How much of an issue was this?

[gcarter]

Apeks ATX40 / DS4 regs, yoke.

Gearing up for a dive yesterday afternoon, I was talking to someone while unscrewing the thumbwheel to remove the ball from the yoke in preparation for mounting it on my tank. When I released the thumbwheel to reposition my fingers for another twist, the yoke connector dropped out of the first stage to the ground. Whoops. In turning the thumbwheel, I had inadvertantly uncrewed the yoke connector from the first stage. It was apparently a bit loose.

I retreived the yoke clamp and spacer, cleaned it off, and reassembled, ensuring it was properly snugged down.

No leaks were evident (no hissing, no bubbles), either on the surface or in the water.

Nonetheless, over the course of ~ 10 minutes, my HP100 bled off ~ 100psi. I chose to proceed with the dive anyway, as it had a max depth of only 45' with an average depth of 25'. I had done this dive before, and it was within easy striking distance of the shore (drift dive in the St Lawrence) so I was comfortable that the risk was low / manageable. I was also diving with a reliable buddy with whom I have done the majority of my diving, and we agreed that we were ok with the issue.

The dive was uneventful, and I had sufficient air to complete with 500 psi remaining.

Upon returning home, I dug out the parts diagram for the DS4. As it turns out, there is an o-ring that belongs at the end of the connector that holds the yoke clamp in place. This o-ring (and its lack) was not evident to me when I reassembled my first stage at the dive site.

I feel fairly safe in assuming that this missing o-ring was the cause of the pressure loss, yet do not understand why the leak resulted in neither hissing nor bubbles.

In any case, I am compelled to ask the question as to what the risk of first stage failure was without the o-ring in place.

 

[halocline]

If there's an o-ring that seals HP air in the yoke retainer, and it was missing, you'd have one hell of a leak, so something doesn't sound right. On a SP reg it would be like turning on the tank with an open HP port, meaning, LOUD. Maybe the apeks is different. By "bled off 100 PSI in 10 minutes" do you mean that with the tank turned on, and your reg connected but just sitting there, the pressure dropped 100 PSI in 10 minutes? That's a pretty decent sized leak. I'm pretty sure you'd hear it or see some bubbles. Or do you mean with the reg pressurized but the valve turned off, the SPG dropped 100 psi over 10 minutes? That's an itty-bitty leak that a less-than-perfect tank o-ring could easily cause with no ill effect.

 

[gcarter]

On this diagram, the o-ring that was missing is #19.



The pressure drop was with the valve open and the regs pressurized.

Neither I nor my buddy could hear or see a leak. I don't understand it. Had there been anything visible, I would have been more likely to just call it.

 

[gcarter]

 

[redacted]

If that o-ring were missing, you would have quite a bit more gas loss than you saw. But that is a rather important connection and should be cleaned, inspected, and properly torqued to prevent it from loosening again. Leaks are best located in the water.

 

[gcarter]

If that o-ring were missing, you would have quite a bit more gas loss than you saw. But that is a rather important connection and should be cleaned, inspected, and properly torqued to prevent it from loosening again. Leaks are best located in the water.

I do plan on getting it properly serviced.

My normal SAC is ~ .7. On this dive, based on air consumed, .97, so all other things being equal there is the loss.

 

[redacted]

I do plan on getting it properly serviced.

My normal SAC is ~ .7. On this dive, based on air consumed, .97, so all other things being equal there is the loss.

If neither you nor your buddy was seeing bubbles where they should not be, I would suspect you were just breathing a bit heavy or the leak was through the 2nd stage seat where it may go unnoticed. A leak from the tank connection should be quite obvious to any decent (or conscious) buddy.

 

[gcarter]

I hear you, but it seems coincidental that a second stage would start leaking on the same dive. The only way to confirm is to test it, which I do plan on doing. I have an IP guage, presumably this should still be a valid test for the seconds even it the first is leaking on the HP side?

My buddy was specifically watching for bubbles or other issues throughout the dive.

 

[herman]

Several things are likely. First off, my bet is the oring is still where it should be. There is an oring groove on part 23. The oring sets fairly deeply in that groove, odds are the oring stayed in place, as it should, so the reason you did not have an air leak is everything is back in place. If it was missing, like the rest have said, you would have known it, no way it would have sealed against HP. The 100psi drop could be anything, including tanks moved from the sun to a shady spot or if you mean they dropped shortly after entering the water, I would expect that much drop and more, the river water is going to be cool. If you SAC rated did increase as much as you say, it had to be nerves, a leak that big would be obvious.

Where did a second stage leak enter the conversation?? An IP gauge is not used to test second stages other than verifying they are getting the proper IP.

 

[halocline]

Apeks ATX40 / DS4 regs, yoke.

Gearing up for a dive yesterday afternoon, I was talking to someone while unscrewing the thumbwheel to remove the ball from the yoke in preparation for mounting it on my tank. When I released the thumbwheel to reposition my fingers for another twist, the yoke connector dropped out of the first stage to the ground. Whoops. In turning the thumbwheel, I had inadvertantly uncrewed the yoke connector from the first stage. It was apparently a bit loose.

I retreived the yoke clamp and spacer, cleaned it off, and reassembled, ensuring it was properly snugged down.

I suspect that the o-ring stayed put inside the reg body or the yoke retainer, and that's why you never saw it. Pull the yoke retainer off again and look for it; you'll find it. Interesting how it says that the yoke retainer is only held in finger tight in your excerpt from the manual. There's got to be another step where it says to torque it to a given spec, isn't there? A yoke retainer should really be tighter than hand tight. That's a classic spot for being manhandled (i.e carrying the tank around by the 1st stage on a boat) and there's a huge pressure gradient on that o-ring.