Adjustment Knobs

[miketsp]

All the time (Micra Adj) as the setting goes from hard to breathe right up to ff (last 1/2 turn as per manual) and according to the user manual you are supposed to close it to the hard to breathe position when rinsing regs to avoid water ingress.

 

[idocsteve]

Sometimes I remember I've got that thing... Like every 100 dives or so

I've crawled into some pretty strong currents, but my G250 never free flowed, while still giving me more air than I can use.

Yeah but how is it set? If it's full on, and it doesn't freeflow, then it's all good, however if you've got it set to impede airflow you're probably adversely affecting your SAC rate because you've gotta work harder for each breath.

 

[Zung]

Yep, full on. With the Venturi thing at midway, the WOB turns positive pretty early and gives me a bit more air than I really need.

 

[jl_va_21]

Never had a problem and never really noticed much difference on any setting. I chose my regulator largely thinking that feature would be nice. In reality though it has not made much difference. I now do not really use it much. Maybe I don't dive in conditions extreme enough to warrant it?

 

[Bubbletrubble]

[I'm going to preface this post by clarifying that my comments relate to the cracking pressure/inhalation adjustment knobs and not the Venturi lever. The two adjustments do different things, but both could affect overall perceived WOB.]

Sure, dive site conditions factor into how much one might fiddle with the knob during a dive. How often you adjust your cracking pressure adjustment knob might also be determined by how the reg was tuned. If the second stage was tuned to allow slight freeflow with the knob fully open, then you'll probably find yourself closing down the knob a little when you aren't actively breathing off of the reg. This could be the case for a backup reg or an octo.

My first-choice reg setup has cracking pressure adjustment knobs on the second stages. I use 'em and like 'em. My spare reg setup lacks the adjustment knobs, but the second stages are tuned appropriately so freeflow isn't an issue.

Some people like the knobs and others don't. Not a big deal either way so long as the second stage is tuned properly.

For those who have the cracking pressure adjustment knob, you should probably open up the knob fully while storing the regs in-between dives so as to minimize wear on the low pressure seat.

 

[idocsteve]

[I'm going to preface this post by clarifying that my comments relate to the cracking pressure/inhalation adjustment knobs and not the Venturi lever. The two adjustments do different things, but both could affect overall perceived WOB.]

I always thought (on my Beuchat regulator) that the lever was more of an open / close, and the knob was the fine tuning.

 

[j yaeger]

...also use all the time...

 

[Bubbletrubble]

I always thought (on my Beuchat regulator) that the lever was more of an open / close, and the knob was the fine tuning.

@idocsteve: Some of the Beuchat second stages employ the barrel poppet design used in adjustable balanced Apeks, Zeagle, and Scubapro second stages.
I don't know which Beuchat model you have, but I'd be willing to guess that the lever is a "+/-" Venturi lever and the knob is a cracking pressure/inhalation adjustment knob. On my second stage, I can still breathe off of the second stage even when the Venturi lever is set to "-" and the inhalation adjustment knob is tightened all the way down.

 

[idocsteve]

I don't know which Beuchat model you have, but I'd be willing to guess that the lever is a "+/-" Venturi lever and the knob is a cracking pressure/inhalation adjustment knob. down.

Yes, that's how mine works, which to me, means that the lever is "open/close" and the knob is "fine tune".

 

[Bubbletrubble]

Yes, that's how mine works, which to me, means that the lever is "open/close" and the knob is "fine tune".

@idocsteve: Please refer to your reg manual for the specifics on how/when to use the Venturi lever. Setting the Venturi lever to "+" usually deflects the flow of gas so that, once flow is initiated, it makes it easier to sustain that flow. Setting the Venturi lever to "-" simply changes the angle of deflection of the flow of the gas. AFAIK, the Venturi lever is not the same as an "open/close" or "on/off" switch. But, then again, I have no experience at all with Beuchat regs.