Valve drill gone wrong...and my regulator died, too

[stretchthepenn]

It had been a crappy morning--Mickey D's had taken forever and then screwed up my order, a semi had kicked up a rock and chipped my windshield, a sharp stick poked my foot when I got to the dive site, and of course, the weather busted loose with the only genuinely warm day we'd seen in two weeks, so I poured sweat inside my drysuit--but this was the big day for my Tec40 checkout dives, and I was gonna get them done.

So there I was at 40', doing a valve shutdown drill. I was diving sidemount, so the procedure was pretty simple: Shut down the tank I was breathing from, use up the air in the hose, and then switch to the other tank's regulator. After that, I had to reopen the closed valve and then repeat the cycle on the other tank. Easy enough, right?

I shut down my right tank, breathed the second stage down, and swapped to the left tank. I then turned the right tank back on and redirected my attention to the left tank...which is the point that I had a massive brain fart. I suddenly didn't remember if I'd reopened the right tank, so I reached for it, spun the right tank's valve, and purged the right-side second stage. Air comes out = good. Cool, baby; I fixed the problem. I then went back to the left tank and shut it down, then reached for my right-side regulator.

Well, it turned out that, being a dumbass, I'd just turned off the air on my right tank, meaning that when I purged the hose, I blew what little residual air it contained. Thus, when it came time to breathe from the right-side regulator, I got a whole lotta nothin'. As in NO THING. Nary a puff.

Lordy... That really, really sucked. It was downright scary. I now understand the bolt-to-the-surface impulse. I kept my head, though, and signaled OOA. My instructor donated his long hose. His eyes just about bugged out of his head, but the crisis was averted. All was well...for about three seconds.

My instructor reached for my tanks and opened the valves on both sides...but when he did, the left side's first stage freeflowed.

WAT. A free-flowing first stage? That's not supposed to happen. EVAR. Oh, gawd. Consider this dive thumbed, in the most emphatic way possible.

Topside, we disassembled my gear and discovered that the regulator's central post that held the DIN wheel had come loose, and air was escaping around the post's base. Thank gawd that the thing busted at 40' instead of a serious depth...but it shouldn't have happened at all.

So, lessons learned:
* Pay the money and get new, top-quality regulators.
* Pay a-friggin'-ttention.
* Lefty-loosey, righty-tighty.
* Consider getting new tanks that can support the color-coded, 1-1/4 turn Pro valves.
* DO NOT make a dive, especially anything even remotely resembling a technical dive, while stressed.

Cripes.

 

[Zef]

* Pay the money and get new, top-quality regulators.

Why do you think another regulator for more money will help prevent the issue you experienced with the DIN wheel of your 1st stage?

I had both of my Mares Mr22 regulators changes from yoke to DIN and when the shop converted them they not only used a torque wrench to tighten the "central post" but also put a drop of locktite on it. I have never had it come loose, and when I temporarily converted back to yoke on a recommendation for diving in the Philippines there was no issue with removal. When I reconverted it to DIN I simply followed what the dive shop did and used a torque wrench along with a drop of locktite....no issues.

-Z

 

[lermontov]

Topside, we disassembled my gear and discovered that the regulator's central post that held the DIN wheel had come loose, and air was escaping around the post's base. Thank gawd that the thing busted at 40' instead of a serious depth...but it shouldn't have happened at all.

* DO NOT make a dive, especially anything even remotely resembling a technical dive, while stressed.

Cripes.

well you managed to rescue that one - well done
curious about the DIN wheel was it broken or did jt work itself loose after depressurising

if this helps- ive been in a similar situation so now ive made some adjustments ie particularly gas swapping - i always hold the exiting reg in my hand until I KNOW that i have a good gas supply from my new supply bottle only then do i put it away/clip it off, same with sidemount I hold the exiting reg in my hand until after a swap and KNOW theres gas

gas shut downs are a little different I know but I t goes to show how being distracted by the pre dive dramas can throw you

 

[w3dge]

Glad you made it out OK, and sounds like you gave your instructor a bit of work to do too!

What, specifically, is the purpose of breathing down a reg after shutting it down in a drill? It just seems an invitation to flood the reg to me?

