Suddenly no air from 2nd stage or Octo; tank at 2800 psi

[sharkbitejeff]

Aqua lung was recalling the titan reg with din set up, Due to drownings. I called about mine and they said it was only on the din set ups not with yoke set ups.

 

[Peter Guy]

Diver0001 (or anyone else) -- just to confirm what another wrote, do any of you know if the normal digital SPG (air integrated computer) is sensitive enough to show the "swing" when doing breaths at the surface?

Crowley, clearly you haven't tried my wife's tanks because if you close the valve and then back off 1/4 turn you MIGHT get air, but I can assure you that it won't be much! I don't know what type of valves are on her 95s but they just "leak" air until they are pretty much fully turned on.

I remember being taught to fully open and 1/4 back when I first was certified (1966) and was told the valves had a tendency to jam open so that was why they were cracked off just a bit. Today, my valves are open all the way and no DM had better touch them after I've set them!

 

[Teamcasa]

Diver0001 (or anyone else) -- just to confirm what another wrote, do any of you know if the normal digital SPG (air integrated computer) is sensitive enough to show the "swing" when doing breaths at the surface?

Crowley, clearly you haven't tried my wife's tanks because if you close the valve and then back off 1/4 turn you MIGHT get air, but I can assure you that it won't be much! I don't know what type of valves are on her 95s but they just "leak" air until they are pretty much fully turned on.

I remember being taught to fully open and 1/4 back when I first was certified (1966) and was told the valves had a tendency to jam open so that was why they were cracked off just a bit. Today, my valves are open all the way and no DM had better touch them after I've set them!

I'd pull that (those) valves apart and see why they operate like that. Mine flow freely after about a half a turn open.

 

[jmorriss]

I was in one of the OW 'safe' overhead environments in Florida back in February when something similar happened.

We had just started the dive and were @ ~30' For a few breathes prior I had heard the first stage "chugging" (The sound it makes when you breathe down a reg prior to removal from tank). Then no air. Just a little bit of pucker factor given the environment I was in. Fortunately the dive buddy (gf) was within arms reach and nicely pass of her second stage and switched to her Air2 -with some strong encouragement on my part.

Have reestablished our air supply and gotten into a non over head environment I tried to figure out what had happened-in retrospect I should have checked my SPG to see what its symptoms were, but I was not exactly thinking rationally at the moment. I did reach back and turn my tank valve like 1/8-1/16 of a turn to full open and heard my first stage recharge. All was good after that but we bagged the dive to 15', did some drills and practice stuff for a few minutes and then got out of dodge-unfortunately not before I cramped my calf...it was an interesting dive.

The tanks were rented AL-80s. I suspected a tank issue due to apparently little/poor use with paper thin orings and very tight valves. I did send my reg-Sherwood oasis with ~25 dives on it at the time down to my LDS for a thorough look over-no issues. Shop owner suspected a tank issue with the valve assembly which did fit my assumptions. Needless to say that experience put tanks onto the next major item purchase list.

 

[Diver0001]

I don't think it's a nonesense at all

Can't say that this came as a big surprise. I'm slowly starting to realise that there is hardly anything that the two of us agree about.... I'm sure we both follow standards but that's probably where the similarity ends....

In itself this is probably not a serious problem but winding a tank open or closed too tightly will eventually round off the valve stem

I should make clear that there is a big difference between fully opening the tank valve and *cranking* so hard on it that you break it or strip it. I'm talking about doing the first. You would seem to be suggesting that I meant the 2nd. You're setting up a straw man here and I'm not fond of that way of arguing a point. YYMV.

In my experience I still maintain that the 1/4 turn is a better check. You might also argue that mistakenly having a tank 1/4 open is better than having it completely closed; at least it will function in shallow water.

You could also argue that it's better to have it totally off so you don't end up in the water with a vague problem, like our OP did (maybe).

