A700 second stage on a MR22 first?

[reefrat]

I am about to install a Scubapro A700 second stage on a Mares MR22T first and have one question for those familiar with tuning scubapro regs.

Without getting into any discussion of brand loyalty, warranties, parts for life, servicing issues etc etc etc!

I know that Mares IP is factory set a little higher than Scubapro's (142 to 148 psi for the Mares and I think 135 to 140 PSI for the scubapro)
Are there any genuine issues to be concerned about with running the A700 at this higher IP?

Cheers
RR

 

[redacted]

That small IP difference will be no problem, especially with a balanced and adjustable 2nd.

 

[reefrat]

That was my impression- thanks!
I think they should be a good match, I have installed the Mares Superflex (Miflex type) MR22 hose on the first already. This is much better than using a standard 1/2" to 3/8" adapter on an MR22 because the there is a chamber inside the male fitting that matches the original 1/2" hose and this allows the DFC tube to function properly.
The MR22T is one of my favorite first stages- a bit clunky but solid, reliable and high performance with minimal IP drop on the inhalation cycle (apparently!), this coupled with the A700 should work very nicely.

 

[blueseal]

Intriguing setup you have, MR22T/A700. Anyway, I have A700 too but yours would be unique. After few dives with MR22T/A700 please let us know the performance or verdict.


seal

 

[DA Aquamaster]

The max IP for SP is 145 psi and unless it's an extreme cold water freeseflow prone MK 25, it makes sense to set it right up at that level.

With the unbalanced Mk 2, the IP drops as the tank pressure goes from 3000 psi to 300 psi and it's important to have the IP in the 140-145 psi range at a full tank pressure to maximize the performance at low pressures and to ensure the IP does not dip too low at low tank pressures.

Which is to say in most cases, mares and scubapro regs, and in particular the SP balanced diaphragm regs should be running at the same basic IP.

Functionally speaking a balanced second stage tuned to an IP of 145 psi won't begin to freeflow until the IP rises to 165 psi or higher, and most SP balanced regs will function at an IP as high as 190 psi as most have enough range of adjustment to accomodate that range if required in odd and non standard circumstances.

 

[reefrat]

DA- I have read a number of your posts and as usual am impressed by the depth of detail and background knowledge!! Thanks for that!

I almost wish I could just have one reg and be happy with it.
But somehow they have fascinated me since I was an 8 year old snorkeler wanting to know what was further down there and watching Cousteau on the the TV every chance I got (we are talking the late sixties here!).
There are lot's of them I still want to own and try for no good reason- I think feel a Poseidon Cyclon or Jetstream coming on next!

 

[Shftrdog]

No I would set it at 138. You will be fine

 

[DA Aquamaster]

DA- I have read a number of your posts and as usual am impressed by the depth of detail and background knowledge!! Thanks for that!

I almost wish I could just have one reg and be happy with it.
But somehow they have fascinated me since I was an 8 year old snorkeler wanting to know what was further down there and watching Cousteau on the the TV every chance I got (we are talking the late sixties here!).
There are lot's of them I still want to own and try for no good reason- I think feel a Poseidon Cyclon or Jetstream coming on next!

I collect guns and regs for the same reason - there is a chinese puzzle/engineering aspect to it that I find fascinating.