Q's about cleaning Alternate/Inflator BC's

[beanojones]

Again, diving gear is designed to tolerate water.

It is is not. Minor corrosion on the filter of the first stage (for instance) causes dramatic decreases in performance. So does flooding the first stage, and flooding a second stage.

There are wet bits and there are dry bits. If you get the dry bits wet, they do not perform as they should.

In the case of an inflator, you don't breathe off it, so you are not as aware of loss of performance. There are two very different inflator designs: the tire valve kind, and supply rods with O-rings kind. The tire valve bits are remarkably hardy. They hold the air in your car tires for years, even if they are uncapped and exposed to road salt etc. So they last longer than the inflators that have Orings on their supply rods. The Oring'd supply rod inflators (like OMS, Dive Rite, Halcyon, etc and the separate ScubaPro type) are the result of a design choice that recognizes that as hardy as those tire valve inflators are, they simply do not provide enough air flow at deeper depths. But there is a (to me) big tradeoff: they fail at at much, much higher rates when they are constantly flooded. It does not matter if you rinse it. There are moving parts meant to seal against clean filtered air, not water with the usual particulate load water carries. Rinsing it out might dilute the salt. It won't get rid of the particulate load the water (even the rinse water) carries into it.

Best practice: Don't disconnect.
Second best practice: Cap it like you would your first stage.

Anything else is making the gear work in a way that it is not designed to work. Because most inflators use incredibly hardy tire valve cores in them, you might not suffer much of a consequence. But if you use the kind that have O-rings on a supply rod, it will fail from being flooded, eventually.

**Note: ALL inflator hoses also have a tire valve in them to shut off air when the inflator is disconnected and the tank valve is open.. So the actual performance benefit of the supply rod with O rings kind of inflator is up for grabs since it is restricted by a tire valve in the inflator hose anyway.

 

[redacted]

I dove with thousands and thousands of different divers, and fixed hundreds of leaky Air2's (and S/P balanced inflators.) They all crap out at the O-rings on the orifice, and on the supply button. Two areas which are supposed to be dry in operation.

The best bet is to leave it all hooked up. But most people do things the way they were taught, and they were taught to disassemble. If you are going to disassemble capping (with a dry unsalty cap) is better than nothing. But it is not as good as not taking it apart in the first place.

Can you describe the failure mode of the orifice o-ring? Extrusion is the most common failure mode of a static o-ring but that is probably not the case here. Are you seeing corrosion or deposits on the seating surfaces? Can you identify specifically where? I'm working on uploading some cut-away views of the orifice so we can better see where this problem may be coming from.

I'll see if I can find suitable3 cut-aways for the power inflator valve so we can do the same thing. What failure modes are you seeing with this valve. Is it leaking when the valve is closed or open? If closed, is the leak through the o-ring and out through the button or through the seat and into the BC?

I agree that not disassembling these parts will keep contaminated water out of where it normally does not go. But most designs have to be disassembled at the QD fairly often. I guess the SS1 keeps the octo/inflator with the regulator thus avoiding this problem.

 

[redacted]

With any luck, this is a graphic of the Air2 Orifice and surrounding parts. The area labeled "LP Gas" is the area that is dry during normal usage which would get wet if soaked without the protective cap. The "Orifice O-ring" is identified. And the area marke3d "Exposed" is the open area inside the octo with would contain breathing gas or water at ambient pressure during use and is always exposed to water during a soaking. The Orifice is shown in black with the knife edge in contact with the LP seat, also shown in black.

So how does fresh clean water have any detrimental effect on the portion of the orifice o-ring that it would contact? Remember, the other side of that o-ring is in contact with whaterver water it is being used in. When under pressure, the orifice o-ring will move away from the LP gas and towards the exposed area. When pressure is removed, it will then move back. This will have an effect on what surfaces are being exposed to the various elements.

 

[LeoS]

Sorry to raise a very old thread, but I had just experienced this when a dive resort staff thought my Octo-Z was a regular inflator and removed it from the QD hose to dunk it in the rinse pool.

What should I do?

PS: This was in Tulamben, Bali.

 

[101recon]

There shouldn't be a problem unless he pushed the purge while rinsing it.If you are in doubt,have it checked.

 

[redacted]

Sorry to raise a very old thread, but I had just experienced this when a dive resort staff thought my Octo-Z was a regular inflator and removed it from the QD hose to dunk it in the rinse pool.

What should I do?

PS: This was in Tulamben, Bali.

Since a "rinse pool" is not necessarily clean fresh water, I'd soak with the inlet protector removed in clean fresh water for a couple hours, shake it out and let it dry well, and then store it normally.

 

[LeoS]

@101recon & awap: Thank you so much for the analysis and advice. Is there anyway to check (without owning an air tank) whether the purge button was pushed or not?

I will it professionally checked this time, but the ability to diagnose this would really be handy if it ever happens again.
(Yes, I will be looking over the porters like a hawk in the future, but you never know!)

 

[redacted]

@101recon & awap: Thank you so much for the analysis and advice. Is there anyway to check (without owning an air tank) whether the purge button was pushed or not?

I will it professionally checked this time, but the ability to diagnose this would really be handy if it ever happens again.
(Yes, I will be looking over the porters like a hawk in the future, but you never know!)

Pressing the purge button is only any issue with a standard 2nd stage that is connected to a 1st stage. With an octo/inflator that is disconnected from the 1st stage, it is not an issue. Checking to see if any water is threatening the 1st stage can be done with a bit of disassembly - probably more than many divers can or will do.

 

[LeoS]

Pressing the purge button is only any issue with a standard 2nd stage that is connected to a 1st stage. With an octo/inflator that is disconnected from the 1st stage, it is not an issue. Checking to see if any water is threatening the 1st stage can be done with a bit of disassembly - probably more than many divers can or will do.

Ok, so if I get this right:

As long as the guy didn't dunk the first stage with any of the second stages' purge button pushed, then it should be ok.

It's ok to push the purge button of the second stage when dunked in water, if it's not connected to the first stage?

 

[tfsails]

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