My 1860 has the Yellow,Green,red,orange,W2,E,C.

Once upon a time it was hooked up to an oil furnace and a central air, now it is hooked to a central heating and air unit.

I am replacing it because it has old mercury switches, and wanted to go digital, I chose a Hunter 44110 which have G,RC,RH,Y,W... RC & RH are jumpered, What I need to know is what wires are used, and what colors connect to which posts, I haveseven wires that were connected to the old, but connecting to the new has proposed a challenge... Help

Look at the low voltage connections on both outdoor unit and indoor unit and wire your t-stat accordingly. Also check wiring diagram it should be on the indoor unit or on outdoor unit. Hope this helps.