BC inflator failure.

[daniel1948]

I recently returned from a trip that involved some scuba and some other water activities. All went well for me and I enjoyed the diving. Saw some big turtles up close (I love turtles) and lots of pretty fishes.

One woman, who was in my watersports group but who I never dived with, reported the following incident:

Her inflator valve stuck open, filling her BC. A long-time experienced diver, she dumped the air as fast as she could, but the inflator was filling the BC faster than the dump valve could empty it, and she made a rapid ascent. Fortunately, she was not deep (something like 35 feet IIRC) and it was only 15 minutes into the dive, and she fought the ascent to make it as long as possible, and she was not hurt. She reported feeling nauseated, but otherwise okay, and the next day was feeling fine.

But this gave me something new to be concerned about. I know how to make a controlled emergency ascent if necessary, and I'm never far from a buddy with whom to share air if needed, but if a BC inflator sticks open when you're deep, what are you supposed to do? I guess you could try to shed your gear and let it ascend, and then share air with a buddy, assuming the over-inflated BC hadn't already dragged you too far up to get back down to your buddy.

Have other folks heard of this happening? What do the "experts" recommend if it does? This woman was lucky: she was not deep and had not been down long. But I think that under other circumstances it could have been serious.

 

[Dr. Lecter]

I dive the old Halcyon stainless steel "precision" inflators. I know it's time to rebuild one when it tries to kill me by turning me into a Polaris missile from way, way deep down.

First priority should be to disconnect the LPI hose while fighting the ascent. Sometimes you can pop them off the inflator one-handed, especially if there's a "hat" or flange on the LPI hose connector, but I'd not hesitate to avoid/stop dumping long enough to use both hands on the LPI connection if necessary. Ounce of prevention, pound of cure, etc.

As long as you realize what's going on and deal with it via the 'slow is smooth and smooth is fast' approach, this should be a non-event for everyone.

 

[redacted]

I dive the old Halcyon stainless steel "precision" inflators. I know it's time to rebuild one when it tries to kill me by turning me into a Polaris missile from way, way deep down.

First priority should be to disconnect the LPI hose while fighting the ascent. Sometimes you can pop them off the inflator one-handed, especially if there's a "hat" or flange on the LPI hose connector, but I'd not hesitate to avoid/stop dumping long enough to use both hands on the LPI connection if necessary. Ounce of prevention, pound of cure, etc.

As long as you realize what's going on and deal with it via the 'slow is smooth and smooth is fast' approach, this should be a non-event for everyone.

To disconnect the LPI hose, you will have to hold the inflator anyway. So hold it up and press the manual deflate button at the same time you are disconnecting the hose with the other hand. It is a skill that can be practiced to develop muscle memory.

 

[TMHeimer]

I've had it happen once in 500 dives--fortunately I was able to detach the LPI and I was quite shallow, as this happened early on after my OW cert. One other time early on I guess I didn't have it completely fastened and it popped off by itself. Again shallow-20-30', I continued the dive by orally inflating if needed.

 

[Patoux01]

To disconnect the LPI hose, you will have to hold the inflator anyway. So hold it up and press the manual deflate button at the same time you are disconnecting the hose with the other hand. It is a skill that can be practiced to develop muscle memory.

Nope, I'm able to do it one-handed. But that's because my inflator is held in place.

My view on this "issue":
- NEVER use a "fast inflator", if it fills faster than you can dump air, detune it (or have it detuned). If it still fills fast, throw it away. (looking at you, uber ultra-double compensated rocket shooter that some are trying to convince us is best to use)
- NEVER inflate for more than half a second (which seems long already).
- ALWAYS be ready to act on it when using your inflator. That is: if you use the inflator, be ready to quickly dump air + disconnect.

With this in mind, I don't think one could get a fast ascent due to his inflator. And one won't drop too fast when going down (which you shouldn't do anyway), because you're supposed to be close to neutral at all time during a dive.

---------- Post added May 8th, 2015 at 12:03 PM ----------

Oh, and being in trim helps as well, because then you're able to duck down and fin to push yourself towards the bottom. If your legs are down, good luck back-kicking your way..

 

[shoredivr]

In very cold water winter diving, say 35-39F, I have learned to dive with the LPI disconnected and inflate orally. There was a fatality ice diving in Ontario several years ago where the diver's inflator froze open, creating an unplanned ascent from 70 ft to the undersurface of the ice. The connector and inflator mechanism was one big ball of ice, making disconnection impossible. Other divers concluded not to connect the LPI to the inflator in very cold water was a good practice.

In warmer waters, popping off the LPI is easy with practice, just like popping off a drysuit LPI.

 

[redacted]

Nope, I'm able to do it one-handed. But that's because my inflator is held in place.

My view on this "issue":
- NEVER use a "fast inflator", if it fills faster than you can dump air, detune it (or have it detuned). If it still fills fast, throw it away. (looking at you, uber ultra-double compensated rocket shooter that some are trying to convince us is best to use)
- NEVER inflate for more than half a second (which seems long already).
- ALWAYS be ready to act on it when using your inflator. That is: if you use the inflator, be ready to quickly dump air + disconnect.

With this in mind, I don't think one could get a fast ascent due to his inflator. And one won't drop too fast when going down (which you shouldn't do anyway), because you're supposed to be close to neutral at all time during a dive.

---------- Post added May 8th, 2015 at 12:03 PM ----------

Oh, and being in trim helps as well, because then you're able to duck down and fin to push yourself towards the bottom. If your legs are down, good luck back-kicking your way..

What is the process for "detuning" an inflator?

 

[TN-Steve]

To disconnect the LPI hose, you will have to hold the inflator anyway. So hold it up and press the manual deflate button at the same time you are disconnecting the hose with the other hand. It is a skill that can be practiced to develop muscle memory.

I had almost the same thing happen a couple of weeks ago. A couple of weeks previous I had noticed that the inflator button was a little "stiff", and just didn't get around to checking it out.

Sure enough, about the 3rd time I touched it on a dive, it stuck open. I hit the purge button, pulled the hose to activate the dump, and popped the connector off. Dove for a bit longer doing oral inflation as needed, but decided that was too much like work for just a 'make bubbles quarry dive'.

Like you experienced, once you start going up, it's really fast, and becomes a positive feedback cycle. I've decided that it's a skill that I'll add to my"practice every dive or so" refresher set.

Steve

 

[Rhone Man]

This has happened to me a few times. First time was at about 180' and I was pretty narc'ed and it took me a long time to work out what the hell was happening. Quite lucky that didn't end badly...

At one stage of my diving life I actually took off my inflator hose off my reg and just orally inflated my BCD for two or so years. But I reattached it eventually, and just try to keep a better maintenance schedule now.

 

[Patoux01]

What is the process for "detuning" an inflator?

That's a good question, I assume it has to do with the spring and its preloading, or maybe not screwing that part 100% in. I've been told it's feasible by a very good instructor, didn't ask more questions since mine does fine, don't think he'd have lied to me...

Anyway, if my inflator allows me to dump more than it can inflate, and yours doesn't, then I guess there's some possibility to tune them. (and the take home message was: you do not want a fast inflator)