2nd stage adjustment...Why?

[rob.mwpropane]

It is a nice feature to have but is it essential/necessary is something else.
I will need an Allen key to turn it in some of my Apeks 2nd stages(depend on model).

Not essential, but unless someone was giving me a reg for free I wouldn't purchase anything new (or used) that didn't have it.

I would feel differently if I only dove warm water.

 

[graham p]

Thanks @halocline. I guess for technical diving where it isn't just a simple ascent to the surface if something goes wrong, it is nice to have a regulator that breathes as well as a primary. At a tech diver level I would expect the receiving diver to have thier wits about them enough to adjust the regulator to suit thier preference.
I think most recreational divers that need to receive an octo are just happy to have air and want to get to the surface a.s.a.p. They wouldn't be of the mindset to adjust the regulator.

 

[rob.mwpropane]

Thanks @halocline. I guess for technical diving where it isn't just a simple ascent to the surface if something goes wrong, it is nice to have a regulator that breathes as well as a primary. At a tech diver level I would expect the receiving diver to have thier wits about them enough to adjust the regulator to suit thier preference.
I think most recreational divers that need to receive an octo are just happy to have air and want to get to the surface a.s.a.p. They wouldn't be of the mindset to adjust the regulator.

It wouldn't matter though. I can still breath fine from a reg with the knob all the way in, it's just not as easy. If a diver was panicked they wouldn't notice until after they calmed down.

 

[Nemrod]

I have regulators with an adjustment knob (Legend, G250, a G260, 109) and regulators without an adjustment knob (Conshelf, R190, Titan LX, Core) and I find an adjustment knob marginally useful and mostly more trouble than it is worth. It is useful when scootering (maybe) or to fine tune a balky reg that wants to free flow and it allows setting the cracking force perhaps a little lower (when servicing) knowing that I can stiffen it up. Mostly more trouble than it is worth because the adjustment knob is another thing and more parts to service, gets full of grit, sand, verdigris and sticks or jams up. Some are worse about that than others.

James

 

[lexvil]

Without rolling around in the weeds just tell her it’s not to make it harder to breath, it’s mostly there to de-tune it when necessary. I prefer my reg to breath as easy as possible without leaking, as the seat wears (sets) that useless knob can save a dive and keep you in the water until it’s tuned up again. You’ll get used to what ever you dive, dive mostly “set to never freeflow” rental stuff you will probably panic once to breath from a properly tuned reg, the know can put you back into your comfort zone. Oops weeds…

 

[Gone for diving]

It's nice when in fast currents,
(Fast currents is relative)
Sometimes we will grap a rock and watch fish, or something like that, when you look up stream the diagram gets pushed from the on coming water, and will free flow like crazy, just crank it down, problem solved, usually I forget to back it off, for a while anyway,

(Also sometimes if you turn your head, in the flow it opens the exhaust mushroom valve and you next breath is pure water, which is a different problem)

 

[rob.mwpropane]

I have regulators with an adjustment knob (Legend, G250, a G260, 109) and regulators without an adjustment knob (Conshelf, R190, Titan LX, Core) and I find an adjustment knob marginally useful and mostly more trouble than it is worth. It is useful when scootering (maybe) or to fine tune a balky reg that wants to free flow and it allows setting the cracking force perhaps a little lower (when servicing) knowing that I can stiffen it up. Mostly more trouble than it is worth because the adjustment knob is another thing and more parts to service, gets full of grit, sand, verdigris and sticks or jams up. Some are worse about that than others.

James

I disagree somewhat about it being more trouble than it's worth. I try to make sure I'm all the way out but not tight (so all the way, then 1/8th turn back) when done for the day. That took care of them getting stuck.

The idea that it could save a dive (to me) outweighs slightly more maintenance.

 

[Angelo Farina]

Hi all.
So I just replaced my wife's old conshelf SE3 second stage due to a crack in the main body. I bought her a shiny new DGX D6 second stage, and while admiring it and showing her all the cool features she didn't have before, she asked " Why would anyone want to make a regulator harder to breath off of ?" Refering to the adjustment knob on the side of it.
I didn't have an answer...
On her unadjustable Conshelf I would set the cracking pressure to 1 inch, and all would be good. No need to fiddle with a knob underwater.
So I am wondering why do other divers out there intentionally stiffen the breathing on thier adjustable regulators?
Thanks.

I always used two identical and complete Scubapro MK5+109 (usually converted to BA).
No crap octopus for me...
The knob is a very important feature for me, in three cases:
1) The unused one is better kept with the knob halfway screwed, for minimizing air dispersion.
2) I feel the need to screw in the knob just 1-1.5 turn on the reg in my mouth when swimming fast, or when hooked and looking against strong current (channels in Maldives, etc.), for avoiding free flow.
3) For fixing the slight free flow that sometimes affects these regs when not serviced for years - typically just 1/4 or 1/2 of turn. When they need more than 1/2 of turn, it is time to service them.

 

[graham p]

Thanks everyone for the replies.
So it sounds like when using the adjustable second stage as a safe second, it is nice to be able to dial it down untill needed.
When in higher currents, sometimes being able to dial it down is beneficial.
And as the seat breaks in, to be able to dial it down is handy.
I just hooked the reg up to my manometer and measured the cracking effort while adjusting the knob and got .75" at the easy end and 2.5" at the harder end.
The low end is lower than I like to set up my regulators, so adjusting the knob in a little bit brought it up. The high end is where I adjust my safe seconds, so it would work for me there as well.
I am happy on land with the regulator so far and am looking forward to diving it later this year as I dive all my family's regulators first after service. If my Conshelfs ever crap out I think I'll replace them with this reg as well.
Anyway thanks again for the answers.

 

[divad]

Shutting off the venturi lever should be the easiest reaction to a free-flow.