Preventing regulator freeze up

[Remy B.]

As mention previously, set it at 120psi or 8bar, I use APEKS DS4 with ATX-50, and Aqua-Lung Titans-LX for Cold Water as well set to 120psi/8Bar, and I have been in Dives with 4*C water/39*F no problem, I had two Free-Flows at that Temp @45m, and it was because the 1st stage was set at 150psi/10.2 bars and my seat on the 2nd stage was not 100% good as well.

I had a Free-Flow with one of my Aqua-Lung Titan, as well at 5*C water, because I didn't have the Cold Water kit in it.

 

[2airishuman]

The best way to avoid that bothersome freeze up is to soak your regs in the Florida Keys. That's where they and you will be happiest anyway. Why resist? You know you wanna!

Quite.

What I find most remarkable about this thread is that you actually attempted to dive in 33F water wearing a wetsuit. If you ask me, you're lucky it was your regulator that froze.....

Depends on the wetsuit and individual physiology. More muscle mass means more thermogenesis, larger frame means more mass per unit surface area, and there's individual variation in circulatory performance. I dive in a two-piece 7mm freedive suit with an integral hood. I'm planning an ice dive in it on New Year's Day. I do not anticipate that I will be uncomfortably cold.

Maybe it was the 2nd stage that froze. In general, bigger all metal 2nd stages will provide better heat transfer and be more freeze resistant.

I've dived in water down to 38 and never had a freeflow. Then again I have metal second stages, and I dive with two 1st stages so I can shut down one of them and let it thaw if it does freeflow.

 

[tbone1004]

I finally read KevinNM's links - very interesting. One thing I noticed was that my tank was slightly overfilled, starting at 3060 PSI, which surprised me given the cold temperatures. A couple of weeks ago my starting pressure was only 2650, and I figured it was low due to the cold. Kevin's links mentioned the tank pressure being a factor. I'll look into tweaking the intermediate pressure. I don't think I'm in a position to do this myself and I'd like to discuss the tradeoffs involved in having this done. I'm at the pool with a local dive shop tonight so I'll try to bring it up then.

A companion's perdix showed max temperature of 33 and min of 32, which is as cold as fresh water gets before it turns to ice. He says it reads warmer when he's done ice diving, so I think I'm just out of luck for these kinds of very cold open water dives.

I'd look at dropping the IP, however it will require adjusting the shims on the Sherwood so that should really be done by a tech. Much easier on the XT's where you can DIY that if you have a pin spanner, whatever size allen key it calls for, and an IP gauge.

Downside of dropping the IP is you may have to retune the second stages because they are getting less force from the IP, and I'm not sure how well the balancing mechanisms are in those two regulators to comment on whether you will need to or not. With a mechanically balanced, or unbalanced second stage your WoB would increase with the drop in IP. At properly deep depths there are some other downsides of the low IP wrt WoB, but that's as a function of gas density, and not really relevant in recreational depths.

 

[vam]

Thanks tbone - I'll look into it. I had to google that WoB = Work of Breath... Posted here in case anyone else comes across the thread and scratches their head too. I will look into dropping the intermediate pressure since I do most of my diving in cold water.