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Hello,

I got a new wifi thermostat today but apparently I need the c-wire to power the wifi function of the unit. I currently have an extra wire coming for the unit outside to where the thermostat is. I have no idea where to attach the wire on the unit outside. Any help would be greatly appreciated Thank You
 

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Hello,

I got a new wifi thermostat today but apparently I need the c-wire to power the wifi function of the unit. I currently have an extra wire coming for the unit outside to where the thermostat is. I have no idea where to attach the wire on the unit outside. Any help would be greatly appreciated Thank You
Sorry i do not understand your question. Package unit?? Do you need a "C" wire to your T/S?? Your "C" 24 VAC wire comes off of your transformer/ goes to your 24 VAC switching devices. Look @ the "C" simular feathers NEG post (-) on car battery // (-) NEG goes to ALL electric/ mtr's /elect components /// you may need to get your post count up & send pics
 

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It looks like you have a regular furnace or air handler and a separate AC outside ( called a split system).

You need to get a C wire from the furnace/air handler 24 volt transformer up to the thermostat. Then you hook it to the C on the circuit board of the furnace/air handler. That extra blue wire outside is useless. In one of the pics it is hanging in the air.

Basically you have a Y and C wire at the outdoor unit. Those hook to Y and C at the furnace and the extra wire you do not use.
 

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Good pics - But I did not see the transformer --// you are looking for LOW voltage! Look @ your pic (bottom) of wiring low voltage transformer - your"C" common 24 VAC wire is on the right side - you can get it from your contactor also but best to go on your transformer- Also recommended put a 3 amp fuse in-line the "C" wire -like a car fuse- you can use a wire terminal with plastic to the fuse or get in-line fuse assy @ auto parts store/ walmart- I will look @ other thread/ has pics
 

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I think yuri is correct / split system - you only have 2 T/S wires going out side/ one is coming from your T/S (Y) to your outside contactor/ other T/S wire on your contactor is going to 24 VAC "C" common - look inside your furnace or AH where the inside blower mtr is- you should find your transformer - high volts coming in -24 VAC going out- check your wiring pics
 

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Before you take your old T/S out - take some pics & make notes - Example// red wire went to terminal "R" on the T/S -- yellow wire went to terminal "Y" on the T/S etc. etc. I read article 1/3 people now have wifi T/S
 

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Yuri's right.

The chances are that you'll need to pull new wire from your furnace up to the stat. If this isn't possible, you can use an "add a wire" or separate wall pluggable transformer/power supply. (similar to your cellphone charger but a different voltage system, 24v AC)

Many of us have had issues with the "add a wire" products on a professional level, so this should be the least wanted plan.

My opinion would be to run the new wire, or use a stat that doesn't require a common. There are many that have Wi-Fi, and use batteries, if that's what you want.

Cheers!
 
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