How does an LP hose seal to a 2nd Stage?

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certainmisuse

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Location
Atlanta GA
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I'm having trouble fitting an LP hose to my used Scubapro g250. It seems as though the protruding center cylinder (don't know what else to call it) of the LP hose is running into the orifice of the 2nd stage. See gap between retaining jam nut of the 2nd and the hose nut when screwed in. Is this proper? If so, the 2nd stage cannot rotate; I assumed all hoses allow rotation. Also, I would have thought a proper connection would require the hose nut screwed all the way down against the threads of the 2nd stage barrel, as opposed to up against the orifice. Is this hose just incompatible? If so, please point me in the direction of one that will work. Any advice for this newbie is appreciated. Thanks.

20190310_205823.jpg 20190310_205521.jpg 20190310_205807.jpg
 
Is the sleeve on your LP hose stuck? Is it possible to push it up to until the outer sleeve is higher than the inner part of the hose?
 
@certainmisuse
first picture, you can see the recess for the o-ring. Should be size 010
The center part of the hose is fixed to the barb of the fitting. The nut is loose. The nut screws all the way up to the jam nut to keep it from moving, many people will put an o-ring on there to keep it from backing off, size 013 btw.
When the hose swivels, the nut doesn't move, but the whole insert in the middle swivels with the hose which is why that o-ring shreds reasonably often.

Are you sure you aren't missing the o-ring that goes on the inside of the jam nut? There is usually one between the case and the jam nut to keep it from moving.
 
@certainmisuse
first picture, you can see the recess for the o-ring. Should be size 010
The center part of the hose is fixed to the barb of the fitting. The nut is loose. The nut screws all the way up to the jam nut to keep it from moving, many people will put an o-ring on there to keep it from backing off, size 013 btw.
When the hose swivels, the nut doesn't move, but the whole insert in the middle swivels with the hose which is why that o-ring shreds reasonably often.

Are you sure you aren't missing the o-ring that goes on the inside of the jam nut? There is usually one between the case and the jam nut to keep it from moving.

Currently no o-ring between case and jam nut. I'll try that tomorrow.
 
the schematic calls for an o-ring on either side of the jam nut as an FYI. I do not know what size they are, but I know Omniswivel uses 013's for similar purposes, so I would start there. Someone more knowledgeable on that second stage may be able to better direct you. @Bryan@Vintage Double Hose would be a good start
 
the schematic calls for an o-ring on either side of the jam nut as an FYI. I do not know what size they are, but I know Omniswivel uses 013's for similar purposes, so I would start there. Someone more knowledgeable on that second stage may be able to better direct you. @Bryan@Vintage Double Hose would be a good start

Thanks a bunch tbone, I'll try the two orings and reach out to Bryan if need be.
 
I'm having trouble fitting an LP hose to my used Scubapro g250. It seems as though the protruding center cylinder (don't know what else to call it) of the LP hose is running into the orifice of the 2nd stage. See gap between retaining jam nut of the 2nd and the hose nut when screwed in. Is this proper? If so, the 2nd stage cannot rotate; I assumed all hoses allow rotation. Also, I would have thought a proper connection would require the hose nut screwed all the way down against the threads of the 2nd stage barrel, as opposed to up against the orifice. Is this hose just incompatible? If so, please point me in the direction of one that will work. Any advice for this newbie is appreciated. Thanks.

View attachment 509298 View attachment 509299 View attachment 509300
Perhaps it's just a camera angle, but the "protruding center cylinder" on the hose in your picture may be the culprit. Pull the 'B' nut forward on the hose. Does the center section recede to near flush with the 'B' nut? If not, try a different hose.
lp hose swivel ends .JPG


Next, ensure you have not torqued down the jam nut too far. It is possible to over tighten the jam nut and pull the air barrel too far toward the hose side. There should be proper spacing on the stop clip/adjuster side:
G250 barrel placement.JPG

BTW not all G250ies had/have o-rings positioned on either side of the jam nut. Checking the diagrams I have, it seems the seals were not added until the HP version came into being. Having said that, adding an o-ring between the jam nut and the case and/or between the jam nut and hose may solve the issue (size -014.) But check the other items first, and please update with your findings.

Edit: One more thing (for now :) ) Is the orifice screwed in at all?
 
Perhaps it's just a camera angle, but the "protruding center cylinder" on the hose in your picture may be the culprit. Pull the 'B' nut forward on the hose. Does the center section recede to near flush with the 'B' nut?
View attachment 509361
If not, try a different hose.

Next, ensure you have not torqued down the jam nut too far. It is possible to over tighten the jam nut an pull the air barrel too far toward the hose side. There should be proper spacing on the stop clip/adjuster side:
View attachment 509362
BTW not all G250ies had/have o-rings positioned on either side of the jam nut. Checking the diagrams I have, it seems to indicate the seals were not added until the HP version came into being. Having said that, adding an o-ring between the jam nut and the case and/or between the jam nut and hose may solve the issue (size -014.) But check the other items first, and please update with your findings.

Edit: One more thing (for now :) ) Is the orifice screwed in at all?

Thanks so much for the details. I will check these ideas when I get home later tonight and report back. BTW, I did screw the orifice all the way in for doing these diagnostics. Obviously it will need to be backed out later so the lever height can return to proper position.

Also, I believe it's a straight g250, so not the HP or V.
 
I had this problem on an octo when I went from rubber hoses to Miflex a few years back. Apparently not all hoses and second stages are created equal. I couldn't for the life of me get it to connect and be able to rotate. I finally called the manufacturer and they told me that some hose manufacturers use different specifications. I got a different second stage and it worked fine. I put the rubber hose back on the other one and use it for a stage bottle now. You may have to try different hoses if the second stage is important to you.
 
I'm having trouble fitting an LP hose to my used Scubapro g250. It seems as though the protruding center cylinder (don't know what else to call it) of the LP hose is running into the orifice of the 2nd stage. See gap between retaining jam nut of the 2nd and the hose nut when screwed in. Is this proper? If so, the 2nd stage cannot rotate; I assumed all hoses allow rotation. Also, I would have thought a proper connection would require the hose nut screwed all the way down against the threads of the 2nd stage barrel, as opposed to up against the orifice. Is this hose just incompatible? If so, please point me in the direction of one that will work. Any advice for this newbie is appreciated. Thanks.

View attachment 509298 View attachment 509299 View attachment 509300

CM...

Try your proprietary ScubaPro LP hose...you'll likely find the sealing tip on the proprietary hose does not protrude as far as the sealing tip on the standard/generic hose...

ScubaPro has lots of proprietary sub-components...

Keeps the purchaser coming back to the source...

In order to tighten the hose properly...you will also need ScubaPro's proprietary multi-tool...

For tightening ScubaPro LP hoses to Scuba Pro second stage regulators...you need two ScubaPro multi-tools...one to hold the splined nut on the second stage so it does not turn...while you're tightening the splined nut on the LP hose...

Before tightening the LP hose...be sure you correctly set the second stage cracking pressure...

Best...

Warren
 
https://www.shearwater.com/products/peregrine/

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