Regulator stutter with 7 ft hose

[divepilot]

I am diving with an Oceanic Zeta. It was breathing good on the standard length hose as I waited for my 7 footer to come in. Today I dove with the long hose for the first time. When I inhale, there is a slight stutter in the air flow. Any ideas?

[awap]

But I would not have expected that much effect. You might try increasing the IP 5 or 10 psi and see if that helps. You might also want to check for a defect in the hose that is interfering with the flow. Give it a hard purge and see that it doesn't do anything strange.

[roturner]

divepilot once bubbled...
I am diving with an Oceanic Zeta. It was breathing good on the standard length hose as I waited for my 7 footer to come in. Today I dove with the long hose for the first time. When I inhale, there is a slight stutter in the air flow. Any ideas?

This is probably caused by the servo assisted pilot valve in the Zeta vibrating. It would do that if the backpressure in the hose wasn't keeping the valve open through your whole inhalation and it would start to open and close quickly, causing a shudder. Other regulators which have used this design have experienced similar problems. From what I understand making it stop for long requires something between magic and witchcraft.

Why you would get it with a longhose but not with a shorthose is a bit puzzling. Maybe someone else can make a stab at that.....

As far as solutions goes:

You could try it with a different first stage that has a higher capacity throughput and/or one that gives a less pronounced fall in IP as you inhale. Increasing the peak IP probably won't help because it's the fall-back in the IP during inhalation that causes this problem, not the peak IP. Having said that, it certainly can't hurt to try it.

I don't know much about the Zeta but maybe there is a way to increase the resistance of the pilot valve (slightly bigger spring?) to better accomodate a 1st stage of the type you're using. Likewise there could be a way to adjust the flow rate of the 2nd stage to limit IP fallback. That would help too but I can't tell you for sure if your reg has that.

Hope this gives you some ideas.

R..

[divepilot]

I finally had a chance to adjust the regulator and dive again. I detuned the 2nd stage slightly and that solved the problem. I appreciate all of the help!

[Norm]

I once bought a new 7' hose and it had a tiny piece of loose rubber inside of it from the manufacturing process. Maybe your's did too?
Norm