Scubapro S600 / MK25 Cold Water Freeflow Issue This Weekend

[ScubaPolishPete]

Had an issue this weekend...

A buddy and I descended to 76 ft, hovering above a platform in quarry (in Illinois), we planned to stay down for a bit, then practice shooting up a safety sausage. However, it was pretty cold, and I was only wearing a 5mm suit, so we very quickly decided to just shoot the sausage, ascend, and play in a different part of the quarry.

Descended, and immediately started at the task. I removed my reg from my mouth, blew into the sausage, and my S600 immediately went into free flow. I stuck my fingers "into" the mouthpiece to stop the flow, didn't work. Bang the side of the reg, didn't work. Took a breath from the free flow, then banged it again, didn't work.

Grabbed my octo, and started to breathe off that, while trying to manipulate my S600 primary to make it stop. It wouldn't stop flowing at any point.

Uploaded data from the dive, and the temp down there was 53 degrees. I dove this same temp earlier in the day, and dove the same temps before this year, with this reg, without issue. However, I've also never removed my reg from my mouth at those temps. So...I'm going to assume that caused the freeflow.

Any info you folks can provide on this would be helpful.

Was my S600 or MK25 out of tune? Is there anything I could have done different, or should do different to this reg for future use in these temps? Was this just failure of an internal part and the reg shouldn't have free-flowed at 53 degrees out of mouth?

 

[beaverdivers]

Was my S600 or MK25 out of tune? Is there anything I could have done different, or should do different to this reg for future use in these temps? Was this just failure of an internal part and the reg shouldn't have free-flowed at 53 degrees out of mouth?

Yes, it may be that your S600 needs adjusting or the intermediate pressure ( IP ) is high on your MK25. Have a bench check done.

When you took the S600 out of your mouth, was the mouthpiece turned down?
Was the adjustable VIVA in the dive position?
Did you try to crank the adjustment knob in?

I don't believe it was a temperature issue.

 

[ScubaPolishPete]

Yes, it may be that your S600 needs adjusting or the intermediate pressure ( IP ) is high on your MK25. Have a bench check done.

When you took the S600 out of your mouth, was the mouthpiece turned down?
Was the adjustable VIVA in the dive position?
Did you try to crank the adjustment knob in?

I don't believe it was a temperature issue.

What do you mean was the mouthpiece turned down? It was in it's normal position, sideways, how it sits in my mouth.

Yes, it was in the dive position.

I did not mess with the knob at that time. I immediately started ascending hoping that warmer temps would allow me to shut the freeflow. It actually never occured to me to turn the knob. It all happened so quick. I was on a full tank of air as we had just descended and this happened maybe 1 or 2 minutes into us being down there (total dive time was only 8 minutes). The temps at 30 feet on our previous dive were about 71 degrees. The water was very warm, warmer than it had been all year at those depths. So, I tried to get as close to the surface, as quickly/safely as possible considering I was loosing air rapidly and knew this tank would be at 0 quick, plus it was much warmer. I actually went OOA on the ascent, with the gauge reading 0 at between 52 and 47 feet...and was able to slowly and calmly surface on my last breath of air.

LESSON LEARNED: Go to your buddy for air. I figured 3 minutes on a full freeflow tank, and my computer, as soon as we reached 76 ft, showed 3 minutes time to surface. So...basically, figured I could safely go up on my own air, and proceeded to do it. Big mistake now that I look back, but thank God turned out ok. I did not expect to be OOA so quickly. I was forced to surface faster than I wanted once OOA, but, I was in the "yellow" on my computers surfacing speed indicator at that point (I was surfacing in the green prior to that point), and looking back at the upload, from when the computer switched to 2 minutes time to surface, I ascended in 1 minute and 20 seconds. All in all, the timing of everything was just about right, but in any worse situation, or being OOA sooner, would have been bad. Again, the lesson here is go to your buddy for air, then ascend together and problem solve. I'm a newer diver so this was a very good learning experience, as well as taught myself a lot about my actions/thoughts/reactions at the time of emergency.

