Poseidon Xstream free flow

[CaptainHornblower]

FYI, I took the regs to the local dive shop which is a Poseidon dealer. They put the reg on the test bench, and sure enough, it started free flowing at about 550 psi. The tech said something was amiss, as that should not happen until the IP is down to about 150 psi.

 

[Puffer Fish]

FYI, I took the regs to the local dive shop which is a Poseidon dealer. They put the reg on the test bench, and sure enough, it started free flowing at about 550 psi. The tech said something was amiss, as that should not happen until the IP is down to about 150 psi.

Around 150 makes sense, as that is around when the first stage should not be able to provide enough pressure to hold the second stages closed. Yours is obviously dropping the intermediary when the tank is about 550.. which would not be a good thing.

 

[tfsails]

An Xsxtream first stage should put out 122-128 psi IP on a full tank. That's what the book calls for. If IP gets much below that figure, the second stage(s) will free flow if they're Xstreams. It takes that much IP to inflate the balloon/condom and seal up the innards. When the diver inhales the balloon collapses and air can flow. When he stops inhaling, the servo valve allows the balloon to reinflate and the whole cycle starts all over again.

That said, your Xstream should work properly at 550psi tank pressure. If it didn't I'd get the first stage looked at to see what the problem is. I wouldn't think the thing would start to free-flow until the tank pressure got down to around 200psi.

 

[CaptainHornblower]

The tech agreed with Puffer and tfsails comments, he too said it should function normally down to 150 to 120 psi. He's doing a full service now and will get it fixed.

 

[geraldp]

Yesterday at the end of a dive my reg and alt (both Posiedon Xstream) started free flowing. We were just about to surface, I was probably 4 or 5 feet down, tank pressure was down to about 600 psi and away they went. I surfaced, manually filled my BC and had my buddy shut the tank valve. My computer said the pressure at the conclusion of the dive was 22psi. The regs worked fine during the dive up to that point.

Any thoughts or similar experiences? I had the regs serviced about 5 dives (and a year) ago.

I had a similar experience with my Atomic Aquatics SS1 air2 a number of years back. I had just surfaced from my first dive of the day with about 600-700 psi, and it started freeflowing. My primary 2nd stage was fine. I had just had the regs serviced. The freeflow drained my tank amazingly fast, and I ended up dumping my weights to get back to the boat. I took the reg back to my LDS who did the servicing, and they couldn't find anything wrong with it. They sent it into Atomic Aquatics, who decided that it had a crimped O ring. At least the LDS paid to replace my lost weight pouches...

 

[CaptainHornblower]

I was too cheap to dump my weights, I used the oral inflation tube to blow up the BC while I tread water

 

[EarlyDolphin]

Hello together,

I’m new on scubaboard. Please excuse possible language mistakes in my postings, because I'm from Germany

@ CaptainHornblower:
Have your problems with the XStream been solved now?
What are your experiences with it after the service?

@ all XStream users:
Has anyone else made experiences with a free flowing XStream (or Jetstream) above the normal pressure limit of around 150 psi tank pressure?

I’m looking for a set of rough and durable cold water regulators. The XStream looks like a very clever peace of regulator and it’s build for extreme conditions. Actually perfect for my needs.
The only thing that makes me worry is this issue with free flow.

Now I’m a bit confused by the experiences other XStream users tell, mainly written on German boards. Some say, the second stage will free flow below a certain intermediate pressure and others say, it might free flow. Some could even breath their tank completely empty without any problems.
What is the more likely behaviour?
With the free flowing itself I would not have any problems, if I could exactly predict the point where it starts. But some users like CaptainHornblower described a free flow above 150 psi and that makes me worry.
Imagine a dive, maybe an emergency situation, where you need the last bit of air out of your tank and then the free flow starts earlier than you expect it.

What can influence it? Only defects? Or is it also a matter of adjustments?

Best regards,
The EarlyDolphin

 

[rab]

Hello together,

I’m new on scubaboard. Please excuse possible language mistakes in my postings, because I'm from Germany

@ CaptainHornblower:
Have your problems with the XStream been solved now?
What are your experiences with it after the service?

@ all XStream users:
Has anyone else made experiences with a free flowing XStream (or Jetstream) above the normal pressure limit of around 150 psi tank pressure?

I’m looking for a set of rough and durable cold water regulators. The XStream looks like a very clever peace of regulator and it’s build for extreme conditions. Actually perfect for my needs.
The only thing that makes me worry is this issue with free flow.

Now I’m a bit confused by the experiences other XStream users tell, mainly written on German boards. Some say, the second stage will free flow below a certain intermediate pressure and others say, it might free flow. Some could even breath their tank completely empty without any problems.
What is the more likely behaviour?
With the free flowing itself I would not have any problems, if I could exactly predict the point where it starts. But some users like CaptainHornblower described a free flow above 150 psi and that makes me worry.
Imagine a dive, maybe an emergency situation, where you need the last bit of air out of your tank and then the free flow starts earlier than you expect it.

What can influence it? Only defects? Or is it also a matter of adjustments?

Best regards,
The EarlyDolphin

I'm one of the XStream users and have never had a free-flow problem under normal conditions (and a majority of my fresh-water dives have a low temp of about 40˚F/5˚C). However, I will confirm that the design of the 2nd stage will "free flow" when the tank has less than the IP of the 1st stage. I think that you want to be on the surface before then in any case. (I'd consider breathing a cylinder below 200psi to be effectively the same as "until empty".)

-Rob

 

[EarlyDolphin]

Thanks for your answer, Rob.

The german posting in which a user explained some very bad sounding problems with the XStream is from the year 2005.
(unfortunately I'm not allowed to post URLs with my few less than 5 posts, the machine says :shocked2
One user wrote his XStreams (he had more than 4!) had different problems, and the worst was a free flowing during deco when he had around 80 bar (1160 psi) on his stage left. CaptainHornblower's problems sound similar.
But another user in the same posting wrote he had made a test in the pool (3,8 m/ 12 ft) with breathing the tank completely empfty. And he had no free flow at all.
... so what now? Will it free flow or might it? What's the reason why it might do so or why not?
We also do not know how old was CaptainHornblowers XStream.
I believe Poseidon meanwhile made some improvements on the regulator, as you can see from some technical brochures about service kits.
Has anyone some more detailed information?

Free flow at 150 psi would not be a real problem (for me). But I'm afraid the limit of free flowing could increase, maybe over 400 psi ... if I could reliably check the reg's limit before the dive.

 

[Underwater Ogre]

I have never had any problems with my Xstream. Its a great reg...