Question O2 sensor calibration

[mr_v]

Does anyone have an experience where an O2 Flush at 20 feet resulted in the discovery of a significant issue with one or more oxygen sensors? In other words, has anybody gotten valuable from this exercise?

In my experience, not really. But flushes may confirm prior concerns. For example, if a cell is slower to respond on a dive and spikes slower than the rest during O2 flushes, I mark it as a replacement candidate.

@justinthedeeps - yes, continuous PPO2 flushes may accelerate deco, but the practice is debatable, especially with long deco schedules. What is helpful is having a loop full of O2 anytime you're above 20'/6m. Remember, you're always diving hypoxic, especially if you're sure you're not ;-)

 

[Alekseolsen]

I would partly agree, though going 100% loop O2 (vs say ~87% O2 @1.4 @6m) can shorten final stop lengths in a deco planner (small and unnecessary in many cases--especially when helium off-gassing is driving deco, unimpeded by 20 or 50% nitrogen in a nitrox deco gas)

So agreed the flush makes sure the sensors will register a high O2 condition, but there is actually nothing magical about the 1.6 number for that, anything between 1.4+ and 1.8 would do (latter for the hardcore 9 metre flush peeps who don't mind a lip tingle or rare catastrophic seizure.)

For that matter, a really easy way to check for 1.6+ might be to vent the loop, go onto open circuit, and blast oxygen through the loop at a deeper depth. It's not science, but that's what dry land oxygen pressure pot testers were made for.

I learned that, for checking, you could simply do your O2 flush at 6m, change to OC and decend to 7 meters. Pretty similar as you described but allows O2 flushing with loop open