My reg freeflowed at 80 feet

[Genesis]

And how full was it?

HP 3500 psi tanks perhaps?

LPs?

AL80s?

Water under 50F CAN cause trouble with piston regs.

IMHO, if you're going to dive water under 50F, then you need to be thinking about using either a dry-bleed reg (Sherwood is the only choice), a sealed diaphram, or a grease-filled piston first.

Yeah, yeah, I know, they claim they're "ok" in colder conditions.

Ok. They keep freezing on people though!

 

[DeepScuba]

Man, either I'm the luckiest guy in the world of cold diving, or you guys are the most unluckiest........

Either way, I'm happy.

 

[buttermanr]

I am glad I looked at this thread. I am looking to buy a new regulator and was doubting between the Scubapro MK25 (seemed to be the most recommended reg) and the Mares Proton Ice (love the small size).

This thread made me look up the MK25 info and reading ScubaPro's website carefully and using their "comparison tool" I now see that they actually recommend the MK16 for coldwater diving. I guess I'll go for the Proton Ice.

Has anyone had those freeze up?

RB

 

[Warren_L]

crispos once bubbled...
Great thread, people. Free flow regs are a killer problem here in Ontario IMHO. Genesis, Bob3 and jetwrench, thanks for enlightening me on my SP G500/MK20 which I have learned by experience to be highly prone to free flowing. Reducing the IP is also a way to reduce FF risk, I heard.

Wouldn't reducing the IP increase FF risk as the gas has to expand more to the lower pressure, thereby drawing more heat???

 

[Charlie99]

wlo93 once bubbled...
Wouldn't reducing the IP increase FF risk as the gas has to expand more to the lower pressure, thereby drawing more heat???

Reduces significantly the probability of free flow of the 2nd, while increasing probability of 1st stage FF only just a tiny bit.

 

[Genesis]

Its the percentage change that matters.

The percentage change is small for the first stage (but in the wrong direction) but large for the second stage.

However, this procedure is not always a good idea, especially with downstream (unbalanced) seconds or even balanced ones without a second (balance chamber) adjustment, as it can make them breathe "wrong" (stiff, uneven, etc.)

Balanced seconds with a balance chamber adjustment can be easily retuned to compensate for the lower IP.

 

[John C. Ratliff]

I've also been reading this thread with interest. There was an earlier thread about regulator freeze-ups that had a post mentioning a web site for Antarctic diving, which had a current evaluation of regulators for extreme cold water. A search should locate that post.

Anyway, I've dove both diaphragm and piston regs in cold water, and continue to do so. My Scubapro AIR I has an environmental unit on its first stage, that is silicone filled and does a good job. I recently placed it back on, and will continue to use it that way.

I have had freeze-up on a diaphragm regulator, the MARES Mk-12 I believe (from years ago), but I think that was a second-stage problem.

Double-hose regs are the best, provided both stages are housed inside the case. That means the DA regulator, DA Aquamaster, and Royal Aquamaster work very well, as does the AMF Trieste. The Dacor Dial-a-Breath two hose even had a duel LP diaphragm, offering even further protection. The Snark III has the first stage exposed, so it may not do quite so well (but it is a diaphragm reg too).

The US Navy experiemented many years ago with under-ice diving in the Arctic waters, and the book Skin Divers In Action by Erik Bergaust and William Foss (G.P. Putnam's Sons, New York, 1965, pg. 43) showed the photo I'm posting here. Since it's an official US Navy photo, I don't think they have copyright protection for it. The Navy divers in the photo are using DA regulators (the predicessor to the Aquamaster), and while they were probably dry and would never freeze up, the reason they are on the surface is probably to catch their breath (this was a very bad, hard-breathing regulator--before venturi assist)

SeaRat

 

[GoBlue!]

I've been reading various threads re: Scubapro freeze-ups with interest. While I'll probably run across this somewhere & apologize in advance for not sifting through tons of posts, can someone explain the "anti-freeze" Mk25 to me? What's different?

(My LDS told me today that the environmental kit is no longer going to be available for the Mk25. True? Is this the same as the "AF"?)

Jim

 

[roamer]

I have a set of scubapro regs and I will not sell them to anyone. Why? Because in the Great Lakes environment they free flow very easily, and I will not have that on my hands. If I considered selling them it would be to a warm water only diver and I would have them sign a document stating that I warned them of the cold water free flow risk. I bought a set of Poseidon Jetstreams and have not had a problem since. One very experienced diver/instructor looked at me with the Poseidons and said "You finally chose to get real regulators, eh?" Enough said.