How To Open The Tank Valve

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Jafo19D

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No this is not about the quarter turn back - I know you’re supposed to open it all the way and then 3/4 back. I’m kidding!!!

My question is if it’s true that when opening the valve you press the purge on the second stage in order to not stress the first stage. I don’t recall being taught this in OW or being corrected for failing todo this during setup but when I went diving a couple of weeks ago I was corrected for not doing this.

Does this practice really lengthen the life of your regs ?
 
Just open slowly, you can see pressure build in the hoses which also allows you to close it is something pops and or leaks. Practice it with the IP gauge that you should own.
 
I just got OW certified this year and my instructors taught me to do it. Less about regulator life, I think more about hose life... not slamming them with sudden pressure.
 
I was never taught this, had anyone mention it, or seen anyone practice it. Can't imagine what purpose this serves other than to waste a little gas. I just crack the valve open slowly to pressurize the system before fully opening it.
 
I just got OW certified this year and my instructors taught me to do it. Less about regulator life, I think more about hose life... not slamming them with sudden pressure.
Interesting. Yeah they definitely told me it was for the benefit of the 1st stage.
 
...Does this practice really lengthen the life of your regs ?
Using the correct rinsing practice is what "really lengthens the life of your regs"
.........But that's a whole 'nuther thread starter.
 
Slow opening the valve is all you should need to do. When you hear the gas start to flow, pause for about 3 seconds as the system comes up to pressure, than fully open the valve. That will be more gently to all the parts than holding the purge and flicking the valve open.

Honestly if your regulator is so far gone that opening a tank valve quickly will fail it, you really should not be using it for life support. Given the condition of some shops training/rental regulators, it may have been taught so they could use there junk one more time.
 
My approach is to open the valve relatively slowly (to pressurize things gently) while NOT looking directly at the SPG (in case the SPG should blow out). Usually I will hold the SPG with its face against the tank as I slowly open the valve. This is what I was taught in my open water course in 1986, and I continue to use this approach.

ETA: My course used Scubapro and U.S. Divers regs. It's possible to open too slowly for some regs (e.g., Poseidon Odins).

rx7diver
 
never heard of this either. and it does not make any sense to do so. If a hose is that fragile then you want to expose that weakness and / or verify it can take the shock of sudden turn on and not baby it. yes hitting the purge says you have air to the mouth piece but that is it. it doesn't even say you have flow at the rate of demand. I think someone has blown something out of proportion. your BC inflator will do more harm to a lp hose than a tank turn on. My thermo valves work well for this. slow opening per turn of the valve.
 
https://www.shearwater.com/products/peregrine/

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