 

[Diving Dubai]

DIN posts generally unscrew because the user hasn't fully depressurised the system and then turns the first stage to loosen the connection. The O ring binds against the valve fractionally loosening the din post.

I don't use thread lock on mine, Before connect I grip the Din lightly between my fingers and try to turn it. if it turns I ni it up with my hex key.

It's really no different from checking yoru O rings or any pre use checks you give with your gear

 

[seeker242]

My first thought in reading this was : How did the instructor not notice that you turned off all the valves?!

What, specifically, is the purpose of breathing down a reg after shutting it down in a drill? It just seems an invitation to flood the reg to me?

I was taught a couple reasons.

To make sure you shut down the correct post and are breathing from the proper reg.
To depressurize the hose and reg in order to find a leak.
To allow buddy to manipulate 1st stage if necessary.
To become more comfortable and familiar, and not panic, when you feel the sensation of a reg in your mouth giving you "a whole lotta nothin".

 

[Lobzilla]

How would this have changed the outcome?

• Valve drill begins with signaling "attention" to team mate(s).
• Team mate pays full attention to what you are ACTUALLY doing and will immediately notify you if that diverges from the intended drill/procedure.
• During entire drill, team mate(s) stand ready to donate gas immediately.

This should also be applied to gas switches. When it comes to our breathing supply, having backup gear AND backup brains is a wise move, IMO.

 

[clownfishsydney]

<b>A free-flowing first stage? That's not supposed to happen. EVAR.</b>
Why do you think that a regulator cannot free flow? In fact, they are made to free flow if they ever fail, so it is the opposite of what you think. It is better that a reg free flows than not give you air at all. In most cases other than total first stage failure, free flows can be stopped by putting a finger over the mouth piece or turning the reg so it faces down.

 

[doctormike]

<b>A free-flowing first stage? That's not supposed to happen. EVAR.</b>
Why do you think that a regulator cannot free flow? In fact, they are made to free flow if they ever fail, so it is the opposite of what you think. It is better that a reg free flows than not give you air at all. In most cases other than total first stage failure, free flows can be stopped by putting a finger over the mouth piece or turning the reg so it faces down.

The OP was talking about a first stage free flow, as opposed to the standard second stage free flow that you are describing. It's a poor choice of words, because what happened to the OP really isn't a free flow (which implies gas going through the normal path), but rather a loose DIN thread in the first stage. So basically similar to not tightening the DIN valve all of the way down and having a gas leak.

That same thing happened to me at the local quarry with my O2 regulator a few weeks ago, and the cause was similar to what Diving Dubai mentioned above. It happened while I was getting set to dive, and it was then I realized that while I had three sets of hex wrenches in Imperial sizes, I didn't have the appropriate (6 mm) metric one to tighten the reg. So I had to drive into town in my dry suit to find a kindly dive shop owner who would lend me a wrench!

 

[leadduck]

I shut down my right tank, breathed the second stage down, and swapped to the left tank.

(...)

My instructor reached for my tanks and opened the valves on both sides...but when he did, the left side's first stage freeflowed.

WAT. A free-flowing first stage? That's not supposed to happen. EVAR. Oh, gawd. Consider this dive thumbed, in the most emphatic way possible.

Topside, we disassembled my gear and discovered that the regulator's central post that held the DIN wheel had come loose, and air was escaping around the post's base. Thank gawd that the thing busted at 40' instead of a serious depth...but it shouldn't have happened at all.

When I took IANTD OW sidemount class, the instructor told us explicitly not to breathe down the SPG to 0 after closing the valve for exactly this reason that the first stage may come loose. Instead, just watch the pressure drop to say 30bar on the SPG while taking a breath, but not to 0bar. One student didn't listen, breathed his reg empty, and it happened: when reopening the valve, a lot of air flowed out between the first stage and the tank; student puzzled, instructor had to intervene.
Nothing broken or busted; the first stage is just coming loose from the tank easily when depressurized. I guess that's more likely in sidemount than backmount because the tanks are not as rigidly connected to your body and move around more. I had my inflator hose come loose at the first stage twice when in sidemount; never happened in backmount.