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Honeywell to Nest. How do I wire this properly?

Community Member




I just need to know any solution that allows me to wire this in, if possible. I know I can consult a professional installer but I really don't want to spend another $100 if someone can assist me on here. 


Silver Product Expert
Silver Product Expert

Silver Product Expert
Silver Product Expert

You need to get a Nest learning thermostat, the current one you have (which is the mirrored face one) is not compatible. 

And once you have purchased your Nest learning thermostat 3rd Generation, you will need to wire it per below: 

Red R to R
Orange O to OB
Blue C to C
Yellow Y to Y1
Brown E to * - set as Emergency heat
Green G to G
White Aux to W2/AUX - set as AUX heat

Is it possible to make the current one work temporarily?

Silver Product Expert
Silver Product Expert

Yes it is, depending on the type of emergency heat you have. I don’t recommend going through the setup to have an incomplete system though.  If you never use emergency heat, then you can afford to just disable it and potentially go ahead with your current Nest. Your hvac setup seems to be a heat pump as its primary source for heat and cold, which then gets help from an auxiliary heating system when it gets too cold, most likely a gas furnace. What is the emergency heat, are those electric coils part of the heat pump system?