Are all HP tank to valve o-rings the same 7/8?

[BlueDolphin]

I have a steel 80HP and my LDS has said that they don't know what O-ring to use on it. Aren't all HP tank o-rings the same?
This is a genesis tank valve by the way. Not sure if this is a special o-ring or not..... but sounded really screwy to me.

What do you think?

 

[MikeS]

I think that all HP tanks use a DIN connector on the tank valve. On a DIN connection the O-ring does not go on tank side of the connection it goes on the first stage regulator side of the connection (the o-ring does not stay with the tank it stays with the reg).

Mike

 

[Mverick]

I think he was talking about the o ring between the tank and the tank valve.

My HP's are fabers and they are 3/4 just like a standard AL 80. Some other HP's are 7/8.

But I don't know what size o ring. I just used one that fits without looking...

 

[BlueDolphin]

Yea...

these are 7/8. HP. This o-ring is the one between the tank and the tank valve. Trying to see if anyone knows if these come in different flavors..... or all 7/8 tank o-rings are the same?

 

[pescador775]

Yes, all O rings which fit HP tanks with 7/8-14 neck are the same regardless of tank capacity. This includes PST, Asahi (Genesis) and Sherwood (Genesis). These O rings are different from those in aluminum tanks both in size and the way they form a seal. They are not compression fit but dynamic fit, similar to the main O ring in a piston regulator. The O rings are standard SAE size and commonly available in nitrile and viton. Your dive shop guy is probably confused about the way the O rings fits down into the neck of the tank without squeezing it. As I said, this is normal.

Edit: I checked the O ring size. The HP ring dimensions are .737 X .103. The ring appears to be made out of a hard rubber nitrile compound. The viton style is a bit softer. Note that .737 is the ID.

 

[BlueDolphin]

If you can believe this... the shop STILL does not have my tank vis'd and filled. It has been almost a month. Still waiting for an o-ring to come in....? Large chain sporting goods store here in S. Cali..

I thought the o-rings were all the same on HP steel tanks.... but I guess we'll see what they come up with.

 

[pescador775]

Why not pick up a ring at a dive shop? Unfortunately, sports outfits like Sports Chalet have frequent personel turnover which may mean noone is watching the store (so to speak). A hardware store or plumbing shop could probably match up the ring if you take them the dimensions that I cited. They may not have O2 compatible viton, however.