DIY Apeks DS4 Servicing

[nickb]

I've just serviced my spare DS4 1st stage, thanks to a friendly & understanding chap that supplied the service kit (£13).

It took around an hour, during which I also managed to cook some fish and vegetables for me and the lad AND drink two bottles of Grolsch.

What a piece of piss. I now have a sparkly clean reg which breathes smoothly and, as I tuned the interstage pressure down to 8.5 Bar (125 PSI) shouldn't freeflow quite so easily.

Obviously a quick check in the pool will be prudent, but I'd certainly do that after letting the YTS grease-monkey at any LDS loose on it anyway.

[Brian of Aquanauts]

I'm not an Apeks service engineer, in fact i'm not a service engineer and mine's not here at the mo so maybe someone out there will have more of a clue. But...

When i worked in Thailand i serviced my own DS4 with some nice tools from the not so local importer (6 hour trip) and the Apeks service manual the nice german man provided me. Definately remember them recommending an interstage pressure of between 9 and 10 bar, preferably 9.5 bar. Is an 8.5 bar pressure a good idea??? Shouldn't you just use your viva control, or detune your 2nd stage slightly.

I do also remember the tests for a correct set up that the manual stated.
1. Interstage 9.5 bar
2. 2nd stage freeflows on surface if purge button pressed all the way in
3. 2nd stage freeflows when put in a bucket of water the wrong way up
4. If you take the diaphragm off, the lever should be level with the edge of the main body of the reg.

Am interested in being educated, maybe all that Thai Sam Song Whisky and real redbull killed some brain cells.

[Scuby]

Originally Posted by Brian of Aquanauts

2. 2nd stage freeflows on surface if purge button pressed all the way in
3. 2nd stage freeflows when put in a bucket of water the wrong way up

Really? If my reg was setup like that i'd be doing some rapid de-tuning! Is that supposed to be for both main reg and octo - it might be right, but seems very very wrong to me...

David

[Brian of Aquanauts]

I thought it was for both, but happy to be corrected if i'm wrong. However with the air flow control in the minus position any possible freeflow just pushes the diaphragm back out and stops it.

Pretty sure that was correct. Surely you want your regs to breath as easily as possible.

There is a difference between a freeflow like this and one underwater when it's in your mouth (caused by iceing or damage and the lever becoming stuck), the freeflow should stop when fingers are placed over the mouth piece thereby allowing the pressure build up to push the diaphragm back out.

It's reasons like this that people should pay a service engineer to do their stuff unless they really know what they're doing.

There must be an apeks service engineer out there somewhere???

[Woz]

Yep the Apeks service manual says:
No more than 2mm play in the purge button before purging starts
In the - position it should stop purging when released
In the + position it should keep on purging when released

They are available online somewhere along with the electronic training thingy.

[Woz]

Aha. Interstage pressure should be 135 psi +/- 5 psi (9.3 bar +/- 0.3 bar).

[Scuby]

Originally Posted by Woz

In the - position it should stop purging when released
In the + position it should keep on purging when released

Ah right, that makes a bit more sense. I didn't really consider the +/- thingy, makes a lot more sense now then :O)

David

[nickb]

Originally Posted by Brian of Aquanauts

Surely you want your regs to breath as easily as possible.

That's exactly what it does now.

As I use a twinset, there's only ever going to be one 2nd stage attached to my 1st stage so it doesn't have to supply 'extra gas in an emergency'. I've detuned my other regs too and they breath just fine at depth thanks very much.

[Brian of Aquanauts]

Originally Posted by nickb

I've detuned my other regs too and they breath just fine at depth.

OK so if you've only got one reg on the first stage, there's never a case when the reg has to deliver gas to 2 divers at a higher rate at the same time even if buddy breathing, so a lower interstage pressure could make sense. Is lowering the pressure standard practice when diving a twinset?

Only asking as i honestly don't know and want to learn.

[nickb]

I believe that the DIR guys do this too.
At least they should, 'cos George says you should

Seriously though, I understand you having reservations about this sort of malarky, but I reckon that having served 4 years as an apprenticed fitter and having an engineering degree probably gives me a bit more experience than the 1-2 day course the 'service techinicians' do with the regulator manufacturers.