Scubapro S600 / MK25 Cold Water Freeflow Issue This Weekend

[rhwestfall]

I wish PADI would make their training a tad more rigorous when it comes to safety issues.

That isn't a PADI issue, its an INSTRUCTOR issue......

 

[OkByMe]

There are 2 types of S600 seconds... One has a nylon tube and the other has a metal tube. The metal tube should be good to go in near freezing water. The g250 has metal, but can be hard to find, so the G250V is what I have in addition to the S600. Take the cover off, the diaphram out and check the tube, if it is nylon, you have the older S600 with the chrome ring around the purge.

 

[ams511]

There are 2 types of S600 seconds... One has a nylon tube and the other has a metal tube. The metal tube should be good to go in near freezing water. The g250 has metal, but can be hard to find, so the G250V is what I have in addition to the S600. Take the cover off, the diaphram out and check the tube, if it is nylon, you have the older S600 with the chrome ring around the purge.

Beaver can correct me if I am wrong. The OP does not need to disassemble the regulator because the gold edition he is buying already has the metal air barrel. Scubapro switched from a nylon to a metal air barrel in 2012 (I think). The gold edition is 2013. Older S600/S555/G500/G250HPs can be converted to a metal air barrel for about $40 when the reg is in for service.

 

[lowviz]

Not going to get into the fray, just reporting what I do.

I have my reg tech set the IP to midrange, and ask that he write down what that is. Next tune the secondary to "normal" breathing rather than "anticipates your next breath". Secondaries come out of the box tuned hot so that they meet factory "ease of breathing" specs. You do NOT want a hard breathing secondary, just normal easy effort. Your reg tech will know what you mean.

 

[underH2Oman]

One thing to remember is that a free flow causes a cooling affect as it goes from a higher to lower pressure. I have forced free flows in an indoor pool and removed ice from the second stage.
It does not take a long time to cause ice build up in a cold water environment with a rapid free flow.

 

[halocline]

I'm considering buying an MK25/S600 (anniversary version) hence checking on potential issues with free flow (and thus the very late post). Overall, the regulator has superb user reviews, although there are occasional free flow issues reported such as yours.

I wouldn't buy one specifically for cold water. You'd probably be better off with a sealed atomic, or if you want to stay with SP, a MK17.

 

[TSandM]

Curt Bowen did an experiment on time to empty a tank with various leaks. If I remember correctly, it took about 90 seconds to empty an 80 cf tank with a full freeflow. Considering that most freeflows won't occur with full tanks, you have VERY little time to solve the problem. Ascending on your own gas, if you are very deep at all, will either require an inadvisable ascent rate or will guarantee you will run out of gas before you get to the surface.

I am FIRMLY of the belief that the proper response to a freeflow that won't stop is to go on your buddy's gas. If you are well schooled in air-sharing ascents, turn the tank off. It will get rid of the bubbles that cloud your vision and the noise that muddles your thoughts.

We have had a number of freeflows, although only one violent one (and that was in a reg that is supposed to be GOOD in cold water). Check the IP of the reg, and if it is out of range, the first stage is the culprit. If not, there may be debris or some other problem in the second stage. At any rate, a regulator that has had a violent freeflow should be examined by a competent reg service person.

 

[RVBldr]

We blew a tank on the surface for a course and it really didn't take long for ice to build up in the 2nd stage of the MK25/S600, to the point where the free flow wouldn't stop. I also had a free flow at about 90' FFW and it took about 3 minutes to drain a 117 cf HP tank - I expect that at high 40's water temp, ice was also involved. That air goes fast! As noted in posts above, if you're deep, at the first signs of continuous flow, I'd be getting on a buddies air first, then work on shutting that down. In my case, it was a fairly new regulator with about 8 months use; when I took it back to the shop for a checkout, the IP was high and the 2nd stage needed tweaking. They indicated that after about 6 months initial use, they like to see the regulators re-tuned.