ATX40 - Is this normal?

[gcarter]

Is this normal or do I need service?

Did lifetime dives 12 & 13 on Saturday, which were dives 8 & 9 on my ATX40 regs.

I have noticed that my primary is easy to free flow if in + position and turned with mouthpice up - so of couse, I don't do that.

On Saturday, 1st dive of the day, son was wearing the GoPro and this was first video I saw of me diving. Max depth was 40 feet, temp 16C. In the video I noticed that the alternate would occasionally flow air when mouthpiece up, stopping when turned down. Lever was in the - position. It was not a full on free flow, just a light bubbling - little enough that I did not notice during the dive, nor did my son pick up on it. Had it not been for the video, would never have known.

Second dive had a mx depth of 60 feet, bottom temp of 12C. After reviewing the video, did not see any occurance, at least not while the camera was on me.

Should I be bringing my regs in for adjustment?

 

[Bubbletrubble]

I'm not an official Apeks rep, but I think I can answer your question. It's a basic regulator question, not one that deals with brand-specific issues.

Assuming that the intermediate pressure (IP) being put out by your first stage is stable and lies within the normal range (130-150 psi), the reg behavior you describe is absolutely normal for a well-tuned second stage, e.g., cracking pressure of about 1.0 inch of water.

If the slight trickle of air on your alternate at depth bothers you, then you can ask your local reg tech to "tighten up"/increase the cracking pressure on that second stage slightly. By "slightly," I mean adjusting the cracking pressure from 1.0 inch of water to about 1.2-1.3 inches of water. As cracking pressure increases, it becomes more difficult to initiate airflow. Obviously, you don't want the cracking pressure to be set so high that breathing is difficult. Tuning can be viewed as a balancing act between ensuring that the reg breathes well and preventing freeflows.

For reference, a primary second stage is generally tuned to a cracking pressure of 0.8 - 1.2 inches of water.
Contrastingly, an alternate second stage (octo) is typically tuned to a cracking pressure of 1.0 - 1.4 inches of water.
Any competent reg tech should already know these numbers.

If you think that your reg is out of tune, don't hesitate to bring it into your local reg tech. He should be able to inspect it for you while you wait (assuming that he isn't busy doing something else at the time). He'll check the IP, the cracking pressure, perform a subjective breathing test, and do a quick visual check of the reg setup. It really shouldn't take more than a few minutes to do.

Hope this helps...

 

[gcarter]

It does help, thanks.

I'll just have it checked when it goes in for the annual later this fall.

From what you are saying, I take it as not being abnormal, and certainly if I had not seen the video, it is a small enough trickle that I didn't notice it, nor did my dive buddy (son) - who has been my buddy on every dive with these regs.

 

[gsk3]

Hint: You can buy a knob to convert your 40 to a 50 (I know this works on more recent ones but believe it works on the ATX as well). That will let you have a nice breather but tune it so it doesn't freeflow when not in your mouth.

 

[Tortuga68]

Hint: You can buy a knob to convert your 40 to a 50 (I know this works on more recent ones but believe it works on the ATX as well)

Yeah you can retrofit a TX50 knob, or there's a guy on eBay who sells copies. You don't get the micro-adjustment of the XTX knobs, but in-water they're the same. Of course you could fit a genuine Apeks XTX knob with micro-adjustment, but it's be cheaper just to buy a 2nd-hand ATX50

 

[tphillipp]

Hi gcarter,
Yes, it is normal for your primary to freeflow with the venturi lever in the + position and the mouthpiece up. A good rule of thumb is to place the lever in the minus position when the regulator is out of your mouth and in the plus position while in your mouth.

Regarding your alternate - what you describe, "occasionally flow air when mouthpiece up" is not unusual. As bubbletrubble stated, you can have it detuned if it becomes a problem. If you have a constant bubble stream then you should get it looked at by the technician.
You should try to find a way to stow your alternate during the dive so that it is not mouthpiece up. Mouthpiece up makes it more sensitive to leaking.

 

[redacted]

I agree that the slight leak in your alternate is not an immediate problem but I would not call it normal either. Leaks tend to get worse - usually slowly. If getting to your tech is easy, I would ask him to make a small adjustment. It is the kind of thing that can be fixed while you are picking up a tank.

 

[gcarter]

Yeah you can retrofit a TX50 knob, or there's a guy on eBay who sells copies. You don't get the micro-adjustment of the XTX knobs, but in-water they're the same. Of course you could fit a genuine Apeks XTX knob with micro-adjustment, but it's be cheaper just to buy a 2nd-hand ATX50

I did a quick search and didn't find this, do you have a link?

TIA

 

[Bubbletrubble]

I did a quick search and didn't find this, do you have a link?

TIA

@gcarter, gsk3, and Tortuga68: I think it's poor form to discuss openly on this manufacturer's forum how to modify a reg with an unofficial part. Either discuss the specifics of this mod by PM or kindly start a new thread in the "Regulator" or "DIY" forum about this. I don't want to scare anyone here, but this situation could raise potential liability issues for the manufacturer.

I mention this out of courtesy to Apeks/Aqualung and all manufacturers who have agreed to establish an online presence here on ScubaBoard.

 

[gsk3]

@gcarter, gsk3, and Tortuga68: I think it's poor form to discuss openly on this manufacturer's forum how to modify a reg with an unofficial part.

Didn't notice this was the mfg's forum. Sorry.