Apeks *tx40

[samjmitchell]

Hi,

This is my first post on here and i'm just looking for a bit of advice/knolage.

I got recently a new Apeks atx40 set up prior to this i used rented/borrowed equipment. On my first few dives with the new rig my air consumption was very high, it felt like the air was being forced down my neck (i used to breathe in and out nice and slow, now i could only breathe out slow).

I attributed this (rightly or wrongly) to the cracking pressure setting and started increasing it slowly, a little before each dive. The rig has stated to breath more like what i'm used to but still a little forced.

So my question is would i do any damage to the seat etc f i were to take a hex key on a dive and adjust the rig under water whilst in use. I know it may not be advisable to make adjustments whilst diving but this is just to get the rig set, i thought it cant be to different to what the *tx50 does but just wantted to check i'm not going to damage anything.

Thanks for any advise

Sam

 

[keyshunter]

You won't do any damage. That is a balanced second stage and the hex key adjustment does exactly the same thing as if it had an adjustment knob like the ATX 50, etc. In fact, an adjustment knob can very easily be added to that second stage.

 

[Zung]

Don't worry about it: it happened to me under the same circonstances many moons ago, and now it's happening to my #2 son. And don't mess with your gear, at least not right now.

Work a bit on your breathing instead, sip on your reg instead of sucking on it; in time it'll come. I personnally prefer a semi-conscious or controlled sort of breathing: in - stop - out - stop.

And bear in mind it's a comfort feature you paid high dollards for, like air conditioning, leather seats, and so forth.

 

[knowone]

Buy a hex key with a nice handle, cut it down, polish it up and glue it in. Adjust when you are inhaling.

 

[samjmitchell]

Thanks for the advice. I was thinking of doing an atx50 convertion at some point but can't source the parts needed so far. I'd leave this until it needed servicing (if it ain't broke don't fix it) but it would be good to have the parts waiting. For now i guess i'll just get a £4 ss hex + learn a different way of breathing.

It seems like a big price difference (*tx40 vs *tx50) for such a simple part.

Thanks again

Sam

 

[herman]

Sam, instead of adjusting the cracking pressure, you might want to try moving the venturi lever more to the - side. It sounds like you are breathing in kinda fast and if the venturi assist is wide open it will tend to force air down your throat. Slow down your breathing to a nice slow gentle inhale esp at the beginning of the breath, which is how it should be anyway and with the venturi set more negative I bet you will find the problem stops.

 

[Fishpie]

I gotta agree with Herman....the "forced down my neck" feeling is caused by the venturi and not the cracking pressure knob.
Try leaving the lever at minus or half way position.
Everybody else is quite right about the knob being an easy replacement to your existing plastic plug.

As far as the high air consumption goes I think it is more a fault of the user than the machine.

 

[samjmitchell]

Thanks for the advice, i think the new regs might just take some getting used to.

I know air consumption needs practice/experience i just didn't expect it to drop so dramatically when changing regs. When i first got the regs i didn't have an LPI hose so the dive leader wasn't that happy with me diving them and lent me a set. After the first dive he was surprised how low my air consumption was, he came up with 20 bar whilst i was on 85, shallow dive from 20 - 5 m for 1hr 20 (similar fills 210 +/- 5). After the first dive he said he was happy for me to take the new regs, after which my consumption was worse then his on a similar dive profile. Detuning has helped but it's no where near where it used to be. I've tried playing with the venturi which helped a little.

Another question about adjusting *tx40/50s - does it have to be made whilst breathing in/leaver depressed? I know when adjusting the crown on other models (coming in from the hose side) this should be done to avoid seat wear but does the seat turn against the crown when using this adjustment or does it just compress the seat spring more?

Hope that was clear - it just hard to tell whats happening from the drawings i've seen and i haven't opened it up yet to find out (serviced).

Thanks again

Sam

 

[Zung]

... he came up with 20 bar whilst i was on 85, shallow dive from 20 - 5 m for 1hr 20 (similar fills 210 +/- 5). After the first dive he said he was happy for me to take the new regs, after which my consumption was worse then his on a similar dive profile...

That's *MILD*.

I think I almost halved my bottom time when I first changed from a rental Spiro (AL) Club to a Spiro Supra some 20+ years ago. I even sucked dry the reserve (those were the days) without noticing it.

The adjustment opposite of the hose side just sets the spring pressure, no harm done to the seat.