Regulator issues after servicing

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Although what you said is substantially correct, in reality fixing the free flow acting on the knob is not EXACTLY what happens when you fix it by moving the orifice slightly "in" using the flat screwdriver.
The knob does not change the relative position of seat and poppet, it just increases the preload on the spring pushing the poppet against the seat.
So, if there was no gap between the lever and the diaphragm, even increasing the force on the poppet does not bring it to a proper sealing against the orifice, as it cannot travel towards it. If instead the reg has the orifice in the proper position, the lever will have a minimal gap between its tip and the diaphragm meaning that the force exerted by the spring is fully effective pushing the poppet against the orifice.
In practice, acting on the orifice ensures the sealing without increasing the force on the poppet, and this ensures lower work for breathing. Acting on the spring through the knob, albeit producing the same effect of stopping the free flow, results in a slightly increased work of breath.
All that said, most of my SP 109 converted to balanced are tuned exactly as the reg described by the OP: with the knob "all out" they hiss very slightly, just a quarter of turn on the knob stops the hissing. I keep them this way as, in some conditions, a reg on the edge of free flowing can be useful.
I had myself at about 50 dives in mind as I wrote and I wrote specifically for the OP not the regulator gurus of SB. I was aiming for simplicity over precision (hence using the term mimics rather then mirrors) but perhaps too much so. Thanks for the clarification.
 
Now that the issue has been brought up by others, let me say that the half turn and more displayed by Alec Pierce on that orifice early in that video is absolutely frightening without some context.
He hasn't connected to an inline adjuster at that point, and is only demonstrating closing the valve. But he makes almost no mention of the critical element of lever drop, and does the potential DIY'er no service with this simplistic video. I am appalled.
 
Now that the issue has been brought up by others, let me say that the half turn and more displayed by Alec Pierce on that orifice early in that video is absolutely frightening without some context.
He hasn't connected to an inline adjuster at that point, and is only demonstrating closing the valve. But he makes almost no mention of the critical element of lever drop, and does the potential DIY'er no service with this simplistic video. I am appalled.
Wow. Ok. Once again I must be missing something. I don't know Alec so can’t speak for him but I don’t think the short video was ever intended to teach anyone how to rebuild a regulator. I included the clip as a visual aid to my post. Nothing more.

It is an example of what I might have tried in her situation, in the field. I had no idea my quick (possible fix) would be appalling.
 
Wow. Ok. Once again I must be missing something. I don't know Alex so can’t speak for him but I don’t think the short video was ever intended to teach anyone how to rebuild a regulator. I included the clip as a visual aid to my post. Nothing more.

It is an example of what I might have tried in her situation, in the field. I had no idea my quick (possible fix) would be appalling.
You may be appalled if you couldn’t get a breath off of your reg after hitting -10 feet.
 
You may be appalled if you couldn’t get a breath off of your reg after hitting -10 feet.
And what exactly from my post (or his clip) would cause that to happen?
 
I
And what exactly from my post (or his clip) would cause that to happen?
F you turn the orifice in too far, the lever will get lower.... Resulting in less functional travel and a lower max air delivery. Can get sporty fairly quick. Just addressing the idea of turning in the orifice without addressing the lever height relationship can lead someone to a dangerous end result.

Respectfully,

James
 
Yes, James has that spot on. When I think of orifice adjustment, I think in 2-3° adjustments with 1/12 of a turn the max at any one time. The only time I'm turning 1/2 turn or more is with an inline adjuster attached, so you can hear the valve about to close, and slow way down.
Just seeing him cranking away as he spoke was hard to watch. It's not that he's wrong for a given circumstance, but rather that that's the visual picture the viewer takes away when they decide they can fix a buddy's freeflow at the beach.
The lever drop from a half turn is profound, if the valve is almost sealed, which is the situation with the typical slight freeflow. Now you have a valve that is sealed, but with a low lever. It breathes "okay" at the surface, but when your buddy takes it to 3 atmospheres he dies, because the opening isn't sufficient for the tripled gas density.

I didn't mean to pick on you, @uncfnp . Alec Pierce has tons of followers. But his easy-going approach doesn't really fit with reg service. It ain't rocket science, and almost anyone can do it. But it is so precise, and the underlying theory is so rarely taught to shop techs, that the law of unintended consequences can really do some damage.
 
Fair enough. I certainly understand your reaction to the degree of turn. I assume it is for effect and to demonstrate the extremes but you are absolutely correct that it is misleading and that his approach is very relaxed and imprecise.
 
Just thinking about Alec's video, for those reading along, has gotten me all upset.
On top of the excessive amount of adjustment for the camera is the additional consideration that Alec is just wrong in this case.
Using the orifice (nobody calls it the "hard seat" any more) to set spring tension is a downstream regulator technique from decades ago. It doesn't apply to balanced regs because you can't set lever height afterward like you can with a downstream reg. Alec is a very experienced guy. But some of his beliefs seem to be rooted in a technology that has been superceded by more modern regulator design.
For a balanced reg, the orifice is ONLY used to seal the valve. To adjust breathing resistance you don't unscrew the hose. You go to the other side of the reg and directly adjust spring tension. If you have a reg with no knob, you take off the cap on the side and screw in the hidden fitting.
If you have a fancy G260 or equivalent, you pry off the cap on the knob adjuster, and once again adjust the hidden fitting.
But here's the rub: if you have any of the myriad balanced regs with a knob but no microadjuster, then the cracking effort you get once the valve is "just sealed" is the cracking effort you get. If it's too low, then you dive with the knob turned in a half turn or more. What you don't do is turn the orifice in more than, say, 15° more, because your lever will fall and impair valve opening.
The orifice is NOT used to set cracking effort on a balanced second stage, beyond adding perhaps 0.1" above "just sealed".

There. I feel better now that I got that off my chest. :wink:
 
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