Ooh that's interesting and a possibility I guess. Crap in the tank blocking the filter?
Aqualung Legend LX First Stage Failure at depth
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R
redacted
Guest
Wth a little luck, this is a link to the ACD tech manual: https://www.google.com/url?sa=t&sou...1Y8H16PF5S-gS6HsA&sig2=ZK8y_C_syi9BK3nYzpmlUA
I do not see how either loosening of the shutter valve (shop called it the inner post valve) or the yoke retainer would have caused the described failure. the loose retainer should eventually cause a major leak. A loose shutter valve might leak and should cause the ACD parts to fall out when the connection is undone.
It also looks like the water seal on the ACD is metal to metal - no o-ring seal. can work but not not very relialbe when the seal is spring activated with a fairly light spring.
If that link does not work, try a search on CALDY.pdf
I do not see how either loosening of the shutter valve (shop called it the inner post valve) or the yoke retainer would have caused the described failure. the loose retainer should eventually cause a major leak. A loose shutter valve might leak and should cause the ACD parts to fall out when the connection is undone.
It also looks like the water seal on the ACD is metal to metal - no o-ring seal. can work but not not very relialbe when the seal is spring activated with a fairly light spring.
If that link does not work, try a search on CALDY.pdf
OP
databob
Registered
I rented a tank with 1500 PSI. Put the reg on it and breathed for a while. All worked fine. Then I slowly backed the yoke screw out a bit at a time loosening the regulator to tank tightness. Breathed for a while, backed off a bit more. I repeated this several times until I started to get a hiss of air. At this point the first stage to tank connection was obviously sloppy and moved noticeably. Through all of this the regulator breathed fine and the tank pressure dropped to about 1000 psi.
I am getting ready to dive in 2 weeks so I am not inclined to loosen the yoke nut and do a similar test maybe backing that nut a quarter turn at a time. I am also not inclined to be messing with a yoke nut at several thousand psi - probably better left to the pros. If Aqualung contacts me I'll ask if they would consider that. There was some earlier discussion about dimple and things related to tightening the regulator onto the tank. That did not seem to have any effect here. Things get sloppy and leak before there are any other effects.
I am getting ready to dive in 2 weeks so I am not inclined to loosen the yoke nut and do a similar test maybe backing that nut a quarter turn at a time. I am also not inclined to be messing with a yoke nut at several thousand psi - probably better left to the pros. If Aqualung contacts me I'll ask if they would consider that. There was some earlier discussion about dimple and things related to tightening the regulator onto the tank. That did not seem to have any effect here. Things get sloppy and leak before there are any other effects.
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You backed the yoke screw off of a tank that had 1500 PSI of gas in it? How big of a pipe wrench did you have to use to make that work, because if you did it with your bare hands, I'm staying away from you.
Just out of curiosity I searched CPSC Home | CPSC.gov for any recalls on this regulator and found nothing. Lots of other models and brands but nothing specific to the ACD model. Apparently this is a very rare failure and no injuries have been reported. The OP could make an entry with CPSC to record this problem should anyone else search in the future.
In my mind, a pretty good reason to join the XXI st century and the civilized world: go from Imperials to metrics and from Yokes to DIN 
R
redacted
Guest
In my mind, a pretty good reason to join the XXI st century and the civilized world: go from Imperials to metrics and from Yokes to DIN
If you have a din ACD, you will need a yoke adapter to service it. We will prevail.
No way, everybody agrees that you need to have a professional and capable service man. These guys CANNOT be found on your side of the pond........just kidding 
Seriously, DIN offers a lot of advantages.
Seriously, DIN offers a lot of advantages.
OP
databob
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I took a trip to the dive shop that serviced my regulator post failure this afternoon. The service manager was there and he took the time to explain to me why he believes what we have been discussing in this thread could cause the out of air situation. There were 2 things loose on my regulator when I took it to them. The yoke nut and the ACD inner post valve. This caused both the outer cylinder (the part you can push in with your finger) and the fixed inner cylinder have play relative to each other. The combination of looseness of both parts of the ACD were sufficient to allow it to go shut. As he was demonstrating (on a fully assembled regulator) it sure sounded believable to me. Please also understand - this is my translation of the conversation so I may not use terms as accurately as he did. He did stress to me that both pieces have torque specifications and that both need to be torqued to the proper specification.
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