AT400 'pinging'

[rehmwa]

I just checked out my new Ion/AT400 in the pool this weekend. I get a light ping at the end of each inhale (on the finish of the breath) - I get it on my 2ndary too, so it's in the AT400, not the Ion. It's like riding in a sub - ping.......ping.......ping......ping.......

It could be the DVT on the AT400 reseating/closing between the breaths. I'm not sure if it's designed to crack open on each inhale, or is always open once the reg is fitted to the cylinder.....

I'm really liking my regulator setup, but would like to know if others hear this too, or if it's an issue or a setup item or something else.

this was just the pool checkout, and it only happened in the last 1000 psi of the tank, not at first.

It was quite a treat, I'm looking at my wife signaling a question to her whether her computer was issuing a audible alert, etc... until I figured out the source of the ping..:blinking:


big trip on Saturday - sure would like to figure out if this is harmless or not beforehand....

 

[irishsquid]

Both of my regs are AT400s and the pro 2nd. I haven't experienced this myself.
I believe that once the reg is pressurized, the DVT remains open.

 

[rehmwa]

Thanks anyway, I-squid. Looking at the design, I doubt any form of pressure would keep that piston open, it would take a delta pressure. But it might just be a contact open on assembly to the cylinder. I'm home now and will take a look. My local rep says it's not a safety issue, but may be annoying. We'll replace the piston and spring after my trip and see what happens. Talked to Aeris on the phone today, they answered immediately and were a big help.

 

[irishsquid]

Thanks anyway, I-squid. Looking at the design, I doubt any form of pressure would keep that piston open, it would take a delta pressure. But it might just be a contact open on assembly to the cylinder. I'm home now and will take a look. My local rep says it's not a safety issue, but may be annoying. We'll replace the piston and spring after my trip and see what happens. Talked to Aeris on the phone today, they answered immediately and were a big help.

I would've thought when you crack the valve on your tank, that is the pressure that opens the DVT (red plunger in the first stage). Is this what you're talking about?

 

[rehmwa]

I would've thought when you crack the valve on your tank, that is the pressure that opens the DVT (red plunger in the first stage). Is this what you're talking about?

Sure, but my question is about whether that valve (red plunger) stays open, or is only open when it gets a demand signal. Pressure is a balance thing. With a spring loaded DVT, the pressure will open the DVT to let the system pressurize. Once the system equalizes, the spring will close the plunger. Then it would open on each inhale (the inhale will cause a small pressure differential) or any draw of air from the cylinder like the LP or a 2nd stage.

Unless there is an additional simple mechanism to keep the plunger open all the time (like something designed to keep a push on it - like a nub that holds the plunger down when clamped). Then it would stay open all the time.

I don't know which. And the 1st stage and a tank isn't here for me to check it. But I'd think it would be the first, not the 2nd.

interesting digression - but I'm still wondering about the pinging......


Edit: Got official note from Aeris, good guys. Not a safety issue, just needs to sometime replace the plunger or spring if the sound is annoying, may be a slight burr or so that's contacting a surface during periods of low delta p. Good explanation from them too.

 

[irishsquid]

I understand what your saying now. Good job! Thanks.

 

[keyshunter]

I dived with an instabuddy recently whose Oceanic Delta 4 with dvt first stage pinged on every breath. It was audible to those around her. She said that the noise had just begun after the reg was serviced. I noted that it had the red dvt plunger, which is supposedly the latest version. I suspected that it had something to do with the dvt, but had no idea what the tech could have done to introduce a ping.

 

[rehmwa]

well, now you know what I know about it

Thank - since I'm leaving for Belize tomorrow, I'm glad you mentioned it and I can infer she didn't have any issues with it.... ; )

I think that red plunger is a great design idea.