installing honeywell wifi 6580

Old 05-31-14, 02:26 PM
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installing honeywell wifi 6580

hi there i am trying to replace my old honeywell thermostat with a new wifi one and i don't have a C wire on my old one although the blue C wire is wrapped around the other wires. when i look at the furnace the C wire there is the same blue color although the humidifier wire is wrapped around it and I'm assuming the aprilaire is getting power from that C wire connection on the furnace.

my questions is since the C wire provides power i would imagine just connecting the C wire on my new wifi thermostat should provide my a display, correct? i don't want to connect all the wires if this thing isn't going to work for me so was trying to just connect the C wire to see if i have power, which i don't. am i missing something? will i need to connect all the wires to get power to the wifi thermostat?
Old 06-02-14, 04:42 PM
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Connect your blue wire to C at the stat and verify that the stat Blue wire is connected to C at the furnace.

It is normal to see 2 wires connected to the C terminal at the furnace.
I wouldn't be surprised to see 3 wires connected to the C terminal at the furnace if a humidifier is installed.

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