Old OMS manifold still considered "safe"

[rjack321]

I'm not so sure of the parts availability as others...

Notice the link that rjack included (for valve seats): they clearly state 'not for Genesis valves'. Your valves are clearly not actual-Genesis valves: they don't have the slanted ports. BUT: OMS didn't design those valves, and I've personally only seen one *manufacturer* of manifolds that used the face-sealed configuration: Sherwood/Genesis.

Or, replace the entire set (after something breaks) with a modern-style manifold. Such things do exist in 7/8" both new and used, and (should) use the same parts as a 3/4" valve/manifold from the same manufacturer. And this would allow you to use modern (thick, wide and fully welded) tank bands, too.

I didn't post an ebay link. Personally I despise ebay lol

I got a few OMS rebuild kits and burst disks for my OMS (branded) valves from NESS.
The rebuild kits aren't too bad at this time - a few years ago before DUI bought out OMS they were actually almost 75% more. Its rare to see a price drop!
OMS/Blue Steel Valve Parts

Good luck finding a new 7/8" manifold. Xscuba is making new valves in these threads but not new manifolds. If I were the OP, I would buy a rebuild kit or two and some spare burst disks and keep using the valves you have.

 

[tbone1004]

To be more specific: these manifolds are fixed at 207mm (8 1/8”) spacing between the valves. Current manifolds have 215mm (8.5”) spacing to allow for 8” tanks. If you have 7.25” tanks and all the parts why should you care?

The biggest issue is the bands. I’ve only seen crappy bands in 207mm. They work if you’re careful, but they’re not rugged. But I’ve got two sets of them, and absolutely no hesitation to dive them.

not all of those manifolds are narrow. I have some manifolds for 8" bottles, obviously not skinny neck valves, but the crossbar is interchangeable between the two. I have two sets of HP120's with those skinny neck manifolds and they're on standard highland 3" bands. I do have an old Sherwood slant back manifold that is of similar design for narrow LP72 doubles that do require special bands.

 

[tmassey]

This never seems to go well...

I didn't post an ebay link. Personally I despise ebay lol

Sorry: @happy-diver . Same point either way. The listed seats won't work on a Genesis valve. Is this a Genesis valve?

I got a few OMS rebuild kits and burst disks for my OMS (branded) [Blue-Steel-built] valves from NESS.

The question is: are the OP's valves Blue Steel valves? I'm certain that there were OMS valves in 3/4" that were made by Blue Steel. But what I *do* question is whether Blue Steel made face-sealed modular valves (for 7/8" or otherwise). And if they did, what valve seat did they use?

I'm not saying "I question" as a substitute for "I doubt". I truly have no idea. But if I'm the OP I'd be cautious about accepting at face-value (ha!) someone saying something about the availability of 'OMS valve parts' without a thorough understanding of exactly what he has, and what that other person is talking about.

Especially because 80% of divers have no more than vague and hazy awareness of 7/8" valves and 95% or more of divers have zero awareness of 207mm tank spacing or face-sealed manifolds or 6300-series valve seats.

Good luck finding a new 7/8" manifold. Xscuba is making new valves in these threads but not new manifolds. If I were the OP, I would buy a rebuild kit or two and some spare burst disks and keep using the valves you have.

XS Scuba Thermo DIN Manifold 7/8-UNF 3500psi

It says "Available to order." I wouldn't assume that meant that they actually exist in this universe until I had them in my hands, but it's a start...

And I would do the same thing as you're suggesting: have some spare parts around and dive them. It's what I *do* with my Genesis 7/8" manifolds. The question is, what parts does the OP need to actually have spares? It *might* simply be the same Blue Steel parts as a modern 3/4" valve. But there's a good chance that it's not that easy.

not all of those manifolds are narrow. I have some manifolds for 8" bottles, obviously not skinny neck valves, but the crossbar is interchangeable between the two.

If by "all those manifolds" you mean face-sealed manifolds, I disagree. If you simply meant 7/8" manifolds, I agree, but that's not what we're talking about!

I assume you were talking about modern manifolds, which is why you brought in the 8" tanks. If the crossbar is interchangeable, then those are *NOT* face-sealed valves. Those are modern modular valves and manifolds. You are 100% correct that there are modern modular valves in 7/8" thread that can accommodate 7.25" and 8" tanks *and* use standard isolators and bands. I too have a set of those. Mine are Dive Rite labelled, made by Thermo. 7/8" thread, 215mm spacing, decent DGX bands!

But that is *NOT* what the OP has. He has face-sealed valves and therefore a completely different isolator.

If you have something different, I would *LOVE* to see photos. I'm in no way saying that such a thing does not exist (that is, a face-sealed manifold with 215mm spacing), but I've never seen or even heard of such a thing, including in catalog lists or in service manuals. I'm always happy to be educated, however!

I have two sets of HP120's with those skinny neck manifolds and they're on standard highland 3" bands. I do have an old Sherwood slant back manifold that is of similar design for narrow LP72 doubles that do require special bands.

