Magnum SRB 9310 Questions

[Marek K]

I've just bought my third Sherwood Magnum regulator since 1986. This one is a current-model SRB 9310:




I've got a couple questions that the Sherwood web site doesn't cover...

First, this has a venturi assist second stage; my older Magnums didn't. I've never had a reg with this kind of adjustment. I notice when breathing in, there's a bit of resistance at first; then I hear a "pop" from somewhere in the second stage, and the breathing resistance gets much, much better. This only happens underwater, and seems to be more pronounced as tank pressure goes down.

Is this the venturi system kicking in? If not, should I be worried?

Second, I read somewhere that the first stage has the typical Sherwood overpressure sealing system, that lets out a tiny stream of very fine bubbles that freaks people out that don't know about it. I haven't had a dive buddy look for the bubbles yet, but is that how this works? There isn't a rubber valve in the first stage body like on the previous models...

 

[Sherwood SCUBA rep.]

Dear Marek,

Thank you very much for your loyalty to the brand. I apologize for the late response. Please contact mauriciomoreno@cramerdecker.com to go in detail about what is happening with your 2nd stage. The first stage on our new 9000 series is an enhanced version of the Genesis GR400; balanced piston, environmentaly sealed and yes, it does have a vent valve but it is not visible as it is mounted on top of the depth compensation diaphragm and covered by the saddle.


Sincerely,


Sherwood SCUBA team.

 

[Marek K]

Thanks. I just e-mailed Mauricio.

Regards!

 

[Marek K]

Well, Sherwood took care of the problem a year ago (above).

Now, I just had an annual service done on the reg. The local shop wasn't familiar with or qualified on the new Sherwood Genesis-clone regulators, and had to send it out somewhere.

When it came back, and we hooked it up to a tank in the shop, it breathed fine when taking a normal breath. But when sucking hard, there was an additional rush of air, which I assume again is the "venturi assist" feature of the second stage. (The "popping" sound that I was complaining about at the beginning of this thread was gone, fixed a year ago by Sherwood).

But what concerns me now is that the rush of additional air was pushing open the left part of the oblong exhaust valve (opposite of the orifice), and some of the air was escaping out through the exhaust valve. While I'm inhaling!

This seemed to happen no matter which position the venturi lever was in; + or -.

IP is good; about 150.

Anyone have any experience with this? Is this normal? Does the problem go away underwater, with increased ambient pressure? Or is something misadjusted on the second stage?

 

[Marek K]

Well, we're on Grand Cayman for our dive trip. I took the reg on a check-out dive yesterday, and it seemed to be breathing fine -- I didn't notice any of the exhaust valve blow-by on inhalation.

However, I did notice that the second-stage valve was apparently adjusted incorrectly. There was a constant hiss of air coming into the second stage housing, even when I was't inhaling or when the second stage was out of my mouth.

I took it to Divers Supply in George Town today, and the tech adjusted it for free (not the first time they've adjusted regs for free -- great shop!). The tech said that these new Sherwoods are, of course, much more complicated than the tried-and-true old ones that my family and I have dived for decades. He said that not many techs know that the second-stage valves need to be adjusted "from both sides."

Huh? Sherwood techs don't know that, when regs are sent to them across the country?

*sigh* Tried-and-true was good, as far as the old Sherwood regulators were concerned... Their simplicity and fail-safe design were Sherwood's niche strong points. I'm afraid those days are gone...

 

[Marek K]

Update: Well, after the second stage was adjusted, the regulator worked fine... for five dives.

This morning it started doing the same thing again -- second stage valve apparently not closing all the way, causing air leakage into the second stage. At the surface, and at depth.

Just took it in again, and the shop will hopefully adjust it again for free. But this is getting old. The tech there says these new Sherwood regs are getting just a bit too complex and tricky as far as adjustment.

So what's going on here? We've been a loyal Sherwood family for decades now, with four divers and multiple generations of Sherwood regulators. This is really affecting my confidence in the product...

 

[Sherwood SCUBA rep.]

Hi,
Hopefully this can get to you on time... Please ask the dive shop you took your regulator in to do nothing but contact us directly. We will issue an RMA and a UPS call tag to bring your regulator back in, so we can look at it closely here at the Tech Department to determine what exactly is going on. It will be on us, no charge...

Sincerely,
Mauricio Moreno
Head Technician Sherwood Team

 

[Marek K]

Hi,
Hopefully this can get to you on time... Please ask the dive shop you took your regulator in to do nothing but contact us directly. We will issue an RMA and a UPS call tag to bring your regulator back in, so we can look at it closely here at the Tech Department to determine what exactly is going on. It will be on us, no charge...

Sincerely,
Mauricio Moreno
Head Technician Sherwood Team

Hi Mauricio--

I just picked the reg up from the shop again (again, we're on a dive trip to Grand Cayman). The tech adjusted it once more; and said that, as far as he could tell, the problem was with the annual service that had just been done. Like I wrote, our local dive shop back home wasn't certified yet with the new Sherwood regs, and had to send it out somewhere out-of-state for the annual service.

The tech here said that the second stage valve seat had been replaced during the annual service, but that the new one was a bit "grubby" (he was British). He also reiterated that the second stage valve needs to be adjusted not only from the high side, but also from the housing side -- which apparently hadn't been done. He added that the valve seat also apparently hadn't been allowed to "set" before final adjustment -- though it seems to me that a "set" problem would have been resolved after re-adjustment.

He said that he thought that techs generally just aren't real familiar yet with the peculiarities of these new regs.

When I get home at the end of this week, I'll ask my LDS to contact you guys. Thanks.

 

[Sherwood SCUBA rep.]

Hi Marek,
No problem, any time. Just let me know if I can be of any assistance.

Mauricio M