Nest thermostst

[Tjj1]

Hello i am changing a 2 wire honeywell furnace  R C are wires tried nest nave 24 volt adapter for c wire on mount where shoul wires go i tried several combos 

[Jenelyn_O]

Hi Tjj1,

Thanks for reaching out in the Google Nest Community forum. I'd like to check it further. Could you please take a photo of the wires connected to your furnace control board? It will help us to see if you have spare wires that we can use, or which of the two wires is responsible for your heating system. Also, in what country are you located? 

Best,

Jenelyn