does anyone use OPV's ( over pressure valves ) on their primary 1st-stages ?

[dannobee]

Here's an incident report on IP creep on ATX-200's.

http://groups.yahoo.com/group/ba_diving/message/23351

And the follow up report:

http://groups.yahoo.com/group/ba_diving/message/23440

And another experiment:

http://groups.yahoo.com/group/ba_diving/message/23493

Bottom line, some inflators will bypass with high IP's, some won't. Take your chances.

After we heard this, I think everyone in our little group who has Apeks regs bought IP gauges if they didn't already own them. An OPV wouldn't be a bad idea, but just backing the 2nd stage from fully detuned seemed to allow them to freeflow and obviating the need for an OPV.


Dan

 

[DA Aquamaster]

A diver should not have to worry about the range of adjustment on a second stage to ensure it still functions as an OPV to vent excess intermediate stage pressure. It's still very much a design flaw and indicates their is not adequate downstream bias.

It really strikes me as a situation where a recall would be in order. The fact it does not happen more seems to be an artifact of the likihood that the majority of the regs in use with the potential to develop IP creep - and the potential to blow a hose or inflator - are being used by recreational divers who breathe off them during the dive and probably do not detune them.

The design really needs a new poppet with greater downstream bias to ensure a freeflow will result at 170-190 psi even when fully detuned - or the amount of spring pressure used to detune the reg needs to be reduced to ensure the reg cannot be excessively detuned.

 

[Thalassamania]

... It's still very much a design ... a recall would be in order.

Yes it is in order.

 

[JessH]

Anyone know if atomics second stages might also be susceptable to this problem? Anyone able to test it out?

~Jess