Question on mouthpieces

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lyonsce

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Location
Scranton PA
# of dives
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I have a Z2 that I changed the mouthpiece on. I put a Comfo-Bite mouthpiece on it and now it seems to freeflow when I purge it on the surface. The tech says that this is common on Atomic regulators and that I have to put my thumb in front of the mouthpiece or put the Atomic mouthpiece back on. That sounds strange to me, is there something about the Atomic mouthpieces that provide some back pressure to keep the reg from free flowing? Is there a comfobite type mouthpiece that works with the Z2?
 
The comfo-bite is branded and patented by Aqualung so you won't see any support from them or Atomic on using that mouthpiece.

The Comfobite is meant for Apeks which have a larger orifice opening than the Atomic, though the Aqualung regulators share the same orifice size as Atomic. 21/16"x11/16" for Apeks, 19/16"x10/16" for Aqualung/Atomic. That won't really make a huge difference, but it makes it a little easier for it to freeflow.

Now, the point is it freeflows at the surface. That means one of two things; that your tech is a knucklehead and tuned it too sensitive, which is a common problem; or, more likely, you have the venturi lever in the on position and the adjustment knob turned all the way so it makes the reg prone to freeflowing. Either way it needs to be backed off because a freeflowing reg due to purge is dangerous, especially in cold water diving, but also in an emergency situation. The regs should only freeflow when turned diaphragm down when they are full of air without a mouth on them. I.e. hit purge button underwater with the mouthpiece up, or take the reg out of your mouth underwater and turn it mouthpiece up before it floods completely.


As this is the Atomic subforum, they will tell you to use Atomic mouthpieces only and I'll probably get a PM saying it's an Atomic forum and we shouldn't be suggesting other brands stuff, though I might escape unscathed since you already have it on there, not sure how the Atomic guys are, I know the Aqualung guys get real fiesty.

Edit: not implying your tech is a knucklehead, but it is quite common for shops to tune the primary regulator so cracking pressure and WoB is almost nothing, and while it is nice to have something breathe that easily, there is a balance point so they won't freeflow when they aren't supposed to.
 
So just an update. I changed the Comfo-Bite mouthpiece with the Trident version of this mouthpiece (they call it the Comfort Bite); and the free-flow stopped when I purge it. I have a hard time believing that a mouthpiece changes this behavior, but I have to believe my own eyes. The Trident is slightly smaller in size and I guess that's what does it (I'm not sure I actually believe that), but at least I have a mouthpiece that my wife will like and it does not free flow, so I guess I will quit worrying about it. Thanks.....
 
I had a Seacure mouthpiece on my B2 and it would free flow. I brought it to Atomic HQ for service and they recommended that I switch to the Atomic mouthpiece. It stopped the free flowing on the surface but it is not as comfortable for me on long dives. I loved the Seacure since I have an odd bite but I made the trade off to stop the free flowing.
 
I use a Seacure mouthpiece with Atomic ST1 and generally have no problem. I keep the knob detuned on the surface and of course you have to point the mouthpiece down when removed from mouth in water.
 
I use a Seacure mouthpiece with Atomic ST1 and generally have no problem. I keep the knob detuned on the surface and of course you have to point the mouthpiece down when removed from mouth in water.
Thanks for sharing that:cool:
 
My GF uses a Seacure on her Z2 with no issues...
 
it still comes back to the regulator is tuned too "hot". Whether that means the IP is too high and the second stage and first stage weren't tuned together/at the same IP, or the lever is set too high, regardless of the mouthpiece it shouldn't be doing that. All that means is that the opening on the mouthpiece is smaller than the opening on the case creating back pressure, but it still stands that it shouldn't be doing that and you are bandaiding the problem with a different mouthpiece instead of fixing the root cause which is an improperly serviced second stage.
 
it still comes back to the regulator is tuned too "hot". Whether that means the IP is too high and the second stage and first stage weren't tuned together/at the same IP, or the lever is set too high, regardless of the mouthpiece it shouldn't be doing that. All that means is that the opening on the mouthpiece is smaller than the opening on the case creating back pressure, but it still stands that it shouldn't be doing that and you are bandaiding the problem with a different mouthpiece instead of fixing the root cause which is an improperly serviced second stage.


I understand your points; however Customer Support at Atomic and the Service and Support Manual from Atomic state:

6. Uncontrolled free-flow Check mouthpiece type. Non-factory mouthpieces may cause this.

The IP is a solid 135 with no creep or drift. I've tested this on a Z2 and a Z3 with exactly the same results.
 

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