Regulator list

['Cuda]

Where might I find the definitive list, encompassing the myriad of POSEIDON first, and second stages, and, if possible, the permitted/allowable/suggested combinations of the 1st and 2nd stage items? Something like a flow chart would be perfect, but I'll take what you've got. It would be real nice to assign the respective different stages to approved combos, if it's necessary at all. I dive POSEIDON Thor and Odin firsts with Jetstream seconds since 1991, and want to try out different combos, models, etc. 2940, 2950, 2960, 2980, 3950, Cyclon 300, Cyclon 5000, X-Stream, etc., etc. Hey, even the yoke adapters! I would like to know the differences (ports, threads, type) and if necessary I'll compile the data...but first the data needs to be correct. A lot to ask, maybe, but nobody said life was easy.
Thank you,
AquaticNeurotic

 

['Cuda]

Wow, this topic sure garnered a lot of interest (not even one reply). Is the rep out there somewhere? Do I need to speak with Melanie? Maybe, I should pull the post, but I'll keep hoping!
'Cuda

 

[smorneau]

Try reposting in the DIY or vintage forums. A few of the regulars have a vast knowledge of older regulators.

Sent from my Nexus S using Tapatalk 2

 

[MarineResearch]

You can always try contacting Poseidon in Houston. However, I'm not sure they will be able to help with the older regulators.

 

[rsingler]

It's my opinion that there are NO restrictions on 1st/2nd combinations, as long as the hoses fit. It's more a matter of tuning the 2nd to the IP of the 1st for best performance, or reducing the IP to compensate for other limitations. That was the huge advantage of the 2900 series 1sts, which had a different spacing sleeve to control the huge flow through the Poseidon "valve piston" (their name for the moving cone orifice). So tuning to the IP of the first stage is key. It's also a reason some Poseidons like the Jetstream may not feel as light on inhale as other regs (e.g. SP D-400) at the surface, but they really come into their own at depth. The huge flows are the beauty of the Poseidon 1sts.

However, there is one BIG caveat: I was repairing a 2900 series 1st the other day, and found two "port plugs" with DIFFERENT threads - imperial AND metric in the same body. It's possible (likely?) that the balance chamber had been switched out from a different model, because I can't believe Poseidon would have put out a reg with the same diagram reference number with different threads. See attached photos.
Although this schematic is for the 2801/2808, and my reg was a 2900 series, it shows the problem.
The key to discovering the issue is in the second photo. A diagram #11 "plug" from Europe with a circle inscribed on the flange indicates IMPERIAL thread. The same #11 plug from Europe with no circle has metric thread. Of course, that only confuses the issue with American manufactured 3/8" plugs, because none of them have the circle, yet are Imperial thread.
In my case, one clue was on the body of the 1st stage:


The "UNF" warns you that the threads are Imperial. So, if the plugs have circles, it all makes sense. If they don't, they're either American-made OR are metric European plugs that have been forced into the body. The plugs should thread easily all the way down. That was the clue for me: after about two turns, the metric one began to bind slightly in the body. When we took the plug out, the photo shows the difference from the true port plugs. My metric plug belonged in the balance chamber, because it was a metric European plug that looked like an American UNF thread.
Bottom line - be aware of the difference, and the possibility that parts have been interchanged over the years. For me, a metric balance chamber was attached to a UNF body. Maybe a 2900 series schematic will show different part numbers for the two (different) plugs if it was designed that way. I hope not, because mixing those two almost identical plugs in a single regulator is a prescription for disaster.

And as for your exchange project? Go for it! Use whatever you want wherever you want if they have the same hose connections, and just work the tuning issue. For the Jetstream, the issue is that the flows may be abrupt if the IP is too high, because the servo is an upstream valve. A 1st tuned for a Cyclon will be way too high an IP for the Jetstream. For the Cyclon, it will be more straightforward, but the IP specified is much higher for early models (~170). Either way, you've got lots of air, and Poseidon remains a very underrated gem for the broader public (plus their American business practices weren't so good, and distributors fell apart). Here's hoping the new arrangement in Texas does the trick. I don't know of any Poseidon 1st "intended" for the Jetstream that can't handle being reset for an IP of 170.

