AL 40 Stage Bottle leaks when under water. Pressure drops

[Jack Hammer]

Perfectly normal.

Pressurized on surface, turn off. Decsend, open valve to account for pressure drop in line from ambient pressure change, close valve.

If you are swimming you will occasionally burp a little gas from line due to bumping reg, water movement over reg, depth changes, etc. Occasionally crack the valve open then back closed to keep line pressured.

Also make sure the venturI is off and the knob turned all the way in. This will help quite a bit. Only open those when you are breathing off reg.

 

[justbillin]

You should try this as an experiment to put things in perspective. Pressurize your stage bottle and shut off the valve on the surface. Then try to take the smallest shot of air out of the regulator you possibly can. I’d be curious to find out what the pressure gauge is now reading! Your stage probably only has a short HP hose & gauge or button gauge, and one 40” low pressure hose. That’s not much volume of pressurized air, and keep in mind that it is mostly low pressure air in the second stage hose!!!

 

[Yoyodyne-88]

I'm with justbillin. If we are talking about the pressure loss being from the second stage,not the tank, and with the tank turned off, it would take very little to cause a drop in pressure.

 

[scubadude223]

The pressure is only what is in the second stage.

I turn it on and off on the surface before I start the dive. My concern is only what is in the second Stage. Every 5 - 10 Minutes I open and close the valve to deal with the 500 PSI of second stage loss. This does not happen all the time mainly when I am moving. My style of diving is to remain in one position for an extended period of time. The reason is I enjoy looking at the life in the ocean.

My style of diving makes me very unpopular with buddies. I like to spend the entire dive in 2 - 3 locations for 10 - 15 minutes at a time. Diving alone sometimes is the only way that I can enjoy this style of diving.

 

[Pavao]

... if he turns the valve off, then the leak has nothing to do with a burst disk. ...

Why?
You better not be relying on saving gas by shutting off a tank valve because a burst disk leak.

---------- Post added May 3rd, 2015 at 09:07 PM ----------

OP, the use of some simple common sense here should help you tremendously.

You have the equipment underwater, will take less than a minute, look at it, do you see bubbles coming out of it?

A) No - Then you have no leak.
B) Yes - Then you have a leak...Where are the bubbles coming from?......

Purge buttons on regs are generally very sensitive, specially when fully charged (3000PSI), the slightest bump on it, or simply a stronger blow of water can/will cause a bit of gas to purge out, it's perfectly normal, it is not a problem and you will unlikely ever notice the exact time it happens.

But again, charge it, place it in front of you, do you see a string of bubbles coming out?.....

 

[NAM001]

It seams that the op is taking the spg reading as an indication of the bottle and not the psi at the reg. open the valve all the way if no leak then there is no leak. any reduction is from bumping the reg and purging. Is that not why we leave the valve shut to prevent loss from such incidents. Of course he could open the valve, then shut it wait for it to shoe loss of psi and then reopen the valve and regain psi. Of course if he had one of them leaky Sherwood regs on it and left the valve open then all is normal.