Scubapro failure at depth

[cerich]

Food for thought: Another LDS I trust mentioned that they thought a specific failure dealing with the composite (plastic) internals and accompanying o-ring(s) in the SP 1st stages (MK20 & 25) could theoretically pump water into the second stage(s).

sure, it seems very likely that 2 orings and 4 other componets at least would fail causing this....NOT! Your first stage would having air come out of it everywhere and fast.

Sometimes a diaphram in a second stage will get folded up in a corner, after out of the water and when you suck on it to test it's holding a vacum the diaphram sets itself.

 

[redacted]

Food for thought: Another LDS I trust mentioned that they thought a specific failure dealing with the composite (plastic) internals and accompanying o-ring(s) in the SP 1st stages (MK20 & 25) could theoretically pump water into the second stage(s).

I doubt it. When seals fail in the first stage, stuff moves from the higher pressure side of the failure to the lower pressure side. Which means gas moves into water and you will see bubbles. Please let us know what your shop discovers.

If the dip tube came loose during your dive, the scenario you discribed would be possible with just a small amount of water in the tank.

 

[gotsand]

sure, it seems very likely that 2 orings and 4 other componets at least would fail causing this....NOT! Your first stage would having air come out of it everywhere and fast.

Sometimes a diaphram in a second stage will get folded up in a corner, after out of the water and when you suck on it to test it's holding a vacum the diaphram sets itself.

So, are you saying the only way a 1st stage can fail is through free-flow?

Both 2nd stages were holding vacuum before and after the dive.

LDS where tanks were rented tipped them and there was no water in any of the tanks. Dum, dee, dum, dum. I'll post once the LDS doing repairs gets back to me.

Thanks for all the help, good forum.

 

[CMAN]

I would take a look at the exaust diaphram(s), but it seems unlikely that they would both have problems at the same time. Maybe DA Auquamaster will chime in and figure what happened.

 

[Thalassamania]

If the dip tube came loose during your dive, the scenario you discribed would be possible with just a small amount of water in the tank.

Bingo, If I were a betting man ...

 

[gotsand]

Would sure make me feel better in the future if it was a tank problem. Thanks.

 

[FredT]

I'd bet onthe exhaust valves as the culprit. Genrally a hard purge will reseat them if it gets folded during entry. These can be replaced by a thumb if nec4esasry, after riping off the exhaust tee.

 

[akscubainst]

If you understand the function of the regulator, it's pretty much impossible for what you are desribing to be a 1st stage failure.

In a nutshell, HP air goes through the body of the piston pressurizing the face of the piston until it overcomes the opposite pressure exerted by the spring, once this happens, the piston seals against the HP seat and waits for you to take a breath. There is no place to get water from. Any leaks would result in air leakage unless the water pressure was higher than the air inside the regulator which would require you to be at least 250' deep with no air to overcome 125 psi intermediate pressure.

Did you purge the regs on the surface after the dive? Did water come out?

Had you disassembled the regs yourself prior to the dive? It's easy to get the frictionless washers mixed up or leave them out and endup with diaphram leaks on the 2nd stages.

It's possible that you had water in the tank but we'd be talking alot of water for it to be as bad as you described. If the dip tube came out you'd hear it in the tank.

I'm interested in hearing the whole story cause, I'm pretty sure we're not getting it and while you're at it how about introducing yourself.

And your other LDS that you trust, They're trying to sell you a new regulator.


Sorry to be so cynical but I have my doubts on this one.

Dave

 

[miketsp]

Hello,

I dive a MK20/G250HP/R390 setup.

On the second dive of the day, my second stage completely flooded while at 85 ft.

After dealing with the annoyance of a sudden lung full of salt water, I was able to clear the flood after 3-4 breaths (a little less water with each breath until clear).

The reg would then breathe fine until I looked down, then it would flood again. I could hear the water filling the hose each time it happened. Again, it was clearable with some work (don't get me wrong, the experience was not fun).

Switching to my octo was no help as it did the exact same thing.

No bubbles were observed coming from my first stage. After some cursing, a topside inspection revealed no cracks, etc.

Both second stages had no leaks when dry breathing on a closed tank.

The reg is currently at LDS, I'm waiting for a verdict.

This seems pretty unusual, any ideas on what happened?

Would anyone recommend diving this reg again even after service, or do I now have a Scubapro paperweight and a story? Thanks for the suggestions.

Not much to add to what others have said.
If you tested both regs before the dive the chances of both second stages getting a folded/damaged exhaust valve seems most improbable.
The only scenario I could imagine that would cause this is a giant stride from a good height as this once happened to me. The impact hitting the water folded the exhaust valves in on both regs and I lost my mask even though I was in the classic position with one hand over the reg and fingers holding the mask.
Otherwise I can't imagine any type of 1st stage fault that would let water in without air getting out.
So the water source has to be the cylinder.

As for getting a lung full of salt water, the way to avoid this is to get more snorkelling practice. After 30+ years of snorkelling you sense the water at the mouthpiece and you don't swallow any.

 

[cerich]

are you absolutly sure you completly purged the octo when you put it in your mouth. I sometimes have been surprised when I breath in after putting a second in my mouth underwater and "thinking" I purged it completly.