I own a Neptune full face face.I was wondering, is there anyone out there can help me with a problem.My mask is fine until I look down and it starts to free flowing.Did I get a bad mask, or is this normal.Seem like it comes out around the bottom of the mask.No matter what I do, I can't seem to get it to work without free flowing if I look down.
free flow
- Thread starter diverwm
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It's inherent in the design of the mask. There's nothing wrong with it. If you swim on your back and look up you'll also notice that it's very stiff.
There is a cracking adjustment on the 2nd stage IIRC that you can use to stop it from freeflowing in the position you swim in most of the time. I've heard that the deeper you go the less dramatic this effect is but I can't confirm from personal experience.
R..
There is a cracking adjustment on the 2nd stage IIRC that you can use to stop it from freeflowing in the position you swim in most of the time. I've heard that the deeper you go the less dramatic this effect is but I can't confirm from personal experience.
R..
It's a case geometry fault issue with the second stage and is normal on most finely tuned high performance second stages.
What happens is that in a face down position (the worst case position) the diaphragm is at it;s maximum distance below the upoper edge of the exhaust valve in the water column and the differences in pressures acting on each is at it's maximum. What happens is that air leaks out the exhaust valve which lowers the pressure in the cace until it is equal to the pressure at the level of the exhaust valve. This causes the diaphragm to be pressed inward with sufficient force to activate the demand lever and start air flowing into the case. This air then leaks out and continues the freeflow cycle.
The solution is to increase the cracking effort by screwing in the adjustment knob. until the force required to initiate air flow is high enough that the diaphragm does not activate the lever. This may result in a higher inhalation effort than you otherwise want in a normal swimming position so you may want to reduce it again when you are no longer looking face down.
What happens is that in a face down position (the worst case position) the diaphragm is at it;s maximum distance below the upoper edge of the exhaust valve in the water column and the differences in pressures acting on each is at it's maximum. What happens is that air leaks out the exhaust valve which lowers the pressure in the cace until it is equal to the pressure at the level of the exhaust valve. This causes the diaphragm to be pressed inward with sufficient force to activate the demand lever and start air flowing into the case. This air then leaks out and continues the freeflow cycle.
The solution is to increase the cracking effort by screwing in the adjustment knob. until the force required to initiate air flow is high enough that the diaphragm does not activate the lever. This may result in a higher inhalation effort than you otherwise want in a normal swimming position so you may want to reduce it again when you are no longer looking face down.
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