Aqua Lung ACD - Is it a gimmick or is it a deal maker?

[Oldbear]

When I installed the yoke I did not over tighten the valve. I tightened the valve until I felt resistance. Same as I did with rental gear. As I,stated earlier, I believe that since the yoke is new, it has a better "seal" than used rental gear. At any rate, just ensure all air is removed from your lines or you will blow a tank seal.

Regards
Glenn

Glenn,

Yeppers you describe the procedure correctly, I must have misread what you said in my mind. I still do not know why the yoke would be hard to unscrew if you released the pressure. There is a lubricant that is used when regulators are serviced called Tribolube or Christolube. You might put a few drops on the thumb screw treads and see if this helps.

Tribolube 71 O2 Compatible Lubricant | Dive Gear Express®

Lubrication Technology Christo-Lube Oxygen Grease

 

[Luis H]

Just dove with my new gear today. Everything worked great. I do however have a little bit of advice. When you shut off the air to the tank, depressurize the Octo lines by pressing one of your mask faces until ALL air is depleted. If you don't and start to disconnect your yoke, you will blow off the O-ring on the tank.

I believe that since the equipment is new that yoke is really tight even when you just snug it up during assembly. When I went to disconnect my yoke today, it would not unscrew. I released the air in the lines using my primary but not enough and it blew out the o-ring.

Hope this helps.

Glenn

The SPG high pressure hose has a very small restriction orifice. By design, it is intended to restrict the flow in case of a hose failure. The side effect is that it also restricts the flow when you are purging the regulator. Therefore, you just need to be a bit patient when purging to make sure all the air pressure is released.

With some SPG hoses, I have seen when sometimes you think you have purged all the air pressure, but a few seconds later you still have some pressure and you have to purge the residue again.


BTW, The Aqua Lung ACD does seem to be a reasonably well designed closure device. It opens mechanically with the yoke (or DIN) and I am sure it doesn’t add any more restriction than the orifices already in the valve, etc.

The ACD does seem to seal relative well against casual water splashing or very casual surface exposure, but I would not dunk it into a tank without a good dust cap with an O-ring. I do not see an O-ring seal in the ACD, but it may have good sealing design.

Even if it has a good seal, you need to make sure that the connection is dry and clean. If there is any water or salt on the surface of the ACD, when you connect it to a tank the ACD will open and it will all be blown into the regulator by the high pressure air. For this reason alone, IMO the ACD is only a backup device to a good dust cap. A good dust cap will keep the interface surface dry and clean, the ACD will not. It is up to you to dry the connection and make sure there are no salt deposits in that surface or crevices.

 

[keyshunter]

That's how we sometimes remove yoke o-rings when we want to change them. Turn air on very slowly with the yoke loose. Takes a bit of practice, but it beats digging it out. I usually just stab the o-ring with a sharp dental pick, being careful not to scratch the adjoining brass. I cringe when I see the tools and methods some people use to remove yoke o-rings.

Originally. AL used the same dust cap as on non-ACD regs. The flat cap would actually open the ACD and if it was not fully seated would allow a bit of leakage. The new dust cap addresses this problem..

 

[Luis H]

That's how we sometimes remove yoke o-rings when we want to change them. Turn air on very slowly with the yoke loose. Takes a bit of practice, but it beats digging it out. I usually just stab the o-ring with a sharp dental pick, being careful not to scratch the adjoining brass. I cringe when I see the tools and methods some people use to remove yoke o-rings.

Originally. AL used the same dust cap as on non-ACD regs. The flat cap would actually open the ACD and if it was not fully seated would allow a bit of leakage. The new dust cap addresses this problem..

That makes sense and I am glad that that Aqua Lung address that design issue. I just hope that the new dust cap seals as well and keeps the ACD connection surface clean and dry. Again, I think the ACD can be a great backup device.

I don't feel a need for it (I have not had any issues in over 45 years), but I have seen plenty of other divers that could have benefit from it.

 

[Glenn Williams]

All good responses, but since I own the gear and have dove with it, the differences in an "open" valve vs the ACD valve is that when you turn the air valve off to your tank and purge the air using your mask, there will still be residual air in your regulator lines. This residual air is enough to keep you from unscrewing your yoke from the tank with ease. As such you must continue to hold your mask purge down until all air is completely out of your lines.

An open regulator will not keep air in your lines and is easily removed.

It is no big deal, it is just different from an open regulator.

