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Discussion Starter · #1 · (Edited)
Maintenance of drysuit inflator valve.

1. Introduction.

1.1 The following is a guide to maintaining the chest inflator valves found on drysuits. The example used is an Apeks non swivel type, one of the most common fitted to drysuits, and is often badged up by the drysuit manufacturer to have their name on it. Although user maintenance is possible, you must be competent with a few basic tools, if you are not able to carry out the operations described then let someone more experienced take a look. Remember that you may be risking your life if you make a mistake in the maintenance of the valve.

2. Inflator valve maintenance

2.1 The first step is the removal of the valve from the drysuit. This is done by holding the external component still and rotating the nut on the inside of the drysuit. Never turn the outside part of the valve when removing or fitting a valve as this can lead to an improper seal and the suit leaking. Once the valve is removed, you will have it in two pieces, the valve body and the nut.

2.2 Inspect the threads of the nut and valve body for damage, grit, or old glue, cleaning it off if you find any. If needed, the hose nipple can be removed, although this is rarely going to cause problems the O ring can fail, which will let gas escape, usually in a small continuous stream. The O ring is arrowed and should be inspected for damage and lightly greased. Blow down the hole to clear any plastic fragments. It is possible to change the nipple for a different sort provided the threads are identical. The example here is a large bore nipple, although most divers have converted to the BCD type to provide redundancy in case of a hose problem or gas supply problem on a twinset.

2.3 Looking from the inside of the valve body [as it would be fitted to a suit] the retaining circlip can be seen. This needs to be carefully eased out of the slot with a small flat screwdriver while depressing the valve button. Beware as this circlip can spring out so take adequate steps to protect your eyes.

2.4 Once the circlip is removed the button and spring are free to be removed, but they are unlikely to fall out on their own. Either push in the middle of the button stem from the inside, or carefully lever it out from the outside of the valve body. You will notice groove for the circlip and the O ring on the stem of the button. The O ring provides the waterproof seal from the outside of the drysuit valve, inspect for damage or debris and lightly grease. The waist in the middle of the stem is the part of the valve that controls the gas flow into the suit. If the button is not being pressed, the lower thick section seals against the internal O ring in the valve body. When the button is pressed the thinner section moves into the O ring, which then lets gas past, inflating the suit.

2.5 The internal O ring is difficult to inspect, but removal is not recommended, as it will be damaged during this process. Instead, clean any visible debris and then lightly grease the thicker section of the valve stem. Press the stem into the valve body from the inside and turn the valve to spread the grease around.

2.6 When re assembling the valve, make sure that all components are clean and O rings are lightly greased. The picture below shows how the various components fit together.

2.7 Fit the valve and spring into the valve body and secure with the circlip. To do this it is easiest to depress the button just enough to expose the circlip groove in the internal side of the valve, and then fit the circlip with a pair of snipe [needle] nose pliers, again being careful of the circlip springing out. Refit the nipple if it was removed, being careful not to over tighten it. You are aiming for a snug fit within the valve, and too much torque will strip the plastic threads.

2.8 It is important to test the valve prior to refitting to the suit. To check the operation of the valve, blow in through the nipple and check there is no flow. Then press the button to make sure that gas flows through the valve. It is possible to do a soak test by connecting the valve to a set of regs, pressurising the regs and then turning the cylinder off. Leave the pressure gauge to settle for five minutes and then make a note of the reading, returning after ten minutes to note the reading again. Any gas release noted indicates a slow leak through the valve, which can be checked by immersing in water.

2.9 To carry out a negative pressure test, suck on the nipple and then stick it to the end of your tongue. After a few seconds press the button to release the suction.

2.10 When refitting the valve to the suit, first of all put some liquid rubber type glue [cycle puncture repair glue] on the raised lip of the nut, the valve block threads and the mating surface of the valve block face where it meets the drysuit. Fit the outer section with the nipple pointing upwards and then rotate it into the correct position for the supply hose, usually pointing to the left or right at 45 degrees below the horizontal. Holding the outer section in this position firmly screw the nut on until it seals against the inner part of the suit. Wait for ten minutes for the glue to cure before diving.

I am a person NOT a number
7,710 Posts
Probably had enough of those that live within short distance of the coast and can access the sea easily constantly knocking those that dont and tend to use quarries more for their diving. (Just a guess though)

Its a shame as informative posts and posters like that are lost.

989 Posts
Yep shame he obviously put up some good posts,

Anyway I have hopefull sorted my drysuit valve after my leak yesterday which resulted in me being pretty wet, this along with shit vis and a swell didn't help.

Hopefully no more leaks for me :redface:

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