Regulators with Flow Adjustable Knobs

[Got2Go]

awap, tbone, got2go - that sounds logical. So why does the Apeks manual state that you should turn the knob in all the way when soaking?

I can't factually answer that question, but can certainly guess: they are being overly cautious? (perhaps unrealistically so?)

Could there be a normal scenario (everything working correctly and/or as expected) where the spring pressure on the seat is so low that at an un-pressurized state, moisture/air/water can breach the seal ?
I do not know and can't think of one at the moment.

Perhaps others will chime in on this.

 

[redacted]

awap, tbone, got2go - that sounds logical. So why does the Apeks manual state that you should turn the knob in all the way when soaking?

Probably means there is a seat saver feature.

 

[kelemvor]

My scubapro s600's have such a knob. I normally have them fully open when in use, and fully closed when not in use (octo or sidemount etc). I can breathe fine with the knob fully closed but it's much more pleasant fully open. I've never found any reason to go in between. Mine don't freeflow unless I am at the surface and they hit the water mouthpiece up while fully open.

I can't really tell any difference in the dive/predive knob.

 

[Got2Go]

Probably means there is a seat saver feature.

That makes more sense.

But, wouldn't that mean that the seat saver feature depends on the knob being somewhere other than the most restrictive setting in order for it to 'save' the seat ?
(as they suggest turning it fully in for the LP seat to have a seal)


I would think the seat saver feature would 'save' the seat regardless of the knob position.
Or, state in the manual that the know should not be fully in in order for said feature to actually work.
(I havent checked manuals, so they might indeed say something like that)


???

 

[keyshunter]

Probably means there is a seat saver feature.

Apeks seconds do not have a seat saver feature.

 

[Aotus]

I find my hogs actually breathe too easy -what is that called, when I breathe in it gives me more gas than I expected - at about 90 feet. So, I turn the Venturi lever away from me and it feels perfect. Is this the wrong way to do this? I just leave the knob (not lever) at full open always.

 

[redacted]

I find my hogs actually breathe too easy -what is that called, when I breathe in it gives me more gas than I expected - at about 90 feet. So, I turn the Venturi lever away from me and it feels perfect. Is this the wrong way to do this? I just leave the knob (not lever) at full open always.

That is called positive pressure breathing and you are controlling it correctly with the Venturi adjustment lever to get a level you are comfortable with. When the reg is used as an alternate, it is common to minimize the venturi effect to minimize the force of any free flows that may occur. The user adjustment knob controls cracking pressure. When the reg is in use, most like to set it to the easiest breathing level that does not result in a slight leak. (I like to adjust my Scubapro Adjustable to a slight leak and then control it with a half turn or so.) On my Adjustable alternate, I usually crank it in 1 to 2 turns to reduce sensitivity to current or being bumped.

---------- Post added November 18th, 2014 at 09:48 AM ----------

Probably means there is a seat saver feature.

I didn't think they did. Perhaps that instruction is to reduce the likelyhood of that valve opening if it is bumped during an unpressurized soak.

---------- Post added November 18th, 2014 at 09:56 AM ----------

That makes more sense.

But, wouldn't that mean that the seat saver feature depends on the knob being somewhere other than the most restrictive setting in order for it to 'save' the seat ?
(as they suggest turning it fully in for the LP seat to have a seal)




I would think the seat saver feature would 'save' the seat regardless of the knob position.
Or, state in the manual that the know should not be fully in in order for said feature to actually work.
(I havent checked manuals, so they might indeed say something like that)


???

My Scubapro 2nds with a seat saver feature have no contact pressure between the seat and the orifice with the knob open (which is the position for use and for storage) until they are pressurized. With it turned all the way in, there is enough contact force to prevent water from passing the valve. I am not sure how that force compares with balanced and unbalanced 2nds that do not have a seat saver feature, but I suspect it is somewhat less so still a reduced tendency to engrave in storage. I say that because it just does not take that much force to seal and exclude water.

 

[mikeycanuk]

hmm, off topic, but I don't think this is the right way to reduce SAC. If you body needs the air, and you restrict the breathing by making it harder, it result in C02 retention, which can result in much worse situation.

What I find is that I tend to gulp or quickly breathe air. I just slow my breathing down, it's worked so far and no ill effects. I assume I'm wasting less air vs actually restrictng air.

 

[redacted]

What I find is that I tend to gulp or quickly breathe air. I just slow my breathing down, it's worked so far and no ill effects. I assume I'm wasting less air vs actually restrictng air.

Your altered breathing pattern is apparently off-setting the increase SAC you should be experiencing due to increased WOB; so it may be working for you for now. But it would be better if you get your breathing pattern under control and then take advantage of all the performance your regulator has to offer.

I used to practice my breathing pattern as I sat at work. Then I consciously practiced that pattern UW. Eventually it just became 2nd nature. It cut my SAC in half.

 

[Bob DBF]

Quote Originally Posted by mikeycanuk View Post
I've found on my XTX200 that I keep the knob all the way in. I've been actively working to get my SAC down and having some resistance helps slow down my inhalation to the point I easily beat my wife's air consumption.

hmm, off topic, but I don't think this is the right way to reduce SAC. If you body needs the air, and you restrict the breathing by making it harder, it result in C02 retention, which can result in much worse situation.

It depends. If the higher cracking pressure and WOB change the pattern of mikeycanuk's breathing, and he takes complete breaths to exchange the air in his lungs there will be no increase in CO2 retention. If you get a longer slower breathing pattern that properly ventilates the lungs, it is better for your SAC than a shorter faster breathing pattern that properly ventilates the lungs (it takes X amount of gas to do the job). You should be aware of the situations that generate more CO2 and what signs your body gives you as it happens because it can be controlled by your breathing pattern, if you are aware.

Is there "a right way" to reduce SAC?



Bob
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I may be old, but I'm not dead yet.