Power inflator malfunction

[gasdiver]

Mine usually leak awhile, before they get to the point of uncontrollable inflation. I have learned to fix them before that happens

I recall having to learn that the hard way!

[speleocrone]

Thanks guys for all the useful information. Even the answers that don't apply to this problem have taught me stuff to do/look out for in the future.

I have been diving for 35 years and never had this happen before. Obviously I have been lucky until now, judging by the assortment of problems you have all had.

It is a Nomad EXP, about 18 months old (bought it new, so only me diving it) with maybe 100 dives on it. I have had no troubles with it before, no slow leaking or button problems at all. This came out of the blue and it inflated very fast and jammed me against the roof (only about 2 feet above when it started) with a fully inflated wing in the few seconds before I could get the post turned off (side mount).

I was exiting a sump after having de-kitted in a dry chamber which had a lot of silt and mud at the spot I got out. Everything had fine silt in it when I cleaned it at home later, so I am very suspicious that was involved in some way.

I disconnected the feed after turning the post off and then completed the dive without the feed connected. When I checked at home later the system worked fine. o rings look good and it is all working now. That's what worries me.

I'm sure I didn't push the button as it inflated ( you do this stuff on automatic and don't even realise you are sometimes) as it took me by totally by surprise and took a second to realise what was happening. If I had been using the inflator at the time I'm sure I would have made the connection instantly; that is: "button jammed on".

I had just done a sharp, 180 degree, turn, as I had been fixing some line and faced into the current to do that, but the way out was downstream. Is it possible that the inflator button hit some part of me as I swung and that, together with grit, jammed it on? How improbable is that ?

[FW]

T.... Is it possible that the inflator button hit some part of me as I swung and that, together with grit, jammed it on?...

That is as good a guese as any. We are glad you are OK. Imagine if that had happened in deep open water, or a deep pit inside a cave.

[a64pilot]

That is as good a guese as any. We are glad you are OK. Imagine if that had happened in deep open water, or a deep pit inside a cave.

I've trained for this scenario, at least for OW tri-mix, you can disconnect the inflator and dump the wing before you lose much depth at all, for me the greater danger was with two 130's and a deco bottle, I'd drop like a rock if I wasn't careful on how much I dumped.

[AB8CD]

It reminds me of the night I was driving a patrol car and smelled pepper spray... It only took a second to realize it was discharging from my duty belt into my shirt... but the effect stayed with me quite awhile!

Sent from my DROIDX using Tapatalk

[speleocrone]

That is as good a guese as any. We are glad you are OK. Imagine if that had happened in deep open water, or a deep pit inside a cave.

I have imagined that. As it was happening actually. Having had this experience, at least if it happens again (heaven forbid), without a convenient nearby roof, I will react very quickly. I hope.

[speleocrone]

I've trained for this scenario, at least for OW tri-mix, you can disconnect the inflator and dump the wing before you lose much depth at all.

I think I'll practice that myself now. Nothing like a lucky escape to motivate training.

[MORGAN]

Over the 12 years my wife and I have been diving, we have had more problems with LP inflator valves than any other piece of equipment. The most potentially interesting one was when Tracy's stuck on halfway around the deep circuit at Twin. We flush them out, keep them clean, and we dive in fresh water much more than in salt, but they seem to be problematic. We keep a new one in our diving toolbox.

Mike

[jcook]

The ones that are on most wings are crap from China anyways. It does't matter how well you take care of them, Murphy will reach up and grab you at some point with them. I rebuild mine every 100 dives or so, basically whenever I service my regs. Coming from someone who works on inflators on a weekly basis, I have seen brand new ones stick or screw up more than older ones.

[DA Aquamaster]

It can be a larger systems integration issue. For example I noted a diver I was mentoring who had an inflator hose length and inflator orientation such that the inflator could become stuck between her arm and the ridge made by the zipper across her chest. That was diagnosed after she reported auto inflates and then asking her what she was doing at the time followed by observing her in the water when she repeated her actions. Out of the water it was totally non-obvious but in the water when she reached across her chest with her left arm it was crystal clear what was happening. Rotating the inflator slightly to prevent the button from being pressed if it is trapped resolved the issue.

Similar issues can happen with dry suit inflators and cross chest straps.

Mechanically, schrader valves are fairly reliable but are not balanced so the inflators tend to lack sensitivity. Balanced inflators use a center balanced valve sealed on each end with an o-ring and they are more precise in operation, but both o-rings are susceptible to damage from sand, etc. so an annual rebuild is important but often skipped. What is worse, is that some (many) use non standard o-rings that shops may not have on hand. In that case mis sized o-rings can cause failures.

Some cheaper inflators are also not intended to be serviced at all but rather are considered to be disposable items.

Another common design issue is a return spring that is retained by the button. If it breaks off (or in some cases unscrews) then the spring ejects itself and the next time the remains of the button is pressed, it will start inflation but then won't stop when you stop pressing the button.

A general safety feature that is *supposed* to be built into a BC or wing is the ability to dump faster than you can inflate. If that is the case, you can immediately dump with one hand while you disconnect the inflator hose with the other. However in some cases this is accomplished with a restrictor in the inflator hose for a drysuit or wing so if the hose is changed (common in tech diving to get the right length) this safety feature is defeated. It's worth checking the stock hose to see if there is a restrictor in the inlet end of the hose. Whites for example did this with their dry suit inflator hoses.