Help With Interchanging These Two Name Brands

[realdiver7]

I have seen several posts regarding mixing one manufacturer's 1st stage with another manufacturer's 2nd stage, but I have not found the answer to my exact question, so I need some good advice. Is it OK, safe and reliable to use the following:

Zeagle Flathead VI 1st stage
with
Scubapro D400 or Scubapro S600 2nd stages :06:

I am naturally concerned about issues concerning intermediate pressure, high air flow, extreme reliability, ease of breathing under heavy workload, etc. I dive mainly in the ocean at water temps of 50-80 degrees, at depths of 25-120 ft.

No offense to Scubapro, or the vast number of Scubapro fans (I am one of them), but please don't recommend the MK16 because I have heard of too many real-world issues regarding air leaks and high maintainence. I have narrowed my choice down to the FH VI because I like the design and test results.

If anyone has a spare FH VI they want to sell without the 2nd stage, please email me.

Any help on this issue of mix-matching would be greatly appreciated.

Thanks!

 

[DA Aquamaster]

Mixing first stages is generally not a problem as virtually everyone uses the same IP range of 120 to 145 psi anyway. The average second stage is not smart enough to know what first stage lives on the other end of the hose - it just cares about intermediate pressure.

It is important to tune the second stage to the specific first stage in order to get maximum performance and relaibility, but that is not a technical problem. It can however occassionally be a practical problem though as some techs get funny about mixing brands. Probably from either a liability standpoint or from a "we don't sell that here" standpoint.

SP will sell all their first and second stages separately - the dealer just needs to order them. I would be surprised if Zeagle did not also make them available separately.

 

[ranger]

There may be another option to explore....if you are the type that wants to maintain their own regs. Check Dive Rite, as their first stage is basically the same as the Zeagle Flathead. They are all really a clone of the Apeks, don't really know who came up with the design first, but its a good design. Check www.DiveRiteExpress as they sell the first stages seperately, and sell the first stage rebuild kits as well as the second stage kits online. The also have the manual which completely walks you through the complete rebuild process. The manual is free, just download. Its just a thought...check it out. Their people are very knowledgeable also, ready willing and able to help, and have free shipping. I have purchased from them, and you would be hard pressed to beat their service. Give them a call and discuss the possibilities...a toll free number....what do you have to loose?

 

[Chad Carney]

realdiver7,

There are some 1st stage regulators that are not compatible, some have upstream valves and such. Some regulators use 1/2" ports that would require adapters to attach to 3/8" hoses.

But Zeagle and Scubapro are quite compatible. Zeagle does sell their 1st stages separately, but a dealer can probably give you a better price on a complete regulator. Do you need an octo?

There is quite a difference between a D400 and an S600 2nd stage. The S600 is more traditional, with exaust valves separate from the diaphragm, venturi and seat tension controls. It's more like the Zeagle ZX or XP second stages. It out performs the D400 on breathing machines, although that's probably not really an issue. I've never been much of a Pilot, Air-1 or D400 fan. They can be trickier to work on and assemble properly.

Chad Carney
FL Zeagle Rep.

 

[rescuediver009]

You are fine mixing the two. The thing that you have to be concerned about is IP. And to elaborate on what DA said, that is the only thing that really matters. Now if it changes then you are really done. The zeagle first stages are overbalanced, so the ideal situation is that your second stage is balanced to compensate. You are ok with the S600, although I am not sure about the D400. But this will eliminate any unwanted freeflowes at depth. Go ahead and mix and match.

 

[DA Aquamaster]

The zeagle first stages are overbalanced, so the ideal situation is that your second stage is balanced to compensate. You are ok with the S600, although I am not sure about the D400. But this will eliminate any unwanted freeflowes at depth. Go ahead and mix and match.

The D400 uses a center balanced valve design and like all downstream balanced reg designs is slightly biased toward the downstream side to ensure the second stage will vent any excess pressure in the event of a first stage seat failure or freeze up.

I've never been much of a Pilot, Air-1 or D400 fan. They can be trickier to work on and assemble properly.

The Pilot was quite difficult to work on and used a different valve design entirely (a pilot valve) than the center balanced valve design used on the Air 1 and D300/350/400. The Air 1 had an odd dual purpose diaphragm exhaust valve that could be fun to work with but the D400 is pretty straight forward as long as you assemble and adjust things in the correct sequence.

 

[rescuediver009]

The D400 uses a center balanced valve design and like all downstream balanced reg designs is slightly biased toward the downstream side to ensure the second stage will vent any excess pressure in the event of a first stage seat failure or freeze up.

There we go then, it won't be a problem to mix in both Scubapro seconds with the Zeagle first stage.