I just bought a new digital Honeywell thermostat - TH8320. I am replacing an old mercury one - the writing in the back is Janitrol HPT18-60, 3AAT86B21A1 HOUSTON, TEXAS. LR 11746, 30 V.A.C.1.5.A, CLASS 2, 9629.
I'm not sure how to wire the new one, looking only at how the old one was wired. Seems like W2 is for heat relay 2, but on the old one there is no W1 for heat relay 1... I don't know what kind my system is (2h/2c, 2h/1c etc) i was hoping to figure this out from the wiring...
The wiring on the old one: W2 - white E - blue C - black Y - yellow G - gren R - red O - orange
There is also a brown wire comming out of the wall that was not used.
Any sugestions on how I need to wire my new one?