Strange IP behavior on a freshly serviced regulator - what's going on?

[rhwestfall]

Brand? (I know this sounds silly to ask, but having just recently completed a class for two brands, there was a very unique procedure required in one of them or you would have some issues)

 

[Scuba-74]

It could be internal sticking or the HP seat not being broken in.

However, if you're not holding in your purge as you pressurize your tank, you're doing it poorly. No, not wrong, but you're slamming that knife edge into the seal at 3,000 psi. Holding the purge softens this initial blow considerably. Try that and tell us what the initial IP sits at when you do. I bet it will be normal.

Do you mean always hold the purge when opening the valve? Or just with freshly serviced reg? I never seen anyone hold the purge when they open valve before diving!

The shop took the reg back to check, so can't try that. It would most likely set to 135 (as this is what happens after the purge), but I thought the behavior was very unusual.

 

[Scuba-74]

What happens if you slowly crack open the tank?

Same - goes to 170. Pressure in the tank around 3500 if that matters.

 

[Scuba-74]

Brand? (I know this sounds silly to ask, but having just recently completed a class for two brands, there was a very unique procedure required in one of them or you would have some issues)

Its an older AL Legend.

 

[rhwestfall]

Its an older AL Legend.

Okay, not that one...

 

[The Chairman]

Do you mean always hold the purge when opening the valve?

Every single time. There was a time when we would hear a seat crack and the resultant hiss from time to time. The plastics have gotten better, but I still pamper my reg and hold the purge when I open the tank. I teach this to my OW students. Far, far more important than pointing the SPG away from you.

Again... in just a few milliseconds, you're going from 0 to 3,500 psi on a valve that's less than a 1/4" onto a plastic seat. Give it a break, or don't give it a reason to break, and keep that purge depressed. Your regs will will last a lot longer.

 

[Scuba-74]

I teach this to my OW students. Far, far more important than pointing the SPG away from you.

...which is exactly what my instructor taught me! I was gonna say it would be hard to do both at the same time. Another instructor that did a refresher for me once, reminded me to take a few breaths after getting an initial SPG reading, to make sure it's not just a residual pressure in the reg. That would also be moot if I held the purge when opening the valve.

I'll give it a thought though. It does make sense.

 

[The Chairman]

Another instructor that did a refresher for me once, reminded me to take a few breaths after getting an initial SPG reading, to make sure it's not just a residual pressure in the reg.

Watch the SPG while you're breathing on it. If the needle swings much at all, your tank is not fully open. I used to do this while seated, but I've had DMs turn off my air on the way to the back, so now I do it again on the dive platform.

 

[Kharon]

However, if you're not holding in your purge as you pressurize your tank, you're doing it poorly. No, not wrong, but you're slamming that knife edge into the seal at 3,000 psi. Holding the purge softens this initial blow considerably. Try that and tell us what the initial IP sits at when you do. I bet it will be normal.

That answers a question I've had about my Hollis 500SE. Whenever I presurize the reg it always does a little bit of free flow that quickly stops. Just a littl Pfft and stops. I wonder if that is by design or accident.

 

[The Chairman]

I wonder if that is by design or accident.

Limits. Everything has it's limit. I bet if you put an IP gauge on that, you'll see a higher IP when you first pressurize it.