How do I wire this thermostat?

Question

Hello I have a Honeywell FocusPRO 5000 Non-Programmable 1 Heat/1 Cool Thermostat, Large Screen.

The wires it needs are:

Conventional Terminals:

• Rc 24VAC power from cooling transformer
• R 24VAC power from heating transformer
• W Heat relay (stage 1)
• Y Compressor contactor (stage 1)
• G Fan relay C 24VAC common.

For 2 transformer systems, use common wire from cooling transformer.

The problem is that my brother said he could install it and took the old thermostat out.

Now the situation is the wire colors do not match. It's an older furnace.

The wires I have to the thermostat are:

• Orange
• Red
• Black
• White
• Green

The box wiring diagram says: No. 17680-1 evaporator control panel

On the furnace panel:

• G = Orange wire
• R = Red wire
• y4 = Black
• y = Black (to ac unit)
• D = white (to AC)

And the wiring diagram on the box... well I have a picture of it if it helps. I just need help put the wires in the correct order for the thermostat; I do not care if it works or not because I just need it back in the right order.

The green wire to the thermostat attaches to a red wire that goes to the furnace itself and the white wire attached to the thermostat is attached to white wire that does the same.

Answer 1

You're going to have to take a look inside the furnace, where you should find the control board where all these wires terminate. Each terminal on the control board should be labeled, so just make a list of letters and colors. Then go back to the thermostat, and use the list to connect the wires to the proper terminals.

If you post the make and model (model number would also help) of the furnace, or a quality picture of the furnace wiring diagram (should be printed on the inside of the access panel), somebody may be able to offer a better answer.