Zung
Contributor
Just come across another case that started kinda like the one I reported here.
I was checking my #2 son's MK20/G250C, and here's what it does:
Open the cover: nothing unusual inside, the diaphragm seems to be OK, if slightly dirty. Turn on the air, no hiss. I rub the diaphragm inside and outside with my finger, put it back... AND THE HISSING IS GONE! The reg nows cracks at 18mm/.7in. of water.
So: when you test your second stage dry, the diaphragm may get stuck a little and causes a slight freeflow. A little cleaning is all it takes to fix that. And I'm convinced the problem will go away in the water.
Btw, here's a simplified version of brother couv's commandments that I use:
I was checking my #2 son's MK20/G250C, and here's what it does:
- Air on, all is quiet, IP: 131, slow creep to 133
- Purge
- The G250 starts hissing
- Tighten the adjustment knob half a turn, still hissing
- Air off, repeat from #1
Open the cover: nothing unusual inside, the diaphragm seems to be OK, if slightly dirty. Turn on the air, no hiss. I rub the diaphragm inside and outside with my finger, put it back... AND THE HISSING IS GONE! The reg nows cracks at 18mm/.7in. of water.
So: when you test your second stage dry, the diaphragm may get stuck a little and causes a slight freeflow. A little cleaning is all it takes to fix that. And I'm convinced the problem will go away in the water.
Btw, here's a simplified version of brother couv's commandments that I use:
- Air on
- Read SPG
- Read IP
- Read cracking pressure
- Leave it alone for 5 minutes
- Read IP again for creep
- Air off
- Leave it alone for 5 minutes
- Read IP and SPG again for leak
- Done