• Welcome to ScubaBoard


  1. Welcome to ScubaBoard, the world's largest scuba diving community. Registration is not required to read the forums, but we encourage you to join. Joining has its benefits and enables you to participate in the discussions.

    Benefits of registering include

    • Ability to post and comment on topics and discussions.
    • A Free photo gallery to share your dive photos with the world.
    • You can make this box go away

    Joining is quick and easy. Login or Register now by clicking on the button

DumpsterDiver emergency ascent from 180'

Discussion in 'Advanced Scuba' started by 2airishuman, Aug 9, 2017.

  1. CuzzA

    CuzzA Percoidea Wetwork for Hire ScubaBoard Supporter

    19,284
    33,645
    It's my understanding it must be replaced.
     
  2. Colliam7

    Colliam7 Tech Instructor Staff Member ScubaBoard Supporter

    # of Dives: 1,000 - 2,499
    Location: Kents Store, VA
    7,363
    4,619
    Both. Yes, it should be replaced at regular service intervals. But, if you open up the first stage and remove the diaphragm for inspection, you have to replace it. There are specific Warnings in the Service Manual about that, in fact. The point of no return is if you loosen / unscrew the diaphragm clamping ring. But, beyond that, if you do anything more than loosen the environmental seal end cap, you are technically committed to replacing it.

    I have inserted a picture of the Warning icon in the regulator service manual, below. You can't read all of the text, but I think this illustrates how serious manufacturers are about this. Note the statement that reusing a diaphragm may be associated with 'causing a severe regulator malfunction.' :) I think that - severe regulator malfunction - is a reasonable description of what DD experienced
     

    Attached Files:

    Last edited: Aug 18, 2017
    uncfnp likes this.
  3. Bryan@Vintage Double Hose

    Bryan@Vintage Double Hose Instructor, Scuba

    680
    886
    It should be replaced along with the washer during service OR anytime the retaining nut (not the adjusting nut/screw) is removed. The two parts are chump change and not worth the worry as to them being either good or bad.
     
  4. stuartv

    stuartv Seeking the Light ScubaBoard Supporter

    # of Dives: 200 - 499
    Location: Lexington, SC
    9,809
    5,611
    Thank you all for the clarifications and explanations.

    My copy of Scuba Regulator Maintenance and Repair arrived yesterday. I am looking forward to having an even better understanding of what you all said soon.

    :D

    Oh, and does this represent a fundamental aspect of diaphragm regulator design that I might take as... I don't want to say inferior, ummm... less long-lived than a good piston design?

    I mean, this makes it seem like any diaphragm reg of necessity has a flexible diaphragm that will need to be replaced every so often - and I don't mean every 10 or 15 years - to continue to use safely (i.e. without significant concern for this kind of catastrophic failure).

    Do the "good" piston 1st stage regs have anything similar? I.e. any part that has to be replaced every 1 or 2 or 3 years or have a real risk of a catastrophic failure?
     
  5. Colliam7

    Colliam7 Tech Instructor Staff Member ScubaBoard Supporter

    # of Dives: 1,000 - 2,499
    Location: Kents Store, VA
    7,363
    4,619
    I only use, and service, diaphragm regulators. So, I won't comment about comparisons with pistons.

    But, insofar as diaphragm first stages go, it really isn't - ordinarily - an issue. You simply replace the diaphragm ever 1-2 years (depending on the manufacturer's recommendations) and be done with it. What DD experienced is really extraordinarily rare. But, when sensible maintenance procedures are not followed, you can have a problem. Probably, the best summary:
     
  6. Diving Dubai

    Diving Dubai Instructor, Scuba

    # of Dives: 1,000 - 2,499
    Location: Ras Al Khaimah, UAE
    3,814
    4,137
    An interesting comment by DD (that I haven't seen discuss here, If I've missed it I applogise)

    His Pony was bungied under his neck, and thus he had issues because of this inflating his DSMB. now I sling my pony, thus don't have that issue, but good thinking point for those with a fixed bungied Alt reg
     
    soggybadger likes this.
  7. stuartv

    stuartv Seeking the Light ScubaBoard Supporter

    # of Dives: 200 - 499
    Location: Lexington, SC
    9,809
    5,611
    I understand. But, I often see posts around here regarding old regs that people have been using for 10 or more years without any service. Are those all piston regs then? I'm not saying I would want to, but if a good piston reg COULD reasonably go 10 years without expecting a catastrophic failure (versus a failure with slow onset) and a diaphragm regular cannot do that, then I would chalk it up as an advantage to a piston reg. Though an advantage that should never matter to a remotely conscientious diver.

    I guess that depends on how you normally inflate your DSMB. My normal inflation method is to hold it beside my face, tilt my head, and let exhaust from the reg in my mouth inflate it. In that case, a bungee necklace makes no difference.
     
  8. Bryan@Vintage Double Hose

    Bryan@Vintage Double Hose Instructor, Scuba

    680
    886
    The diaphragm in the picture I posted it at least 40 years old and the regulator still functioned when pressurized. IMO a high pressure diaphragm failure is right up there with being struck by lightning. Certainly not something to get another chicken little scenario going over.
     
    northernone likes this.
  9. uncfnp

    uncfnp Solo Diver ScubaBoard Supporter

    # of Dives: 500 - 999
    Location: North Carolina
    6,711
    5,543
    For routine inflation I just switch to the bungee and use the primary to inflate. I have tried Stuart's approach and does well enough at depth but for shallow deployment I find it difficult. In a pinch though I can.

    Its making me wonder the same thing. SB members often recommend service when needed rather than routine and use the IP gauge checks to moniter "as needed" status. Wondering now if this is a good approach to diaphragm first stages. May give the piston firsts a boost as the choice for DIY'ers.
     
    stuartv likes this.
  10. 2airishuman

    2airishuman Solo Diver

    # of Dives: 100 - 199
    Location: Greater Minnesota
    2,634
    1,890
    I have a couple of pistons and would hate to see this thread degenerate into a piston vs. diaphragm discussion. From a dive safety standpoint, I think it is sufficient to consider that any 1st stage has the potential to fail catastrophically. From what little data I've seen, the only two classes of regulators that are more prone to failure than the general population of regulators as a whole are: those that have been very recently serviced, and those that have not been serviced in a very long time.
     
    Schwob and northernone like this.

Share This Page