Wire designations don't match current Honeywell thermostat

[BobK486]

My current Honeywell HEAT/COOL digital T87 thermostat has five wires. A red and white from my furnace are connected to R and W And the three wires from my AC unit are connected to (red) Rc, (green) to G, and (yellow) to Y. So do I connect the furnace red and white to Rh (red) and W1 (white), and the AC to (green) G, (yellow) Y, and (other red) to C? See picture of old connections below.

[Patrick_Caezza]

Your thermostat is only compatible with the Nest Learning Thermostat, 3rd Gen.

Try this wiring.

Warning - make sure that the R and W wires are not mixed up with the Rc and Y wires

Red - Rc to Rc

Green - G to G

White - Y to Y1

Red - R to Rh

White - W to W1

I strongly suggest since you don't have a common wire, that you add one which will help eliminate problems dow the road.

Nest thermostats generally work without a common ("C") wire. If one is required, the Nest Power Connector is a simple C wire substitute.

[aatienza]

Hey BobK486,

Thanks for the help, Patrick_Caezza.

Chiming in to ensure everything is covered here. How's your device? Let us know if you still need help, and the community will be happy to lend a hand.

Thanks,

Archie

[aatienza]

Hey BobK486,

Chiming in to check if you still need help with this?

Feel free to respond to this thread if you have additional questions or concerns and I'd be glad to answer it for you.

Thanks,

Archie

[aatienza]

Hey BobK486,

Just checking in to make sure that you've seen my response. Please let me know if you have other questions or concerns as I will be locking this in 24 hours if I won't hear back from you again. Feel free to start a new thread and we'll be happy to help.

Thanks,

Archie