I have a manifold system set up for acetylene and when I go into shed it smells like there is a gas leak, I checked all the fittings, hoses, and valves. I talked to my sales rep and he tells me that the handwheels are back seated, this goes against everything I have been taught or have read in text books, he told me this is the new AWS standanrds. I am not too sure about this so I have looking into it, most people are saying 1 1/2 turns max; which is what I have always done. Any advice on this topic would be great.
p.s I get my gasses from Prax Air.
Ask him to "show" you the standard, and see how/if it applies to your specific equipment.
You might also ask the supplier for a cut sheet showing the valve cross section view and the backseat. The old style tanks had a removbeable handle with a square head and you used a "T" wrench on them. we used to crack them a 1/4 to 1 turn so they could be quickly shut in the case of a fire, accident etc. The newer tanks are different so there may be some truth to the valve thing. The important thing here is that they should not leak at the valve stem. It's just another place for an accident to occur.
Forget the valve. Keep looking till you find the leak.
JMHO