It finally happened - my CCR tried to kill me

[tbone1004]

By length of time I think the sorb in an EAC will also create a caustic cocktail if left soaking long enough.

How long it has to soak, and to how caustic vs loose sorb I have no idea(and would love to know).

no dust in an EAC so it takes forever to get a caustic out of it and with the orientation of the O2ptima it's almost impossible to get water in the scrubber itself *you have to be head down and upside down to get water to drain in there*. There was a video when the O2ptima first came out of them pouring water through it -edit, found it

 

[Dusty123]

Wait, so no pile driver with the optima either? i thought it was supposed to be the best.

 

[Heat Miser]

95 hours on the loop now. ... This incident that I reported to you all have definitely served to reinforce my desire to get the next level of training - so that I can also get that review and check on the basics....To be clear, the lid was on properly. I THINK the problem was that the O2 cylinder was pressing on the side of it, after it was seated properly.

@stuartv I believe the O2 tank feet not seated properly and banging against the scrubber lid is the main suspect for the flood. You also mentioned the external battery box flooded. Is it possible for water to travel through the battery box into the lungs along the solenoid/rms cable and flood the rEvo?

 

[Heat Miser]

Based on other responses, I'm going to also investigate looking at cell mV readings during the pos/neg tests.

mee too ... good tip

 

[michael-fisch]

The sorb soup in my counterlung was measured by the hospital at 14.0 PH.

Michael

 

[AfterDark]

OP glad you made it back!
You CCR guys are making your mark on diving history, much like the early divers and cave divers did with your lives, sometimes. Years from now when divers will look back on ya'll like we look back at DH divers.
My hat is off to you all!

 

[jgttrey]

This all sounds very complicated.

No doubt. Seems like "building the unit" is literally that. The checklist just to make sure the lid is sealed sounds as long as the checklist to build my whole rig.

 

[Rose Robinson]

I hope @Dsix36 pipes in as he has a lot of hours on the Revo.

My takes on this. Lady Luck is a ~100ft wreck and I don't disagree with 18/45 as a bailout gas if it was also dil, but would probably have used 30/30. Either way if you had planned deco a 40 of O2 or 50% would probably have been a good idea, but low priority.

Staying on the loop matters in a cave, and it matters when you are doing deep expedition/project diving where you really don't want to bail out if you don't have to due to limited filling resources. For normal open water diving, it's not a priority to figure out and you haven't been trained on what to do to stay on the loop yet, so I'd hold out on that.

I disagree that positive and negative checks won't ID small leaks. They can and will, but ONLY if you have an ambient pressure sensor. Thankfully your unit has 5 of them, and normal rebreathers have 3. When you do your positive and negative checks, watch the mV or ppO2 and you can see what the internal pressure is doing. I bet that it would have caught that leak, small though it was. I would recommend adding that in to your pre dive checklist

Hello tbone,

With rebreathers, I know there is no such thing as standard for all brands.

With that in mind, during pre dive checks, how long should a rebreather ''hold seal'' during positive and negative checks.

It seems logical to me that if a dive lasts for one hour, your positive and negative tests should hold firm without leaking for at least as long as the duration of your planned dive.

Rose.

 

[lostsheep]

By length of time I think the sorb in an EAC will also create a caustic cocktail if left soaking long enough.

How long it has to soak, and to how caustic vs loose sorb I have no idea(and would love to know).

As a CCR newbie, I've been wondering this too.

I've seen the video Tbone posted and it seems like the extra cost of the extendaire might be justified if it really makes that much of a difference for a caustic. I want to repeat what they did but actually test the PH. Taking a drink at the end of the video shows some serious confidence but I prefer numbers.

 

[Zebra 1]

There are numerous reports of overbreathing EACs. There is no empirical "over breathing" test, you are stuck with the anecdotal evidence which is not favorable.

I would think Extend Aire would/should have done some kind of study on overbreathing their cartridges.

I'm skeptical of the anecdotal evidence with so many variables in play. At the same time I agree and think it would be foolish to ignore that evidence.