Screeching first stage

[LeFlaneur]

You all know the drill on removing a regulator from the tank: close the valve and bleed the air with the purge. Usually if you don't bleed it you can't get it loose. This time it didn't resist enough to remind me to bleed the air. So I took it off, put the dust cap on and rinsed the reg.

Upon pulling it out of the rinse tub the first stage let out a high pitched screech that was loud enough to stop everyone in their tracks and make my ear ring. The only thing I can come up with is that air trapped in the first stage had built up enough pressure to push out past the dust cap.

I took the cap off and everything looked dry, but is there anything else to consider? After all, wasn't air moving the wrong way though the first stage and blowing out through the in door? That doesn't seem good.

For his part, the divemaster laughed and said my reg farted and didn't think there was any reason for concern. I just haven't encountered anything like that before.

Any thoughts?

 

[David P]

sometimes if you purge the air quickly, remove the 1st stage, you can hear air still escaping from the HP hose out the first stage. The HP port has a very small orifice that the air goes through slowly and it is a direct path from the tank to the HP hose, so there is no check valve or anything like that.

 

[ClayJar]

sometimes if you purge the air quickly, remove the 1st stage, you can hear air still escaping from the HP hose out the first stage. The HP port has a very small orifice that the air goes through slowly and it is a direct path from the tank to the HP hose, so there is no check valve or anything like that.

That might not be the case for a first stage such as the AquaLung Legend ACD, eh? Might the auto-closure device hold pressure in?

 

[David P]

oh yeah that little thing, yeah that would probably slow down the exit of the HP gas even more. Add the dust cap and pressure will build untill it finds an escape route, then some strange noise, pop, whine, whatever will happen.