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DIN First Stage Problems

Discussion in 'Regulators' started by Scuba_Noob, Aug 16, 2012.

  1. Scuba_Noob

    Scuba_Noob Solo Diver

    # of Dives: 200 - 499
    Location: Victoria, BC
    1,000
    195
    0
    With my DIN first stage (Aqualung Titan LX), the o-ring sometimes pops out randomly when my gear is set up and pressurized during a surface interval, making an extremely loud noise and wasting air. After I shut off the tank, and detach the first stage from the tank, I can see that the o-ring has popped out. Once in a while, after a dive, when I detach the first stage, the o-ring is shifted too.

    I dive at least 10-15 times a month, and it occurs around once a month. This month, it has occurred twice, all during surface intervals between dives, never in the water. It's unnerving always having the thought in the back of your mind, and it's happened once with the tank on my back. The first time it happened was about two months after I got all my gear and tanks, and it's happened around 8-10 times since, many happening in the last three months.

    I tighten it pretty tightly when I attach it to the tank. Maybe it's a tank problem, but it occurs with both my tanks. The o-ring is correct. I purge the regs completely when I remove the first stage. Someone suggested that I lube the o-ring, which I did - it has still happened twice since then.

    Anyone have a similar problem? Any suggestions of the cause and what to do?
     
  2. Scared Silly

    Scared Silly Regular of the Pub

    # of Dives: 500 - 999
    Location: on the path to perdition
    5,559
    1,106
    113
    The problem is that the o-ring gets a blast of air when the reg is being disconnected from the valve. The blast of air will unseat the o-ring. It gets this blast of air because not all of the air was released when you purged the regulator. Purge your reg better and you will eliminate the problem.
     
  3. aquaregia

    aquaregia NAUI Instructor

    # of Dives: 500 - 999
    Location: Santa Cruz, CA
    1,969
    190
    63
    I read it as while pressurized rather than while disconnecting. Long shot... try a harder o-ring? As salt dries out on the existing one... as I said, long shot.
     
  4. fire_diver

    fire_diver Solo Diver

    # of Dives: I just don't log dives
    Location: NW Oklahoma, USA
    3,547
    517
    113
    If you are losing an o-ring while the 1st stage is connected and pressurized, you have a serious problem somewhere! Stop diving until you get it figured out and corrected. Loosing that at depth will result in a rapid loss of all your available air.
     
  5. Wookie

    Wookie Secret Field Agent ScubaBoard Business Sponsor

    24,182
    34,256
    113
    Just guessing here, but are you using 300 bar din valves? Maybe the Genesis valves on PST HP steels? The ones that are at an angle? Some regulators just don't thread deep enough for those valves. Maybe your reg isn't quite bottoming out? The DIN ring is hitting the valve? Maybe?
     
  6. randy88k5

    randy88k5 ScubaBoard Supporter ScubaBoard Supporter

    # of Dives: 200 - 499
    Location: Lynchburg, VA and New Orleans, LA
    732
    515
    93
    I would make sure the DIN barrel nut (I think that is what it is called, the piece the DIN handle rides on, has a hole for a hex wrench) is tight and secure on the regulator body. There is usually an o-ring on the end of this barrel. I have seen leaks like the one you describe, and it was the barrel nut loose or its o-ring.

    By any chance, could you possibly be twisting the first stage slightly as you are unscrewing the regulator from the tank? The added leverage makes it a little easier breaking the first stage loose from the tank, but may also loosen the barrel nut and pop the main exterior o-ring out of its groove.
     
  7. Scuba_Noob

    Scuba_Noob Solo Diver

    # of Dives: 200 - 499
    Location: Victoria, BC
    1,000
    195
    0
    I think this is possibly the case. I am using 300 bar din valves. How should I solve this then? Do I need to replace my first stage with an older model that fits with my tanks?
     
  8. Scuba_Noob

    Scuba_Noob Solo Diver

    # of Dives: 200 - 499
    Location: Victoria, BC
    1,000
    195
    0
    Had the technician at my LDS look at my regs and tanks thoroughly. He found that there was a slight problem with the first stage where the intermediary pressure would sometimes gradually rise when the regs were pressurized. So eventually, it would find the weakest point where the pressure could escape (i.e., the DIN o-ring). Underwater, I guess breathing would relieve that extra pressure.

    He fixed it, and I'll go diving tomorrow. Hopefully everything goes smoothly.
     
  9. fire_diver

    fire_diver Solo Diver

    # of Dives: I just don't log dives
    Location: NW Oklahoma, USA
    3,547
    517
    113
    Sorry Noob, but that explanation is garbage. The IP is downstream of the first stage. The pressure exerted on the DIN o-ring will always be the tank pressure.
     
  10. kierentec

    kierentec Captain

    # of Dives: 5,000 - ∞
    Location: High Springs, FL; Tulum, Mexico
    378
    223
    43
    agreed, while IP creep is a problem and it's good it's fixed, the tech either didn't know what he was talking about or feeding you a line of BS. Im with wookie, the DIN isn't bottoming out in the valve for some reason, giving the O-ring room to shift and pop out.
     

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