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