That 'old Sherwood slant-back manifold' is the face-sealed design, which requires bands designed for their 207mm spacing. Those are a very well known and understood item. (And we just discussed the valves that use modern isolators.) And I just looked it up: the Sherwood/Genesis manifolds uses the same (odd) valve seat as the 6300 slant back single-tank valves, which is what I always assumed. It is, after all, a 6300-series manifold. (The service manifold says that there *are* 6300-series single- and face-sealed manifold valves in 3/4". I've never seen one in real life, and I'd simply swap it if I did! )

The problem is, the OP has something that is kinda between those two. He has a set of OMS-labelled valves that are FACE SEALED, and therefore will not use the same isolator that would be used with a modern manifold. That means that the tank spacing for that manifold is fixed to whatever it is right now.

Question 1: Is the spacing 207mm or 215mm? If it's 215mm, it can use standard bands. If it's 207mm, it needs bands designed for 207mm, and the only ones I've ever seen in real life are the thin, spot-welded ones. (Probably doesn't matter to him: he says he has the valves and bands that work together.)

Question 2: EITHER WAY, what valve seat (and other internals) does his valves use? I think we all agree that OMS never built a valve in their history -- they relabelled someone else's. So, who made *this* decidedly-unusual (face-sealed, dual-outlet, isolatable, yet not slanted) valve, and which seat does it need?


Without understanding *any* of the complexity involved, people will usually say something like "It's a Blue Steel -- OMS relabelled Blue Steel". Recently, and for 3/4" valves, sure. But those were also modern valves -- not just 3/4" but also with the modern isolator design. The valves we are discussing are not those valves: they're face sealed valves. I wouldn't just *assume* that those were Blue Steel.

Personally, I only know of exactly one company that made face-sealed isolatable manifolds: Sherwood. Did OMS tweak a SHERWOOD design for these? If so, what seat do they use? The 6300-style valve seat?

If there *is* another company that made face-sealed isolatable manifolds, I'd love to know. And then, find out what seat does these valves use!

Confused yet?

 

[rjack321]

And I would do the same thing as you're suggesting: have some spare parts around and dive them. It's what I *do* with my Genesis 7/8" manifolds. The question is, what parts does the OP need to actually have spares? It *might* simply be the same Blue Steel parts as a modern 3/4" valve. But there's a good chance that it's not that easy.

I bought my 4 OMS valves as part for two sets of micro lp45 doubles. I sold the bands and straight crossbars. Then NESS hooked me up with seats, crush washers, burst disks, and the caps to seal off the manifold hole for the OMS valves. They were the OMS/Blue steel parts as linked. I bought a few extras at the time (6yrs ago) because I wasn't sure about future parts availability. Mine are 3/4" valves, but the internals are no different for the 7/8" neck threading. Special ordering a xscuba manifold seems like a waste of money compared to ~$45 in rebuild parts which is enough to get you through quite a few years of use.

And I am not sure they are appropriately called "blue steel built" Blue steel is importing Italian made valves. Similarly, Xscuba valves are made in china (DGX valves are made there too) but rebranded.

 

[SomeGuy509]

Awesome discussion, thanks all.

Here are some pictures to help address a few points. As I said in the original post with only 28 dives I'm a ways from doing serious tech. At most it will be ITT so I can learn about it and start developing good habits.

Here as some better pictures of the manifold. Since I am going to want to rebuild them myself anyway I can start tearing them down to help confirm parts. Would just need some direction on how to do it. Not sure if there are any weird press fits I have to deal with.

Also a picture of the spacing measured on center at the dip tube. 8.5in as I measured it is pretty darn close to 215mm. Within the error range I'd say.

Bands are OMS. Pictures of those attached too. They don't seem particularly flimsy but since it's the only ones I've really handled I don't have much in the way of reference points.

Given that these were under pressure when I received them (for a few years according to the prior owner) how critical would it be to replace the seat? I know only a bit about valving and then it's mainly on the industrial side.

 

[TrimixToo]

I'm not so sure of the parts availability as others...

Notice the link that rjack included (for valve seats): they clearly state 'not for Genesis valves'. Your valves are clearly not actual-Genesis valves: they don't have the slanted ports. BUT: OMS didn't design those valves, and I've personally only seen one *manufacturer* of manifolds that used the face-sealed configuration: Sherwood/Genesis.

Here's my question: while they say OMS on the outside, what type of parts are in the *inside*? Especially the seat. For the most part, everything else is pretty generic, but the seat might be an issue.

Now that I type this, I'm not certain what type of seat a Genesis *manifold* valve uses. I've always *assumed* that it used the same seat as the single-tank 6300 slant-back valve. And it's not impossible to get parts even for those (Northeast Scuba Supply has seats for the 6300-series, for example), just not from your LDS. Can anyone with specific knowledge comment on that? (I've never had to replace a valve seat.)

