Question How to check an analyser O2 cell?

[Agro]

This is pretty rich coming from someone diving a liberty without any training. Apparently, you have no mixing cert either.

Never ever I would dive any rebreather without training. Some peole here believe I do so, I don't care about it.

Mixing cert????????? Does this really exist?????? Perhaps a PADI cert, Put Another Dollar In? I fully agree that you must know what you are doing when analysing a dive gas. But spending money for a cert that tells you what is said in the manual? Do people realy spend money for such a nonsense?

I guess you have such a certification? Obviously it is good for nothing.

 

[Agro]

If you add 14% O2 and top with air you get 32% every time. The analyzer is just confirming that your original math was correct.

If you KNOW what's inside a bottle, you do not need any analyser at all
If you are not 100% sure you need an analyser. If you need an analyser you must be sure it works. Therefor good sensors and calibration are necessary.

 

[RedSix]

It is a good habit to analyse every bottle I breathe or I might breathe before the dive. Even if I think I know what's inside.
Actually I do not dive with people not analyzing their breathing gas, but that's a different topic.

Regarding cell testing:
I'm quite sure that more or less everybody is aware, that testing a cell with 3.5bars of O2 is stress for the cell. It will reduce lifetime of it.

Agro, on the one hand you want to store your cells in an inert gas to make them last longer. On the other hand you test the cell with a partial pressure of O2, which under normal circumstances will never be reached during a dive. Not even half the pressure. That doesn't make sense to me.

A cell which has 2% deviation at let's say 2bars shows 1.96 pO2. At 1.6 it's 1.57. Does it matter? Don't think so.

Yes, it surely has reached a part of it's life in a rebreather, where it should be changed.

But coming back to analyzers: I don't care about 2% deviation for NX32, or 50%... The variances resulting from the body, hydration etc. are much larger than these 2%.

The world is not black and white.

Testing a cell with 3.5bars of O2 and kicking it out when it has a deviation of 2% for me is even for a rebreather a too strong criteria.

And for an analyzer it totally over the top.

But since I am writing nonsense all the time, just ignore it, Agro ;-)

 

[Agro]

I'm quite sure that more or less everybody is aware, that testing a cell with 3.5bars of O2 is stress for the cell. It will reduce lifetime of it.

Divesoft says the oposite. It's best way to test a cell. It's best way to find out, if cell will fail within next time at range zero to 1.6 pO2.

 

[Agro]

Agro, on the one hand you want to store your cells in an inert gas to make them last longer.

I do not want to do so. I was asking if this makes sense. This forum made clear it does not make sense, I will not do so.

 

[Agro]

On the other hand you test the cell with a partial pressure of O2, which under normal circumstances will never be reached during a dive. Not even half the pressure. That doesn't make sense to me.

Not to you but to Liberty divers, they have the chance to do so as Divesoft is offering this option.

If you want to find out if cell is in good shape from zero to 1.6 bar pO2 then you have to test them at higher pO2, thats easy to understand.

 

[Agro]

Testing a cell with 3.5bars of O2 and kicking it out when it has a deviation of 2% for me is even for a rebreather a too strong criteria.

Nobody sais to do so. 2% deviation at 3.5 bar pO2 is perfectly OK.
2% at 1 bar is someting else. In this case you should test it at 3.5 and see how it behaves at 1-3.5 bar pO2.

 

[Agro]

But since I am writing nonsense all the time, just ignore it, Agro ;-)

You only often write nonsense. Not all the time.

 

[Manatee Diver]

It is a good habit to analyse every bottle I breathe or I might breathe before the dive. Even if I think I know what's inside.
Actually I do not dive with people not analyzing their breathing gas, but that's a different topic.

100% agreed. I dove with a GUE dude as a non-GUE diver. And I noticed that he looked that I analyzed that day.

But coming back to analyzers: I don't care about 2% deviation for NX32, or 50%... The variances resulting from the body, hydration etc. are much larger than these 2%.

I know a couple of people that never change their computers. They still analyze, but they keep it set to standard gases.

 

[rjack321]

If you KNOW what's inside a bottle, you do not need any analyser at all
If you are not 100% sure you need an analyser. If you need an analyser you must be sure it works. Therefor good sensors and calibration are necessary.

Because the math is a single point of failure. The analyzer is a backup to the math.