Current C wire not powering on the Ecobee


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Old 11-09-17, 10:28 PM
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Current C wire not powering on the Ecobee

I have a C wire (blue) in my current thermostat which isn't connected. When i tried using it with Ecobee it didn't power it on. I looked at the furnace and there are two blue wires. One of them is connected to C but there is also another blue wire which is simply connected with the green wire.

Any help is appreciated. I have attached the picture
 
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Old 11-09-17, 11:14 PM
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Most likely different blue wire. See the one that is not connected and wrapped around the blue cable? Unwrap that one, strip the end, and connect it to the C terminal along with what is there now.
 
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Old 11-09-17, 11:20 PM
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Brown is common.
It was labeled 24C on the old stat. That means 24volt common.
 
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Old 11-10-17, 10:24 AM
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Good point. I didn't look. The brown wire should not be labeled R|Rc but just C.
 
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Old 11-10-17, 10:36 AM
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Thanks Hoston and Astuff. There is a open C wire in the old thermostat. Curious why and what that would be.

Also i have both heating and cooling system so don't i need both Rh and Rc besides a C wire?

@Astuff the blue coiled wire is the one connected to the green wire together.
 
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Old 11-10-17, 11:08 AM
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There is a open C wire in the old thermostat.
Do you mean just an open/extra wire at the stat ?
There is no color dedicated to common.
It can be brown or blue or some other color.

A real pro will always run a thermostat cable with extra wires for future use.

Rh = R 24vac for heat
Rc = R 24vac for cooling
Many stats need a jumper between the two if there is only one R wire. Since you only have one red wire.... you may need a jumper. It will be explained in your manual.
 
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Old 11-10-17, 12:21 PM
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Cool.. I'll give this a try. Using brown as C
 
 

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