Oops, Bernt, you're right. I forgot that the spill muffler is in the
back on most upright Duo-Arts. So instead of using the Post-It trick
to check the spill valve position, you'll have to just do it the linear
For example, on the _accompaniment_ side "0" int. = 5" stack pressure.
Then depending a little on the overall system, your #10 int. = 17.5"
(these are rough, and taken from a particular D/A chart I dug up.
They're all a little different. The main thing is that they should
chart a straight line.
#1 = 5" H2O #6 = 12.5 #11 = 19
#2 = 7.5 #7 = 13.8 #12 = 20.2
#3 = 8.8 #8 = 15 #15 = 24
#4 = 10 #9 = 16.3
#5 = 11.3 #10 = 17.6
Sorry I couldn't get your pump pressure, but this will easily get you
there. If the measurements slope a little more or less, that's okay.
The main thing is that they are in a fairly straight line. Say, (I
don't know) between 10% of the perfect point on the chart. (Just
guessing, here). When you do the Theme side (if you have one), 15
should be somewhere between 34 and 36", and begin on chart at about
5-1/4" to 5-1/2". It's the "regulator" spring difference that creates
more slope for the theme side of the box, but it too must be flat!