Partially opened tank valve

[ianr33]

For my students later in life; when someone totally screws the pouch and rightie loosies, there will be some air flowing at the start of the dive.

Speaking for myself,I would rather have a valve totally closed on the surface with no air flowing rather than just cracked open. When completely closed the problem is obvious after a couple of breaths. (And EVERYONE breathes their regs before getting in the water don't they?)

Which is the better place to find the problem,on the surface or at 100 feet??

 

[LeadTurn_SD]

Both of my tanks use the new indicator valve:

Vindicator Valve Handle

which makes it easy to see if the valve is fully open -- the indicator is all green.
It's a useful safety feature and I highly recommend it.

Adam

That looks like the XS-Scuba Safety Hand Wheel. For something that adds very little cost, I find them a great feature; especially when charging a lot of bottles at once. A couple of charter boat dive masters told me they like them as a quick visual before divers go overboard.

I'm normally a "Less is More" kind of guy, but I sort of like the idea behind that "safety" valve.

Having an instant visual "Open" or "Closed" indication on the valve is a great idea, and might actually help prevent the overly-helpful boat crews that are "righty-tighty, lefty-loosey" challenged from making a mistake.

Best wishes.

 

[boulderjohn]

I think I've probably made every dive in my life with a partially opened tank valve & have never had a problem-------> I ALWAYS back it down a quarter turn after fully opening it....

I don't believe the OP is talking about a valve that is 95% open. I believe that when talking about partially open, the meaning is more like 5% open. This is a very common occurrence of for a number of reasons. In my experience, it happens most often when a diver cracks the valve, looks at the gauge to be sure there is enough pressure for the dive, and then stops opening it beyond the initial crack. I have to admit that I have done it more than once myself. Fortunately, I have caught in later checks.

 

[copter53]

Can any1 answer my Q?

 

[halocline]

Can any1 answer my Q?

You mean about the reg malfunction and the slow breathing? To start, most reg malfunctions are leaks or freeflows, so it doesn't really apply there. If you do feel at some point in a dive that you can't seem to get enough air, you should stop swimming, try to relax and breathe deeply and slowly, but that probably has nothing to do with a reg malfunction. In fact, this thread's situation didn't either; it was about a mostly-turned-off tank valve. There really aren't typical reg malfunctions that act like that; maybe a clogged valve or broken mainspring, I suppose. In those cases taking a long slow breath might help you to feel that you can get sufficient air.

As a general rule of thumb, I would say that reg malfunctions should be dealt with by sharing air from your buddy if necessary and calling the dive. (Or using an alternate air source if you have one) That's because most reg malfunctions result in rapid air depletion from your tank, and some (rarely) might result in immediate air stoppage or flooding. Does that answer your question?

 

[copter53]

Does that answer your question?

yes sir thnx

 

[CrispyCritter]

I don't believe the OP is talking about a valve that is 95% open. I believe that when talking about partially open, the meaning is more like 5% open. This is a very common occurrence of for a number of reasons. In my experience, it happens most often when a diver cracks the valve, looks at the gauge to be sure there is enough pressure for the dive, and then stops opening it beyond the initial crack. I have to admit that I have done it more than once myself. Fortunately, I have caught in later checks.

Yes, that is what I meant. I think Diver 85 was just pointing out that my original question was ambiguous in this regard.

This thread got me thinking about flow rates throughout the system (i.e. first stage, second stage, tank valve), and I found this informative thread. Just pointing it out if anyone is curious about the flow rates and hasn’t seen it yet.