I am replacing my old Honeywell thermostat but am not sure of the correct part number of the old unit. The following numbers are printed on the old unit - T8085D1008 or 890121The replacement is a Honeywell, part# RTH7400D1008 Programmable Thermostat and I'm badly in need of some guidance regarding the wiring. My A/C system is an apartment combination heating and cooling unit.
Thanks!!