Using a regulator in cold water.

[KOMPRESSOR]

Hello from Norway! We've solved this discussion once and for all, at least here. You simply won't find any warm water regs sold here. At least not in any serious shop. and if you do, at least expect them to be thoroughly described as "southern holiday regs".
Anyways, the word around here is that if you expect to do diving in water temps around 50-55F, it's all about sealed cold water regs for you. I can't really say I do much diving in warmer water than that at all, but that's another story.
Now if the air temps are low, below 32F, things are a bit more demanding for you. We arrange OWD courses in the winter occasionally, and it's hardly ever temps above freezing. We make it through with our school gear, and the students do get some extra knowledge about cold water diving this way. Lots of good advice up here in this thread, and I can't say I've found any "bad" advice from anyone. Good! I set my regs a bit tight when it's cold, and open for better flow when I get down. I NEVER(!) test breathe the regs out of water when it's cold! You're supposed to, but hey, are you going to dive or just blow your tanks for nothing after getting all that gear on? That's a choice...

here's my video from a few years back. Enjoy!

YouTube - PADI Ice Diver


(It has been -20F for weeks here now. Getting a bit tired of it. Especially getting my car started every morning with electric heating for an hour before I can even touch it!)

 

[Markos Valsamis]

One relevant question- when people say get the regulator serviced "specifically for cold water diving", what do they mean? How can a reg be serviced specifically for this situation?

 

[JackD342]

One relevant question- when people say get the regulator serviced "specifically for cold water diving", what do they mean? How can a reg be serviced specifically for this situation?

You will have to direct that question to whoever those "people" are who made that statement. Any other interpretation is purely speculation of what they meant.

 

[TMHeimer]

I've dived as cold as 33F with my old used non-sealed reg. -- for what it's worth. I dive regularly here in winter with water temps. at 40F or maybe even in the high 30s.

 

[Storker]

Don't pre-breathe your regulator

There's no problem with pre-breathing, but make sure not to exhale into the reg.

If you have a decent cold-water-capable reg, inhaling from the reg won't be a problem. Moist air exhaled into the reg, where it can form frost, may well become a problem.

If the temp topside is above freezing, don't worry. Again, assuming you have a decently cold-weather-capable reg. But be aware that if it's close to or below freezing topside, a 2nd stage freeflow on the surface, after the dive, is quite likely. Be prepared to handle it.

 

[Ayisha]

One relevant question- when people say get the regulator serviced "specifically for cold water diving", what do they mean? How can a reg be serviced specifically for this situation?

I didn't see the source of your question in this thread, but there are good cold water reg technicians that will tune a reg (or de-tune it) for cold water. Regs may have a range of First Stage Intermediate Pressures within their specs, and a lower IP within the range will reduce the chance of freeflow in extremely cold water.

 

[lowviz]

One relevant question- when people say get the regulator serviced "specifically for cold water diving", what do they mean? How can a reg be serviced specifically for this situation?

Maybe "adjusted" rather than "serviced" is a more intuitive term for cold water.

The intermediate pressure is important for even a novice diver to understand and be able to measure in any dive situation. Your secondary regulator (in your mouth) will only work over a range of 'feed' pressures. Get an IP gauge from your LDS.

Most reg techs will tune your secondary for the easiest breathing effort, aka warm water setting. That usually means that the IP (intermediate pressure that your first stage delivers as a constant <even though your tank pressure varies massively>) will be set to the high end of the working range.

I used to ask that my first stages be tuned to the midrange of what they are capable of, aka coldwater setting. I asked for the tech to write down the high and low values along with where the reg was set. Now I do it myself.

Oh, and have your secondary balanced to the primary's IP. Done and done.

 

[Bigbella]

Typically, cold water is considered ten degrees Celsius and below; and, while that temperature won't strike many as being that cold, the air traveling from your tank, through the first stage, as it expands, can quickly cause ice to form on valves. Workloads, increased air density at depth, and heavy breathing will only add to that. If you doubt that, rapidly open a valve some time, even at, say, room temperature, and keep your hand on the top. I have had ice visibly accumulate, while diving, at seven degrees Celsius.

One relevant question- when people say get the regulator serviced "specifically for cold water diving", what do they mean? How can a reg be serviced specifically for this situation?

To combat that, some first stages run at higher IPs (the Cyklon immediately springs to mind); have some form of heat sink, whether a combination of "ribs" and an exposed spring, like the Poseidon XStream and some others; or, simply the sufficient metal mass of the stage, where size indeed counts, in cold water. My older regs actually possess a rubber cap, which can be filled with vodka or glycerin, as an effective antifreeze. Other brands, insist upon silicone oil or grease packed into the first stage . . .

 

[JackD342]

If you want more than a passing understanding of cold water use, (and it is NOT just a simple yes or no design question) then I highly recommend reading both this article, and the "bonus" link at the end of the article.
Why Scuba Diving Regulators Freeze

And then there is this single slide I created to try and explain it in brief:

 

[lowviz]

@JackD342, Nice link. Cheat for those who aren't going to read the whole text:

“In the right conditions, you can make any reg freeze,” he says. “That’s nothing against the reg; it’s just physics.”