My first dive with the ACD, resulted in a blown seal on the tank as the air trapped in the lines made removing the yoke thumb screw difficult to remove. Subsequent dives have been made with no issues as you simply just hold your mask clearing device down and then unscrew the yoke.

All that said. My next opinion on the ACD is that as Luis H said. I ensure the ACD is dry before installing the yoke to the tank. The earlier dust caps would open the ACD when installed and snugged up. The current design has an undercut that fits over the ACD to prevent this from occurring. As for dunking the regulator in water without the dust cap, well the design of the ACD is to keep water out of the line to keep the lubrication in place. Personally I will always have the dust cap in place but would have no issues dunking the regulator in a bucket or rinse station with the dust cap off. As I stated earlier. Aqua Lung got it right with this design.

My 2 pennies worth haha

Glenn

 

[Luis H]

All good responses, but since I own the gear and have dove with it, the differences in an "open" valve vs the ACD valve is that when you turn the air valve off to your tank and purge the air using your mask, there will still be residual air in your regulator lines. This residual air is enough to keep you from unscrewing your yoke from the tank with ease. As such you must continue to hold your mask purge down until all air is completely out of your lines.

An open regulator will not keep air in your lines and is easily removed.

It is no big deal, it is just different from an open regulator.

Glenn

Glenn,

In the first two paragraphs of post number 42, I was just trying to explain the typical reason why you have to hold the purge button on your second stage to bleed all the air out. This is very common. I am sorry if it wasn’t clear.

Here is what I wrote:

The SPG high pressure hose has a very small restriction orifice. By design, it is intended to restrict the flow in case of a hose failure. The side effect is that it also restricts the flow when you are purging the regulator. Therefore, you just need to be a bit patient when purging to make sure all the air pressure is released.

With some SPG hoses, I have seen when sometimes you think you have purged all the air pressure, but a few seconds later you still have some pressure and you have to purge the residue again.

This happens with many of the modern SPG (submersible pressure gauge) hoses due to the restriction orifice in the hose. It has nothing to do with the regulator design or the ACD. The SPG hose is what holds the air and it just takes time to bleed down.





BTW, I am a bit confused about you calling the regulator second stage a mask. We normally refer to our mask as we wear over our eyes and nose with clear glass to be able to see underwater.

The regulator second stage is often referred to the regulator mouthpiece. It is also the second stage demand valve, but I have never heard anyone call it a mask.

Are you using a full-face mask with the regulator attached to it? That would explain your terminology, but the purge button is still on the regulator second stage.

I know this is just terminology, but it does help to use the standard terms that we are already using.

Have fun diving.

 

[Glenn Williams]

Yep you are right. The words I used are incorrect. I apologize for the confusion, I was trying to over simplify. Also I hope that my responses don't come across as being mean. Thanks for your input, it is much appreciated.

Thanks
Glenn

 

[extremetito]

I have a Legend LX with ACD, and I have dived Cozumel and the Philippines on dive boats where the staff handled the set up, cleaning, and storage. On occasion, I witnessed some careless rinsing of regulators, and I was glad for the ACD device.

 

[TheWarmerTheBetter]

The ACD system does change the filter that the regulator uses from a standard filter available from Trident to a smaller one that I haven't been able to find from a third party. So if you service your own stuff and can't get Aqua Lung service kits just keep that in mind.

I always put the dust cap on my regulator. If you take apart the ACD system and look at it carefully you'll notice that the seal between the center post and the outer yoke nut when the ACD is closed (not on a tank) is a metal to metal seal. You would probably be ok to dunk the reg without the dust cap, but there is a chance that water might work its way in since there's no o-ring. That being said, it's probably unlikely in a normal dunking. I just figure why take the risk?

It is nice to have when I go kayak diving. Changing the reg to the second tank on a kayak sometimes things get splashed and with the ACD the water hits that and you can wipe it dry before putting it on the second tank.

So basically I would use it as a backup and use the dust cap like you normally would.

Just my opinion.

 

[Diver0001]

Hoping users of ACD regs would chime in with their experince.

Well.... from what I can see they have some utility in rental stock because some students and people who rent regs do not take care of them very well. It just lowers maintenance costs/effort if these regs are in rental stock, which for a large dive centre can be a big deal.

If, however, you are not sloppy with how you treat your own regs then it's a completely unnecessary feature.

As for performance etc, my buddy has a reg that has this and I've never heard him say anything bad about it. He also services regs for the shop and says that he's seen a few stick open but that mostly they work as advertised.

R..