Inhalation adjustment knobs

[dumpsterDiver]

I was recently doing a solo dive to 180 feet. On the descent at around 160, I was inhaling and felt something "snap" in the regulator and it started to blast more air at me then I needed and started to freeflow a little. I never felt anything like that before.

I quickly de-tuned (tightened up) the second stage and the freeflow stopped , but the reg felt weird until i got down to around 2,500 psi. I finished the dive with no problem.

Check the IP and it was too high and drifting upward, so I took it to the shop and they said the HP seat partially failed in the first stage.

I don't think I could have completed a normal dive if I was not able to adjust the knob. It is nice in strong currents and it also allows you to delay servicing for longer, because as the seat wears in the second stage, I just tighten the knob down a little.

 

[Zung]

... I see that LeadTurn recommends turning the cracking pressure adjustment knob all the way out for storage...B.S.

No disrespect to the veterans here, but I do have some data points that might be of interest:

• We had a SP MK20/G250, and a MK10/M5(G200), last serviced and dived in 2000, then thrown in a closet while the kids grow. We also have a spare rig, a AL Supra-Cousteau/XL last serviced in the mid-90's.
• The kids were certified last year, so I dusted off the regs, gave them a quick check, and went on diving.
• After a couple of dive trips, I serviced the MK10/M5; the seat of the M5 is clearly but neatly marked. Note that the M5/G200 is not balanced and has a much stiffer spring than the G250.
• I'm still wondering if I should service the MK20/G250: it still breathes wonderfully, cracking pressure is in the 20 mm/.8 inch range and the intermediate pressure is rock steady at 9 bar/130 PSI. Maybe next winter, or before next major trip.
• The AL rig still works, but now it's downgraded to backup of backup.

Bottom line: without any precaution, a "shelf life" of 10 years or more can be expected.