Aqualung Conshelf XIV schematic

[Gonzo_G22]

what about a Scuba Pro G250, would this mix/match be a good one?? i know it is not a metal 2nd stage but would this be good or would a balanced 109 be a better choice and how hard would it be to balance a 109 yourself giving that i have never worked on a reg befor... but pretty darn good with my hands and have done many small projects.. by know means am i encapable to rebuilding things.. for the most part things like that come easy to me..

another thing: i was thinking of building on the conshelf 14 and or the 21, was looking at puting a titan 2nd or a micron 2nd and octo with maybe something like a sunnto computer, just trying to at least stay in the same Aqualung family...
and hear is a goofy question... what does "balanced" mean????

 

[herman]

The 250 would do fine, just harder to find and you are going to pay a lot more for it. Converting the 109 is pretty simple, remove old internal parts, install new internal parts and tune up. I would suggest converting the 109 if for no other reason than it makes a good first reg repair/conversion.
You can use pretty much any second stage.
I highly suggest you get the 2 books I list below, they are pretty much the Bibles of the reg tech world. Reg Savvy is a little more on the technical side (the physics of how regs work) and Scuba Regulator Maintenance and Repair leans a little more to the DIY side. The combination of the 2 will give you a really good understanding of scuba regs. I encourage you to make these 2 books your first purchase, they will save you a lot of money and are well worth the cost.

"Regualtor Savvy" by Pete Wolfinger Scuba Tools
"Scuba Regulator Maintenance and Regair" By Vance Harlow Airspeed Press Homepage - Books For Serious Divers

Your balanced questions is covered in detail in both books but I will try a short answer. First off, the first and/or second stages may be balanced. It is not a requirement that both stages be balanced, nor does it hurt anything if both are. Each stage handles balancing differently and is not dependent on the other to accomplish the job. The overall purpose of balancing is to keep the second stage performing at the same level (cracking pressure and work of breathing) over the entire range of tank pressures - ~300 to 3000+ psi. This is done by building the first stage in such a way that it's output to the second stage, known as IP (intermedient pressure) stays at a constant (usually somewhere in the 130 to 145 psi range) as the tank pressure changes. With a constant input pressure the second stage operations stay constant. The second stage may also be balanced. This is accomplished by constructing the second stage valves in such a manner that it compensates for varing input (IP) pressure, keeping it's operation constant. I have purposely avoided the details because it gets kinda long winded and the books above do an excellent job of descibing the process in great detail.
All USD/AL Conshelf/Titan/Legend/SEA first stages are balanced. They use the same internal parts in different looking outside packages.
And for what it's worth, balancing is the most misunderstood subject on this board. Read the books, you will be glad you did.

 

[Gonzo_G22]

herman,
you are truely a Guru, to me at least, thanks for the info.. but i got some more questions for you... i have been trying to aquir some conshelfs becuase i mad the choice awhile back to go with this type of gear for differant reasons but im glad that i decided to go with this set up...
looks like it will suit me well and for the purpus of getting some equiptment that is going to be tuff and dependale and for the stuff im going to need to do with it im sure its going to be a great set up...
here is the questions,

i have noticed that the conshelf 21's (1st stage) are marked 3000 psi but have noticed on some of the pics of conshelf 14's they are marked 4000 psi, what is the diferance??? (other than 1000 psi of coarse)
i mean to ask why the differance and what is the bennifit for the extra 1000 psi. on some of the older 14's

and if later down the road, i well i know later down "my path" i'm going to want to breach the tech diving aspect of the sport, and well is that where the "4000 psi reg" going to come to play???

is the conshelf 14 (souped up) a reg that will work for some deep tech diving??? that is if you can soup up a conshelf 14... is the something that could be done to get this reg capable to dive tech diving??? or is it true that you would have to buy the most expensive high performance model to do tech diving?

main thing i want to know is what is the 4000 psi models used for???
the reason i ask is most all the tanks i have looked at are 3000 psi or under??
is there 4000 psi tabks out there that i just havent seen yet or is there some other reason for the 4000 psi first stage reg??

 

[herman]

herman,
you are truely a Guru, to me at least, thanks for the info.. but i got some more questions for you... i have been trying to aquir some conshelfs becuase i mad the choice awhile back to go with this type of gear for differant reasons but im glad that i decided to go with this set up...
looks like it will suit me well and for the purpus of getting some equiptment that is going to be tuff and dependale and for the stuff im going to need to do with it im sure its going to be a great set up...
here is the questions,

i have noticed that the conshelf 21's (1st stage) are marked 3000 psi but have noticed on some of the pics of conshelf 14's they are marked 4000 psi, what is the diferance??? (other than 1000 psi of coarse)
i mean to ask why the differance and what is the bennifit for the extra 1000 psi. on some of the older 14's

and if later down the road, i well i know later down "my path" i'm going to want to breach the tech diving aspect of the sport, and well is that where the "4000 psi reg" going to come to play???

is the conshelf 14 (souped up) a reg that will work for some deep tech diving??? that is if you can soup up a conshelf 14... is the something that could be done to get this reg capable to dive tech diving??? or is it true that you would have to buy the most expensive high performance model to do tech diving?

main thing i want to know is what is the 4000 psi models used for???
the reason i ask is most all the tanks i have looked at are 3000 psi or under??
is there 4000 psi tabks out there that i just havent seen yet or is there some other reason for the 4000 psi first stage reg??

Not sure I remotely rate a gruru title but thanks. The only real difference is the yoke is beefed up a little in the higher pressure versions which is pretty much a screw off/screw on mod. I don't know for sure but I suspect it was as much a marketing ploy as much as anything. By the time you are into HP tanks and tech diving, you will need a bunch of training and a lot more equipment anyway so I would not worry about that for now. You can always use the lower pressure ones for deco bottles. I don't recall seeing any 4000 psi rated tanks but there are some in the 3500 range.

 

[Couv]

Not sure I remotely rate a gruru title .....

I'm sure you rate the guru title….spelling not withstanding.

c

 

[Luis H]

I also have a few Conshelf that are stamped 4000 psi. They are the same yoke (and of course internal parts) as the ones marked 3000 psi (or 230 bar, etc.). They are all designed the exact same way.

The only difference is that someone at CGA (Compressed Gas Association) or similar association for some strange reason decided that yoke connections should not be used for high pressures and then they arbitrarily decided that high pressures are 3500 psi and higher. Since then some tank manufacturers have actually de-rated some steel tanks to 3442 psi just to pass below that rule and been able to be marketed to a bigger audience.

So any modern yoke connection can be used to 3442 psi but not to 3500 psi. I know that a line has to be drawn somewhere, but it is kind interesting that the Cousteau team used yoke connections to 5000 psi for years without any issues.


For most tech diving you can definitely use a Conshelf, but the preferred connection in the tech diving community is the DIN connection. You can convert a Conshelf to DIN, but the conversion kits are not always easy to find. As Herman said, don’t worry about it for now.


As a side note: I have used yoke and DIN connections for close to 40 years (long before it was known as DIN connection and long before it was used in the US) and my general preference is the yoke connection. If properly used I have found either as reliable, the DIN is a bit more stream lined, but IMO it is not as convenient and on the long run the threads get a lot of wear.

Also in the case of a Conshelf (and several other regulators with similar geometry) the DIN adapter tends to make the first stage kind of long and may tend to get a bit close to the back of your head of neck.

 

[herman]

Deleted, it appears I can't hit the send button the correct number of times either.

 

[herman]

I'm sure you rate the guru title….spelling not withstanding.

c

Ahhh bleep! I thought I got that....Oh well, never claimed I could spell.