Balanced vs unbalanced 2nd's

[captain]

As for second stage seats taking a set during storage I store them with the purge button depressed to prevent it. The Scubapro 109 second came with a key that was inserted into the purge cover to keep the purge button depressed. On my other non Scubapro regulators I made devices to keep the purge depressed during storage.

 

[Luis H]

Scubapro had a key and before that they had a paddle that you stuck under the metal cover to press on the rubber diaphragm cover. I think the key worked well and does not put too much stress on the diaphragm cover, but the paddle will permanently deform the diaphragm cover if used for long term storage.

The way I figured is that seats are readily available and can be easily replaced, diaphragm covers are becoming harder to find at times and there may be the day (if it hasn’t happened yet) were Scubapro will not produce them again. The subject about reproducing them has come up… and we know who has the contacts to do it.

For long term storage I would try to avoid putting any stress or deformation on the diaphragm cover.


I have one of those keys (and a couple of the earlier paddles), but I don’t use them. For the most part I just converted most of our 109s to 156s. I just personally like the design.

 

[The Chairman]

The balanced second stage seems to really shine when the diver inverts. I spend a lot of time looking at fossils in ceilings and miss a balanced second.

 

[redacted]

oops - sorry

 

[redacted]

The balanced second stage seems to really shine when the diver inverts. I spend a lot of time looking at fossils in coelings and miss a balanced second.

Other than that a balanced 2nd may be able to be tune a little closer to the edge, I can see what effect position would have as a function of balanced vs. unbalanced, other variables (like case geometry) being equal.

 

[Packhorse]

I'm sorry. I meant 190 nor 109. I can't tell you how many times I have screwed that up. Yes, the 109 uses a clearly heavier spring. I corrected my post also. Thanks

Ok now you have me even more confused. The 190 doesnt have a air barrel like the G250 does it? And if not it will certainly not have the same spring??


Anyone have a pic of these keys and paddles for the 109 regs? I managed to score a couple of unused diaphragm covers and face plates for 109s a few months back.

 

[halocline]

Ok now you have me even more confused. The 190 doesnt have a air barrel like the G250 does it? And if not it will certainly not have the same spring??


Anyone have a pic of these keys and paddles for the 109 regs? I managed to score a couple of unused diaphragm covers and face plates for 109s a few months back.

You are correct that the G250 is a barrel poppet reg and the R190 is not. They use the same spring, but that's basically a coincidence; the G250 uses it in the barrel just like you'd think, the R190 uses the same part for the highly compressed spring inside the housing for the poppet/lever connection. I'm sure SP was saving a little money by having the same spring for both regs.

 

[Packhorse]

Ah, never taken the 190 valve apart before. Very interesting info if I ever get stuck for G250 spring.As you say it must be highly compressed.
I like the way they use the same parts in different regs.

 

[redacted]

One nice thing about scubapro is they don't have a lot of unnecessary parts. So all the balanced barrel poppets and all the R-series (including the Air2 and grand daddy 108) use the same spring, 01-020-216. They just crank it down more with the R-series.

Pics are the paddle and the key are in my photo gallery. The key is inserted into the "S" and turned about 1/8th turn, pictured installed in a 108.

I'm having problems loading the pic. I'll try again tomorrow.

 

[hg frogman]

The covers of Scubapro R190 and G250 have a special purge button than can remain depressed during long term storage. It prevents engraving the seat of the second stage.

This can be done also (for long term storage) with any second stage by slightly unscrewing the part connecting the poppet and the seat (while keeping the purge button depressed, to not damage the seat). Don't forget to screw it again before using the reg, though, and also check that the second is still properly tuned. (Disclaimer : all these operations should be done only by a competent technician)

If even done, this (and storage) should be done in a dry, really clean place. There seems to have been somes cases of bacterias etc ... growing in the hoses when the second stage remains open this way, and you don't want to breathe that !

Your choice then. Take care.