What to do when regulator free flow in cold water?
- Thread starter Kylebee
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There are a few different causes for a sudden freeflow...
Common:
- 2nd stage being out of your mouth and facing upwards (solution: turn it to face down, possibly hit mouthpiece against hand)
- 2nd stage being out of your mouth and hitting the purge button (solution: same as above)
- 2nd stage facing heavy current or scootering with reg tuned for light action (solution: detune reg, turn off venturi)
- 2nd stage starts leaking on shore, boat, after being pressurized for a while means slow IP creep of first stage (not a problem while breathing from the reg, make it stop and go diving if you have enough gas + after dive service reg)
- Breathing too much on a reg on the surface in very cold conditions (solution: ensure buoyancy, shut down valve and dunk regs if in saltwater)
Less common:
- Extremely cold water leads to icing (abort dive, sip air while ascending, share gas if necessary)
- Very cold water and improper first stage for the conditions leads to icing (same as above)
- Sudden fast leak (o-ring failure?) leading to rapid increase of IP in first stage (same as above)
This might not be exhaustive, but they are the ones I could think of for now. As you can see, the more common ones are quickly resolved, and many less likely to happen while you're breathing off the reg. The less common, and more serious ones, you sip the air and abort the dive - share gas if needed. It shouldn't create a dangerous situation if you stay calm and handle the situation with your buddy.
It would probably happen during an inhalation cycle. Just like the venturi effect kicks in and accelerates the gas going through the second stage it almost feels like gas is being forced into your mouth, the gas would just keep coming instead of closing the valve when your inhalation stops.
You won't get a lung overexpansion injury by breathing off a freeflowing reg. The second stage's exhaust valve opens and vents the excess gas.
If you are that worried about it, schedule a pool dive with your dive shop or instructor and practice dealing with a freeflow by breathing from the reg while holding down the purge valve. You can try the PADI method of letting one side of the mouthpiece hang out of your mouth. I prefer using my tongue to block most of the direct stream of incoming gas.
Tipping your head may be useful in getting an eye outside the bubble stream so you can see better. It doesn't have anything to do with breathing.
The questions about additional air sources are better addressed from a general scuba perspective instead of as a solution to a single perceived problem. Pony, backmount twins, or sidemount twins all have pluses and minuses depending on what kind of dive you are doing. More importantly, they also all require additional training and practice to use effectively. A dive in a potential icing situation is not where you want to add complexity to your rig for the first time.
If you are that worried about it, schedule a pool dive with your dive shop or instructor and practice dealing with a freeflow by breathing from the reg while holding down the purge valve. You can try the PADI method of letting one side of the mouthpiece hang out of your mouth. I prefer using my tongue to block most of the direct stream of incoming gas.
Tipping your head may be useful in getting an eye outside the bubble stream so you can see better. It doesn't have anything to do with breathing.
The questions about additional air sources are better addressed from a general scuba perspective instead of as a solution to a single perceived problem. Pony, backmount twins, or sidemount twins all have pluses and minuses depending on what kind of dive you are doing. More importantly, they also all require additional training and practice to use effectively. A dive in a potential icing situation is not where you want to add complexity to your rig for the first time.
gschaut
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