Mysterious Leak In An Xs Scuba Argon Regulator

[kr2y5]

I'd appreciate any suggestions how to diagnose my argon regulator. Now, I might just have it serviced, but that will take time, and maybe it's not necessary... any advice would be greatly appreciated.

Symptoms:

- I pressurized my argon bottle at least an hour before the dive when loading my gear, as I always do, and definitely heard no noticeable gas leak either then, or when gearing up for the dive.

- Upon entering the water, as soon as I submerged, the regulator started leaking gas. It's 50F here, so no condensation issues. It took me a good 30 seconds before I closed the post (at first, I was confused about the source of the gas, since I also had deco bottle with me, I just shut the latter down without thinking before I realized where the gas was actually coming from and closed the argon bottle as well).

- A bit over an hour later, after the dive (which, having backup inflator hose off the left tank, I continued uneventfully), the regulator was still pressurized as I was disconnecting it from the argon bottle.

- Back home, after I connected the regulator back to the tank a day later, I've heard a hissing sound that continued for a good 10-15 seconds before I decided to shut it back down.

- While submerging the hissing regulator, I would see a stream of bubbles coming from a round opening right next to the overpressure valve.

- As I continued to close valve, depressurize, and repressurize the regulator, the hissing sound would get shorter, and eventually it would only last for a few seconds. The bubbles would continue to come out, but just about every 10 seconds or so.

- Right now, it appears to behave normally: the hissing sound upon pressurizing lasts for a few seconds, as it always had, and apart from an occasional bubble, it appears as if nothing wrong was at all with it.

- The IP seems to be very stable at 135-140psi.

- No crack on the rubber hose or any other issues I would've noticed externally with any other part of it.

Any ideas?

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[NotSure]

A complete rebuild only requires two o-rings and a HP seat. I would probably replace o-ring 19 first assuming the air is coming from the ambient chamber.

 

[kr2y5]

This is very encouraging! I like simple. And, the kits are sold on Amazon. Thanks very much!

 

[fmerkel]

As pointed out. it's a pretty simple piston reg. Either the stem O-ring or the piston O-ring is likely leaking. There's the possibility there is some corrosion/crap on the cylinder wall. Whatever, the system is leaking and should be re-built. You need to see what the cause is and remedy it. Since the kit's are readily available it would be worth having one around if you decide to take it apart.

 

[kr2y5]

Internal DIN inlet o-ring looks a bit chewed up, everything else being normal, in particular piston o-rings all look fine. Maybe the leak I have experienced was coming from elsewhere, but in that case, does that mean a bit of bubbling from the ambient chamber through the openings in the body is normal, and to be expected?

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[fmerkel]

No, shouldn't leak. The only piston that does that is Sherwood by design, their dry bleed system.
If you are still waiting for parts, just clean, lube, and assemble. See if that takes care of the problem, it might. Inspect the cylinder bore for corrosion, the piston seal end for nicks, the HP seal for problems, and the 2 main O-rings, stem and piston. Magnification and good light help a lot.

 

[redacted]

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- While submerging the hissing regulator, I would see a stream of bubbles coming from a round opening right next to the overpressure valve.?



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Can you be clearer about where the bubbles are coming from?

 

[rhwestfall]

- While submerging the hissing regulator, I would see a stream of bubbles coming from a round opening right next to the overpressure valve.

that is called the "ambient chamber".... see post #6

lube up the piston head o-ring (20), and stem o-ring (19). Possibly replace/flip the seat (18).

I had a very similar ScubaPro MK-3 that just needed a little attention there, and all is well.

 

[kr2y5]

Thanks, guys!

It's these rounded openings I'm pointing to:

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[redacted]

Unless there is a crack in the metal of the piston shaft (extremely unlikely) the problem would be the seal on the piston head or piston shaft o-rings. Inspect the sealing surfaces or both o-rings and replace both o-rings, unless you just want to play around and find which o-ring is the culprit.