What makes a Conshelf 30 different?

[Green Frog]

The Conshelf 30 (Royal) 1st stage had from memory a 7/16 UNF HP outlet thread from the get go for the submersible pressure gauge. While the Conshelf XIV 1st stage at the time still had the 3/8 UNF thread
Only later did the Conshelf 14 and Conshelf 21 etc go over to the 7/16" HP Thread.

That corresponds with what I’ve experienced. The biggest complication after all these years since these regs were in current production is that I’m sure lots of people other than me have thought of a “better” combination than what came from the factory. So what we might encounter as a “set” now may be far different from original.

The Conshelf 21 I have came from the distributor with 1 HP port in 7/16” and 4 of the LP ports in 3/8”. Then I when got the SEA 1st (orphan - no hoses, 2nd stages, etc) with the 1/2” LP port, I was kinda surprised!

Following up from your previous post, is the Gates SAE 100R3 hose with the 1/2” ID hose that would have come on the Pro et al? Would they have “aged out” by now, or would that high end Gates rubber still be good?

 

[Scott G. Bonser]

The intermediate low pressure hose back then was supplied by The Gates Rubber Company
known today as Gates Divers Hose. Originally it was to specification above SAE 100R3 and 1/4" ID bore for the Conshelf range.

Later it was supplied as Gates 33HB Divers Air hose but 3/8 and 1/2" ID

The metal end fittings were proprietary as the internal quill diameter and external hose crimp strength to each specific hose diameter is crucial to avoid leaks and pull offs.

I don't think they supply it anymore but you can still get SAE100R3
However most scuba suppliers have gone over to coloured thermoplastic material and the inferior PVC core tubes with fabric braid style and a replace every 2 years caveat. Iain

…Hmmmm. That may be a good reason to have ‘spares’ of these fabric-covered hoses in ‘save a dive‘ kit. It seems to be all that is available anymore…

 

[scrane]

Although there are some substantial differences between Conshelf firsts, the only easy way to tell the model is the decal on the knob. Unfortunately these knobs are freely interchangeable and there is no certainty that the knob is original.
One of my favorite things about the Conshelf's is that the yoke can easily be removed for convenient packing. That and the IP is externally adjustable. That and it's simple to work on and parts are available. That and it's reliable and trouble free. That and the inline radial port layout is ideal for my setup.
Not a big fan of the second stages, though. To me it's just another unbalanced downstream design.

 

[DIVER1969DOWN]

Mention of the Conshelf 30 shows up from time to time, but in spite of several serious searches here and via Google, I can’t find a definitive answer. What was it really? It appears that AL found a batch of unused Con XIV seconds and just made a new purge button sticker and hung them on some general C 22 or 23 firsts and sent them out. Those I have seen don’t have the external poppet adjust of the Conshelf 14. Can anyone solve this problem for me?
TIA ~ ~ Froggie

The Conshelf 30 is USD telling what 1st stage is attached to a Conshelf 2nd stg, The 30 was made during the geat 1/2" hose experiment and was the highest flow of their bal diaphragm 1st stages

 

[Green Frog]

The Conshelf 30 (Royal) 1st stage had from memory a 7/16 UNF HP outlet thread from the get go for the submersible pressure gauge. While the Conshelf XIV 1st stage at the time still had the 3/8 UNF thread
Only later did the Conshelf 14 and Conshelf 21 etc go over to the 7/16" HP Thread.

Yes, all the early Aqua Lung first stages seem to have had the 3/8” HP port. I was recently minded of this when checking the IP of my Aquarius first stage. I hooked the IP gauge line up to the HP port. When I turned on the tank valve, things were very exciting for a few milliseconds!

Now that I have the painful admission off my chest, here’s the real question I had for tonight. Finding the necessary 1/2” hose with its proper Aqua Lung fittings involves a special effort, or for the purposes of casual diving, is the step down adaptor and a 3/8” hose sufficient? I’m still having a hard time getting my head around what happens to that 1/2” diameter stream of compressed air gets to the same diameter inlet in the second stage regardless. Does this produce an increase in IP to the second stage? One More Chance Scuba in Charleston, SC says he has that adaptor in stock or he can probably get a 1/2” hose if I decide to go that way. So my question is, would I gain sufficient additional performance to justify buying the somewhat more expensive hose, or should I simplify things by using the adaptor and all standard hoses? Decisions, decisions, decisions!

