Apeks XTX50 free flow question

[gshak]

I've always had a non-adjustable second stage, so I'm not sure if this is normal, or if something is dangerously wrong with my second stage.

I was trying my new XTX50 (Tungsten first stage) out in the pool at about 4' depth, 83 deg. water, and noticed that when I took the primary out of my mouth, it would free flow every time until I turned the adjustment knob about halfway in. One of the times, I could not stop the freeflow without surfacing and turning off the tank. OK, I realized later that the venturi should have been set to + during the dive (but maybe not during a 4' dive?), and maybe I should start with the cracking pressure knob turned all the way in and adjust it out until it breathes properly, but is this really normal?

I've always been able to remove my old reg (non-adjustable Poseidon Triton) from my mouth at any depth and not worry about a free flow, but this has me concerned. Is it normal that if I forget to set the knob properly, I can expect the second stage to free flow when taken out of my mouth? This is not a minor flow, but enough to knock my mask off if I'm not holding it against my face. Is this only happening because I'm in shallow water? I did have the tech check the IP when I bought it, and he said it was good, but I guess that could have changed too. This was the first time I've used a second stage with any adjustment knobs.

 

[redacted]

Sounds to me like you have a great performing, well tuned reg. You could detune it a bit if you can't manage the freeflow, but it would be better to learn to manage the freeflows. First step is technique. When you remove the reg from your mouth, make sure you are not doing so during an inhalation cycle. Stop inhaling, short pause, then remove the reg by relaxing your mouth so you do not initiate any vacuum as you remove the reg. Also, as you remove the reg, rotate the mouthpiece downwards or escaping gas will start it freeflowing. If you are handing that reg off, make sure you keep the mouthpiece pointed downward and the recipient needs to do the same. And practice it often.

If you are removing the reg for other than an OOA situation, you can turn the venturi down and even crank down the user adjustment knob. If you are going to switch to your alternate and clip your primary off, you probably should make both those adjustement to insure the reg behave well. It is possible to quickly make a detuning adjustment during an OOA situation but you would need to do it without delay - more practice. Work on technique before you resort to such adjustment during an emergency.

 

[scubafanatic]

I've got (2) XTX 200's, and I consider them to be my favorite regs, along side my 2 Atomics regs...I've got a bunch of nice reg sets (Aqualung/Apex/Atomic/Mares/Poseidon) so I have a reasonably wide experience across many brands.....adjustable and non-adjustable 2nd-stages. I've got my Apeks tuned for EASY breathing, so yeah, if I have them in max mode, and I take the 2nd stage out my mouth, they'll freeflow big time....so I tend not to do that! I'm gonna ask a dumb question: Why are you taking the 2nd-stage out of your mouth while underwater anyway ??? If I were to feel the need to remove the 2nd-stage from my mouth while underwater, I'd remember to 'detune' the 2nd-stage BEFORE doing that...at this point I'm gonna chalk this one up to 'operator error' and not a reg problem.

 

[ianr33]

With the cracking knob all the way out, and the venturi set to +, they are supposed to freeflow (out of the water at least) when the purge is pressed. Turning the venturi to - should stop the freeflow.

I can send you a pdf of the service manual if you want.

As awap said,its a good idea to wind the knob in a couple of turns before taking the reg out of your mouth. I do it instinctively now but it caught me out a few times at first.

 

[Kevin R]

This is not normal for one of these models.

Could you describe the "freeflow"? Freeflow is often a misused description for regulator problems. Is it a runaway freeflow every time as if you were purging it, or bubbling constantly until you turn the knob in.

It sounds to me like this reg is not tuned correctly and the purge lever is set too high. It should not freeflow unless the user knob is all the way out, the venturi lever is set to + and the purge button pressed out of water. Putting your hand over the mouthpiece should stop the freeflow in these circumstance, which does the same thing as turning the venturi lever to - will do. I would find a competent and experienced (not just someone who took the mfr's course and fixes regs as a hobby) Apeks technician and have them look at it. If it is simply bubbling constantly and you have to adjust it on the fly all the time to get it to stop then the 2nd stage spring might need to be replaced.

 

[gshak]

When I say 'free flow' I'm talking full pressure flow, as if I was holding the purge button. Like I said, the first time I did it, it blasted my mask off. I was able to stop it all but one time by 'fiddling' with the knob, shaking it, or covering the mouthpiece. The venturi lever was set to - when this happened. One of the times I couldn't stop the flow, which was what really bothered me.

I can accept that I might have to learn to adjust the knobs and my breathing before posing for a pic, practicing an OOA drill, or sampling my octo, but what happens when a panicked OOA diver just grabs my primary and it starts to gush? Are we both just doomed?

 

[Kern]

When I say 'free flow' I'm talking full pressure flow, as if I was holding the purge button. Like I said, the first time I did it, it blasted my mask off. I was able to stop it all but one time by 'fiddling' with the knob, shaking it, or covering the mouthpiece. The venturi lever was set to - when this happened. One of the times I couldn't stop the flow, which was what really bothered me.

I can accept that I might have to learn to adjust the knobs and my breathing before posing for a pic, practicing an OOA drill, or sampling my octo, but what happens when a panicked OOA diver just grabs my primary and it starts to gush? Are we both just doomed?

Such drama.

No, it's not an uncontrollable free flow. They just put it in their mouth & exhale. This increases the pressure in front of the diaphragm, which will close the valve seat. Shutting down the air flow until the next inhalation. Inhaling will decrease the pressure in front of the diaphragm & open the valve. Repeat as required.

Just follow awaps advice. Or have it detuned to the point that it becomes much less likely.

 

[gshak]

Such drama.

No, it's not an uncontrollable free flow. They just put it in their mouth & exhale.

Apparently not enough drama to get the point across that there was too much air flow to get it back in my mouth (I tried to put it back in).

If it's working properly, and I need to learn new habits to prevent this from happening at depth, I'll do that. If as Kevin is suggesting, the purge lever is adjusted improperly, I should probably have that checked before my trip to Cozumel next month. I really don't think it's a good idea to have it de-tuned to something other than the manufacturer's specs based on a 4 foot deep pool dive. It sounds like this is a pretty common occurrence with this reg.

 

[Kern]

If the inline pressure, & everything else is as per the manufacturers specs, it would not blow your mask off & you would have no problems getting the reg back in your mouth.

The rate & volume of air flowing from a 2nd stage is the same whether it's being purged, free flowing or upon inhalation. A reg flowing enough air to blow masks off, & can't be returned to the mouth must be very uncomfortable to breath from.

I have 5 Apeks regs. They're all tuned to crack with the absolute minimum inhalation effort. Therefore if not handled correctly when they are removed from the mouth during a dive they will free flow. I suspect that almost any reg tuned this way will. I have never encountered a reg that flowed so much air I couldn't pop it back into my mouth.

 

[SangP]

It's rather common among high performance regs to free flow when they are taken out of the mouth if the ip is set too high.

A detune would be all you need to get it to stop free flowing yet have an easy breath.

SangP