Question SP G250V so were now ready to do the final testing.

[Open Ocean Diver]

From the G250V step-by-step maintenance procedures…

At this point, it’s now time to verify, that we are able to generate a venturi assist.
- Remove the inline adjusting tool and attach the LP hose directly...
- Now simply position the DIVE / PREDIVE control in the PREDIVE position and purge the second stage.
- The flow of air should stop crisply, each time the purge is released...
- Now move the control to the DIVE position, depress the purge and a venturi initiated vacuum assist will sustain a free flow...commonly known as VIVA.
- To stop the flow of air, simply block the mouthpiece opening with your finger...

I have two V’s and can’t seem to pass this test. (VIVA free flow)

Any insight from the experts would be much appreciated.

Thanks,

 

[happy-diver]

Good, why would you wish to initiate freeflow under any circumstance

 

[Open Ocean Diver]

Good, why would you wish to initiate freeflow under any circumstance

It’s done without the mouthpiece, to test the VIVA according to the SP maintenance manual. Works on G260’s

 

[Geo7]

What direction is the cutout in the VIVA vane facing? We puzzled over this in this thread...

 

[Open Ocean Diver]

What direction is the cutout in the VIVA vane facing? We puzzled over this in this thread...

I switched it to facing inward, lever kissing the diaphragm cracking .9

 

[Open Ocean Diver]

What direction is the cutout in the VIVA vane facing? We puzzled over this in this thread...

Thanks I was part of that, memory loss. Lol

 

[Geo7]

So cutout facing diaphragm for maximum VIVA. To be honest I have to re-read that thread myself to refresh my memory on what made the difference in the end...

 

[Open Ocean Diver]

So cutout facing diaphragm for maximum VIVA. To be honest I have to re-read that thread myself to refresh my memory on what made the difference in the end...

On a flow bench with the cutout face diaphragm it does make difference. I just read the whole thread and there was no real conclusion other than if it doesn’t instantaneously FreeFlo when you press the purge button not to worry it should still be fine on a dive as long as you have a strong purge. The other thing was Simon found that if he played with his adjustment knob at the end stop turning it clockwise a bit he could get his to free flow.

I just powered up my 250 V and hit the purge and it free flowed like a banshee. Check the cracking effort and I went from .9 To .6-7 Seat must’ve taken a set. I forgot and I left the tank on all night long. Although I did turn the adjustment screw to where it was cracking at about 1” and it’s still free flowed. Go figure

 

[Geo7]

Interesting! This simple regs are magic when all the part fit. I think my conclusion was that some adjusters might not have perfect tolerances and perhaps not be perfectly level and thus vary in pressure as they are turned? This sounds a lot like tuning my D400 where I don't know how in the end it accepted the super-low cracking effort setting.