Regulator failure on a solo deco dive

[Bigbella]

Except he was futzing with it: specifically, rotating the regulator while under pressure (that was mentioned in a separate post, so you may not have noticed).


And here is a definite example of just such a thing happening on a properly torqued regulator, in a separate post he says this occurs when rotated on pressure.

I'm not saying you’re wrong. Just that you are jumping to conclusions, and exposing a bias.

I still contend that a properly torqued regulator, even if somewhat mishandled, should not loosen — though I don’t typically grab them by anything other than the tank valve; but I have occasionally done so in the past, while handling gear on boats, to no misfortune.

Yes, there‘s that account of a “properly torqued” regulator becoming loose, though likely mishandled in some way, not necessarily by the diver in question; but why haven’t I ever experienced that over decades and thousands of dives?

Ain't that lucky.

My job, as a kid, was disassembling regulators for the tech; washing the crap; and getting new gear up to specs, which occupied a good deal of my time. Some of the new gear arrived as loose as the OP described his first stage DIN connection, with fully loose blind screws rolling around in boxes, often set with IPs off the charts. All of the biggest brands were offenders.

Quality control was an issue then and now.

I challenge you to loosen a pressurized regulator, properly torqued to 30 nm — I can’t do that, and I am not a delicate little flower . . .

 

[L13]

Fair, but I wouldn't call shotgunning a tank futzing with the regulator. If anything, this makes me wonder if the reg rotating in that fairly regular use case was the first indication it was coming loose.

Fair, so @Bigbella might be right in this case.

 

[L13]

I challenge you to loosen a pressurized regulator, properly torqued to 30 nm — I can’t do out, and I am not a delicate little flower . . .

I've never tried it, and don't plan too (intentionally) because I don't want to have to re-torque it if it does loosen. Maybe I will next time I'm going to service a regulator anyway, if I remember. I'm a little surprised you have tried that hard to loosen a pressurized regulator.

 

[John C. Ratliff]

Red loctite and an impact is all you need

I don’t think I’d allow red loctite anywhere a regulator of mine. But then, I don’t dive DIN regulators either.

SeaRat

 

[SlugLife]

I'm not a reg tech (yet), so forgive the following: the bit that takes an allen key and holds the DIN o-ring was a little loose.

Your regulator itself is probably completely fine. I've had that problem as well, with a regulator where I swapped it from yoke to din myself. I didn't quite realize that you're supposed to disassemble the din unit, install that, and then re-assemble. (I'm not explaining it very well). The short story is that it was hard to assemble and get to a proper tightness, and kept coming loose. Now, it only ever happened to me BEFORE a dive, but never during a dive. I think it would normally come loose when removing the din-regulator from the tank.

Just taking a wild-ass guess, but regulators are probably converted to din fairly late in the process, and there's a chance that whoever did that last step may not have quite done it properly.

I'd also caution against over-torqueing that piece, as that can also lead to first-stages cracking. Some 1st stages are more prone than others.

I hesitated to post anything about this because it didn't even fluff up my SAC rate.

I had a regulator-hose come loose and I was too embarrassed to post about it for a year.

The incident is what ultimately lead me to starting Sidemount. The way I look at things, is an incident like this would have been VERY scary, had it happened without significant redundancy. However, having two completely separate air-systems, where either can get you to the surface turns an "oh sh!t, I may be about to die" incident into .... "well, this is annoying."

 

[Robert H. Diver]

I don’t think I’d allow red loctite anywhere a regulator of mine. But then, I don’t dive DIN regulators either.

SeaRat

Yea definitely not, all sarcasm

 

[Dark Wolf]

Glad it all worked out fine. I carry a small mirror on every dive, and has come in handy a couple of times.

Gas availability is one big advantage to BM doubles, in my opinion.

DW

 

[SlugLife]

I dive DIN almost exclusively -- almost cannot recall the last time I attached a yoke, and have yet to loosen a properly-torqued valve stem, over thousands of dives.

This incident in Tahoe likely resulted from piss-poor quality control from the manufacturer, given its age and usage (just a few months, it was claimed); and something that has been brought up on a number of threads, over, sadly, a number of brands.

I don't see how you could possibly know this is true (or not true) based on the info from OP.

This seems to hint at an alternate explanation, but is not very conclusive either.

I STRONGLY agree with Bigbella. Specifically, the quality-control is not a defect in the parts, but rather the parts not being torqued to spec at the factory.

When I actually did learn to properly torque mine, the problem went away.

rotating the regulator while under pressure

Which only really happens when the din-adaptor is not installed/torqued properly.

 

[Bigbella]

Just taking a wild-ass guess, but regulators are probably converted to din fairly late in the process, and there's a chance that whoever did that last step may not have quite done it properly.

I'd also caution against over-torquing that piece, as that can also lead to first-stages cracking. Some 1st stages are more prone than others.

That would depend upon the brand -- some of which were DIN by default, such as Poseidon, which were originally supplied with a screw-on yoke, out of the box, years before DIN became popular in the US; so too, other European brands, for which yokes were a rarity and typically intended for foreign distribution.

Agreed, over-torquing can be a significant problem with regulators; and many that I had worked upon, had been cranked into the stratosphere by previous techs. One first stage had been visibly cracked and was condemned.

Few seem to realize that chromed brass is a great heat sink but is terribly soft as metals go.

The torque wrenches that I have are either set to the standard 30 nm or are adjustable over a range, so that over-torquing will not pose an issue . . .

 

[Etmutt]

Hey,

very intereting story here !

1st point on the reg : yes those DIN knobs need to be torqued at quite high value. Unfortunately reg tech not bothering to do it properly are legion... Altough this is true across all reg brand; some are a little more prone to this issue if not torqued properly (such as the ones using the ACD system from aqualung)

2nd point on the solo dive sidemount setup : you are going in with plenty of single failure points, so this incident was just waiting to happend... You migth consider to have a double valve on at least one of your tank, this way you would be able to mitigate a 1st stage failure