Your question was safety: there is none, especially without the slant back. (With the slant back: allows water to pool in the valve, and elevates the first stage which can make it stick out more and easier to whack.) If you have all of the parts and they're functional, use them, no problem.

However, for long-term issues: they require matching valves, isolator and tank bands, and the only bands I've ever seen are narrow and thin and spot-welded. If any of them break, you'll need to likely replace them all, or try to cannibalize another set.

Or, replace the entire set (after something breaks) with a modern-style manifold. Such things do exist in 7/8" both new and used, and (should) use the same parts as a 3/4" valve/manifold from the same manufacturer. And this would allow you to use modern (thick, wide and fully welded) tank bands, too.

Everything takes the same parts except for the O-rings (of course) and for older ones, the burst disc assembly. For LP tanks the availability of the burst discs is spotty. John Allen was going to have some made, but I bought a new Blue Steel one at the time and never checked back.

 

[tbone1004]

@tmassey
they're made by Blue Steel, all parts are still available from Lake Jocassee Scuba. I'm not aware of any of those manifolds being 207mm, only the Sherwoods.
Blue Steel made the face seal and the barrel o-ring seals simultaneously. They are not Sherwood design, completely different sealing type.

From the pix, they'll take standard bands, and the parts are hard to find, but possible, just have to ask nicely.

@TrimixToo Lake Jocassee has the burst discs too btw

 

[Akimbo]

Here's a trick for accurately controlling the distance between cylinders and keep them parallel. Add a spacer to the bands like this:

You can shim bands if the want to spread cylinders so they squeeze the spacers instead.

 

[tmassey]

@tmassey
they're made by Blue Steel, all parts are still available from Lake Jocassee Scuba. I'm not aware of any of those manifolds being 207mm, only the Sherwoods.
Blue Steel made the face seal and the barrel o-ring seals simultaneously. They are not Sherwood design, completely different sealing type.

Awesome! A nice clear answer -- and with confirmation! Combined with @SomeGuy509 's photo evidence, I think it's clear that his manifolds are exactly that.

And thank you, I learned something: at least one other company made face-sealed isolatable manifolds, and they did it on 215mm center. (As a person who owns 7/8" tanks and dives backmounted doubles, it's nice to know what the options are. I really dislike the Sherwood bands.)

Thank you all very much for the details.

 

[tmassey]

Here as some better pictures of the manifold. Since I am going to want to rebuild them myself anyway I can start tearing them down to help confirm parts. Would just need some direction on how to do it. Not sure if there are any weird press fits I have to deal with.

Unless you get crazy tearing something apart, there's no real press-fit items, but there are some single-use-only parts to consider:

1) Once a bust disc is disturbed, it often needs to be replaced. My very weak understanding is that in the 3-piece ones the disc *must* be replaced when disassembled, but the 1-piece ones can be removed and replaced. But take that as more of an indication of an area where you will need to do more research. I've never personally replaced a burst disc assembly: I let that take place as part of the valve maintenance and O2 clean I get during a hydro, and @BoneCrusher does that for me. I don't care about them as long as they're not leaking.

2) If your valve bonnet uses a copper crush gasket, that gasket "must" be replaced once it's been used. I say "must" because I didn't know that and simply re-used it in the past without issue. However, in one case, I couldn't get a valve to properly seal without replacing it, and in doing research, I found that they were supposed to be replaced *each* time. (I also found that I could buy them for like $8 for 25 on Amazon instead of $3 each. More details: Thermo Valve copper crush ring .)

I'm pretty weak when it comes to valve internals -- and certainly for brands that I don't own. Honestly, it's an area of maintenance that I consider "if it ain't broke, don't fix it". If a valve's handwheel is stiff and makes valve drills too hard I'll disassemble, clean and thinly lube, but a hydro usually comes along before I need to do that.

Bands are OMS. Pictures of those attached too. They don't seem particularly flimsy but since it's the only ones I've really handled I don't have much in the way of reference points.

They don't seem as wide or as well-assembled as modern bands. These are middle-of-the-road brand new bands: DGX Premium Doubles Bands Set w/Bolts And even those are not as nice as Highland bands. (Though even for 8" tanks, 3" bands seems excessive!) But those bands should be just fine. And your bands are *worlds* better than the tack-welded, paper-thin, 1.5" wide Genesis bands. Which I have to use because the manifold is only 207mm on center... (No, I'm not bitter... )

Given that these were under pressure when I received them (for a few years according to the prior owner) how critical would it be to replace the seat? I know only a bit about valving and then it's mainly on the industrial side.

I honestly would love an answer to that question as well. My current practice goes back to "if it ain't broke don't fix it": Does it leak? Do you need more than gentle force to close it? If the answer is no, then the seat is just fine. It's not like a regulator HP seat that opens zillions of times and is trying to moderate pressure. This is simply on or off. As long as you don't have to try to ape down the knob to seal the seat, I personally think it's fine.

But like I said, I'm no expert and would love to be better educated!