C wire not getting power...but it powers my current thermostat!

[TheShadow]

 

 

 

I was able to identify all the correct wires and label them and I removed my old thermostat and And connected the Appropriate wires to the nest thermostat however using the app to set it up it says that there’s no power getting to the thermostat and it also didn’t detect the wiring that I installed, but then I took the nest off and put my old thermostat back on and it works just fine

[Patrick_Caezza]

@TheShadow 

Post a picture of the original thermostat's wiring here

[TheShadow]

OK, I added a few pictures of the original thermostat wiring

[Patrick_Caezza]

@TheShadow 

Thanks for the pictures.

Give this wiring a try,

Orange - O to */OB

Red - R to R

Green - G to G

Yellow - Y1 to Y

White - W1 to W (jumper to E not needed)

Brown - C to C

I am guessing that the terminal the brown wire is connected to is the C terminal.

[TheShadow]

Thanks for the reply. That’s exactly what I did and I took the jumper. The blue jumper that was going from one port to the other. I removed that and everything else just like you listed is how I hooked it up

[Patrick_Caezza]

@TheShadow 

With it wired like that it doesn't work and says no power?

[Charleshall76]

Your current thermostat has power because it's using batteries and there's no common wire powering it. Common wire is required to be hooked up in your air handler at the control board it will be a blue wire on your thermostat wire coming from the thermostat run into your air handler. Tie that in with the common wire from the outdoor unit on the common connection labeled C sometimes it's brown but most of the time it's c blue. Make sure you power off your unit completely by turning off the breaker before doing this or you will blow your fuse you should be fine after that.

[TheShadow]

where are the batteries? I don’t see any batteries in my thermostat and when I cut the power off, the thermostat shuts off too

[CoolingWizard]

@TheShadow, Well, allow me to add my two cents worth. 

Your old thermostat is controlling a heat pump. You’ll notice that there is a blue jumper wire running between the W and the E terminal. Your old thermostat links, the auxiliary heat to the emergency heat in this way.
Since you haven’t heat pump, the orange wire has to go into the OB terminal and it’s configured as an O model heat pump. 

I can’t read the letter behind the brown wire My assumption is that is where the C terminal is. Even though you have a wire in the C terminal, your old thermostat did not require the common side of the transformer to be able to operate. But we need to verify is indeed is there a common voltage on that brown wire. To do this you need a Volt Ohm multimeter.  Set the meter to AC voltage and check the voltage between the red wire and the C wire. If you do not see any voltage there specifically you do not see approximately 24 V. The brown wire is not attached to common in your air handler.  

AC Cooling Wizard

[TheShadow]

 

 I cropped one a little bit closer you’re right that brown wire is on the C terminal. and if you look close straight above all the wiring, there’s a loose black wire that was just in the wall, not connected to anything. What do you think that would be for

[CoolingWizard]

@TheShadow, since you have a heat pump, I would make the black wire your Emergency Heat wire, and leave the white wire in the Auxiliary heat position.  The brown wire more than likely not connected at the air handler end and this is why you have no power on the Common wire.  So why do I recommend the Emergency Heat? In the case that your heat pump outside should fail in the winter, the homeowner can activate the Emergency Heat with the Nest Thermostat and have some heat while you wait for the HVAC repair company arrive to fix the heat pump. On the Nest Learning thermostat the emergency heat wire is inserted to the * terminal.  This is a programable function terminal and you will define it as Emergency Heat.   

AC Cooling Wizard

[TheShadow]

 this is the Google Nest wiring terminal set. Where would you recommend those lines you mentioned connect, or is it just not going to work with my setup?

Where would my heat pump be located? I didn't even realize that I had one.

[CoolingWizard]

@TheShadow , that is the basic nest thermostat while supported heat pump. It does not support both auxiliary heat or emergency heat. The W terminal on that can be configured for auxiliary heat though

AC Cooling Wizard

[TheShadow]

So how would you suggest I connect the existing wires on the old thermostat to the Nest thermostat terminal for it to work?