Cold water performance of SP D series.

[elan]

I did a few dives on my lovely D400 with a pink label

On the first dive with a cranking effort set at 0.6 it started slowly bubbling in 39f water right from the start.

On the second dive tightening up the cranking effort make it stable in 36F water. No free flows even after a 3 second purge.

The reg was running on an MK20 with IP set at 135psi

 

[DA Aquamaster]

I used to dive Mk 20 D400s as my technical diving reg of choice - and at the time the usual bottom temps below 100 ft were in the 35-39 degree F range. I never had an issue with a D400 in cold water.

As far as inhalation effort, some metal orificed D400s will be stable as low as .5, but .7 is a more realistic number. With a plastic orificed D400 you'll have to go a bit higher.

 

[elan]

Thanks for sharing the experience DA, I tightened it up to .8 for the second dive. I will relax it a bit for the next dive. Mine has a metal oriffice.
My GUE buddies look very suspeciously at the D series "You cannot unscrew the faceplate underwater" which is not exactly true though.

 

[DA Aquamaster]

Yes, it's not very GUE compliant, but that does not bother me a whole lot.

Oddly enough, even with SM diving in some tight, silty, sandy and gravelly areas, I've never managed to fill a G250 second stage with anything that requiring removing the face plate. And, if I had to remove a face plate, I'd be doing it in a low flow cave in an area where I could set the parts down to avoid losing the diaphragm, friction ring or cover. When I hear about divers discussing this as a viable open water option, it's evident that it's just a theoretical discussion - not something that will work in mid water in current while hanging on a deco line.

 

[halocline]

Tell your DIR buddies that you don't need to unscrew the D series faceplate, you just pull it off, or just demonstrate. That should shut them up for at least a minute... And the irony is that you could finish the dive without even replacing the cover.

Or you could say something like "Yes you can't unscrew the faceplate to repair the reg underwater, but this reg looks like a Darth Vader mask and will scare away any annoying space aliens underwater, which is about as useful"

 

[elan]

The irony is also that the problems that require unscrewing the faceplate to clean only happened with highly regarded by DIR community Apeks regs. The purge buttons stuck on me twice. Never happened to the D series. Last summer I purposely was dropping the stages into the silt at the entrance to test , and never had issues so far They also stop joking when I give them the reg to test underwater