New Trane furnace without c-wire for wifi thermostat


Old 07-17-19, 08:33 AM
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New Trane furnace without c-wire for wifi thermostat


I am trying to install a Emerson Sensi wifi thermostat and need assistance adding a C-wire. I have a Trane gas furnace install last year in a much older home. The old thermostat had only 3 wire and so they left it at that, only connected to 3 terminals. RH, G, W/E at thermostat terminals. W1, R, G at furnace terminals. I see a B/C empty at furnace.

Was wondering if I can just move G to B/C at furnace and G to C at thermostat? Will this work? Any harm running 3wires like this with wifi capabilities?

thank you

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Old 07-18-19, 06:28 AM
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you can do that but will lose control over continuous fan.

better to run a new wire with more conductors if possible.

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