OMS Power Inflator

I have a borrowed OMS twin tank wing, whose power inflator was sticking open, so that when I pressed the button to inflate the wing, it would continue pushing air into the bag even after I’d stopped. The only way I could dive it was to disconnect the inflator hose and inflate it orally when necessary.

As a reminder for next time, with the usual caveats of “Don’t try this at home” and “this may not be the right way to do it”, and “Don’t come crying to me if it all goes horribly wrong”, here’s how I fixed it.

1. Take the inflator valve off the wing’s hose.

2. The air intake nipple doesn’t have a hexagonal nut to unscrew, so use a pair of pliers to unscrew the nipple, having wrapped them in cloth so as not to damage the metal.

3. Then take off the o-ring from the nipple

4. There are two grooves on the inflator button, one on either side. Use a pair of snap ring pliers (circlip pliers) to grip either side of the red button and unscrew the inflator valve.

5. Use 6.5mm socket wrench to take spindle out of inflator barrel.

6. Push the pin out of “wing-end” of the plastic. If there is a fast pull-dump on the corrugated hose, this pin is to hold the wire that connects to the shoulder dump valve. This OMS one doesn’t have one, but it does have the pin.

7. Use a pair of pliers to grip the outlet valve on the end. Push a 9/16″ socket into the other end and use it to undo the nut, allowing the outlet valve to come free.

8. Take off all the o-rings and discard (or retain if you’re really short of money and they’re in particularly good condition)

9. Soak all the other parts in an ultrasonic bath for 10 minutes or so.

10. Rinse and dry all parts.

11. Get a new set of o-rings ready. Put the 2 small ones onto the spindle and grease them with silicone grease

12. Put the rest of the o-rings on and grease

13. Put spindle through inflator barrel and put spring and button on. Use 6.5mm socket to tighten. This should be hand tight.

14. Screw inflator barrel into the plastic. Don’t overtighten as you risk damaging the plastic.

15. Screw air inlet nipple (with o-ring) into plastic. Don’t overtighten as you risk damaging the plastic.

16. Put paper round the deflator button to prevent scratching and grip with pliers. Then use 9/16″ socket wrench to tighten nut, locking deflator button in place.

17. Put the pin back in.

18. Hook the the inflator valve up to a regulator on a tank and make sure that it’s working. I do this before reconnecting it to the corrugated hose in case it doesn’t work and you have to cut it off again.

19. Use a cable tie to fasten the inflator valve back to the corrugated hose and reconnect to the wing / BCD.

20. Test again with a regulator.

You’re done, but be careful with it when you take it out diving.

About Neil Hambleton

I am a British Sub-Aqua Club (BSAC) Advanced Diver and an Open Water Instructor. I have been diving since 1992, after joining South China Diving Club (SCDC), which is a Hong Kong-based branch of the BSAC. Having moved to New Zealand, I am now a member of BSAC New Zealand.
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4 Responses to OMS Power Inflator

  1. Taucher says:

    Aaaah! Please, please, PLEASE, if you absolutely have to have a go at your own equipment – DO NOT use serrated-jaw pliers like those shown in the preceding pictures for Any part of your Scuba gear. They are primarily for plumbers and those serrations are designed to cut into whatever material they grip – no good at all for precision diving equipment.
    If you do not have a complete range of suitable hand tools, one viable alternative would be a “PlierWrench” from Knipex – the German tool company who make probably the best pliers in the world – but don’t take my word for it, I’m only an aircraft engineer… Seriously, the PlierWrench is a “slip-jawed” style plier with SMOOTH parallel jaws which do not mar the surface they’re gripping. And their design is such that the harder you push down on their handles, the harder they grip.
    Expensive? Yes. Available in Hong Kong? Yes – have a look around better tool shops in Mong Kok ‘s Reclamation/Soy Street areas. Worth buying? Yes – though think of buying tools like this as an investment, rather than an expense. Knipex pliers are also sold by Snap-On, Mac and all the other Aircraft Engineering tool suppliers, with this particular item available in three sizes.
    So, if you absolutely, positively, have to mess around today with the life support equipment that you may be breathing from tomorrow, at least get the right tools for the job…
    … But ideally, if you don’t know what you’re doing, don’t touch it at all.
    Safe diving,

  2. neil says:

    Thanks for that Nick. I assumed you would have something to say on the subject.

  3. Tai says:

    Hi Neil,
    I come across your page because I open up my inflator lately (i.e.- the H brand I brought from Big Steve , the bladder is gone due to raging but I keep the inflator).

    Suddenly I noted your name appear on the screen and the word “borrowed wing”.
    Look like you two enjoying diving in NZ too. great to know.

    Unfortunately, I was using the same plumber plier as you do with a cloth of course…my view is having a good non-scratching plier is definitely great but using whatever tools you got in hand is nothing wrong as long as you aware the possible consequence.

    Nice work.

  4. Neil Hambleton says:

    Thanks Tai. Diving here is good, but the water is colder, and the marine life less colourful but much more prolific. And from Auckland it doesn’t seem as easy as it used to be jumping in a van, then getting on a junk, with plenty of beers for the way home. We tend to make more of a weekend of it and get out of the city, which means we dive less often. But Rita’s just had the neck seal fixed on her drysuit so we need to test it soon.

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