Oxygen under 21%

[Sly]

Hi,

If I want oxygen under 21% I have an error:

[img]http://img11.hostingpics.net/pics/572014NX18.jpg[/img]

But if I add some helium the bug disappear:

[img]http://img11.hostingpics.net/pics/242242TX181.jpg[/img]

Greetings,

Sylvain

[sailor]

Hello,

I don't think that's a bug.
It is not recommended at all to reduce the oxygen content below 21 % by creating a mix with an elevated percentage of nitrogen.
The only commonly accepted method to reduce the oxygen content below 21 % is to add helium.


Reiner

[heinrichsweikamp]

Hi,

The "Err" is intentional. It's very uncommon (these days) to use a mixture with less then 21% O2 and no Helium.

Regards,
Matthias

[Sly]

Of course a Nitrox under 21% isn’t a good idea, but a Trimix 18/1 isn’t a good idea too

So it’s look like a bug… but if it’s not a bug it’s ok for me.

Thanks,

Sylvain

[sailor]

How do you achieve 18/1 without adding nitrogen?
Adding nitrogen is not an accepted method to mix diving gases.

[F4de]

I think here are some misunderstandings... hope it`s ok to help you out

In the first picture Sly showed 18% Ox without Helium. In that case there would be more or less 82% nitrogen in the mix, which is not ok and therefore the OSTC showed the error.

In the second picture he added just 1% Helium but still had 18% oxygen. It`s a Tx18/1. In sum, we have 19% Ox and He and the rest is 81% nitrogen, which should again not be ok because we have added nitrogen to our mixture. Even though I think nobody would fill his bottles with pure nitrogen to get more nitrogen than in the atmosphere, in this situation the OSTC does not show an error!
I think that is the bug he wants to show us?!?

Best regards
Chris

[Sly]

That's it !

Thank Chris

[sailor]

OK, got it.