Apeks ATX100 question

[Pao]

I just had my 3 yr old reg (Apeks ATX100) serviced. It has an environmentally sealed 1st stage with an external and an internal diphragm. I noticed that the external diaphragm is slightly bulging. It is usually concave even if attached to a tank with the valve open. Is this normal? I asked the technician and he said that this was normal and he tested the reg after service and found no leaks. I am alittle concerned and am wondering if air may be leaking into the isolation chamber between the diaphragms which may cause freeflow. Any similar experiences/advice?

Thanks in advance.

 

[Bubbletrubble]

Could you please clarify exactly what the hydrostatic diaphragm looks like: (1) when the reg is not pressurized and (2) when it is pressurized?

The external (hydrostatic) diaphragm is supposed to be a little puckered in (concave) at rest when not pressurized. When pressurized, the hydrostatic diaphragm should be relatively flat or ever so slightly convex. The reason for this membrane posture is that the first stage is pressurized prior to installing the load transmitter/hydrostatic diaphragm/end cap. If the hydrostatic diaphragm looks like it's going to pop (clearly bulging out) or if you can visualize water inside (underneath the hydrostatic diaphragm), that's an indication that something is wrong.

If the hydrostatic diaphragm is convex (bulging out or distended) when not pressurized, then assembly was performed incorrectly during the recent overhaul. Take it back to the shop. Politely ask the tech whether he installed the load transmitter/hydrostatic diaphragm/end cap while the reg was pressurized. If he says he did, then ask him to consult the "Troubleshooting" section of the official Apeks reg technician manual. The manual lists six possible causes of a distended hydrostatic diaphragm.

If you own a reg, you should purchase an i.p. gauge. It's a handy tool to periodically test whether the first stage is functioning properly. It can also help you diagnose the cause of a free-flow (second stage issue vs. first stage i.p. issue).

Hope this helps...

 

[Pao]

Thanks! The hydrostatic diaphragm is definitely convex and my reg is definitely not connected to a cylinder. I'll try to take it back tomorrow.

 

[Babydamulag]

I have the service manual if you want it.

 

[super7]

I have noticed the same thing happening with my Apeks regs.
My 200's clearly concave, and the Tek3s are bulging.
I guess it's time to get it serviced.
(This time, I'm looking forward to getting instructed and doing it myself)

 

[Pao]

I have the service manual if you want it.

Thanks Babydamulag. I have the manual for the TX100. Is it the same?

 

[Bubbletrubble]

Thanks! The hydrostatic diaphragm is definitely convex and my reg is definitely not connected to a cylinder. I'll try to take it back tomorrow.

Thanks for the picture. I'd call that slightly convex.
FWIW, that's not what my regs look like immediately after servicing.

Before my last servicing (March 2010), the hydrostatic diaphragm on my FST first stage was decidedly outward bulging (convex) with the i.p. registering on the high side of the acceptable range (manufacturer specs: 130-150 psi). Over the preceding 6 months, the issue seemed to be getting progressively worse. The i.p. had initially been set at 140 psi...and I was measuring i.p. near 150 psi. I didn't notice any change in the way the regs were breathing. I didn't detect any obvious air leaks during bubble checks. Eventually, the i.p. got to be slightly over 150 psi and I had minor issues with my primary reg free-flowing when the inhalation adjustment knob was not cranked down. Essentially, what was happening is that I was compensating for the increased i.p. by detuning the second stage. I suppose that I could have simply made adjustments to the lever height in the second stage...but I figured it was prudent to finally overhaul the reg (first stage and both second stages). The interval between overhauls was 2.5 years and approx. 150 dives. I'm sharing this info with you as a datapoint on how long Apeks regs can go in-between overhauls.

FYI, I'm just a divebum on the Internet who services his own regs. I don't have a ton of experience with reg repair. It's possible that the reg tech who overhauled your reg has more experience than I do. Still, that doesn't necessarily make him right, eh?

 

[Russ_UK]

I've got 2 Apeks TX50 regs & 1 TX40 reg & they are all same - nothing to worry about.

 

[Pao]

Update: Just brought back the reg to my LDS. It seems that the apeks service kit used in my reg had a convex (or concave depends on what side is out) hydrostatic diaphragm. The technician took it out and showed it to me. No leaks were detected and he did put on the environmental cap with the reg pressurized. The diaphragm bulged out so slightly when the reg was pressurized but was still convex when the reg was de-pressurized. Thanks to everyone for the posts .

 

[Bubbletrubble]

It seems that the apeks service kit used in my reg had a convex (or concave depends on what side is out) hydrostatic diaphragm.

That's a new one on me.
I have two different unopened Apeks first stage kits in my dive locker: AP0241/AA (light blue) and AP0241 (yellow).
Both kits were sourced from overseas, yet they contain all of the same parts.
Each kit includes a replacement hydrostatic diaphragm part (AP1482)...which is flat -- with no curvature at all to it.

Inside the first stage service kit, the HP valve (AP1419) is protected within a plastic vial. I wonder whether the hydrostatic diaphragm in the kit that was used for your overhaul somehow took a set when it was stored on top of the HP valve vial.
Another possibility is that Apeks has changed their official kits. (Any official Apeks reg techs out there who can confirm this? Russ_UK's post above makes me wonder whether this is the case.)
Yet another possibility is that someone is re-using parts in their overhauls.
The skeptic in me would ask to see the shop's other unopened Apeks kits (AP0241). But that's just me...

I can tell you that when I removed my old hydrostatic diaphragm during the most recent overhaul, it had taken on a misshapen convex/concave character.

Enjoy the reg.