freeflow again

[divemaster2011]

hi i posted on here not long back about having a freeflow and not handling it very well.
well i had my regs serviced and thought that should solve it but it hasnt!! i have done 50 dives with these regs with no problem and now they seem to be giving me hassle. my regs are dacor eagle second and dacor viper octo. i am wondering what i would need to change to stop the freeflows? do i take it that when a freeflow happens its because the first stage has frozen open and allowing air to be pushed out? the only thing is that i was diving in water that was 6 degrees today and have dived colder water with no problem? on a more positive note at least i managed to controll myself and not do a rapid ascent to the surface lol...any ideas what i should do regards my regs would be appreciated thanks shaun.

 

[rstofer]

What first stage are you using? Freeflows are often caused by the first stage freezing open. If this is the case, you may see both the primary and the octo flowing at the same time. Or not.. One might flow enough to purge the excess gas.

You are diving in 43 deg F water. Oceanic, for one, says you should not use their piston first stages below 50 deg F. Does your first stage have a cold water kit? Is it a diaphragm stage?

Freezing may occur if you breathe a lot or if you put a lot of air in the BC or if you do both at once. It would be nice to know which stage is freezing but I'll just go ahead and guess it is the primary.

Richard

 

[don Francisco]

Expanding air requires heat to do so and draws it from the immediately surrounding area. Conversely the ambient water warms the regs, but only when they cool below the surrounding water temp. In cold water there's only a narrow band of temperature differential for rewarming before the reg is cold enough to freeze.

Whether a reg freezes or not, depends on both the rate of air usage (cooling rate) and the ambient water temp (warming rate). At greater depths, or with more breathing effort a reg that did fine yesterday might freeze and freeflow in the same temperature or warmer water today.

Short of buying an environmentally sealed reg, and/or keeping tighter tabs on your depth and breathing rate, there's not much you can do except to be aware of the causes and ready to deal with it.

 

[eponym]

When the air is cold, breathing off the reg or using the BC inflator (on the surface) can cool the first stage to the point where it will freeze up once in the water. This is in my experience the most usual cause.

So your gear assembly and testing routine needs to be different in cold weather. Don't take more than a sip of air on the second stages, if you must. Keep the first stage out of the wind--put a heavy sock or a watch cap over it if it's going to sit out on the tank for a spell before you get in. Inflate your BC orally to start. Once you're under the surface the water will transfer enough heat to the first stage (even very cold water has heat) to keep it from freezing, as long as you're not breathing hard or leaning on a BC or drysuit inflate button. Short bursts with long pauses between them is ideal. I've also seen freeze-ups start underwater during reg retrieval drills, because of overuse of the purge valve.

Turning off the air for a couple of minutes is usually enough to allow the first stage to thaw underwater. Of course, breathing hard off your buddy's tank now puts that reg in danger of freeze-up, so sometimes ascending while sipping from the free-flow is the way to go.

There have been some good threads on this over the years. Search on "freeze" and you'll see lots to read.

-Bryan

 

[NorthWoodsDiver]

I managed a freeflow by just feathering the valve on and off with each breath but this isn't going to work if you cant reach your valve(s) so that may be something to familiarize with.

Every thing bad that happens underwater is part of a chain of events. That chain starts to show up in cold water then add some over exertion due to current or the cold and then add some extra air use for inflating the bcd and drysuit and pop you have a freeflow.

I solved the problem by investing in a sealed diaphragm first stage and an adjustable second stage (scubapro MK17/S600) you can get this reg for about $360 (american $$) from Scuba store. Online Scuba gear and Scuba equipment shop. so that may be something to look into.

If you should have to share air or someone were to need air from you then you will put increased stress on the reg and make it more likely to pop off. Having an octopus can lead to problems also, sometimes its just poor adjustment or even some sand and the thing leaks a bit without you noticing. At 100ft it doesn't take much leaking in combination with your breathing and bc use to cause problems.

Pay attention to when you add air and how you breath. Take a breath and hold (while slowly exhaling) and then add air to the bc slowly in small bursts then when your done take another breath and repeat during the descent.

 

[elan]

Diving cold water you have to make sure that:
Your first stage is environmentally sealed.
When you put your reg on the tank make sure water or moisture does not get inside the first stage through the opening or even the environmentally sealed 1st stage can freeflow,
when you inhale you need to take longer breaths
as it was pointed out using BCD while inhaling will increase the chances.
my ice diving instructor warned us not to use piston first stages as they more likely to freeflow (cannot comment on this just passing his words). dacor eagle seems to be piston

 

[dave4868]

Was the freeflow just a slight trickle of air like the last time? Or did it steadily increase to severe once it started? You're getting into some pretty cold water now. Did it seem worse than the last time in the warmer water?

Just for info, could you measure the cracking pressure and post your result? (Pressurize the system and slowly dip the second stage, with mouthpiece upright and diaphragm horizontal, in a tub of water until it just starts to hiss. Estimate how deep the diaphragm is when the hissing starts.)

What did the shop say about the situation? Did they do another full servicing, even though you just had one? What exactly did they do this time?

This is getting interesting, but it must be a real frustration for you!

Dave C

EDIT: I confused your situation with another poster's, but the cracking pressure would still be interesting to know. Good job handling the situation!

 

[Garrobo]

I think I'd be buying myself a new set of regs which are made for cold water diving.

 

[divemaster2011]

What first stage are you using? Freeflows are often caused by the first stage freezing open. If this is the case, you may see both the primary and the octo flowing at the same time. Or not.. One might flow enough to purge the excess gas.

You are diving in 43 deg F water. Oceanic, for one, says you should not use their piston first stages below 50 deg F. Does your first stage have a cold water kit? Is it a diaphragm stage?

Freezing may occur if you breathe a lot or if you put a lot of air in the BC or if you do both at once. It would be nice to know which stage is freezing but I'll just go ahead and guess it is the primary.

Richard

my first stage is also dacor and as far as im aware has no cold water kit attached would you recomend that i should buy a enviromentaly sealed first stage and see how i get on with that before buying new second and octo ?

 

[ScubaSarus]

Let me ask is the shop overhauling them properly. Some Dacor parts are very hard to get. Are all the springs etc new?

If you are diving cold, a Sherwood blizzard or othe cold water reg may work better. I know in the winter I have my regulator tightened and in the summer have it loosened abit. Ask your shop to tighten them up for cold water diving if possible.

I believe the Viper and Eagle were simply rebranded and parts should be available.

Can I ask if you got regulator service traing in you divemaster course. The Naui divemaster manual has a nice chapter on Regs.