Vintage Double Hose

Any experts on the Snark II? I have a friend whose, 1st stage has what looks like some sort of bleeder valve (mounted on the 1st stage itself, as if it were a LP port). It is leaking air from this part. Are replacements available?

Thanks,

George

Hi, "US diver" it appears you refer to the pressure relief valve which is easy to replace have spares here in the uk. Will try to upload diagram with this posting, however, if you have problems email me on "[email protected]" with a mailing address regards regulator bj.ps have tried to up load but ext. png has any how not been allowed.

Snark III repair manual is already in the download section....I think they are the same 1st stages.

Nemrod Snark III Silver repair manual

Not the best image. Comes from Basic Scuba by Roberts.


The second stage is an upstream (tilt valve) thus the overpressure valve is on the first stage. The valves are available at most good dive stores or they can be ordered.

Like the others have said, that is a relief valve. It's purpose was to relieve pressure from a leaking first stage. Unlike most modern second stages that second stage is a upstream valve and will not open if IP gets too high resulting in an exploding hose. Before going any farther you need to check the IP, the thing might actually be doing it's job. It's been a long time since I took one apart but seems like there was an Oring in the hole that you can replace. If (and I think it is) the threads are 3/8-24 - standard hose- you can use the modern ones like this one: http://www.piranhadivemfg.com/item/OPV-16 or if you simply add a downstream second stage you can just plug the hole. DO NOT plug it if you don't use a down stream second stage.

I though I had a shot of that thing, here it is. Turns out that is not an oring as I remembered.

Wow, Thanks for all of the replies. Herman your photo is spot on. I will check the IP tomorrow (I assume it should be about 115 - 130 psi. The Snark III repair manual said that the relief valve should open at 150 psi, and that IP should be set at 125) and after adjusting it see if the relief valve is doing it's job or needs to be replaced.

George

I have not measured it but looking at the photos of my dissambled reg, I think you may can use a DA seat if your HP seat is the problem.

The IP on the Snark III Silver is supposed to be at 145 PSI. I got that from Annectens (SP) aka Enrique Dauner on this board. My Snark III works great, but of course it is a double hose after all.

He has the single hose version Jim. On all of the tilt valves I have seen, the IP tends to run in the low 100s. As bad as the second stage is on them, it doubt it makes much difference.

Hi, have looked up the IP for the Snark 11 and it should be set at 110psi thats according to Fred Roberts "Basic Scuba" if using an upstream second stage regards regulatorbj.

Herman wrote:He has the single hose version Jim.

Oooops. Disregard my posts. Sorry about that

Bryan wrote:

Herman wrote:He has the single hose version Jim.

Oooops. Disregard my posts. Sorry about that

The double hose info is still usefull, looking at the III manual and compairing it to the photos I took of the single hose II I have, the HP stage and relief valve are the same so any service info on one will be valid on the other.

Well I finally got together with my friend to go over his Snark II. The overpressure bleeder valve is missing its cap, (see Herman's exploded photo of the pieces) so I guess the first place to search would be for that part. Anyone have an idea where Nemrod parts can be found?

I checked mine last night and have a little more info. The outer screw is a locking screw/protective cover. It's not needed for the OP valve to function. I now remember why I did not fully dissamble the op valve, the internal adjustment screw on mine is staked in and will not move- not worth damaging it for a photo since it works. The threads appear to be 24 pitch but the bore is slightly larger than a standard 3/8-24 so I suspect it's metric. The good news is a 3/8-24 will screw in but the bad news is the hole is too shallow for most plugs to go into and the face of the hole is not bored to accept an oring. SOOO, you either have to fix the one you have, disable it (rubber gasket in place of the current gasket????) or have the hole bored to accept an oring. If you intend to use the second stage, the disabling option is a bad idea, exploding hoses are not fun. How to fix what you have?? Since the internals of the op valve are just a spring and a plunger, they are almost certainly OK, sticking maybe but a good cleaning would fix that. The most likely problem is the rubber seal which you should be able to reproduce. That leaves the cover. An original is going to be hard to find without buying an entire reg. Making one would not be too difficult but finding a suitable chrome plated brass plug the right size might be difficult. My suggestion is to replace the gasket and see what happens, it you get it to seal, dive it. Lets face it, it's not likely anyone would want to dive this reg in serious conditions, it's a play in the pool or quarry reg.