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View Full Version : Freeflow from secondary after moving it to new first stage



BubblesMcCoy
02-24-2010, 16:29
I've been using an aeris atmos first stage with an atmos second and a mares secondary and hadn't experienced any free flow issues. However, I recently got a 30cf pony with a zeagle rezort first stage. Accordingly, I moved my secondary from the aeris first stage to the zeagle and have started experiencing minor free flow on my pony set up when I'm at the surface. At depth its fine, but its a bit of pain because I'm now used to clipping my secondary to my bc before I ever get in the water.

Question is this, do I need to have the first stage and second stage on my pony balanced together? Is there any reason why I would experience a free flow on one first stage but not the other. Or is it just coincidence that the free flow started when I attached the secondary to the new first stage?

Tassie Diver
02-24-2010, 16:51
Your old first stage was probably set to a lower intermediate pressure, and the second stage was tuned to match. The new first stage sounds like it has a higher intermediate pressure. You will need to tune the second stage to match the higher IP or it will continue to freeflow.

navyhmc
02-24-2010, 19:30
I agree with Tassie, the IP is higher on the new first stage. Either tume the 2nd stage to the higher IP or adjust the IP on the 1st stage. either way, you'll need to have it set up by a technician. This is not a DIY unles you're trained on that particular gear.

BubblesMcCoy
02-24-2010, 20:53
Thanks for the advice. I'm not a DIYer when it comes to life support gear. Will get the secondary retuned during its annual service next month.

ScubaToys Larry
02-24-2010, 20:58
Keep in mind, whoever you have working on this will have to have all the pieces to tune them together.

I remember a guy who sent us just a second stage and said it was free flowing. Of course, we put it on one of our 1st stages, and it doesn't. You really need all the stuff and the symptoms to try to cure it.

My great analogy is "Every time I'm driving along at 50 miles per hour, if I turn the steering wheel to the left... there a bumping sound. So I gave the steering wheel to the dealer, and they were so stupid, they couldn't figure out what was wrong."

BubblesMcCoy
02-25-2010, 08:46
Keep in mind, whoever you have working on this will have to have all the pieces to tune them together.

I remember a guy who sent us just a second stage and said it was free flowing. Of course, we put it on one of our 1st stages, and it doesn't. You really need all the stuff and the symptoms to try to cure it.

My great analogy is "Every time I'm driving along at 50 miles per hour, if I turn the steering wheel to the left... there a bumping sound. So I gave the steering wheel to the dealer, and they were so stupid, they couldn't figure out what was wrong."

I understand. In terms of tuning the first stage, can the intermediate pressure be increased in my aeris? There's no problem with it, but I really like the way the new zeagle seems to provide more air per breath. Cracking pressure on the aeris is fine, but it just doesn't feel like its producing the same amount of air.

ScubaToys Larry
02-25-2010, 09:08
Yes, you can increase or decrease the IP of any first stage. With pistons, you have to normally do it with shims on the piston (although there are a few that do it different) and with diaphragm regs like most oceanic and aeris, you just turn the big nut with a big ole' allen wrench. We do that hooked up to a flow bench which lets us check the IP at 300 and 3000 and with the magnahelix, adjust the crack pressure of the second as well.

But actually, if you say the crack pressure seems fine, "but it just doesn't feel like its producing the same amount of air", it is virtually impossible to over breathe any 1st stage at the surface - so I think it has to be illusion, or if comparing to a different second stage, they may "feel" different - but neither should starve air in this situation.

naplestreasures
11-20-2010, 17:13
The IP is probably different.....try adjusting the second stage.