Technical

As I'm restoring one of my A3's I had to open up the safety valve because it was jamed by dirt or corrosion, whatever.

It seemed that it also was been fiddeled with as I assume that the two holes of the screw must be allined with the holes in the lid?

Putting it back together, the depth, the screw is turned in, that makes the calibration at what pressure the valve should open.

So the question is at what pressure should the valve open?

Other question is what Is the normal working pressure?