Scubapro chrome plated brass regulators...

[Open Ocean Diver]

Usually we call this behaviour "pendolation", and of course it means something is wrong.

I think you hit it on the head... blockage. Interesting to be able to measure it.

 

[rsingler]

Sounds like a leak downstream of the first stage. Submerge the whole rig in the bathtub while you told your tank upside down, and see what you see.

 

[Open Ocean Diver]

Sounds like a leak downstream of the first stage. Submerge the whole rig in the bathtub while you told your tank upside down, and see what you see.

If I shut the tank off and it holds pressure for hours doesn’t that prove theres no leaks?

 

[rsingler]

If I shut the tank off and it holds pressure for hours doesn’t that prove theres no leaks?

Yes

 

[Couv]

I think it's because @Overweighted brought an Atomic regulator into a SP thread. :-D

 

[rsingler]

Wait. You did say you had your little micro vacuum set to suck at some small little amount, correct? If so, then you must be pulling from the first stage in some tiny way. I would guess that your situation is due to intermittently developing enough vacuum to crack the valve and drop the IP. Then the IP recovers and it starts again.

 

[Open Ocean Diver]

I think it's because @Overweighted brought an Atomic regulator into a SP thread. :-D

Crap sorry. Yikes

 

[Open Ocean Diver]

Yes

So were tight.

Wait. You did say you had your little micro vacuum set to suck at some small little amount, correct? If so, then you must be pulling from the first stage in some tiny way. I would guess that your situation is due to intermittently developing enough vacuum to crack the valve and drop the IP. Then the IP recovers and it starts again.

Yes my small vacuum pump. However there’s nothing intermittent about it, it’s continuous suck very precise. On my other first stages including the MK10 once it cracks the IP dips then recovers after which it stays steady at the effort it was adjusted to. Even at 6 SCFH which is enough for me to hear the rushing air through the open demand valve. On this reg it keeps oscillating from dip to recover to dip to recover to dip to recover and on and on. What I’m thinking is this small micro vacuum pump setup is enabling me to see something inside the first stage that under conventional methods we wouldn’t normally detected. I was think before I take it apart to flow test it to see if I can detect a problem.

What do you think? I’m I way off.

 

[BoundForElsewhere]

I just took apart and put back together my first 109. Looking forward to getting a pony tank to play with pressure.

 

[Open Ocean Diver]

Wait. You did say you had your little micro vacuum set to suck at some small little amount, correct? If so, then you must be pulling from the first stage in some tiny way. I would guess that your situation is due to intermittently developing enough vacuum to crack the valve and drop the IP. Then the IP recovers and it starts again.

Yes... I double the SCFM 6 and it wasn’t as erratic. Below is the Atomic at 3 SCFM, the MK10 would be stable this low.
https://share.icloud.com/photos/0F5bO9lhXbQxWvNtN_BsopviA#Downtown_Toronto