OPV plug failed open at 120psi

[guruboy]

Do OPV plugs have a shelf life?

I have one on a spare reg set I use for my car tires. Today it suddenly decided to fail open (leak). It will leak until there is no pressure left.

I thought maybe the 1st stage finally needed to be serviced but the IP is steady at 120psi.

 

[Caveeagle]

Do OPV valves have a shelf life?

I have one on a spare reg set I use for my car tires. Today it suddenly decided to fail open (leak). It will leak until there is no pressure left.

I thought maybe the 1st stage finally needed to be serviced but the IP is steady at 120psi.

Did you plug the LP port and re-check the IP?

 

[guruboy]

Did you plug the LP port and re-check the IP?

Yes

 

[Peter69_56]

I dont see the need for them on a normal reg set. If the IP increases then the secondary regulators will free flow thus acting like an OPV. That being a primary cause of free flowing secondary regulators.

Thus an OPV just becomes another piece of gear that can fail. I like the KISS theory (Keep It Simple Stupid). Less toys hanging off gear the less to fail.

 

[w3dge]

I dont see the need for them on a normal reg set. If the IP increases then the secondary regulators will free flow thus acting like an OPV. That being a primary cause of free flowing secondary regulators.

Thus an OPV just becomes another piece of gear that can fail. I like the KISS theory (Keep It Simple Stupid). Less toys hanging off gear the less to fail.

Presumably if the OP is using the reg in question to fill car tyres, there's no 2nd stage on there

 

[Caveeagle]

I dont see the need for them on a normal reg set. If the IP increases then the secondary regulators will free flow thus acting like an OPV. That being a primary cause of free flowing secondary regulators.

Thus an OPV just becomes another piece of gear that can fail. I like the KISS theory (Keep It Simple Stupid). Less toys hanging off gear the less to fail.

Well, who knows what "normal" is? I think you mean: typical downstream second stage..

Where people can get into trouble is combining 2nd stage with upstream valve onto a first stage with no OPV. Most common example would be a Poseidon jetstream or xstream, which was solved in early versions with an opv integrated into the LP hose end. Later versions have an opv built into the 1st stage. If you start swapping parts or hoses around and you could Create a dangerous combination.

An opv on a dry suit inflator reg would be a requirement, because a free flow could cause uncontrolled suit inflation. I am sure there are other applications or this...

 

[rhwestfall]

I wondered about the life of them... I actually found ones that are rebuildable, and adjustable. Haven't implemented it yet. I guess, as cheap as they are, I'd carry a spare in a "save a dive kit" if I depend on them (which I do as I have Poseidon Mk-2 firsts and Xstream seconds with non-OEM hoses). I also run a suit bottle occasionally.

 

[Caveeagle]

I wondered about the life of them... I actually found ones that are rebuildable, and adjustable. Haven't implemented it yet. I guess, as cheap as they are, I'd carry a spare in a "save a dive kit" if I depend on them (which I do as I have Poseidon Mk-2 firsts and Xstream seconds with non-OEM hoses). I also run a suit bottle occasionally.

I like the idea of the opv being serviceable and adjustable. Fortunately, I have only experienced one time where the OPV on my Jetstream (hose-end) was venting due to a HP seat failure. It was an intermittent, loud "psst" and not the prolonged venting I have heard from others. It would be nice to know exactly what the burst pressure was for both the hose-end, and the 1st stage integral versions. ..as well as the add-on versions.

 

[Peter69_56]

Well, who knows what "normal" is? I think you mean: typical downstream second stage..

Where people can get into trouble is combining 2nd stage with upstream valve onto a first stage with no OPV. Most common example would be a Poseidon jetstream or xstream, which was solved in early versions with an opv integrated into the LP hose end. Later versions have an opv built into the 1st stage. If you start swapping parts or hoses around and you could Create a dangerous combination.

An opv on a dry suit inflator reg would be a requirement, because a free flow could cause uncontrolled suit inflation. I am sure there are other applications or this...

Yes I agree a Poseidon/xstream can cause problems, and yes normal implys downstream, I should have said that, however the majority of secondary regs are downstream (I believe), but I take your point.

Everyone is taught or should be taught on how to deal with an uncontrolled dry suit inflation, you disconnect the inflator hose then dump gas from the suit, I know I had to demonstrate, so I don't really see that as an issue unless the drysuit is the only device off the primary reg (as I dont know how a dry suit inflator valve reacts to overpressurising, does it bleed like a down stream reg on overpressurised situation, or simply contain the pressure until something blows?).

 

[tbone1004]

Poseidon hoses are designed to open around 18bar/260psi for the new ones, and 17bar/250psi for the older ones.

3790 first stages have a release pressure or 15-17bar, so 210-250psi and are designed to go before the hoses.

I don't have the mk3 manual so don't know what they release at, but I imagine they would be similar 15-17bar release pressure