I gotta say, when it was freeflowing, and I needed to breath, and took that breath from the freeflow, that was a scary moment, but after that, no panic, just thought process and reaction (even though my thought process was initially was wrong). Sort of like a math problem, where you screw up a simple addition early in the problem, and the rest of the problem is done correctly, but the answer is wrong. I learned a lot from this.

 

[tplyons]

I dive that setup almost every weekend in the same range of water temps, even a little lower. Never had a free flow issue, so I can assure you its not the temperature.

Regulator adjustment comes to mind. When was the last time yours was serviced?

And yes, going to your buddy for air is always a good thing in this case.

Its amazing how quickly you can lose 80cf of air when freeflowing.

On the brighter side, looks like you actually had an opportunity to practice your CESA.

Enough armchair quarterbacking, it sounds like you realized your errors and how you could have done it better.

 

[agilis]

Basic scuba training should emphasize that you turn the regulator mouthpiece down so it's lower than any other part of the 2nd stage as an initial anti-free flow action. We all do this when we surface if take out the mouthpiece at that point. The small increase in pressure that happens when you hold the mouthpiece in a down position will often stop a free flow. If not, then turning the adjustment knob inward will almost certainly stop the free flow, especially if you use your thumbs at the mouthpiece opening to BLOCK the flow of air as much as possible. Putting a finger into the mouthpiece will do nothing good, and banging the side is worse than doing nothing. It's not an old TV set.

53F is not very cold water, and should have zero effect on the regulator. The reg may need to be adjusted, but unless something major malfunctioned, and it does not sound that way, you should have been able to stop the free flow if you remembered what you learned in basic certification training. I sense a reluctance to adjust the regulator when using it. If so, that is a very bad perspective. You should be completely familiar with and totally comfortable using your equipment, especially anything involving air supply.

 

[ScubaPolishPete]

I dive that setup almost every weekend in the same range of water temps, even a little lower. Never had a free flow issue, so I can assure you its not the temperature.

Regulator adjustment comes to mind. When was the last time yours was serviced?

And yes, going to your buddy for air is always a good thing in this case.

Its amazing how quickly you can lose 80cf of air when freeflowing.

On the brighter side, looks like you actually had an opportunity to practice your CESA.

Enough armchair quarterbacking, it sounds like you realized your errors and how you could have done it better.

Thanks, and yes...learned a whole lot through that experience. And absolutely...that 80cf went QUICK!!

Basic scuba training should emphasize that you turn the regulator mouthpiece down so it's lower than any other part of the 2nd stage as an initial anti-free flow action. We all do this when we surface if take out the mouthpiece at that point. The small increase in pressure that happens when you hold the mouthpiece in a down position will often stop a free flow. If not, then turning the adjustment knob inward will almost certainly stop the free flow, especially if you use your thumbs at the mouthpiece opening to BLOCK the flow of air as much as possible. Putting a finger into the mouthpiece will do nothing good, and banging the side is worse than doing nothing. It's not an old TV set.

53F is not very cold water, and should have zero effect on the regulator. The reg may need to be adjusted, but unless something major malfunctioned, and it does not sound that way, you should have been able to stop the free flow if you remembered what you learned in basic certification training. I sense a reluctance to adjust the regulator when using it. If so, that is a very bad perspective. You should be completely familiar with and totally comfortable using your equipment, especially anything involving air supply.

Honestly, I can't say that I learned to put the mouthpiece down to stop free low in my OW class. 2 fingers on the mouthpiece (not "in" the mouthpiece) was the advice, followed by a light smack. I agree, abusing it is not the way to treat your regulator. Thanks for the tip.

As for the adjustment...again, never came to me, and especially not during that situation, to adjust it down. It totally makes sense, and I understand how and why the regulator works and why that would make sense to do...it just wasn't my reaction to do that.

As I spend time on this forum, and in the water, I learn new things all the time. OW is just for basics. Knowledge comes experience and learning (reading, talking to people, listening, etc). My fiance says I spend too much time reading this forum. Clearly I HAVEN'T spent enough time...as I've still got a lot to learn.

