Tuning my Proton Reg

[bkotheimer]

Zak,

I have a Proton XL second stage (the one with the alloy ring and the blue dot) that I recently retired as a primary reg and now have as my bungied backup regulator. It's on a V-16 first stage with a HOG reg as the primary.

Anyway, I just had it and the first stage serviced right before I bungied it. It performed fine on its first dive trip as a backup. However, on its second dive trip this past weekend, it freeflowed on me at about 80' in 58 degree water, draining my tank in short order.

Should I have asked the tech to de-tune it if it is going to spend most of its time upside down under my chin? Can this be done? Can I do it myself?

Thanks for your help!

-bk

 

[Greg Barlow]

Zak,

I have a Proton XL second stage (the one with the alloy ring and the blue dot) that I recently retired as a primary reg and now have as my bungied backup regulator. It's on a V-16 first stage with a HOG reg as the primary.

Anyway, I just had it and the first stage serviced right before I bungied it. It performed fine on its first dive trip as a backup. However, on its second dive trip this past weekend, it freeflowed on me at about 80' in 58 degree water, draining my tank in short order.

Should I have asked the tech to de-tune it if it is going to spend most of its time upside down under my chin? Can this be done? Can I do it myself?

Thanks for your help!

-bk

Due to the case geometry of the Proton, the cracking effort should be adjusted between 1.1-1.3" for a back-up. I suggest having the first stage intermediate pressure tested prior to adjusting the cracking effort. I adjust V/MR16 first stages to have an IP between 135-142psi. The drift after initial lock-up should be no more than 2-3psi max.

When a Proton is adjusted to such levels, it will typically begin venting excessive IP at approximately 150-155psi. Therefore, it is important to stabilize and adjust the IP prior to working on the second stage.

You can adjust it yourself, but I suggest having the cracking effort verified.

When the Proton is adjusted to 0.9-1.1" for a primary reg, it will typically exhibit an overall work-of-breathing score of less than 1.2 J/L at the USN testing standard of 198' and 62.5LPM. That type of performance is what earned it the USN Class "A" rating when used with one of Mares balanced diaphragm first stages.

I own and dive with 3 of my own V16 first stages. I am a big fan of that particular design.

Greg Barlow
Former Science Editor for Rodale's Scuba Diving Magazine

 

[bkotheimer]

Wow, maybe I should switch back to the Proton as the primary and the HOG -- which has user-adjustable cracking pressure and a venturi lever -- as the backup. I was always pretty cool with the way the XL breathed.

 

[Zak OHara]

Cheers Greg, couldn't have said it better! Thanks,

Happy Diving,