Poseidon - overpressure

[Paul Desmarais]

The problem is that the Cyklon first stage is set to 166 psi and the Jetstream second stage regulator which has a built in pressure relief in the hose fitting is designed for 124 psi IP. The Cyklon first and second stages are not compatible with the Jetstream second stage. The over pressure relief is being activated by the high IP setting for the Cyklon second stage.

The newest Jetstreams may have removed the over pressure relief (it was in the hose end fitting to the second stage body, you can pull on it to test) because it was incorporated into the first stage. Poseidon has to set the IP specific to their product lines. The Jetstream is a servo assisted upstream regulator thus the need for either a relief in the hose fitting or in the first stage or pair it with a conventional second stage that is downstream design. I run my Jetstream with a Mark V set at 124 psi and a Scubapro R190 to act as the over pressure relief.

The BC, I suspect it does not like the high IP.

James

Thanks for sharing. The guy at the dive shop who did the service mentioned htis, but thought he could adjust so the over pressure would not push through the hoses. I guess not.

Since the issue is systemic; I am trying to fit the proverbial roung eg in the square hole, I guess need to either buy Cyclon second stages so they match the rfirst stage, or buy a jet stream first stage.

 

[Paul Desmarais]

Is it possible to use a HOG D 1x first stage with my Jet Stream seconds? The HOG has an IP of betyween 130-145 according to the specs.

 

[Bigbella]

The problem is that the Cyklon first stage is set to 166 psi and the Jetstream second stage regulator which has a built in pressure relief in the hose fitting is designed for 124 psi IP. The Cyklon first and second stages are not compatible with the Jetstream second stage. The over pressure relief is being activated by the high IP setting for the Cyklon second stage.

Few today seem to recall that the Poseidon Jetstream (with the 2960 first stage, aka Odin) originally specified an IP of 10 bar (about 145 pounds) for years -- with that integral OP on the hose, which typically vented at about 14 bar, just over 200 psi); and it could even play reasonably well with a Cyklon second stage, though the breathing of the latter wasn't really that optimal.

Its predecessor, though, the Thor (or Oceanair), was set, according to the service manuals, to 12.5 bar (about 182 pounds) with the 2940 first stage; so both a Jetstream and a Cyklon second once worked well together on the same first. I used that set-up for quite a while, back in the 1980s; and both regulators were very comfortable to breathe.

It seemed to be only with the advent of the XStream in the early 2000s, that the IP was lowered, across the board, to about 8.5 bar (123 pounds or so) for just about everything but the Cyklon and Triton; though the more recent Cyklon X had it kranked to 10 or 10.5 bar.

The OP has been a bit unclear about his regulator's IP -- couldn't find any info about it, in this thread; and I would venture that it's either tuned way out of specs; or that there may be a problem with the piston or HP seat. A damaged seat, piston or sealing surface will not allow for a stable IP; so too, any grit in the first stage, will throw things off -- even detritus from a dirty air supply. Poseidon regs really require(d) absolute cleanliness -- something of a rarity in many of today's shops (one that I recently visited had its cat mascot walking across its service bench, over a trove of disassembled gear). So common were those problems -- unstable IPs and serial failing seats -- that Harlow mentioned it at some length in his regulator book.

Also, were the seconds leaking at the OP valves on the hoses, if that was the model; or, at the point where they are actually attached?

There's no reason at all why Jetstream seconds could not be used on that regulator, with a proper IP setting . . .

 

[Nemrod]

Is it possible to use a HOG D 1x first stage with my Jet Stream seconds? The HOG has an IP of betyween 130-145 according to the specs.

Yes. The IP can be adjusted downward, 130 would be fine IMO.

 

[Nemrod]

Few seem to recall that the Poseidon Jetstream (with the 2960 first stage) originally specified an IP of 10 bar (about 145 pounds) for years -- with that integral OP in the hose, which typically vented at about 14 bar, just over 200 psi); and it could even play reasonably well with a Cyklon second stage, though the breathing of the latter wasn't really optimal.

Its predecessor, though, the Thor (or Oceanair), was set to 12.5 bar (about 182 pounds) with the 2940 first stage; so both a Jetstream and a Cyklon second once worked well together. I used that set-up for quite a while, back in the 1980s; and both regulators were quite comfortable to breathe.

It seemed to be only with the advent of the XStream in the early 2000s, that the IP was lowered to about 8.5 bar (123 pounds or so) for just about everything but the Cyklon and Triton; though the more recent Cyklon X had it kranked to 10 or 10.5 bar . . .

That is good info. I will leave it to a Poseidon expert like Robert to comment as he cautioned me (as did several other) to not use a high IP with my Jetstream.

I think going directly to the service manuals for the equipment in this case is appropriate because we have discovered numerous errors in Poseidon website tech specs. Namely specifying 124 psi for the Cyclon X which is incorrect.

As to when the hose fitting pressure relief should release I note that mine begins to want to flow at around 160 on my Jetstream second stage. There is probably some variability due to age perhaps since like you said, it should not relieve until about 200 psi if I recall.

 

[Bigbella]

As to when the hose fitting pressure relief should release I note that mine begins to want to flow at around 160 on my Jetstream second stage. There is probably some variability due to age perhaps since like you said, it should not relieve until about 200 psi if I recall.

That may indeed be an age issue. Mine will vent at 14 bar, like clockwork; and I run a few older Cyklons at about 10.5 bar with those integral hoses.

When I am working on a regulator, I like the old hoses for an initial baseline test, More often than not, they wind up venting . . .

 

[Nemrod]

And for the OP, when using a Jetstream only one regulator (or the first stage) needs to have an overpressure vent or be downstream. I run my Jetstream with a Scubapro R190 and a solid hose adapter from DGX. I also have the Omni swivel adapter I can opt for and it has the built in relief and is a quality piece of work.

James

 

[rx7diver]

I purchased my Odins in 1995 or so. At that time, the 1st stage (model #3960), having one flat end and one cone-shaped end, was referred to as the "new" first stage. (It replaced the model having a "cone" on both ends.)

The #3960 has a built-in OPV (on the flat end), but mine also came with IP hoses that had an OPV built into the end of the hose. I remember thinking that Poseidon Inc must be using up its stock of already-built hoses.

Because of the built-in OPV, the Poseidon hoses were pretty pricey. I remember that my 7' Odin hose cost north of $100--pretty steep in the mid-1990's.

rx7diver

P.S.: I attached a pic of my Odins in the OP's other thread that is currently running.