Aqualung Legend LX First Stage Failure at depth

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I just read through most of this thread very interesting. Kudos to the individuals who did all the research. You are like underwater matlocks. I had no idea the ACD even existed and it seems like a completely unnecessary complication that could cause serious issues. Seems like the design team at did not due a proper risk assessment when they added this part. Aqualung went on my list of regulators to never buy along with Sherwood and Zeagle.
 
Aqualung went on my list of regulators to never buy along with Sherwood and Zeagle.
Well, Aqualung makes one of the most stable, high performing diaphragms on the market. So if you're interested, we can always retrofit a yoke bolt without the ACD mechanism from a sister model. That swap-out is working just fine. I've done that for my two Legends, and am very pleased.
As @Diving Dubai will tell you, the ACD is very nice to have in sandy environments to keep foreign material out. And rental guys love them, in case a knucklehead doesn't put the cap back on before rinsing the regulator after diving. But you're right - there was a flaw there that demands some attention.
A Scubapro Mk17 or Poseidon XStream are equivalent quality, but if you run across a used Legend for a good price, we can take out the ACD, no problem!
 
Wondering if there are any updates to this topic? FWIW, my inclination, without knowing more, would be to consider updating the first stage with the "new" shutter valve with the ridge, although I was told this was not supposed to be a replacement part for current regs. There are times when I like having the ACD in place, although I would not be opposed to removing it either.
While Aqualung has yet to come out with formal guidance, you can have your shop replace the shutter valve with the new "ridged" part very easily.
If you want to remove the ACD, our swap-out with the Titan yoke bolt is working just fine. I'm not sure many shops will do the Titan swap-out without formal approval from Aqualung, though I wouldn't hesitate to do it for you. @JackD342 may have an opinion as a shop owner.
So you have both options for an otherwise great regulator, and neither is very expensive.
 
Well, Aqualung makes one of the most stable, high performing diaphragms on the market. So if you're interested, we can always retrofit a yoke bolt without the ACD mechanism from a sister model. That swap-out is working just fine. I've done that for my two Legends, and am very pleased.
As @Diving Dubai will tell you, the ACD is very nice to have in sandy environments to keep foreign material out. And rental guys love them, in case a knucklehead doesn't put the cap back on before rinsing the regulator after diving. But you're right - there was a flaw there that demands some attention.
A Scubapro Mk17 or Poseidon XStream are equivalent quality, but if you run across a used Legend for a good price, we can take out the ACD, no problem!

I can certainly see the advantages to that if you are already invested in that regulator or run a rental shop. If i was invested i would probably change the parts. It cant malfunction if its not there! so many other good regs on the market why bother with all this hastle and possible warranty issues.
 
What's wrong with Sherwood and Zeagle??

I decided to go the piston reg route since i don't dive in caves, rivers or dirty water. from what i understand the SR1 and SR2 had a fair amount of issues bc they were sherwoods first piston regs manufactured in house.

As far as zeagle I read the story about the non serviceable first stages that were being "serviced" even though there were no parts for them. I saw the video of the reg blowing up on the spearfisherman
 
I decided to go the piston reg route since i don't dive in caves, rivers or dirty water. from what i understand the SR1 and SR2 had a fair amount of issues bc they were sherwoods first piston regs manufactured in house.

Wow, I don't know where you heard that, but Sherwood was the first manufacturer of piston regulators…

Sherwood was manufacturing piston regulators for the other Scuba companies before they were selling their own Scuba gear directly. This is back in the 1960’sand 70’s.

The earliest piston regulator companies like Healthways, Scubapro (a spin off from Healthways), White Stag, Dacor, etc. all had piston first stages manufactured by Sherwood.

Sherwood was manufacturing gas valves and regulators for industrial and commercial applications before the Scuba industry existed.

I have not been able to confirm it, but I have heard from different sources that the patent for the original pneumatic piston pressure reducing regulator was owned by Sherwood before it expired. Again, I have not being able to verify about the patents on piston regulator.


I did hear that they had some issues with those regulators, but it is definitely not because it was their first piston manufactured in house. I don't know what was the issues.
 
Wow, I don't know where you heard that, but Sherwood was the first manufacturer of piston regulators…

Sherwood was manufacturing piston regulators for the other Scuba companies before they were selling their own Scuba gear directly. This is back in the 1960’sand 70’s.

The earliest piston regulator companies like Healthways, Scubapro (a spin off from Healthways), White Stag, Dacor, etc. all had piston first stages manufactured by Sherwood.

Sherwood was manufacturing gas valves and regulators for industrial and commercial applications before the Scuba industry existed.

I have not been able to confirm it, but I have heard from different sources that the patent for the original pneumatic piston pressure reducing regulator was owned by Sherwood before it expired. Again, I have not being able to verify about the patents on piston regulator.


I did hear that they had some issues with those regulators, but it is definitely not because it was their first piston manufactured in house. I don't know what was the issues.
I didn't hear of any issues, but that 1st stage is new-ish. Every other Sherwood uses the same 9000 series 1st stage, but the SR2 design is only 2-3 years old. Still, nothing radical about it when I look over the parts diagram. Pistons are pretty vanilla.
 
As you said, the Sherwood SR design is pretty vanilla. A piston is a piston. But where Sherwood has excelled is in its dry designs. It caught a lot of flak over the years for its bubbling, and that filter in the base of the piston was classic for getting gunked up by naive technicians who smeared silicone grease everywhere, thus killing the reg. But it was still unique. And Sherwood's Belleville washers are a very sturdy way to balance the design. Classic!
The SR-1/2 approached dry design differently, using an approach I hadn't seen in decades, but I can't remember which other regulator it was:
There is an environmental chamber that seals the area behind the piston. Instead of ambient water pressure pushing on the back of the piston, there's a cylinder that gets depressed by a secondary environmental sealing diaphragm, which has three thin legs that pass through the wall of the reg body, and come out against the back side of the piston. I sure wish I could remember the old brass reg that had three pins that did the same thing. In any case, it's an ingenious throwback technique to sealing a piston that is very underappreciated. And the piston itself has a HUGE bore. In fact, it's a two part piston that's assembled at the time of service, because the overbalancing head with the knife edge is too large to fit through the bore where the shaft seals. Instead, the shaft is inserted in the reverse direction and mated to the piston head at the time of reassembly.

@Luis H , can you remember which old piston had those three transmitter pins in the wall? I'm wracking my brain!
SR1.png

Anyway, without piling up too much on @Jiminy , the Sherwoods are very underrated. They just don't market well on the West Coast. The SR's had a brief issue with turret bolt torque, and the SR-1 second had a brief issue with the spring catching, but that was fixed in the -2 with a simple metal washer. Great regs! There just aren't as many of us out West here with service experience.
 
https://www.shearwater.com/products/perdix-ai/

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