 

[rsingler]

I gave a cursory answer to a good, if complex question. I'm trying to put together a flow chart as requested, that will cover 1st stage identification, threading, IP and 2nd stage compatibility.

The bad news is that a couple of 1st stage designs indeed had a mix of metric and UNF port plugs, specifically metric for balance chamber and UNF for LP ports. Can't imagine what they thought was good about this at the time they were designed.

Specifically, the following 1sts have mixed parts by design:
3580 for Jetsream (truncated cones at each end of the body with the flats ground into the body)
3585 for Cyclon 5000 (as above)

2962 for Jetstream/Odin (side DIN or Yoke with truncated cones at each end of cylindrical body with no flattening of the body except at ports)
3257 for for Diveair/Cyclon 5000 (as above)

The good news is that none of the newer 1sts with flat bottoms and the little 3/16" dia safety valve in the bottom have mixed plugs.
If you have a 3070 1st stage for the Cyclon 300 or Oceanair/Thor you're also fine.
If you have an unbalanced 2305 1st stage (Cyclon 300) with the DIN/yoke on the bottom, you're also pure UNF threads.
If you have a 2801 or 2808 1st stage (like the picture I posted above) you are also pure UNF threads.

So, the parts weren't "mixed up" over the years between the balance chamber plug and the LP ports. On some regs, they were designed that way.

Plug dimensions:
Metric G1/8" has 9.728mm diam and 28 turns per inch thread
Imperial UNF 3/8" has 9.525mm diam and 24 turns per inch thread

More to follow, when I get the flow chart with the design Interstage Pressures listed. As in my previous post, I see no reason you can't lower the IP on a Cyclon 1st stage to feed a 145 psi Jetstream, but I'll give you a chart of how they were originally marketed.

 

['Cuda]

This was most appreciated and a good stepping stone on the path to a myriad of Poseidon regs. I'm just trying to compile an overall list of the various # regs, both 1st and 2nd, and I was planning a tree (flow chart) showing the possibilities of pairing the Poseidon regs with the appropriate counterparts. Anyway, thank you very much, and I hope that there is more to come. Melanie at Poseidon has been great, but I'm doubtful that she even wants to hear of this undertaking. The rep, however surely doesn't want to hear about anything. Most disappointing.
'Cuda

 

[rsingler]

Sorry I've been out of pocket for the past week. Haven't even started on the Intermediate Pressure cross reference, but here's a start for you:
View attachment Poseidon001.pdf
It's a pdf from an old manual that lists a whole series of 1sts and 2nds. The cover has some pics that can even help you identify a regulator without the numbers that Poseidon started engraving in the body later. Hope this helps. More to follow tomorrow if I get lucky.

Rob

 

[rsingler]

Got a PM from one of our bloggers doubtless comparing two sets of Poseidons that were on EBay last week (with vastly differing prices):
"What's the difference between a Poseidon 2960 and a 3960?"
I thought it might be useful to reprise my reply here, because I can add some pics via an attached document: View attachment PoseidonComparison.pdf

Both 2960 and 3960 refer to a full regulator "set", consisting of both a first stage and second stage.
I presumed the question really referred to the first stage supplied in the set, but I'll answer both halves.

The 2960 consists of either the 2962 or 3257 first stage and the 2961 or 3546 Jetstream second stage.
A "-10" following the first stage number means YOKE, while the number alone (e.g., 2961) means a DIN 1st stage.

The 3960 set includes the 3790 or 3790-10 first stage and the same 2961 or 3546 Jetstream second stages.

The biggest change has to do with the addition of a safety valve on the bottom of the regulator.
The attachment above shows both exploded views and cross sections.

The Jetstream second stage has an upstream servo valve, which bothers some folks about the possibility of a first stage o-ring failure blowing out the LP hose and exhausting a tank in a short period. In fact, the Jetstream continues to be breathable as you make a controlled ascent under those conditions, and Poseidon has a safety valve in the hose connection which vents when gas pressure gets excessive. Note, it is only the servo valve which actuates the pneumatic mechanism which is an upstream feature, not the pneumatic mechanism itself, which is pretty slick, and almost unique in the industry. And it's important to note the absolute rarity of a HP o-ring failure with the Poseidon 1st stage design and a well-maintained reg. Of course "well-maintained" doesn't apply to lots of our recreational family, but there's a reason Poseidon is so heavily used by military divers around the world.

