I doubt your chimney will be a problem as you said you had good after cyclone temps & there is one straight shot for the flue gas. Glad this seems to be fixed, Randymuncybob said:Well...problem solved!
I'm not sure why it didn't dawn on me to insulate the cyclone, but that was the fix! I have just temporarily insulated it with R-13 faceless fiberglass but the long term fix will be to insulate it with the special very high temp blanket type insulation. I am surprised at how much warmer the bottom of the cyclone is, I'm now experimenting with the aquastat differential dial to get lower without any condensation.
My next question is, if the temp difference in the cyclone caused condensation there am I getting condensation in my exterior non-insulated SS chimney liner? I don't have room for insulation.