Nitek Duo says I died on my last dive... default gas mix?

drbill · Apr 7, 2008

Some of you may remember that my Uwatec Aladin Pro Nitrox had started spontaneously changing my gas mix from air (the only gas I dive) to as high as 50%. According to it, I died on several dies of ox tox! Scubapro was nice enough to give me a good deal on a new Tec 2G to replace that computer.

I had purchased a Nitek Duo in the interim to serve as my primary dive computer until the Tec 2G arrived. I dive with both of them now.

This past weekend, my Nitek Duo started switching gas mixtures on me. I ONLY dive air, no Nitrox, yet it apparently reverted to the default for some unknown reason. The actual mix was not displayed for gas 1 OR gas 2, so I'm not sure what the default setting is. Pretty strange (IMHO) that it doesn't default to air.

I guess I'll actually have to wade through the manual to see what this computer did and how I can prevent it from resetting the mix unbeknownst to me.

willgr1 · Apr 7, 2008

strange, when i dive with my duo it defaults to 21% O2 for mix 1, and no mix 2.

jimdiverman · Apr 7, 2008

drbill:
Some of you may remember that my Uwatec Aladin Pro Nitrox had started spontaneously changing my gas mix from air (the only gas I dive) to as high as 50%. According to it, I died on several dies of ox tox! Scubapro was nice enough to give me a good deal on a new Tec 2G to replace that computer.

I had purchased a Nitek Duo in the interim to serve as my primary dive computer until the Tec 2G arrived. I dive with both of them now.

This past weekend, my Nitek Duo started switching gas mixtures on me. I ONLY dive air, no Nitrox, yet it apparently reverted to the default for some unknown reason. The actual mix was not displayed for gas 1 OR gas 2, so I'm not sure what the default setting is. Pretty strange (IMHO) that it doesn't default to air.

I guess I'll actually have to wade through the manual to see what this computer did and how I can prevent it from resetting the mix unbeknownst to me.

Bill,

I dive with Dual Duos and I reset both during the SI between every dive. I don't trust them to "default" into a known mix. I am usually diving something like 32 on the back gas and 99 on mix 2. I reset them between dives.

divenutny · Apr 7, 2008

DrBill - my duo did the same behavior during my last dive trip. Once I did a dive above 21%, the computer expected me to set the O2% every subsequent dive after. I expected it to default to air, it defaulted to 50% or higher. I presume it will behave this way going forward, time will tell. I agree with you, I would have expected it to default to 21%.

Tom

drbill · Apr 8, 2008

Very interesting... and very strange. As I mentioned, I have never dived Nitrox and have never re-set the mix. I don't understand why it defaulted to something other than 21% and why the mix it reset to wasn't displayed on the computer. I hope Dive Rite has a way to "reset" the computer so it no longer goes to whatever this default setting is.

ianr33 · Apr 8, 2008

Take a look at page 20 of the manual "Understanding FO2 default"

looks like if you set both mixes to 21% it should stay there.

Any chance you have mix 2 set to something other than 21% which is causing the FO2 default to kick in?

Some computers will default to 21% for nitrogen calculations and 50% for O2 calculations. IF it is defaulting without being asked to 50% for deco information then that HAS to be a fault and a dangerous one at that.

Best bet is to check the displayed O2% just before your descent and to do a quick sanity check on the NDL. e.g. if you drop down to 100 ft and it says NDL 30 minutes then it is not set to air!

I have my Aeris computer set so it stays where I put it. Never have cared for the automatic resetting for "safety"

drbill · Apr 8, 2008

I have always had it set to 21% for both mixes. Why it changed the setting makes no sense to me. I don't like this autoresetting to default but will more closely monitor it in the future. Of course I'm diving with two computers so even if one goes a bit wacky, I have a backup. It just seemed so strange that both the Uwatec and now the Nitek Duo would do this without my input.

jimdiverman · Apr 9, 2008

drbill:
I have always had it set to 21% for both mixes. Why it changed the setting makes no sense to me. I don't like this autoresetting to default but will more closely monitor it in the future. Of course I'm diving with two computers so even if one goes a bit wacky, I have a backup. It just seemed so strange that both the Uwatec and now the Nitek Duo would do this without my input.

I always used the DR Nitek prior to getting my Duos. It doesn't do gas switching, but does do Nitrox, and it only took one time of hitting my OTU limit (according to my Nitek) to not forget to reset my defaulted Nitrox setting after every dive. So when I got the Duos, I just expected to have to do that.

HowardE · Apr 9, 2008

Dr. Bill... I'm sorry to hear about your untimely death. I there's anything I can take from you - let me know... :laughing:

drbill · Apr 9, 2008

Ha, Howard... you can take my advice and come back out with Michelle, Pete and the crew in June before the Long Beach Show. No one would want my well-aged equipment!

Nitek Duo says I died on my last dive... default gas mix?

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