Free flowing reg and what should one do?
- Thread starter LollyO
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You already got excellent and interesting answers about stopping a freeflow that was willing to be stopped. Most are momentary and can be stopped.
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Because you also seemed interested in this, I'll tell you what I was taught about the freezing kind of freeflow, the kind that won't stop until you get the gear back indoors and let it warm up.
I was taught cold water and under the ice diving by older divers in our club that have been doing it for 10, 20 even 30+ years. The important things I was told from the 1st time out were
1) Before the dive don't let your gear get any colder than necessary -keep it in the warm car as long as possible.
2) If the outside temperature is freezing or below freezing, don't start any airflows until the item you are using is in the water. Don't breath the regs, don't add air/add air minimally to suit and BCD/wing until you have it underwater -it's warmer underwater! If something has frozen shut at or above the surface it will often start working just fine once you get in the water.
3) Once underwater, don't create any unnessary greater flows of air -never fill anything from air using the purge, learn to use your reg's exhaust air instead and don't let yourself get winded and start breathing hard or fast.
Air exhausting fast will very quickly cool the equipment through which it is flowing. That's why a freeflowing 2nd stage may soon create a frozen 1st stage and that's why you never want to create any unnessary large flow of air from the reg.
The good news is that quality, sealed regs that are properly maintained and properly handled on-site will rarely freeflow (meaning "runaway freight train"-freeflow, not the mild discontent momentary type). This is what the "old boys" have told me and I have to admit that after visiting winter dive sights almost weekly, and at popular sites seeing at least 10 divers a single afternoon, I've very rarely seen a (runaway freight train-type) freeflow.
***
Because you also seemed interested in this, I'll tell you what I was taught about the freezing kind of freeflow, the kind that won't stop until you get the gear back indoors and let it warm up.
I was taught cold water and under the ice diving by older divers in our club that have been doing it for 10, 20 even 30+ years. The important things I was told from the 1st time out were
1) Before the dive don't let your gear get any colder than necessary -keep it in the warm car as long as possible.
2) If the outside temperature is freezing or below freezing, don't start any airflows until the item you are using is in the water. Don't breath the regs, don't add air/add air minimally to suit and BCD/wing until you have it underwater -it's warmer underwater! If something has frozen shut at or above the surface it will often start working just fine once you get in the water.
3) Once underwater, don't create any unnessary greater flows of air -never fill anything from air using the purge, learn to use your reg's exhaust air instead and don't let yourself get winded and start breathing hard or fast.
Air exhausting fast will very quickly cool the equipment through which it is flowing. That's why a freeflowing 2nd stage may soon create a frozen 1st stage and that's why you never want to create any unnessary large flow of air from the reg.
The good news is that quality, sealed regs that are properly maintained and properly handled on-site will rarely freeflow (meaning "runaway freight train"-freeflow, not the mild discontent momentary type). This is what the "old boys" have told me and I have to admit that after visiting winter dive sights almost weekly, and at popular sites seeing at least 10 divers a single afternoon, I've very rarely seen a (runaway freight train-type) freeflow.
I won't expand on the technical issues, they've been covered in enough detail.
I will suggest that if you have a "freeze flow" you can shut off the valve for a minute or two and then turn it back on. Generally that will be enough time for the ice that formed to thaw, so if you can bail out to your buddies octo, you should be able to go back on your reg to finish the dive. That in many cases will leave you in warmer water for the safety stop with the ability to finish the stop, inflate your BC etc in a normal manner. Something to consider if you can reach your valve or have an on the ball buddy and minimize the gas loss.
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If you are in a cave or wreck, the first priority, believe it or not, is not to stop the freeflow, but rather to get on the line and then deal with the reg. The extra second or two that takes will be a lot more gas efficient that the time it might take to locate the line if the viz gets blown. Even if you don't contact the silt and stir things up while shutting down the valve, switching regs, etc, the high gas flow will cause percolation and potentially water movement in a small space that can easily blow the viz. The same is true if you are donating a reg, donate the reg and get on the line immediately.
I will suggest that if you have a "freeze flow" you can shut off the valve for a minute or two and then turn it back on. Generally that will be enough time for the ice that formed to thaw, so if you can bail out to your buddies octo, you should be able to go back on your reg to finish the dive. That in many cases will leave you in warmer water for the safety stop with the ability to finish the stop, inflate your BC etc in a normal manner. Something to consider if you can reach your valve or have an on the ball buddy and minimize the gas loss.
----
If you are in a cave or wreck, the first priority, believe it or not, is not to stop the freeflow, but rather to get on the line and then deal with the reg. The extra second or two that takes will be a lot more gas efficient that the time it might take to locate the line if the viz gets blown. Even if you don't contact the silt and stir things up while shutting down the valve, switching regs, etc, the high gas flow will cause percolation and potentially water movement in a small space that can easily blow the viz. The same is true if you are donating a reg, donate the reg and get on the line immediately.
The only thing I can add is that some brands and models of regs freeflow quite a bit easier than others. If purchasing a new reg, ask about it. I had one model of reg, that the first thing I hear on my first dive dive was "I used to have one of those, loved it, but it free flowed a lot". Sure enough, I could count on a controllable freeflow on almost every dive.
DaleC
Contributor
This is a freeflow. A lot of people poo poo the use of redundant air sources for rec diving but with an appropriately sized one, a freeflow is an inconvenience, not a disaster. Shutdown, wait a minute and most likely the reg will breath again:
[video=youtube;BKKpuHxGENY]http://www.youtube.com/watch?v=BKKpuHxGENY&list=UU5zvhnU0XYpf_cadpYJYkhQ& index=4&feature=plcp[/video]
[video=youtube;BKKpuHxGENY]http://www.youtube.com/watch?v=BKKpuHxGENY&list=UU5zvhnU0XYpf_cadpYJYkhQ& index=4&feature=plcp[/video]
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