I just brought home a Honeywell RTH230B thermostat, with terminals that look very unlike the wires connection to my old thermostat (put in by the builder in '94). The wires coming out of the wall are White, Orange, Blue, Red, Yellow, Green, and one that is kind of Pinkish. Can I use the RTH23B with this? If not, can anyone offer some guidance as to what sort of thermostat I need to look for? Thank you for any advice you may have.
Brian

It looks like you had a two stage heat pump thermostat and that is what you will need to replace it with. Do you know what the wires were connected to on the old thermostat?

Thank you for your help! All seven wires within the cable go to the terminal strip in the existing thermostat (see image). There's a letter, seeming to correspond with the first letter of the color of the wire, next to each connector on the strip.

I take it that my choice of a replacement for the original unit isn't going to cut it; that I need to find one that supports the two-stage heat pump? Is that correct?

Thanks again for your time.

Brian
4450

You have a three stage heat - heat pump thermostat, what letter is that behind the blue wire?

Thanks, acetc.
It's an X.

The X may be a "C" or common , the other wires will go to the same lettered terminals on a new thermostat, check at your air handler terminal board to see what letter it connects to. Mike

I'm grateful for your help, Mike.

Thanks,

Brian