regulator freezing up

[CuNanoTube]

I would like to note that my Mk. 17 / A700 have free flowed twice on my, once at about 3m after 2 minutes in the water, and another time under the ice after about 5 minutes in the water. This is not a good track record considering I have 4 dives on them. (which may be a factor)

 

[flots am]

Yet another question about regulators. When a newer reg would freeze, are they suppose to freeze open and cause a free flow or do they and can they freeze closed and prevent you from getting any air at all??

It really depends on how crapped-up or broken it is.

Regs will generally fail "open" in a free-flow, but this really isn't guaranteed. If there's something seriously wrong inside, it's entirely possible for it to not deliver air.

Regardless of the reg, it's possible to suddenly have "no air" if the tank dip tube, valve or first stage inlet filter gets crapped up, so no matter what kind of reg it is, you always need to be aware that you might not get another breath, regardless of what the pressure gauge says.

If you're talking about actual "freezing" where ice builds up inside the first stage, then yes, you should get a freeflow. But I wouldn't bet my life on it.

 

[tddfleming]

It really depends on how crapped-up or broken it is.

Regs will generally fail "open" in a free-flow, but this really isn't guaranteed. If there's something seriously wrong inside, it's entirely possible for it to not deliver air.

Regardless of the reg, it's possible to suddenly have "no air" if the tank dip tube, valve or first stage inlet filter gets crapped up, so no matter what kind of reg it is, you always need to be aware that you might not get another breath, regardless of what the pressure gauge says.

If you're talking about actual "freezing" where ice builds up inside the first stage, then yes, you should get a freeflow. But I wouldn't bet my life on it.

The reg is mostly new, bought it Sept 2010. LDS said they could deturn it but it would not breath as nice as it does now. I honsetly don't know what I mean by freeze up, I am just going by what the LDS owner said and his tone of voice when he said it. It got me wondering what he meant exactly and what that meant to me. Since I am not a betting person, your statement is on the money, at least in my mind.

Do you work on regs to have a pretty good working knowledge of them?

 

[ECpirates96]

It sounds like you are talking about a 2nd stage free flowing due to the adjustment of the cracking pressure. You may want to consider an adjustable 2nd stage if you would like to have one that can be adjusted in the event you want to have an easy breathing regulator but would like to adjust it down in the event of an occasional free flow. I would check the IP on the 1st stage to make sure its in range. 135psi +- 5psi is usually where most are at. If that is fine then the 2nd may be the problem or the shop tech. I am not sure which 2nd you have but several adjustable 2nds are on the market and top performers like SP S600 and G250, HOG D1 and Apeks to name a few. Learn the working of the regulator and consider it part of your journey to be a better diver. Check out Regulator Savvy at scubatools.com or Regulator maintenance & repair at Airspeed press.

 

[tddfleming]

It sounds like you are talking about a 2nd stage free flowing due to the adjustment of the cracking pressure. You may want to consider an adjustable 2nd stage if you would like to have one that can be adjusted in the event you want to have an easy breathing regulator but would like to adjust it down in the event of an occasional free flow. I would check the IP on the 1st stage to make sure its in range. 135psi +- 5psi is usually where most are at. If that is fine then the 2nd may be the problem or the shop tech. I am not sure which 2nd you have but several adjustable 2nds are on the market and top performers like SP S600 and G250, HOG D1 and Apeks to name a few. Learn the working of the regulator and consider it part of your journey to be a better diver. Check out Regulator Savvy at scubatools.com or Regulator maintenance & repair at Airspeed press.

Yep, ip is 140. I do think it is the 2nd stage. The EOS has a venturi and a cracking pressure adjustment. Some advise was given as to how to better handle this at the surface, but then I started thinking about what the LDS owner said and about it freezing and that brought up this topic.

 

[JB]

Notice, I said MOST, not all. In a freeze up (icing) conditions most will freeze in the open position.

I suppose we are talking at cross purposes, you are specifically referring to 2nd stage and I am considering the whole reg. Logic tells me that the 1st stage is more likely to freeze than the second stage, as the pressure drop is greater across it and therefore the cooling is greater, but then logic can be flawed!

I would contend that as far as 1st stages go.

1. all balanced pistons are downstream
2. all balanced diaphragms are upstream

It seems to me that for cold water, diaphragm regs are generally recommended. Then most cold water regs have upstream valves?
I would like to know if a failure (not freezing) is more or less likely to be free flow in a diaphragm vs piston reg? Don't seem to be able to reason this one out myself, other than diaphragms are more likely to fail closed, hope I'm wrong as I use diaphragm regs!

 

[ajtoady]

I actually got my Mares to free flow in 33 degree F water. It was in part my fault as i use HP tanks and when I hit the water it was at 3450 psi which is the worst case scenario for freezing. I found that if I hit the water with about 2500-2800 psi I had no problems at all. The other contributing factor was I may have inflated my BC at the same time as a large inhale thus increasing the amount of air flow. I had however been under for about 20-25 minutes and was starting to get a little chilled in my wetsuit. Why I was breathing heavy could have been related to that.

 

[tr3a]

Diaphragm first stages tend to be more reliable in cold water. Despite being upstream they will fail in an open position. When a diaphragm first stage (balanced or unbalanced, doesnt matter) is unpressurized the valve is open. when a valve fails it tends to leak past the seat which tends to open the seat further, a free flow in the making.

Some Poseidons (jetstream/ odin. extreme) have upstream servo assisted valves. There is alot of mis-information circulating regarding these.
In the rare instance where they do freeze they also fail in an OPEN position. Only the servo is upstream, the main ballon that closes the valve is downstream, and icing in the second stage will take the servo out of the equation resulting in a very powerfull free flow.

 

[marcbeaudry]

i'd be curious to know which regs are likley to fail 'closed' preventing free-flow ?
i'd argue that ALLregs are designed to fail 'SAFE' and therefor open - but there seems
to be some of the opinion that fail 'off' is a design feature of some regs ?
granted - 'something terribly wrong' as in damage or serious neglect with a reg could possibly create an out of air situation - but i feel THAT isnt something that sneaks up on you - people who dive un maintenanced gear typically know it right !?
I started ice diving this last winter and can confirm beyond any doubt that both a second and first stage CAN freeze up on you - both are designed to fail 'SAFE' therefor open - i'd love to know which brand\model fails 'closed' .
marc

 

[tr3a]

I do not know of any regulator that will fail closed.
As I stated in my previous post alot of mis-informed people believe that Poseidon (or any other upstream servo assist second stage) can fail closed. That is not true.
On a Poseidon if the first stage freezes the second will continue to breath normally, due to the design the increased pressure will not affect operation. In order to prevent a LP hose from bursting there is an overpressure relief built into the first stage, and also in the LP hose itself. If the second stage ices up (rare) it will free flow just like any other regulator.

30-40 years ago alot of cheaper single hose regulators used upstream tilt valves in the second stage. Even these will fail open.

There are alot of old wifes tales floating around that get passed on and on by individuals that believe everthing they are told without question and have never seen a regulator taken apart.

It would be helpfull if part of a basic SCUBA class consisted of taking apert various regulators. They are not as complicated and mysterious as some would have us believe.

My favorite regulator for diving is a 1959 US Divers Mistral Double Hose. This design is a single stage upstream valve. The design is/ was considered bullit proof, so much for progress