 

[Zef]

Yes, all the early Aqua Lung first stages seem to have had the 3/8” HP port. I was recently minded of this when checking the IP of my Aquarius first stage. I hooked the IP gauge line up to the HP port. When I turned on the tank valve, things were very exciting for a few milliseconds!

Now that I have the painful admission off my chest, here’s the real question I had for tonight. Finding the necessary 1/2” hose with its proper Aqua Lung fittings involves a special effort, or for the purposes of casual diving, is the step down adaptor and a 3/8” hose sufficient? I’m still having a hard time getting my head around what happens to that 1/2” diameter stream of compressed air gets to the same diameter inlet in the second stage regardless. Does this produce an increase in IP to the second stage? One More Chance Scuba in Charleston, SC says he has that adaptor in stock or he can probably get a 1/2” hose if I decide to go that way. So my question is, would I gain sufficient additional performance to justify buying the somewhat more expensive hose, or should I simplify things by using the adaptor and all standard hoses? Decisions, decisions, decisions!

1/2 inch LP regulator hoses are not hard to come by. Mares was still using that standard until just a few years ago for the primary 2nd stage port on their MR22 1st stage.

Also, you will find no real world performance degradation using an adapter and a hose with a 3/8th end.

Either will work but you will have more versatility with the adapter, as although 1/2" threaded hoses are available, the 3/8th variety are much more ubiquitous.

-Z

 

[GJC]

Yes, all the early Aqua Lung first stages seem to have had the 3/8” HP port. I was recently minded of this when checking the IP of my Aquarius first stage. I hooked the IP gauge line up to the HP port. When I turned on the tank valve, things were very exciting for a few milliseconds!

Now that I have the painful admission off my chest, here’s the real question I had for tonight. Finding the necessary 1/2” hose with its proper Aqua Lung fittings involves a special effort, or for the purposes of casual diving, is the step down adaptor and a 3/8” hose sufficient? I’m still having a hard time getting my head around what happens to that 1/2” diameter stream of compressed air gets to the same diameter inlet in the second stage regardless. Does this produce an increase in IP to the second stage? One More Chance Scuba in Charleston, SC says he has that adaptor in stock or he can probably get a 1/2” hose if I decide to go that way. So my question is, would I gain sufficient additional performance to justify buying the somewhat more expensive hose, or should I simplify things by using the adaptor and all standard hoses? Decisions, decisions, decisions!

The 1/2 inch hose thing was a sales gimmick that didn't last long with Aqualung. Unless you are doing very deep or very high flow testing, you will not notice any difference using the 3/8 inch adapter. Using the adapter gives you many more options for hose type, length and availability (especially at remote dive destinations in case you need a replacement there).

 

[Green Frog]

Thanks to @Zef and @GJC! You have pretty much confirmed my opinions I had developed from previous posts on this thread. I may get a 1/2” hose if one falls in my lap, but will definitely get the adaptor for maximum flexibility. Thanks again to all who participated in this thread.
Regards,

 

[Green Frog]

PS I am assuming that a Con 30 second stage differs from a C XIV or other late 1085 boxes only in its powder coated face, with the internals being the same. Am I correct? Does it take the same routine service parts?

 

[Zef]

Thanks to @Zef and @GJC! You have pretty much confirmed my opinions I had developed from previous posts on this thread. I may get a 1/2” hose if one falls in my lap, but will definitely get the adaptor for maximum flexibility. Thanks again to all who participated in this thread.
Regards,

If/when you get an adapter, it is highly recommended to put the adapter on the 1st stage and leave it there...the 1st stage is brass and repeated tightening/loosening of the adapter into the threaded port of the 1st stage is best kept to a minimum....tighten in place and then attach your hose hand tight plus a little extra to secure in place. There are wrench flats on the hose end of the adapters to counter the small amount of torque necessary to break your hose free for maintenance, storage, etc.

-Z