2nd stage free flow control device

[Web Monkey]

I must disagree here. Unless your not using an Environmentally sealed 1st or your getting crappy fills 1st stage free flows are extremely rare. In order to freeze up and free flow you need ice, to get ice you need water. If water can't enter the sensing element of the 1st stage it can't freeze. That is why they are now sealing most regs.

"Most" regs aren't sealed.

Terry

 

[fppf]

Just about every manufacture now uses a sealed design, or has the option to seal most of there middle and high end regulators.

 

[Web Monkey]

Just about every manufacture now uses a sealed design, or has the option to seal most of there middle and high end regulators.

Atomic has one regulator that comes sealed (the M1). The rest of their regs can be ordered sealed and seal kits are available for installation later, but this isn' t apparently done very frequently, since few come in for service with the kit installed.

SCUBAPro, AFAIK, has no sealed regs available.

According to their website, two out of Oceanic's six first stages are sealed and rated for cold water.

In any case, I'm assuming the OP doesn't have a sealed, cold water reg, since if he did, the freeflow question probably wouldn't have come up.

Terry

 

[elan]

Atomic has one regulator that comes sealed (the M1). The rest of their regs can be ordered sealed and seal kits are available for installation later, but this isn' t apparently done very frequently, since few come in for service with the kit installed.

SCUBAPro, AFAIK, has no sealed regs available.

According to their website, two out of Oceanic's six first stages are sealed and rated for cold water.

In any case, I'm assuming the OP doesn't have a sealed, cold water reg, since if he did, the freeflow question probably wouldn't have come up.

Terry

SP has MK17 which is sealed.

Sealed regs do free flow, I see it quite often, mostly due to improper handling. Last weekend when we dove I saw a couple terminating a dive due to both regs flowing, as I was observing them it was simply due to improper handling.

 

[fppf]

Even still, most free flows occur in the second stage, not the first.

Oceanic's current line up of first stages include the FDX-10, CDX-5, SP-5, and PX3. The first 2 are diaphragm regs the second 2 are piston. The FDX-10 comes sealed, the CDX-5 has the option to seal, the pistons don't. Our LDS orders all regs from the mfgrs sealed for our area.

 

[Crush]

Cold water freeflows are usually caused by ice forming inside the first stage due to adiabadic cooling.

Adiabatic cooling occurs in both firs and second stages. Ice formation requires water. The second stage is far more likely to have moisture in it, unless you are using questionable air. So while the pressure drop across the first stage is larger, it is more lacking of moist conditions required for ice formation.

 

[elan]

Adiabatic cooling occurs in both firs and second stages. Ice formation requires water. The second stage is far more likely to have moisture in it, unless you are using questionable air. So while the pressure drop across the first stage is larger, it is more lacking of moist conditions required for ice formation.

It is very easy to get moisture in the 1st stage even if it's sealed. Easier than most people think. Just not blowing the valves when they can be wet, putting the reg on the tank when condensation can occur, etc.

 

[Crush]

It is very easy to get moisture in the 1st stage even if it's sealed. Easier than most people think. Just not blowing the valves when they can be wet, putting the reg on the tank when condensation can occur, etc.

If you are saying that a first stage can get wet, I agree with you. If you are saying that a first and second stage are likely to be equally wet, I can't agree with you.

 

[Jimmer]

Even still, most free flows occur in the second stage, not the first.

Oceanic's current line up of first stages include the FDX-10, CDX-5, SP-5, and PX3. The first 2 are diaphragm regs the second 2 are piston. The FDX-10 comes sealed, the CDX-5 has the option to seal, the pistons don't. Our LDS orders all regs from the mfgrs sealed for our area.

Up here, all the CDX-5's come sealed out of the box, and for the canadian market, SP5's and PX3's are almost unheard of. They send CDX5's in their place, which as far as I'm concerned is a great decision for us northern divers.

 

[jmorgan007]

An isolator valve is for use with doubles...

He's referencing the sliding screw inline isolators valves you can put between your LP hose and 2nd stage inlet. Not the isolator on a twin tank behind the divers head.