Aqualung’s ACD - safe or not?

[Divin'Papaw]

I've been using the Legend with ACD for over 13 years without issue. Initially as my primary singles reg and then I purchased a second and they are my doubles regs. They are fantastic regulators. I have close to 500 dives on them without ever having an issue.

Edit: Mine are DIN. DIN regs are all that I dive and all that I own.

 

[WarrenZ]

I still dont see the problem whenever I am on a livaboard when I put my tank in the tank rack I remove the first stage dry the dust cap and cover my reg that way the tank can be refilled and my regulator stays water/debris free. Are you suggesting that you never touch your own gear on a trip? I always look at it as my responsibility to make it easy for the crew to fill my tank and it is my responsibility to take care of the rest of my gear.

 

[NYCDiverBlue]

We're talking about Cocos Island here. Unlike in the Caribbean, there are only two sites where the liveaboatrds can moor, so all the dive sites are accessed by panga. The island itself is uninhabited expect for a few park rangers, so diving with one of the liveaboards is the only way to get there. It's a fantastic place, said to have the second highest shark population on the planet. I'll be back for my third trip out there in a couple of weeks.

After looking at the panga thread, it's clear that the Aggressor Cocos boats use RHIBs instead of pangas, but pangas are what they call them. I don't recall the details about the other company's boats.

@rongoodman Given that this is the case, I am wondering what you and others here think of a work around strategy for this. Some do not repair their own gear. Some do not repair their own gear. If they do, they could simply do this after such a trip. If they do not, one is supposed to get their gear serviced once a year. One could simply schedule the servicing after such a trip and let the LDS know the conditions that the reg set was exposed to make sure that all salt crystals are removed. Would this strategy then negate any argument that one could make that an ACD device is of advantage in this situation with the exception that one is diving this type of dive trip multiple times a year.

Thanks for explaining as I will definitely investigate Cocos Islands as future dive locations especially since you are going there for a 3rd time. Which Cocos Islands are you speaking of?

Cocos Island - Wikipedia

Cocos (Keeling) Islands - Wikipedia

 

[rongoodman]

Costa Rica.

 

[JackD342]

@rongoodman Given that this is the case, I am wondering what you and others here think of a work around strategy for this. Some do not repair their own gear. Some do not repair their own gear. If they do, they could simply do this after such a trip. If they do not, one is supposed to get their gear serviced once a year. One could simply schedule the servicing after such a trip and let the LDS know the conditions that the reg set was exposed to make sure that all salt crystals are removed. Would this strategy then negate any argument that one could make that an ACD device is of advantage in this situation with the exception that one is diving this type of dive trip multiple times a year.

Thanks for explaining as I will definitely investigate Cocos Islands as future dive locations especially since you are going there for a 3rd time. Which Cocos Islands are you speaking of?

Cocos Island - Wikipedia

Cocos (Keeling) Islands - Wikipedia

That could work for a few folks in certain situations, but not really a game plan to count on. First of all, manufacturer recommendation on all Aqualung regulators is to overhaul every two years, and just inspect/test (nothing is disassembled in the inspection) in the off year. Cleaning out salt is an overhaul. You are also assuming this type of trip is only once a year, and always at the same time each year. Not too many folks fit that description. But.... yes, if you believe your regulator has been flooded or contaminated with sea water or anything else, then it is wise to have it serviced upon return from the trip.

 

[NYCDiverBlue]

That could work for a few folks in certain situations, but not really a game plan to count on. First of all, manufacturer recommendation on all Aqualung regulators is to overhaul every two years, and just inspect/test (nothing is disassembled in the inspection) in the off year. Cleaning out salt is an overhaul. You are also assuming this type of trip is only once a year, and always at the same time each year. Not too many folks fit that description. But.... yes, if you believe your regulator has been flooded or contaminated with sea water or anything else, then it is wise to have it serviced upon return from the trip.

@JackD342 Thanks for explaining.

 

[RalphJ.]

