If the foam is curing properly, but the gun has no fan pattern, the problem is most likely in the main port of the mix chamber.
Fan pattern is made in the main port were the foam exits. You could have some trash in the main port or a small blockage on one of the side ports. The other problem it may be is your Reactor pressure is set below 1000psi.
Remember - the air pressure has nothing to do with the pattern and neither do any of the o-rings.
If the foam is NOT curing correctly, you have a blockage in the side port.
Turn off one of the shut off valves on the manifold and pull the trigger. If a pee stream comes out, try the other side. The side that is plugged will not have any flow or it will be very small.
Either the "A" or the "B" side is plugged and this will help you find which one is the problem.