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Thread: New checklist for JJ, request for comments

  1. #11
    RBW Member hamishmorrison is an unknown quantity at this point hamishmorrison's Avatar
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    JJ DiveCAN

    Re: New checklist for JJ, request for comments

    Yes I forget the tube weights sometimes. I'm going to add them in to the next update.

    I take them out as it makes the unit very heavy & also I'm not convinced that they are not corroding the inside of the tubes, even if they are pretty much enclosed in plastic!

    Interstage pressure gets checked from time to time to see if its creeping, but I don't do it every dive.

  2. #12
    RBW Member doctormike is an unknown quantity at this point doctormike's Avatar
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    JJ

    Re: New checklist for JJ, request for comments

    Quote Originally Posted by hamishmorrison  View Original Post

    I like the flow stop. Never had to use it for real but it made using the the unit as an O2 rebreather at 6m on the course one of the easier drills to accomplish! Just isolate the dil, O2 flush & you're at 1.6 PPO. Having said that, its probably the one part that consistently causes the unit to fail a negative test. It's been taken apart & cleaned on multiple occasions which seems to help, but before long, same problem. On balance though I rather it was there than not.
    Yeah, I was wondering about the utility of that - haven't had the ADV fire when I didn't want it to at depth yet, is that the main advantage?

    What would the flowstop do that just shutting off the dil wouldn't do? I guess I would still have my wing inflator if I was using a flowstop, but it's pretty rare that I would add gas to the wing after my initial descent anyway.

    From your description, it sounds like an unnecessary failure point.

  3. #13
    RBW Member ECho is an unknown quantity at this point ECho's Avatar
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    Meg

    Re: New checklist for JJ, request for comments

    Quote Originally Posted by doctormike  View Original Post
    Yeah, I was wondering about the utility of that - haven't had the ADV fire when I didn't want it to at depth yet, is that the main advantage?

    What would the flowstop do that just shutting off the dil wouldn't do? I guess I would still have my wing inflator if I was using a flowstop, but it's pretty rare that I would add gas to the wing after my initial descent anyway.

    From your description, it sounds like an unnecessary failure point.
    During my MOD2 training, whilst dragging myself down the desecent line in a fairly strong current, my ADV was firing most of the way down and the dil was going straight out of the OPV... Admittedly, I was so focused on the task of pulling myself head first down the line that I never noticed the bubble trail that I was leaving! I did, however, notice that the PO2 in the loop had dropped below my low set-point, which was a bit disconcerting, due to the continuous dil flush... Had I been properly utilizing the ADV flow-stop, I wouldn't have wasted a significant amount of dil. To me, besides being a lesson learned, this only reinforced the importance of being able to isolate and manage all gas sources.

    Just my two cents....

  4. #14
    RBW Member hamishmorrison is an unknown quantity at this point hamishmorrison's Avatar
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    JJ DiveCAN

    Re: New checklist for JJ, request for comments

    As it explains in the manual:

    "The JJ-CCR does not meet the requirements of EN 14143 section 5.6.1.4 (Hydrostatic imbalance test) with a pitch of -90 degrees (Vertical head down position). A vertical head down position during a dive is an extremely unusual position for a diver and normally never used when not absolutely necessary. Within a vertical head down position an unintentional activation or freeflow of the ADV can possibly occur. To avoid it when the diver is forced to a vertical head down position he can close the in line shut-off valve on the ADV and use the manual diluent adding valve to maintain an optimized loop".

    Pulling down a line into current has the same effect & exacerbates the hydrostatic imbalance, so I can see how that would be a problem. Not sure I'd have persevered with the descent!

  5. #15
    RBW Member doctormike is an unknown quantity at this point doctormike's Avatar
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    JJ

    Re: New checklist for JJ, request for comments

    Got it, thanks... guess that didn't come up in mod 1 with my International edition JJ (no dil MAV, no ADV flowstop).

    I was thinking that I might add the MAV at some point. I guess you wouldn't bother with a flowstop without the MAV, since in that case there would be no difference between just shutting off the dil and using a flowstop (apart from the wing inflation).

  6. #16
    RBW Member hamishmorrison is an unknown quantity at this point hamishmorrison's Avatar
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    JJ DiveCAN

    Re: New checklist for JJ, request for comments

    I guess you get used to what you have, but I always struggle to reach the ADV. I hear you can use the hydrostatic imbalance your benefit if you're really proficient, when you do a dil flush!

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