K valve vs J valve

[TwoBitTxn]

OD,

I see your point. I missed the part in your first post about removing the guts and converting it to a K valve. I may just do that.

Down is open. The tag on the knob tells you what is open and what is closed. I'm not prone to panic when I run out of air either. I'm an ex volunteer fire fighter. Been there. I did almost freak in Level A training when my air wasn't turned on.

Thanks

Tom

 

[Ontario Diver]

No problem Tom , as long as you know you can make a decision

Enjoy

 

[miked]

Tom,
Glad you got a definite ID on the J valve.
OD's description of the functioning of the valve is right on the money. Having gotten my OW gertification with a J valve, I'd probably agree with swapping it or disabling it.
I can still remember the "thrill"???, during the OW certification dives, of feeling that sudden shutdown of the air supply, "calmly" reaching back for the pull rod, while praying that it was up at the start of the dive, and that there really was another 500 PSI in the tank.A trip to be avoided, if possible.
Please let us know what you do.
Miked

 

[Rick Murchison]

Since no one has mentioned my number one reason to disable the "J" valve (or at least lockwire it to the "ON/down" position) I will - the inevitable short fill.
Should the tank be depleted to 300 psi or less and the valve be left up (or get put in the up position) and the person filling the tank doesn't notice it, it won't allow the tank to fill - putting pressure on the outside orifice won't force the valve open. So the fill station will show a full tank when only the fill whip is pressurized, and when you get ready to dive you'll have an empty.
And that won't make you very happy.
Rick

 

[DivingGal]

here I popped on this thread 'cus I was curious about the topic.

The mix of humour and serious stuff kept me reading. Well done!!! I even found out a few new things.

 

[TwoBitTxn]

Rick,

Wow thanks dude. Now that is good solid reasoning to disable the valve. I wonder honestly how many people running fill stations, especially when its a member of a younger generation, know that.

Tom

 

[herman]

Hi Guys,

I have a "J" valve tank that I have been using for years. Mine has the valves opposite each other, looking down on the tank with the air opening tward me, the reserve knob is on the left and the open/close valve is on the right. I don't see any real need to replace the valve assuming it's in good shape. Trust me, you WILL know if the valve is in the "normal" diving position. Mine was in the "normal" position several years ago and scared the dickens out of my buddy. The spg will fluctuate up and down as you breathe, with a full tank mine goes from about 3000 to 1500 and back. The old timers at my LDS tell me that this is normal. That's the only difference I can tell with mine when it is in "normal" mode until it gets to about 300 psi (which I did on purpose in a guarry just to see how it worked). At that point, breathing got a lot harder but you could still inhale. When you flipped the lever to "reserve" it breathed normally. I keep mine as a conversation piece and it makes a great buddy "checker", flip it to normal and see how long it takes for him to have a cow. By the way, I dive mine on "reserve" all the time.....unless I have a new buddy....

 

[jobowker]

When I was getting certified, most of the tanks were old LP steel 72's with j valves. No big deal. We all would turn on the air and flip the level down (no reserve). Since we started out that way, it was no big deal. Now that I'm used to k valves, I'm not certain that I would remember to flip the lever down when truning on the air, so if I owned one, I'd have the lever removed.

 

[Rick L]

I still use a set of steel 72s with J valves!
I just leave them in the down pulled position!!
Rick L

 

[Campana]

Don't worry. As a part time tank monkey, I can tell you that if the valve is in the up position, the tank won't fill, at all. You have to move it down. I can't imagine someone accidentally not filling your tank cause the J valve was in the up position.

They work fine. Just make sure they're in the down position as part of your predive check.

Replacing it would cost about $35 for a K valve, IF the tank has a 3/4" neck opening. If it's the old 1/2" or whatever, it's hard to find valves and your stuck with it.

I would just keep it and not worry. I've got three or four tanks with J valves and never had a problem. Our shop has several, same deal.