Poseidon 1st Stage Exchange

[oya]

you have 3960's with blank bottoms? I have 6 of them on Jetstreams from at least a 15 year timespan that all have them built in. I am unaware of Poseidon building any 3960 style first stages without what they call the "safety valve" on the bottom

plain blank bottom? I have never seen a 3960 without an OPV.
The earlier 2960, without the OPV don't seem to have a flat bottom.

Are you two messing with me?

I'm talking about the Xstream first. Before it became the MK3 it didn't have an OPV on the bottom.

Yes, the 3960 always had a valve, but for a time the Xstream didn't.

[oya]

Reference

[tbone1004]

ahh hah, that makes sense. I didn't get the bit where you were talking about the intermediate first stage step. Sorry. I would never switch from a 3960 to that style first stage without the OPV if I was using anything with any sort of upstream valve only, i.e. jetstream/xstream/ccr with shutoffs etc, but that's just me. Aftermarket OPV's are too much of a pita

[MarkR]

Are you two messing with me?

I'm talking about the Xstream first. Before it became the MK3 it didn't have an OPV on the bottom.

Yes, the 3960 always had a valve, but for a time the Xstream didn't.

I understand you now. As a matter of fact, there is an xstream reg for sale on fleBay right now that has the OPV valve called out specifically in the item description. I thought that was odd at the time.


Any idea if the Dive Rite 4500 (rebranded xstream/Jet combo) came with the OPV on the 1st? I came close to buying one a few months back and did not even notice.


Just out of curiosity, how (or why) is the xstream 1st a better performer than a 3960?

[oya]

Any idea if the Dive Rite 4500 (rebranded xstream/Jet combo) came with the OPV on the 1st?


Just out of curiosity, how (or why) is the xstream 1st a better performer than a 3960?

First question:
Yes. In fact they had them before the general runs.

Second question:
Not exactly better performers (unless you're diving in sub-zero waters). They're just a lot simpler. Far fewer failure points, parts, and sealing surfaces.

[FW]

Are you two messing with me?

I'm talking about the Xstream first. Before it became the MK3 it didn't have an OPV on the bottom.

Yes, the 3960 always had a valve, but for a time the Xstream didn't.

You must be planning to use 5000 2nds. You wouldn't need an OPV on an Xstream 2nd.

[MarkR]

....You wouldn't need an OPV on an Xstream 2nd.

how is this possible? (unless you are assuming the OPV integral to the LP hose) ...don't both the xstream and the jet have upstream demand valves?

[FW]

how is this possible? (unless you are assuming the OPV integral to the LP hose) ...don't both the xstream and the jet have upstream demand valves?

Yes, and Yes

[MarkR]

Yes, and Yes

haha... gotta love it.


Folks need to be careful thought. If you buy a new xstream 2nd stage, it will have the adapter to attach to a normal LP hose. Then you will be flying with no OPV. *assuming you don't have one on the 1st stage, or on another LP hose.


Please correct me if I am wrong! ..Forrest has probably forgot more about Poseidons than I know.

[FW]

haha... gotta love it.


Folks need to be careful thought. If you buy a new xstream 2nd stage, it will have the adapter to attach to a normal LP hose. Then you will be flying with no OPV. *assuming you don't have one on the 1st stage, or on another LP hose.


Please correct me if I am wrong! ..Forrest has probably forgot more about Poseidons than I know.

You have it right.