Why do we spend time teaching people to close the valve 1/4 of a turn and then go through all kinds of convolutions to make "really really sure" that it's open when we could just tell them either open it or close it and if you forget it will be immediately evident and completely clear what happened... oh and btw you'll notice it before you ever hit the water..... ?

To be perfectly honest, many of the arguments you make, with all due respect Chris, come across to me as rationalisations of the status quo. This would appear to be another one. Personally, I think continually challenging your assumptions is the only way to keep yourself sharp.

Note that the 1/4 turn back will make no difference to the dlivery of air from the tank. The valve will probably function fully even if the tank is only half open (certainly at recreational depths anyway).

This we do actually agree about but it's not relevant to the topic at hand. As far as I know, mistakenly opening the valve 1/2 way isn't a significant problem.

Do you put your finger on another point that I like to stress to students though, which is that when they're putting their gear together they should focus on the task at hand and put it *all* the way together before doing something else. I've noticed over the years that many avoidable problems happen because people get distracted.

R..

 

[Diver0001]

Diver0001 (or anyone else) -- just to confirm what another wrote, do any of you know if the normal digital SPG (air integrated computer) is sensitive enough to show the "swing" when doing breaths at the surface?

Not that I'm aware of. Most computers have a sampling rate of 2 seconds or longer so to see the drop in pressure I would think you'd need to inhale large volumes of air continuously for more than double the sampling time. I guess if you let it freeflow for 5 seconds then it would show up on a computer.

It's possible that some computers have something built into them especially for this but I wouldn't count on it.

R..

 

[redacted]

Diver0001 (or anyone else) -- just to confirm what another wrote, do any of you know if the normal digital SPG (air integrated computer) is sensitive enough to show the "swing" when doing breaths at the surface?!

My only experience with AI was a Scubapro EDI and it was too slow responding to pressure changes to see such a momentary swing.

 

[ScubaSteve]

Well, this has turned interesting because I am the one that commented on breathin my AI Cobra on the surface and watching the pressure drop. I am certainly not imagining it but I do have large lungs and will usually breathe off it for 10 or so seconds before I stop. Each and every time I see it drop so this has now piqued my interest.

Is the concensus out there that this is not possible?

Posted via Mobile Device

 

[Slonda828]

Aqua lung was recalling the titan reg with din set up, Due to drownings. I called about mine and they said it was only on the din set ups not with yoke set ups.

This recall was for the DIN adapter itself. The actual regulator was fine. It was also only ONE reported failure, and of all the DIN adapters I've seen from Aqualung (including mine) they all have the MAX! designation, which means they are post recall.

Also, regarding the AI computer, I used my Suunto cobra with one of my J valve tanks, and just to see if it would swing, I left the J valve up. My cobra would swing air pressure as I breathed in and out. A mostly closed tank valve poses a similar restriction to an activated J valve, so at least on a cobra you would know if your tank was mostly closed.

Next point, regarding Devondiver's comment about the SPG. If you do a proper check, consisting of this set of steps, you will never dive with a bad SPG (unless it fails mid-dive):

-Hook up reg

-Check SPG, is it at 0?

-Turn air on

-Check SPG, note pressure

-Turn air off, purge regulator

-Check SPG, is it at 0?

-Turn air on

-Check SPG, is it at the original pressure?

This seems long, but it takes seconds and makes sure that your SPG is as good as it will ever get. I did this ever since I saw an SPG stuck at 1200 psi with no air in it.

 

[Diver0001]

Well, this has turned interesting because I am the one that commented on breathin my AI Cobra on the surface and watching the pressure drop. I am certainly not imagining it but I do have large lungs and will usually breathe off it for 10 or so seconds before I stop. Each and every time I see it drop so this has now piqued my interest.

Is the concensus out there that this is not possible?

Posted via Mobile Device

Well, you obviously have more experience than the rest of us so I'll defer to your experience. I do, however, have doubts that every computer would do what you're noticing so I wouldn't advise people to rely blindly on that.

R..