Thank you for the insight though. Learned 2 tips here. Mouthpiece down, and adjust your regulator's knob (if you have it, like the S600). As basic as these are, sometimes someone needs to tell you something for you to know.

 

[tplyons]

...and adjust your regulator's knob (if you have it, like the S600). As basic as these are, sometimes someone needs to tell you something for you to know.

Keep this in mind. I don't bother with the dive/pre-dive most of the time unless I've got a long surface swim on choppy water (which may cause it to free-flow) but will just leave it in dive.

However, the diver adjustable inhalation control is ALWAYS used. When I dive, I open this as much as I can until it freeflows, and then back it off so it stops. Makes it very easy to breathe without freeflowing. This knob is your friend, use it often.

 

[OkByMe]

You don't have to drain the tank with a free flowing second stage. The IP pressure is only 150psi max on most first stages. Swap out to your backup, put a sharp bend in the free flowing regulator hose and squeeze like hell. That will usually cut off the air flow completely... depending on how hard you can squeeze. I usually carry a short tag line and that can be used to tightly wrap the kink in the hose so you do not have to hold it. You could also use the line from the SMB spool too. I have been told that the type of octopus holder that pushes into the mouthpiece opening will stop it too, but I have not checked that out. Seems like it would though, since there is only a minor pressure differential across the diaphragm that operates the lever on the spool. I used to dive ice, back in the day and free flows were common.

By the way... IF you kink the hose and your other regulator starts to free flow, then your IP is way too high. When that happens, you will have to allow some of the air to escape the kinked line so you can breath off the backup. The first stage is creeping and you need to get that checked before you dive that gear again. It is unlikely that water that warm would have caused the free flow, but the rapid air flow through the first stage could freeze it up. You have some good gear for cold - not freezing water.

I guess it goes without saying that the tank losing air that fast will cause you float up, so watch your ascension rate

 

[ScubaPolishPete]

You don't have to drain the tank with a free flowing second stage. The IP pressure is only 150psi max on most first stages. Swap out to your backup, put a sharp bend in the free flowing regulator hose and squeeze like hell. That will usually cut off the air flow completely... depending on how hard you can squeeze. I usually carry a short tag line and that can be used to tightly wrap the kink in the hose so you do not have to hold it. You could also use the line from the SMB spool too. I have been told that the type of octopus holder that pushes into the mouthpiece opening will stop it too, but I have not checked that out. Seems like it would though, since there is only a minor pressure differential across the diaphragm that operates the lever on the spool. I used to dive ice, back into day and free flows were common.

By the way... IF you kink the hose and your other regulator starts to free flow, then your IP is way too high. When that happens, you will have to allow some of the air to escape the kinked line so you can breath off the backup. The first stage is creeping and you need to get that checked before you dive that gear again. It is unlikely that that water that warm would have caused the free flow, but the rapid air flow through the first stage could freeze it up. You have some good gear for cold - not freezing water.

I guess it goes without saying that the tank losing air that fast will cause you float up, so watch your ascension rate

Thank you for the response / tips / info.

 

[bada3003]

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 frequently dive in colder waters (60 feet plus), temps in the low 40s, and free flow is an important concern. Just wanted to note that when you switched to your octo and it worked, it was because the problem was with the second stage, not the first stage. When the latter freezes, then switching to your octo won't help. As you did, sip from the free flow, and unless your buddy is nearby (sometimes they are a ways off), perform a controlled ascent. As you noted, air drains fast (in the ballpark of 60 feet depths, a full AL80 may drain in about 1.5 mins per published stats). Also, first stage freezing and causing panic due to free flow is a known accident cause. IMO, as with SMB inflation, it's an important practice drill.

Lastly, I also was not taught to move the mouth piece downwards in case of free flow during PADI OW. Came later from diving experience. I wish PADI would make their training a tad more rigorous when it comes to safety issues. But that's another topic.