Valves "full open" or not?

[cowdog77]

Fully open, but not "hard cranked" open.

 

[Diver Dennis]

1/2 turn back. I'd like to see a cut away diagram of a valve, anyone have one?

 

[Dive-aholic]

Mexico = poorly maintained equipment.

Yeah, but for some reason I thought the DIN valves I had would be a little better maintained...

 

[lamont]

I initially put myself in the "full open to eliminate abiguity camp" since it made more sense to me. I think I had someone on a boat manipulate my valve thinking "oh its at the stop its closed, move it the other way and back 1/4 turn" and wound up diving it 1/4 turn open and it basically quit on me around 60 feet down. Because of that and because of getting worn down reading all the claims that it'd get stuck open or closed and such, i started doing the 1/4 turn back too. Now I take Cave 1 and Fred tells us to keep it fully open to eliminate ambiguity. So I'm back to the way I started diving...

I've never had an issue with my valves getting jammed one way or the other, but I tend to like to break my manifolds down and lube them up like crazy with cristolube...

 

[theITdiver]

I am working on SSI AOW and my instructor teaches full open then 1/4 turn back. I don't remember this being written in any of the books other than just from his mouth in the OW classes.

 

[jscott099]

The quarter down back thing is old school from a time of unreliable valves that got stuck open. There is no standard for PADI or SSI (or anyone else is my guess) to teach it this way. It's just another one of those things that gets mindlessly passed down through the ages. I teach my students the way I learned for caving, full open. Why bother them with one more piece of useless info?

Thank goodness for those who question why we do things the way we do.

 

[DeepSeaExplorer]

As a PADI Instructor, I teach all my students "fully on or fully off".

I'm curious... when your student goes to jump off the back of the boat and you're checking their valve and it doesn't turn, how do you know for certain that it isn't jammed shut, rather than open all the way?

 

[Capt Jim Wyatt]

Fully open.

When the failure arises that requires you to close one quickly there will be no doubt as to which way is off. If they are partially open/closed then when you go to close it in the possibility exists to fully open rather than fully close.

 

[XXXL]

All the way open then back 1/2 turn. When tech diving with twin tanks it is always possible that one of the tank valves could become closed, if it is scraped alongside a wreck or cave.

 

[DeepSeaExplorer]

So we're in agreement then.

I'm honestly not sure. You seem to have contradicted yourself.

You started out by saying that it's either open or closed. Then you responded to TS&M's post by saying you close slightly. Obviously, I like the second answer better than the first.