First stage flooding, possibly how to avoid it

[orange_diver]

i like to do periodic flow checks of backgas not only to ensure everything's kosher but also to make sure that i can easily reach the valves should i need to in a hurry. in a wetsuit this is a non-issue, but in a drysuit i wanna make sure i'm not TOO squeezed and arm-mobility limited. so i can see added value to bizmark's point.

i frequently check the gauge on my deco bottle cuz those things can get depressurized at the drop of a hat. i dont know if that's considered a "flow check", more like a glance and if needed a turn and turn-back of the valve.

 

[Bismark]

i like to do periodic flow checks of backgas not only to ensure everything's kosher but also to make sure that i can easily reach the valves should i need to in a hurry. in a wetsuit this is a non-issue, but in a drysuit i wanna make sure i'm not TOO squeezed and arm-mobility limited. so i can see added value to bizmark's point.

i frequently check the gauge on my deco bottle cuz those things can get depressurized at the drop of a hat. i dont know if that's considered a "flow check", more like a glance and if needed a turn and turn-back of the valve.

If you check all your valves, then that is a flow check.

 

[Bismark]

Well, there are some things I do as routine, and other things that I do when conditions trigger a response. Touching the ceiling triggers a flow check, but swimming along in the water doesn't. I think it's important to recognize when you have done something, or when you are in an environment that threatens your valves, and there you need to check them. But in big spaces or open water, how often are your valves going to be any way but where you left them?

I don't say this with respect to deco cylinders. I have no training there, and maybe one needs to check them more often, since the second stages are susceptible to being bumped or jarred, and releasing the charged gas.

With all enormous respect for your additional training and experience, Bismarck, isn't checking your backgas valves every five minutes, whether you need to or not, not the act of a thinking diver?

It is very easy to bump your deco reg and de-pressurize it when dealing with multiple bottles and scooters, etc, potentially leading to the problems I mentioned earlier. A complete flow check is just part of my regular "everything going along like it should" check, that includes monitoring gas. I know how much gas I am expect to use at every stage of the dive and that is something I keep track of. Think of it as something similar to routinely checking the gauges in your vehicle as you drive. A pilot will be even more particular about this. I don't have different flow checks for different situations: I just do everything. No big deal. I am a pretty methodical and disciplined person (ex military) so this comes pretty natural for me. Personally, it is comforting to know that everything is proceeding according to plan.

I understand your comments about backgas valves, but a valve check is a valve check and includes them all. If you do some more technical training with multiple bottles, even your valve drills themselves will include powering up and closing each valve on every single bottle you are carrying. Just one more step in the process. I do it every 5 minutes because that is a good block of time for monitoring my gas useage. I know you know that a lot can happen to your gas supply in a very short period of time at 7 or 8 ATA's.

 

[lemon]

I've read that the regulator first stage on a pony is more likely to flood since the tank's turned off until you need it, my question is if you pressurize it before the dive (final air/reg check) and turn off the tank, but don't purge the air from the regulator will it be less likely to flood during the dive?

Sounds right. My Aeris Ion reg recommends keeping the reg pressurized after removing from a tank post-dive and while rinsing to prevent water getting into the first stage. Of course, any time a deckhand touches my rig after a dive the first thing they do is purge the pressure from the reg... :doh2: