Double hose regulator freezing under the ice

[luis]

Everywhere I read about ice diving it is mentioned or implied that a double hose is the preferred regulator since it is less susceptible to freezing. It is less susceptible, but it is not immune.

I went ice diving last weekend (water temperature 35 F) and my regulator developed a free flow and it seemed to freeze.

In the beginning of the dive it was performing great, but we were heading back to the opening since one of the other divers was having BC inflator problems from the beginning.

Near the opening we stopped momentarily while he was tinkering with his inflator. The second diver and I got upside down and decided to walk on the bottom of the ice. That is when the free flow started.

At first I didn’t believe my regulator was free flowing, but I turn right side up to check it. The noise was the first indication of a free flow, but it was quickly followed by higher than normal air pressure in the mouthpiece. The pressure got quickly high enough that I couldn’t exhale into the mouthpiece.

A good part of the problem might have been my fault for having it tuned so sensitively (IP about 150 psi, inhalation cracking resistance about 0.5inWC). That is probably what started the free flow. In some positions my regulator has been known to bubble a little bit…I say that is a very bad idea for an ice diving regulator. I should have detuned it some.

The other problem probably came from some water (about two table spoons) that I found inside the regulator can. I am assuming the water made it past the mouthpiece valves, but I am not positive. My mouthpiece valves do seem to leak a bit.

At one point the free flow was so severe and the exhalation resistance so high I thought that maybe ice was forming on the duckbill and pressing on the diaphragm, but after re-thinking it I don’t think that is possible. The air out of the duckbill has been around the hose loop and should have warmed up some.

I am thinking about doing some experiments in an ice bath to try to duplicate the free flow, but I don’t know how successful it will be.

Has anyone had icing/ free flow experience with any double hose, in particular a two stage such as a RAM or an Aqua Master? Everything seems to indicate a second stage freezing so it wouldn’t mater if it was a DA, a RAM, or PRAM.

[swimjim]

I've had some experience ice diving and about thirty dives past 60 fow in water that was around the 35 degree mark using my Phoenix. The octo would free flow on me, but never the double hose end.
I checked the IP and it was set for 150. I backed it off to 140 and never had another problem.
I would suppose as you were inverted and if the mouth piece got above the cans, that would start a "normal" free flow. In water that cold, that could cause the first stage to stick open due to literally freezing that way from the now super cooled air. A common enough occurance on the great lakes with single hosers. I've had the misfortune to experience that more then once at 120 fow. Not fun. The air will freeze your gums requiring a trip to the hospital if you are unwise enough not to take it out of your mouth. A major bummer.
I think detuning slightly may help the situation as the regulator may be less prone to free flow. By all means though test away. I think the results will bear me out.

Jim

[luis]

Thanks Jim

I though about detuning it by backing up the IP and in retrospect I obviously should have.

My impression is that it was the second stage that froze, not the first stage, but I don’t know that for a fact. It is a diaphragm first stage and it is basically dry, but as I mentioned there were about two table spoon of water in the can. My thought is that the water could condense and freeze right on the cooled down second stage seat carrier stem. This would not allow the seat to return to the closed position.

The magnitude of the forces in the second stage are not large, therefore it wouldn’t take much ice build up to impede the motion of a part. In particular a sliding part like the seat carrier. A little bit of surface frost would probably be enough for it not to slide.

A regulator that is setup to deliver air with minimal effort means that the summation of forces in the second stage are very close to a balance point and a minimal force from the diaphragm will offset the balance of forces causing the valve to open. Therefore, small interference or sticking from icing could also, IMO, interfere with this forces.

A few of the second stages on single hose regulators also experienced freezing and free flows last Saturday (I think some BC inflator malfunctions also occurred due to freezing).

[Sea Explorer]

That's interesting. I know that the Aqualung typically detunes their regs especially the cold water ones. My Legend Supreme was significantly detuned when I first got it (IP 135) and the balanced second stage was also conservatively adjusted.

I have experienced similar free flow on deep dives with a highly tuned Royal. I do not run above 145IP and when I tune the second stage I adjust the tension on the spring until it free flows and then back it off a quarter to half a turn then I bend the lever to optimally contact the diaphragm. This solved the free flow problem and still offered very good performance. I have found that an IP of 140-145 is a practical compromise that yields near optimal performance with greatly increased dependability in a variety of settings. With settings 150 and above I have consistently experienced free flows in water never below 42degrees.

The higher the consequence or likelihood of free flow the more I detune the reg.

-Ryan

[Nemrod]

I have been reducing my IP down for sometime now after experimenting with it as high as 150 or more. I get good performance with all of our "improvements" and a stabe regulator at 135/140. I do that setting after a break in period.

It seems to me for you ice divers if your on a single you better get yourself a pony bottle and sling it and get one of size sufficient to get you back to the hole and put a good old fashioned metal Voit or USD Conshelf on it and detune the crap out of it so you know you have a fully independent air supply with a solid regulator on it.

When I start finding water in the cans that is usually the first sign the cage valves are beginning to curl and need to be replaced.

Nem

[luis]

Thanks

Actually I did have a 19cuft pony with an environmentally sealed Titan first stage and a metal balanced adjustable Scubapro second stage. I think that combination is a close to “bullet proof” as it comes, but in light of the subject…nothing is totally “bullet proof”.


My mouthpiece valves are flat and seem to be in good shape, but they are leaking when I blow on them. They seem to barely reach the inside diameter of the sealing surface. I thought they were reproduction black silicon valves that I bought from Ron, but I am not sure about that. They are good looking very thin valves with fairly low flow resistance, but they have never been totally dry sealing.

A good portion of the times my can stay dry during several weekend dives, but it is not uncommon either to find a table spoon or two of water in the cans. It normally doesn’t bother me and I even think it is a major reason why I never get dry mouth. After a weekend of diving I just rinse the inside of the cans if there was any water.

Obviously the presence of water inside the can during ice diving can cause an extra complication if a free flow is initiated.

I am looking forward to trying Bryan’s new clear silicon mouthpiece valves.

[Nemrod]

The silicone valves I got from vss also leak a bit due to barely reaching the edge of the cage surface. I figure it hurts nothing in normal use--under ice I might worry.

Another place water leaks is the gasket between the body and the can--make sure it is good and not to tight or to loose or it will leak there.

The other place is the diaphram sealing surface to the can. Use of clips--to tight or to loose wil cause leaks and if to tight it may also damage the can causing them to scallop and not seal. The use of band clamps prevents damage but you must--MUST--make sure the diaphram is seated and that the cans will not rotate with strong hand pressure or the diaphram will leak or even unseat and flood the regulator.

Usually water in the cans is the cage valve curling or such as that.

I realize you all know all of this but just for posterity.

Nem

[luis]

The silicone valves I got from vss also leak a bit due to barely reaching the edge of the cage surface. I figure it hurts nothing in normal use--under ice I might worry.


Nem

What is the OD of your mouthpiece valves?


The ones I am using are 1.15" OD, but I also have some thicker ones that are 1.25" OD.

The small ones are also very thin.

Thanks

[Robohips77]

Luis, Is it possible that due to the cold that a contraction factor may have occurred. Could the water infiltration have come from a loose hose clamp due to contraction? Take some of your mushroom valves and place them in ice water for a period of time and conduct a table experiment with them and see if any of them actually shrink after 15 -20 -25 minutes in 35 degree water. I don't have the micrometer? to measure but I see that others may have one. Just curious. When you finally determine the reason please post. Thanks Robohips

[Nemrod]

The valves I am using came from Dan several years ago and I really like them. Unfortunatly I got only three pairs an another fellow gave me a fourth and I quickly installed them into my small fleet. The measure around 1.16 to 1.17. They are very soft but springy and do not curl. They are as soft today as the day I put them in. I know something similar might be coming soon, maybe even from our "hostess with the mostest" but until then these are the bomb.

Yeah, robo hit another thing there, some of the curved mouthpieces have flashing or an uneven parting line that seems to allow water to leak in on the upstream side of the valve, a drip at a time. I will often see a small bubble coming from the parting line right where the hose comes over it so I know they leak. I have carefully trimmed etc and now they don't leak.

Nem

[Bryan]

The valves I am using came from Dan several years ago and I really like them. Unfortunatly I got only three pairs an another fellow gave me a fourth and I quickly installed them into my small fleet. The measure around 1.16 to 1.17. They are very soft but springy and do not curl. They are as soft today as the day I put them in. I know something similar might be coming soon, maybe even from our "hostess with the mostest" but until then these are the bomb.
Nem

The new silicone valves were made using the ones you are talking about as the model. Samples are 1.16-1.17 so I have no reason to think the production ones will be different.

[Nemrod]

Oh, that is great, good news indeed. I bet they remain more flexible also when cold.

Nem