type of leak is to insure that you have both a good o-ring and the correct o-ring in your DIN connection. You should also check the sealing surface inside the valve outlet (the flat part at the bottom of the outlet). If something has scratched that significantly then the connection will leak as well. And finally, insure that you have a 300 Bar DIN connection on your regulator and not a 230 Bar DIN connection. While the 230 Bar DIN connection is very unusual in North America, it is the most prevalent connection in Europe. If you put a 230 Bar DIN connection into a 300 Bar DIN valve the connection will like like a sieve.

Hope this helps.