First Stage Environmental Sealing

[Scared Silly]

The only regs I have sealed are my Ti and O2 regs. No need to seal any others as it is a PITA and $$

As for using the regs as deco regs and turning the off. I do not.

 

[SaltyWombat]

For a deco regulator, am I wasting $$ sealing the first stage given the higher probability of first stage internal contamination?

Do you environmentally seal this reg because you dive in very cold water? Or dirty water?

If you only dive in the Pacific in California, many would say environmentally sealing is not necessary. Mountain lake dives could be much colder, of course.

 

[stuartv]

I use an inline shutoff (and an OPV) on deco regs.

Without an inline shutoff, you charge the reg and turn the cylinder off. Then, during the dive, when something hits the purge on the 2nd stage, the line depressurizes and then water can enter the 2nd stage (freely, on an Atomic) and the 1st stage can become loosened a bit on the tank valve.

When you turn the gas on, if the 1st stage has gotten loose at all, you can have it blow out its O-ring and freeflow at the valve. I've seen it happen on students' deco regs.

With an inline shutoff (and OPV), you have the cylinder turned on during the whole dive. The inline shutoff is in the Off position until you are ready to start breathing from the reg. This ensures that the 1st stage can never get loose on the valve, no water can get into anything except the 2nd stage itself, and you won't accidentally lose a bunch of your deco gas by accidentally pressing the 2nd stage purge (i.e. one of the reasons you don't have deco gases turned on during the bottom portion of your dive, if you don't have an inline shutoff).

 

[BoltSnap]

and OPV

This a separate part from the online shutoff gizmo and is connected directly to a LP port on the first stage?

 

[rsingler]

With an inline shutoff (and OPV), you have the cylinder turned on during the whole dive.

I like it. But you have a different setup for a stage bottle that you leave in a corridor of the wreck, right?

 

[stuartv]

This a separate part from the online shutoff gizmo and is connected directly to a LP port on the first stage?

Yes. Without an inline shutoff, if you have IP creep from the first stage, it will eventually exceed the cracking pressure of the 2nd stage and release the excess pressure from the line via the 2nd stage. In that case, you do not need an OPV on the 1st stage.

With an inline shutoff in the Off position, there is no outlet for excess pressure from IP creep. So, eventually, the pressure in the LP hose can get so high that the hose ruptures. If your 1st stage is in good condition, you won't have IP creep and the OPV will not do anything for you. But, you cannot just assume your 1st stage won't start to have some IP creep at some point.

If you use an inline shutoff, you MUST have an OPV on the 1st stage.

 

[BoltSnap]

Yes. Without an inline shutoff, if you have IP creep from the first stage, it will eventually exceed the cracking pressure of the 2nd stage and release the excess pressure from the line via the 2nd stage. In that case, you do not need an OPV on the 1st stage.

With an inline shutoff in the Off position, there is no outlet for excess pressure from IP creep. So, eventually, the pressure in the LP hose can get so high that the hose ruptures. If your 1st stage is in good condition, you won't have IP creep and the OPV will not do anything for you. But, you cannot just assume your 1st stage won't start to have some IP creep at some point.

If you use an inline shutoff, you MUST have an OPV on the 1st stage.

I know that xsscuba has two models of the inline shutoff gizmo, but who sells the OPV?

 

[stuartv]

I like it. But you have a different setup for a stage bottle that you leave in a corridor of the wreck, right?

I have never done that, specifically. But, I have clipped off a stage bottle and left it in a cave, which I think is the moral equivalent.

On a stage cave bottle, I have not used inline shutoffs. That scenario does not have the same concerns as exist for a deco cylinder.

And in that case, I would turn the valve off before leaving it - whether it has an inline shutoff on it or not.

 

[stuartv]

I know that xsscuba has two models of the inline shutoff gizmo, but who sells the OPV?

2 options on this page:

Accessories for Regulators

Accessories For All Regulators: DIN-to-Yoke Adapters, Threaded DIN Caps, Over-Pressure Relief Valve, Octo Holder, Hose Clip Retainer, Necklace

www.divegearexpress.com

The cheap ones are okay. Just know that it will start to leak eventually and you'll just need to replace it when it does.

I use one of the cheap ones on my drysuit inflator reg (because those should also always have an OPV, if it's a dedicated inflator reg).

I use the expensive ones on my CCR bail out regs.

 

[BoltSnap]

2 options on this page

Thank you! I see that xsscuba makes one too.