Hello,
I had a carrier Thermostat that I broke while moving a book case. I quickly bought a Honetwell Thermostat from Home Depot but am now confused about the wiring. The old Carrier had the following terminals:
White (W/W1),
Yellow (Y/Y2),
Green (G),
Red (R),
Black (S2),
Brown (S1),
Orange (HUM) and
Blue (C).
I used Gas heating and electric cooling,there is no heat pump. This thermostat used to warn me when the filters needed cleaning - never paid attention to it and reset it after cleaning by pressing two buttons (could they be terminals S1 and S2?).

The new Honeywell has the following terminals: B O G Y W Unused R and Rc.

A Honeywell phone rep said that I only need the White, Yellow, Green, and Red.

Can someone help?
Thank you.

Can you tell us what color wires are in the cable coming out of the wall? Are there more than 4 wires in it?

Regarding the old feature of telling you when the filters need cleaning - I suspect that was simply an automatic alarm set for every 3 months or so, and didn't actually rely on any signal from the HVAC system itself, so there is no need for any special wiring for that.

If you follow the directions that came with the new thermostat you should be fine. Should work fine with the four wires the rep told you to connect - the only question is whether you may also have a blue wire in the cable (common), and whether the R and Rc terminals should be jumpered together.

This is a very helpful reply, thank you. I am doing exactly as you said and focusing on the 4 basic connectors. I have ordered a wi-fi thermostat that will use the C connector... my non-wifi new thermostat is working great.

Thank you!