The 2000 series first stages have the "safety valve" in the hose.
If you wanted to pair a Poseidon first stage with a different UPSTREAM second stage regulator without the safety valve in the Poseidon hose, you theoretically would have no overpressure protection for the LP hose. In fact, any second stage but a pure upstream valve would vent just fine through the exhalation valve itself, but Poseidon addressed this issue by adding a safety overpressure valve in the bottom of the 1st stage regulator in the 3970.

The cross section views in the document shows how similar they both are. They are both balanced diaphragm seconds, with huge airflow via a moving orifice (which Poseidon calls a valve piston). The balance chamber is similar in both regs, except that in the 3790, the chamber is integral to the body, and you drop the parts in. In the older 2962 or 3257, the balance chamber was fitted with the parts and then screwed in from the bottom. That accounts for the differing shape of the bodys, which in the 2962 has truncated cones on both ends (one for bal chbr, one for diaphragm spring). The 3970 has a flat bottom machined to accept the overpressure valve, because the balance chamber is already inside. There's a single truncated cone screwed into the top to hold the diaphragm spring.

I'll try to generate some A.I.R. bench "flow vs. inhalation vacuum" graphs to show how similarly they perform, if I can get hold of another 3790.
Bottom line: the 2962 (which by the way has 2960 stamped on the body - go figure) is still a great performer and a good value.

Re: the original intent of this thread, which I've just hijacked, although the 2962 and 3970 regs were released for the Jetstream, and were thus tuned to an IP of 8.5-9 bar (123-130 psi), they are also tunable to higher IP's to give good performance to a Cyklon second stage. I'll PM Jorgen Nilsson and ask him to weigh in here if I've made any mistakes in my claims, but you can get the 167-181 psi the Cyklon 300 likes with ease. The advantage over the old Cyklon 300 first stage is that both of these (2962 and 3790) are balanced diaphragms and won't drop their IP with a full tank, so that the second stage will breathe as well throughout the dive.
Of course, the Cyklon 5000 is intended to go with the 3585 balanced 1st, but as the attachment shows, the internals are close to identical to the 2962, so I still believe you can choose whatever IP your choice of second stage wants. That also means (oh, no! heresy!) that if you have a favorite non-Poseidon second stage, you can take their ultra-reliable balanced diaphragm and tune just where your 2nd breathes best. But if you dive deep, it's hard to beat a full Poseidon set.

Rob

 

[rsingler]

OK, here goes my first attempt. :tmi2: I think I've got this all down, but again, I'll defer to Jorgen Nilsson for the final word:

Poseidon Approved Combos
These are the combinations of first and second stages that Poseidon released at various times, together with IPs for the first stage. Data is taken from Service Manuals and owners manuals displaying or specifying certain combinations. The service manual does not include some of the combinations in owners manuals, and vice versa, so I'm not really sure what the complete release history is. Many of the second stage models are merely different body colors, a confusing practice which apparently has been discontinued with the Xstream.

NOTE: All IPs are set at two specific tank pressures, since the early unbalanced firsts showed a significant IP rise with declining tank pressure. IP is first set with input pressure of 20 bar, and then finally adjusted with IP at 200-300 bar.

