com1

Hi I am new in CCR diving, just made my first 1000 minutes on my Inspiration Vision.
Unluckily for me there is more noise than diving OC since I am on CC.
I do get cell warnings almost during every dive.
I am diving a brand new unit with cells with date code from January 2010.
Measured output voltage is around 9mV in Air at 1 bar.
Seems like that for some dives the voltage of 2 cells droped?
I made a small table where you can see what I am talking about:


So as you can see sometimes it seems to be ok, and sometimes the readings are very bad.

What could be the problem?
-Cells (I think 1 and 2 are bad)?
-My Inspiration?
-User failure (me)? (there was never water in the unit, only condensate, about same amount as in the units of my buddies)

Tom

[IMG]file:///C:/Tmp/moz-screenshot.png[/IMG][IMG]file:///C:/Tmp/moz-screenshot-1.png[/IMG]

Attached Images

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dragerdiver

Tom,
It looks like to me that the #1 & #2 sensors are current limited, as they look good at your 1.3 set point but when you do your 1.6 check at 6m, they are not able to reach that set point. I would contact the sensor mfg and arange for a couple of replacements. I am not all that familiar with that rebreather, but you say that it is making lots of noise, I would think it should only alarm during you 6m test, as during normal operation the numbers look good.
Lee

Tienuts

It would seem you cells 1&2 are current limited. Throw them out, and don't dive them.

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Dive Sprite

Looking at your tables, I see that you are conducting a cell check at 6m when the 'spike' in your third cell occurs.

Are you pressing the O2 manual add button and flushing with pure O2 at 6m to do your cell check?

Cell 3 is closer to the solenoid, and this might explain the variance in reading when flooding the head with O2. Give AP a call and send them your log files - and tell them what's going on. They would be best to advise you here, but please report back when you have an answer.

All the best,
David.

com1

Hi,

I do not have my user certificate in my hands (due to my instructor has other priorities ...).
So I can not expect much support from AP at the moment

I am flushing O2 manual for the cell check.
It´s not really a spike at cell 3, the reading/deviation is stable for the time I check (last dive I checked for about 2 minutes).


Tomorrow I am doing a dive with borrowed used "good" cells from a friend.
After the dive I know more.


Tom

jaksel

How are your measurements taken?

Usually when I flush with O2 at 6 m, I get cell warnings. This is mostly due to the cells having slightly different settling times, so that when ppO2 rises quickly they will initially differ alot. After a few more seconds, the "slow" cells settle and after that they are all within 0.05 bar or so.

But if you have stable readings (> 10 seconds) and the unit still gives cell warning, then there might be a problem with the cells.

Fun Under Pressure

Your instructor has other priorities than to give you your certification...???? Ok god luck.....

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Nitrogenius

Well if it is new cells in a brand new unit there neither should be any problems with slower cells causing a cell warning. That's something to be expected when the cells get closer to the "end of the lifespan" and would be a first indicator that I should prepare to have some new cells ready for replacement..

Also looking to the tables.. the cell 3 seems to be the only accurate (linear enough) one looking to the 6m O2 flushs..
If that proves to be the case com1 you can consider that you probably did your dives on a higher PO2 than desired.. since the Inspo's controller have been thinking your wrong cells are right, because the measurements ar closer and the controller logic excluded the "right" cell.. Quite a dangerous position to be in..

Wonder what will happen with the exchange cells you mention..

Some thing I do not understand is, how you are able to dive a brand new unit without having your cert. yet?
Where did you buy the unit from? I assume the same organisation as you have been trained from and that is too busy now to get your cert filed?
That would explain why you do not contact them with your problem, because that's what I'd do with such a problem on a brand new piece of equipment to the shop where I bought it and have them sort out the problem..

Good luck!

com1

Yes, the one where I bought my Inspiration from is also my instructor (the one with the other priorities ...).
Did and passed all the theoretical and practical stuff. And now waiting since weeks for this f... peace of paper.

PS: Don´t ask me for the instructors name, he is a friend of mine, still ...

heyydude

Well - tell your "friend" that this rig is preparing to kill you, and it would be nice if he assisted you in sorting out what is wrong with cells 1 & 2.

It only takes 2 Sensors in a Voting Logic system to end your life. Which is why this is such a serious event you've posted.

I personally was shocked when I saw your log entries, since it illustrates a point I'm making elsewhere on RBW - Current-Limited Oxygen Sensors MUST be found out, and eliminated from the rig. It looks to me that you've got 2 of them, and given what I said in my second paragraph, you should be very, very concerned.

Have you shown these charts to SDS or AP in the UK? If not, you should, and follow their recommendations.


Kevin Juergensen
Juergensen Marine, Inc.