Conshelf 21 regulator

[Npallasi]

I am considering a used Conshelf 21 1st, 2nd and alternate (octopus) stage regulator set. The regulator set looks good, no crust buildup, no hose cracks, very few scratches, and I can get it serviced locally and not too expensively. I have read good reviews of the Conshelf series, most of which focus on their durability.

I have run into a snag on the information regarding this regulator set though.
1) Is the 1st stage balanced? Diaphragm or piston? (Definitely yoke.)
2) Is the 2nd stage balanced?
3) Is the octopus balanced?

I have found lots of information on the Conshelf XIV online, but I have no idea if the information pertains to the Conshelf 21.

Any help is appreciated.

p.s. Detractors of buying used gear, desist!

 

[Luis H]

All the Conshelf first stages are basically the same: balanced diaphragm and bullet proof. You will not find a more reliable first stage.
They are easy to service, parts are easy to find, and their performance is excellent.

The second stages do vary some, but most are basic downstream non-balanced demand valve. The XIV has a metal second stage, but I believe that the 21 second stage is plastic. If tuned properly, they are both (metal or plastic) amazingly good breathing second stages, for such a mechanically simple design.

 

[Npallasi]

Thanks. I also suspect that the second stage and octopus are not balanced. It is good to know what I will be getting.

 

[Eric Sedletzky]

Conshelfs are one of the all time best regs, if not possibly the best overall if you take into consideration many factors.
In short, the design has not changed internally since the 60's.
Parts are plentiful and easy to obtain.
The military has used that reg for many years.
Only one of the two reg components needs to be balanced, either the first or second. There are differing opinions on which one, but having both balanced is a little redundant and overkill, some say a marketing ploy. To me either one is fine, or none of them. I don't mind the slow draw down of a completely unbalanced reg set.
There's nothing wrong with a simple unbalanced poppet second stage. They are very simple and not much to go wrong.

 

[Npallasi]

Yes, those were the factors that swayed me towards the Conshelf series rather than the fancy new regs with venturi levers and side exhaust. Not that there is anything wrong with fancy new regs! But I like the proven regs better.

 

[AFdivedoc]

I recently procured and overhauled a Conshelf XIV. It cleaned up great, and I had people asking where I got the "new" reg. I was very pleased with the performance of the unbalanced downstream second stage. No adjustment to make but lever height. Parts are easy to find at vintagedoublehose.com . It's a great addition to my stable of old regs (Mk5 and Mk10 Scubapros with 109 seconds, and a couple of USD double hoses). I find these easier to work on and tune than much of the newer stuff.

Anyone have a good source for Conshelf XIV second stage exhaust tees?

By the way, I bought the second stages on eBay. The first stage was given to me by a friend who said a LDS wouldn't work on it!

 

[herman]

Kinda hard for me to add much behind Luis but there are a couple of things to look at on the second stage. Some of the plasic housings were prone to cracking around the hose, it's mostly cosmetic but none the less they do tend to crack there. Also, inside the housing there is a plastic diverter that channels air tward the mouthpiece adding some ventri effect to the design. I have had 2 of those come unbonded from the housing making the housing useless. I have a good number of them and so far only 2 have failed but it's worth taking a hard look to make sure they are not about to come loose.
I tend to agree with Eric on the second stage balancing although a good quality balanced second stage does tend to breath a little easier and I like a cracking pressure adjustment. If you want possibly the best reg ever made, add a Scubapro 109 second stage to the Conshelf, don't get any better than those 2 combined.

 

[Eric Sedletzky]

Kinda hard for me to add much behind Luis but there are a couple of things to look at on the second stage. Some of the plasic housings were prone to cracking around the hose, it's mostly cosmetic but none the less they do tend to crack there. Also, inside the housing there is a plastic diverter that channels air tward the mouthpiece adding some ventri effect to the design. I have had 2 of those come unbonded from the housing making the housing useless. I have a good number of them and so far only 2 have failed but it's worth taking a hard look to make sure they are not about to come loose.
I tend to agree with Eric on the second stage balancing although a good quality balanced second stage does tend to breath a little easier and I like a cracking pressure adjustment. If you want possibly the best reg ever made, add a Scubapro 109 second stage to the Conshelf, don't get any better than those 2 combined.

I actually run a G200B off my Conshelf 21. Yeah I know, two balanced units, but the G200B needed a home and the MK 20 sits.
Between my MK5/109 BA & 109 adjustable setup that I got from Couv and my Conshelf setup, there isn't really anything else I need.

---------- Post added May 9th, 2014 at 09:49 AM ----------

They still sell metal Conshelfs brand new:
Aqua Lung Conshelf XIV Regulator

A little pricey but it can be had.

 

[herman]

I actually run a G200B off my Conshelf 21. Yeah I know, two balanced units, but the G200B needed a home and the MK 20 sits.
Between my MK5/109 BA & 109 adjustable setup that I got from Couv and my Conshelf setup, there isn't really anything else I need.

---------- Post added May 9th, 2014 at 09:49 AM ----------

They still sell metal Conshelfs brand new:
Aqua Lung Conshelf XIV Regulator

A little pricey but it can be had.

Everyone needs an Argonaut with red hoses.

 

[ams511]

Anyone have a good source for Conshelf XIV second stage exhaust tees?

There was a thread a while back (which I thought I bookmarked) that listed a supplier for these.

Edit: Found it: Aqua Lung Exhaust Tee for Conshelf XIV 1019-19