It is a question of proper torque for the ACD valve and the yoke fittings. There is a Consumer Safety Notice out which you can find at www.aqualung.com. It applies to Titan LX ACD Yoke SNs beginning with E, F;
to Core ACD Yoke regs with SN's beginning with E, F, G and H prior to H043301;
to Legend ACD Yoke regs with SN's beginning with E, F, G and H lower than H043301.

It should be a ten-minute disassembly/reassembly of the ACD & yoke fittings.

DIN is not affected.

There was apparently one gas shutoff incident related to rocking of the yoke under pressure, where the ACD valve unscrewed.

With only one incident that I'm aware of (third-hand), and Aqualung's retorque request, you should be fine. BUT! Make sure your shop is aware of the Bulletin and is completely conversant with the reassembly and torque settings. The service is no charge. If they don't know about it, change shops!

But IMHO, the whole ACD concept is a solution looking for a problem. What diver needs a valve to keep water out of his first stage? And it won't help the diver who has a wet yoke and reconnects it to his second tank on the boat. As soon as he tightens the yoke and pressurizes, the droplets of salt water are blown past the now open ACD, and get inside the reg anyway.
Old fashioned is better: dry your yoke with a bit of towel before you fit the cap between tanks. It's why I don't let the boat crew ever switch my tank between dives. They're just moving too fast.

Retrofitting to pre-ACD yoke is only possible for a few early ACD legends.

Just go get it checked, if your serial numbers are in the range above.

Here's a reported incident:
Aqualung Legend LX First Stage Failure at depth

I agree the ACD's are problems waiting to happen. I had an Aqualung legend with the ACD fail closed, luckily in 8 ft of water so a safe outcome. My argument against ACD's is that modern regulators are supposed to have the advantage of "down stream" failures if a failure occurs so the the reg is still delivering air in a failure. The ACD is a COMPLETELY UNNECESSARY feature and has the potential, as small as that may be, of a catastrophic, closes failure which negates the "down stream" failure advantage of the modern reg.

 

[RalphJ.]

I suspect that Aqualung has researched the function of this feature pretty well, and looking at the schematics, it's very tough to see a way in which it could actually cut off air without simply falling apart.

But, I personally would never buy a regulator with one of these. There is simply no justifiable reason to put any possible obstruction in the air path. The oceanic system, which involves a plastic ball on a spring that opens and closes with each breath, is far worse, but why bother at all?

I'll tell you why, because it gives the salesmen something to talk about that can sell new regulators. That is the sole motivation behind a design like this. It will never make the reg breathe better or be more reliable. Dust caps have shown that they work perfectly in keeping water out of the HP section of the first stage. And the consequences of a small amount of fresh water getting into the first stage are minimal anyhow, easily fixed with a cleaning.

Plus, these things don't address other real causes of water in the first stage anyhow, which are wet fills and water on the fill whip (notorious in boat fills) or on the regulator and/or tank valve (when switching tanks). What they DO accomplish is hiding the filter from plain sight, which makes inspection for water intrusion much more difficult.

I agree that there is no truly justifiable reason to have an ACD feature. I have had one fail and even though it was an error on the service technicians part, the fact that the ACD is a completely unnecessary feature and has the potential, however small, to cause catastrophic closed failure is all the reason I need to never use that reg. or any reg with an ACD again.

 

[Divin'Papaw]

Never mind ... not worth it

 

[Nemrod]

I've been using the Legend with ACD for over 13 years without issue. Initially as my primary singles reg and then I purchased a second and they are my doubles regs. They are fantastic regulators. I have close to 500 dives on them without ever having an issue.

Edit: Mine are DIN. DIN regs are all that I dive and all that I own.

Same here. I like the ACD feature. I have two AL regulators with the ACD and have updated the older Legend to the new shutter with the integral ridge. But I do know how to use a torque wrench and do.



The problem with Aqualung today is not the ACD but that they, and inclusive of Apeks, are now owned by an investment holding company and parts (and product) have dried up.