As much as it pains me to add a follow-up to this thread, unfortunately it seems I might need advice once more on what to do with this reg... So I finally took it for its maiden dive this past Saturday and suffered another failure. I set it up on an HP steel tank for dive 1 and had an uneventful dive of approx 1 hour. I liked how the reg breathed just fine, despite the relatively shallow depths of the dive (up to 45 ft or so only) and the fact that I usually like to draw long slow breaths from the reg, I didn't experience some of the annoying fluttering action some people sometimes complain about. The only unusual thing I noticed was some sort of small "bubbling" action when drawing gas from the second stage, as if there was a little mist in the air. Is that normal? I'm not sure how to describe this feeling.
Anyway, all was apparently ok until the surface interval, when I proceeded to switch tanks. After removing it from the first tank and setting it up on the second HP steel I had brought, I immediately heard a leak from the first stage upon opening the tank valve. It was quite audible and I could not immediately detect where it came from, apart from the fact that all hose connections seemed to be secure and it didn't seem to come from any of the ports, but rather from the DIN connection to the tank itself. Switching to a different tank from a friend produced the same leak. I then hurried to switch my reg over (I had brought my older Apeks yoke with me fortunately but needed to switch the drysuit hose, reinsert the yoke plug into my tank valve and octo securing clip as my hose lengths are different on the two setups scrambling to do this in my drysuit in the heat while my buddy was already all geared up waiting for me, melting in his drysuit and heavy doubles on his back, pretty annoying!)
Yesterday, I had a chance to examine this leak further and reconnected the Poseidon reg to the tank I had used on dive 1, which still had 1800 psi left in it. The leak manifested itself again, quite audible. This time, I monitored the gauge (digital since I received a new cobra 3 in replacement of my old cobra following the recent class action lawsuit against Suunto which I use as a glorified digital spg), and noticed the leak was somewhat slow. I left the valve fully open for 10 min and noticed a decrease in pressure of about 20 psi. The sound is definitely coming from the DIN connection and can be muffled by wrapping your fingers around the plastic ring that makes contact with the reg body. The IP gauge still locked at ~132 psi and didn't move. After closing the tank valve, and not purging the lines, the pressure on the gauge kept dropping slower and slower (several hours later it was still at 400+ psi).
So clearly the leak is in the high pressure system, and highly dependent on said high pressure. It seems likely caused by either an improperly torqued DIN stem, or perhaps a defective or extruded o-ring at the DIN stem/reg body connection. Now I understand that this type of leak is most commonly caused by user error, but honestly, I'm not sure what I could have done to cause this if the DIN stem was properly torqued in the first place (and it was just serviced by Poseidon themselves under warranty). I pay attention not to move the reg body after securing the DIN wheel to the tank valve in order not to inadvertently untorque the stem. Also, accidental bumping of the reg once attached seems unlikely to loosen the thing as the torque settings in the manual specify 30 Nm, and measuring the first stage, its extremities are 3-5 cm away from the axis of the DIN adapter, meaning one would need to apply a force of ~60-100 kg with their hands on the first stage body to loosen it (unlikely to happen in my opinion especially when you consciously pay attention not to do that). Clealry, the leak happened or was aggravated by switching tanks, since I couldn't hear anything out of the water following dive 1 before I disconnected the first stage.
Now I am left with a reg that has failed TWICE over the course of a grand total of ONE dive! What should I do? Try to fix this by torquing the DIN stem (unfortunately, I don't own the thin jaw wrench head/torque wrench combo needed to grab the stem and do this properly)? Also, if the problem is the o-ring inside, this won't solve anything, I need to remove the stem, check the o-ring, and re-install the stem, but is this advisable to attempt without the specialized tools needed for the job? Also, to be honest, the DIN stem still seems quite tightly screwed into the reg body and isn't loose at all (although the leak does appear to be small and certainly pressure dependent).
Not sure if this guy needs to be shipped back to Sweden for a second time, but as much as I really want to like this reg, circumstances are making this pretty hard for me.
Thanks very much for any suggestion you may have, and apologies for the long post!
