I'd be most grateful for some assistance in wiring a new Honeywell RTH7600D to a heat pump system that has AC as well as Aux and Emergency heat (which I guess makes it a multi-stage system?). My old system was a Honeywell 841A1217, which had the following wires; I wired them to the new system as follows:

Color: Old: New:
White W2 Aux
Black X C
Orange O O/B
Brown E E
Green G G
Yellow Y Y
Red R R (jumpered to Rc)

Absolutely nothing happens when I throw the power to the AC/furnace back on. Can't get anything to work--fan, heat, nothing. I can't tell whether the problem is with the wiring, or whether something else is wrong. I believe I did the settings properly (setting 170 is set to 7, 190 is set to 0), but we're basically living in a meat locker now that I've disabled the old thermostat, and Honeywell seems to take Sundays off (can't blame them, I suppose). Can anyone lend a helping hand and prevent my girlfriend from leaving me for forcing her to live in Siberia? Thanks so much!

Is the black wire connected to "C" at the indoor unit? If not, the new thermostat may not function.

You mean is the black wire connected to "C" on the new thermostat? The answer to that is yes. If you're asking how it's connected to the indoor portion of the heat pump/AC, I can't tell--all 7 wires are bundled in a cable that goes to the indoor portion of the pump/AC, and I can't tell where the individual wires go from there. I only know that the black wire was connected to "X" on my old thermostat, and that I've connected it to "C" on the new one. Thanks for your help.