Regulator Set	First Stage	Second Stage	IP adjustment --->	@ XXXX psi tank pressure	LP port Threads
2940 Oceanair/Thor	3020	2961	11.5 bar/167 psi ----> 8.5-9 bar/123-130 psi ->	at 300 psi at 3000-4350 psi	UNF 3/8”
2940 Oceanair/Thor	3020	3546	11.5 bar/167 psi ----> 8.5-9 bar/123-130 psi ->	at 300 psi at 3000-4350 psi	UNF 3/8
???? model Jetstream/Odin	2962 (DIN) 2962-10 (Yoke)	2961 Black	10 bar/145 psi ----> 8.5-9 bar/123-130 psi ->	at 300 psi at 3000-4350 psi	UNF 3/8 See NOTE ++
???? model Jetstream/Odin	2962 (DIN) 2962-10 (Yoke)	2941 Yel/Blk	10 bar/145 psi ----> 8.5-9 bar/123-130 psi ->	at 300 psi at 3000-4350 psi	UNF 3/8 See NOTE ++
2940 Oceanair/Thor	3070	2941 Yel/Blk	10 bar/145 psi ----> 8.5-9 bar/123-130 psi ->	at 300 psi at 3000-4350 psi	UNF 3/8 See NOTE
2960 Jetstream/Odin	3580	3546 Yel Octopus	10 bar/145 psi ----> 8.5-9 bar/123-130 psi ->	at 300 psi at 3000-4350 psi	UNF 3/8 See NOTE ++
3960 Jetstream	3790 (DIN) 3790-10 (Yoke)	2961	10 bar/145 psi ----> 8.5-9 bar/123-130 psi ->	at 300 psi at 3000-4350 psi	UNF 3/8
3960 Jetstream	3790 (DIN) 3790-10 (Yoke)	3546	10 bar/145 psi ----> 8.5-9 bar/123-130 psi ->	at 300 psi at 3000-4350 psi	UNF 3/8
???? model Jetstream	2801	? 2961	? like 2962		G 1/8
???? model Jetstream	2808	? 2961	? like 2962		G 1/8
2980 Cyklon 300	3070	1133	12.5 bar/181 psi ----> 8.5-11.5 bar/123-167 psi	at 300 psi at 3000-4350 psi	UNF 3/8
2980 Cyklon 300	3070	3536	12.5 bar/181 psi ----> 8.5-11.5 bar/123-167 psi	at 300 psi at 3000-4350 psi	UNF 3/8
???? model Cyklon 300	1908	? 1133	? like 3070		G 1/8
???? model Cyklon 300	2422	? 1133	? like 3070		G 1/8
???? model Cyklon 300	2305	? 1133	? like 3070		G 1/8
2950 Cyklon 5000 Diveair	3257 (DIN) 3257-10 (Yoke)	1133	11.5 bar/167 psi ----> 9-10 bar/130-145 psi -->	at 300 psi at 3000-4350 psi	UNF 3/8 See NOTE ++
2950 Cyklon 5000	3585 (DIN) 3585-10 (Yoke)	1133	11.5 bar/167 psi ----> 9-10 bar/130-145 psi -->	at 300 psi at 3000-4350 psi	UNF 3/8 See NOTE ++
3950 Cyklon 5000	3720 (DIN) 3720-10 (Yoke)	1133	11.5 bar/167 psi ----> 9-10 bar/130-145 psi -->	at 300 psi at 3000-4350 psi	UNF 3/8
2950 Cyklon 5000	3720 (DIN) 3720-10 (Yoke)	3536	11.5 bar/167 psi ----> 9-10 bar/130-145 psi -->	at 300 psi at 3000-4350 psi	UNF 3/8
3750 Triton	3720 (DIN) 3720-10 (Yoke)	3755	10 bar/152 psi ----> 8.5-9 bar/123-130 psi ->	at 300 psi at 3000-4350 psi	UNF 3/8
???? model Cyklon 5000	3880	? 1133 ? 3536	? like 3720

NOTE ++ : Although the LP ports were UNF 3/8, the balance chamber plug is G 1/8. DO NOT MIX THESE!
NOTE: The 3070 first stage is tuned differently depending upon whether paired with a Jetstream or Cyklon

From the service manual, these regulators are internally VERY similar, and should thus be interchangeable with the approved model listed above. There are some significant differences between models, however.

2961: 2710, 2941, 3546
2962: 3257, 3580, 3585
1133: 3224, 3354, 3536
3070: 2305, 2422
3880: 3720

More to follow when I incorporate the Xstream data, but one early comment is appropriate here:
I had previously stated that I thought you could use any first with any second, as long as you adjusted the IP to match the 2nd stage's requirements. Apparently that is NOT true for the Xstream. In their FAQ it states that an Xstream cannot be mated to a Cyklon, although a Jetstream is OK. The feeling is that driving an Xstream first stage up to 167-181 psi may exceed the plastic deformation threshold of the spring and ruin the regulator. I stand corrected.

I heard back from Jorgen Nilsson, and I hope he will step in and edit heavily here wherever I've made a mistake.
(I also found a 3960 in my Poseidon box, so I'll try to run some A.I.R. dynamic flow charts to compare with the 2960 first stage)