Free flow at 94' ffw

[JackD342]

Did the freeflow originate from the first or the second stage???

Unless I misunderstood the original narrative, it was the alternate 2nd stage, seemingly a spontaneous event.

 

[happy-diver]

If the first stage is the cause I don't want extra flow going through my primary
when you block the secondary with one of those valves
and the pressure has to go somewhere


Does anyone here fold the hose in half to stop freeflow

 

[JackD342]

Good point and a compelling reason to think hard before putting one on BOTH 2nd stages.

 

[tursiops]

Does anyone here fold the hose in half to stop freeflow

How would this be different than using the shutoff valve?

 

[0321tony]

Did the freeflow originate from the first or the second stage???

It came from my alternate second stage regulator I had on a necklace around my neck. Strange thing at least for me that cought me off guard was that it was the alternate and I wasn't using it so it had no airflow going through it. For me it would have been easier to understand if it had been my primary and it froze up while in use. My primary continued to work all the way to the surface. I was half expecting that with the amount of air going through and the mid 40's water temp my first stage would freeze up but it never did.

 

[JackD342]

I wonder if you somehow accidentally compressed the purge and started a flow, then by the time you noticed and/or repositioned it had iced up. If the mouthpiece was pointing up in the water column where it was positioned, then even easier for it to happen.

 

[stepfen]

Very well done for handling the situation and informing us about it!

It seems it took more than 6 minutes for the tank to drain. That's my estimate based on: 3+ minutes problem solving and ascent, 2 minutes SS, 1 minute further freeflow on the surface. Can you give us a more accurate figure?

In any way I am glad to know it is much more than the 2 minutes usually mentioned for 2nd stage/LP hose problems.

Thanks for sharing and welcome back

 

[happy-diver]

Did the freeflow originate from the first or the second stage???

It came from my alternate second stage regulator I had on a necklace around my neck. Strange thing at least for me that caught me off guard was that it was the alternate and I wasn't using it so it had no airflow going through it. For me it would have been easier to understand if it had been my primary and it froze up while in use. My primary continued to work all the way to the surface. I was half expecting that with the amount of air going through and the mid 40's water temp my first stage would freeze up but it never did.

Right so if you didn't inadvertently operate your necklace reg then the first was stuck open or not completely closing or closing slowly with each breath, whereby your breathing did dot keep up with the amount of air your first was delivering increasing pressure in the necklace, opening the thing when the pressure became too high for the reg to remain closed.

They are after all downstream safety valves, regs anyway

Makes sense to me


It's better to have a freeflow from your secondary second, than a freeflow in your mouth

when your first stage is stuck open, utilising a shutoff increases pressure to the other reg

Go for a dive with your finger on your primary purge

There is no place for shut off valves in open circuit especially when
they're available in on with the flow, and on against the flow, versions

Does this stuff really happen or am I talking through my A

Very good.

 

[chris kippax]

Have you checked your IP?

 

[Gareth J]

One preventative solution to consider? Although I think the usual suggestion is to put it on the primary, and if that starts to FF you can shut it down and then move to the alternate. In your case you would have had to have it reversed, or one on each 2nd stage.
View attachment 525615
Freeflow Control Device

Treat Flow stops with caution. If it is the second stage that as free flowed, then shutting off the flow stop would be OK. However, if it's the first stage, the second stage acts like a pressure relief valve, closing the Flow stop, would result in a burst hose.

One other point, is it a flow restriction, even when open. Therefore it will have an adverse effect on the performance of the regulator.