Question on G250V adjustment knob ?

[idive2]

Is the adjustment knob the same as the adjustment done internally to tune
the regulator. My adjustment knob is almost all the way out and then back in
a bit. My air flow with diaphragm down in water starts just under the clamp
for the mouthpiece. I'm trying to find a reason this knob is even there and thought if
it was in fact tuning the reg then a free flow just before completely open and then turning
back in to tune would be useful.

 

[Fishpie]

No...it increases the spring pressure and makes the lever harder to depress making the reg less sensitive.

 

[redacted]

But it is another way of adjusting cracking pressure. If you don't mind fiddling with the adjustment knob while diving, you can get maximum performance by setting the orifice adjustment with the user adjustable knob turned in about 1/2 turn and then adjusting the orifice. This should result in a slight freeflow with the user adjustment knob all the way out and maximum performance with 1/2 turn.

 

[idive2]

Thanks for the comments. I checked the parts illustration and trying to get an idea about how these
balanced second stages work. May wait a bit before I tinker with this reg any further. I see a special
tool listed that hooks between second stage and incoming low pressure supply line. Does this tool allow
the adjustment of orifice without removing and reinstalling hose after each change in setting ? I am more
familiar with an older second stage where the point where the air enters stays in one place and the adjustment
is only made with the nut attached to the poppet valve. Thanks again for the comments.

 

[redacted]

The special tool is unnecessary unless you are in a hurry (like in a shop). Sure, you have to turn off the pressure and unscrew the hose each time but that is back to the in a hurry thing. I like to adjust the orifice and get it right on the edge of leaking. Then control it with the user adjustment.

 

[dumpsterDiver]

I try to remember to unscrew the knob when storing. I figure it puts less pressure on the seat and my seats seem to last a long time.

 

[elan]

I try to remember to unscrew the knob when storing. I figure it puts less pressure on the seat and my seats seem to last a long time.

If yours is G250V pressing the purge slightly and turning it counterclock wise will lock the purge in that position depressing the lever and releasing the pressure of the seat. No need to unscrew the knob.

 

[elan]

AFAIK there is no need to tune the reg except adjusting the lever height with the orifice. The springs on G250ies are manufactured to high tolerances and set to 1". So you just need to adjust the height and you should be set.

 

[mainedvr]

I was just about to post a question concerning this very topic. I have an A700 and a DR forget what model but its my back up.

I try to remember to unscrew the knob when storing. I figure it puts less pressure on the seat and my seats seem to last a long time.

 

[idive2]

Thanks for all the comments. Just trying to get an idea of what may be adjustable. They show a smaller
screw behind the other end of the barrel to adjust balance chamber or something like that. The reg is
breathing well and not far off but I do run the user adjustable knob all the way out then back in
less than one turn. Did not know if I was suppose to be able to adjust the knob out far enough to
create a free flow or not. Sounds like maybe adjusting orifice to this point and then back a bit may be
the way to confirm the adjustment.