Vintage Double Hose

Seems like a lot of regulator tinkerers and professional repair techs tend to get locked into thinking 135 to 140 psi for intermediate pressure settings on regulators. I have usually been a little more flexible, cranking that upward if needed to get the performance I desired.

In 1985 US Divers issued a technical bulletin (PN 7802-88) that clearly stated "The recommended acceptable intermediate pressure for diaphragm-operated, first-stage regulators is 130 to 160 psig". It specifically listed this as applying to the Conshelf XIV, as well as a number of other similar first stages enumerated in the bulletin. They did not specifically mention any double hose regulators.

I ran into that bulletin in an old manual of mine, and can email a copy of the two page document if anyone is interested.

I would like to get a copy of the document, just to have it. That is interesting that they published that big of a range back then.

I have run the IP of a Conshelf and a RAM above 150, but I have found that many conventional second stages will start free flowing if you get around 160 or above.

I do have two Conshelfs that are set to around 165 psi, but those are feeding Poseidon Cyklon second stages. They are great performing second stages when they have a constant IP at that level.


Thanks

Conshelf XIV Manual This is for the most current Conshelf XIV as it shows the metal 2nd stage with the adjustment port on it.

In my experience anything over 140psi is risky for most safe 2nd stages.

luis wrote:I would like to get a copy of the document, just to have it. That is interesting that they published that big of a range back then.

I have run the IP of a Conshelf and a RAM above 150, but I have found that many conventional second stages will start free flowing if you get around 160 or above.

I do have two Conshelfs that are set to around 165 psi, but those are feeding Poseidon Cyklon second stages. They are great performing second stages when they have a constant IP at that level.


Thanks

I find the same thing about second stages going wild, and have only used the higher pressure on MR12 second stages to run Poseidons properly. Like you say they prefer that higher pressure for good performance. I'll scan the USD bulletin and email to you.

Bryan wrote:Conshelf XIV Manual This is for the most current Conshelf XIV as it shows the metal 2nd stage with the adjustment port on it.

In my experience anything over 140psi is risky for most safe 2nd stages.

They do get frisky! Rarely I would find a second stage that just didn't crack as easily as I liked, and had to go up above 140. Probably a variation in second stage spring. I don't recall going even up to 150 except to use on Poseidon second stages. After a few rebuilds on Poseidon first stages, I began to prefer the simplicity of the Conshelf/MR12-type first stages. Made field repairs easy. In those cases I wasn't using a conventional octo, which would not have worked out well.

Link To Conshelf XIV intermediate pressure bulletin

Courtesy of Bill....