Unrealistic D4i Novo NDL

[Drashka]

Hi ! I hope it's the good topic for my message. So think my wife has a trouble with her D4i (the kind of trouble which keep you safer but still) basically today we did to nitrox 32 dives. The second was 1m deeper than the first. First dive was about 28 max depth and 21 average with around 40mn bottom time at 25. We're three divers with a suunto d4i. Everything went good, no deep stop violation, safety stop ok, one hour srf interval, fully desat before the two dives. Then come the second one, every single diver barely the same profile but She runs to 1 ndl way faster than everyone (she was not deeper than me and was set on 1.5ppo2, i was 1.4 so even more conservative. I don't mind extra safety but for nitrox it was disappointin to shallow up too soon. Any ideas or experience about over conservatism in D4i ? Our instructor said it was weird and might need a reset ? We're going full nitrox liveaboard soon and would love to enjoy it as much as possible. Thanks in advance for your answers, hope there is enough éléments in my post.

 

[scubadada]

Pressure sensor dysfunction? Was it set correctly for 32% on the second dive, log should confirm?

pO2 does not affect NDL

 

[tursiops]

If you can download her profile, look at her ascent rates. Suunto doesn't like fast ascents, especially near the surface.

 

[kelemvor]

Check out page 3.17 in the manual here: https://ns.suunto.com/Manuals/D4i/Userguides/Suunto_D4i_UserGuide_EN.pdf

There are some adjustments that can make the computer more or less conservative. Make sure you guys are all on the same setting. Suunto has a rep for being a very conservative dive computer that uses RGBM. That means the most safety, but conversely can mean shorter dive times.

 

[0321tony]

First thing I would check is to make sure it was set for the proper air.
Is there a way to adjust the conservatism on the D4I? I dont own one so I dont know this. On my Garmin I can set it to low medium or high conservatism and it changes my NDL by a fair amount.
Also could she possibly have it set for altitude diving? That could change it.

 

[BikerBecca]

Suunto dive computers do not like fast ascents. I have a D6i and a Zoop. My D6i will violate all the time when I'm working with students because if one of them shoots to the surface it means I have to shoot to the surface. That annoys the D6i ascent rate and I violate.

Did you download the dives? You should see exactly what irritated your dive computer.

 

[Drashka]

Thanks for your fast answer guys !! So yes it was correct my set on nitrox 32,was not in altitude mode. I don't think she ascend too fast near the surface because ndl issue occurs before but I'm gonna check the log on computer to be sure. I'm gonna read more the manual maybe we can adjust conservatism (i like it to be safe as possible but yeah frustration to spend 25 min on shallow depth under nitrox !)

 

[tursiops]

The problem caused by a fast ascent would be caused on the PREVIOUS dive, not the one with the NDL problem. Look at the previous log....

 

[Drashka]

That's awesome to have fast answer from divers community, and sorry if sometimes my sentences are hard to understand but I have this freaking french autocorrector on my Phone which is messing with me

 

[Drashka]

OK could be that ! I'll log everything on DM5 and check it asap