nest thermostat c wire I bought a 24-volt adapter where do I hook up the wire to

[claybur43204]

I bought a 24-volt adapter for my nest thermostat where do I hook up the wires to

[MrVacca]

Hi @claybur43204 - are you talking about the Google Nest Power Connector for your thermostat?

[claybur43204]

MrVacca yes the 24 volt transformer  that you plug into wall outlet on my thermostat i dont have rh i only have r and i know the other one goes to c 

[CoolingWizard]

Hang on a second, the Google Nest Power Connector does not plug into a wall. You need a COMMON source that is from your HVAC system.  In your HVAC system has a step down transformer that produces 24 Volts AC power.  This 24 VAC is the voltage used to control the HVAC system. The R in your thermostat is the POWER IN from that step down transformer.  
The Google Nest Power Connector uses existing wires to bring the COMMON from the transformer by attaching to the COMMON in the in the HVAC equipment.  It then feed the common to the thermostat using the Y or W wire depending on which mode your system is running in. 

So, behind your thermostat, inside the wall, are there any wires not being used? 

Ken, The AC Cooling Wizard

[claybur43204]

coolingwizard this is a plug i bought from amazon and its suppose to keep power to thermostat i just don't know where the 1 wire goes i know the other go to c i have a very old furnace standing polit just a transformer there is a blue wire there but i am the one that put the new wire in i don't know where to get power for the nest thermostat 

[CoolingWizard]

Clay, The step down transformer in your heating system has two wires in, and two wires out.  One of the wires coming out and connected to your thermostat cable is the R wire, the other wire that is on the same side as the R wire, is the COMMON wire.  Connect an available wire conductor in the thermostat cable and at the thermostat, connect that wire to the C terminal. 

Ken, The AC Cooling Wizard

[EdwardT]

Hi folks,

I wanted to follow up and see if you are still in need of any help. Please let me know if you are still having any trouble from here, as I would be happy to take a closer look and assist you further.

Thanks,

Edward

[Jhonleanmel]

Hi everyone,

I'm just checking in to make sure that you've seen our response. Please let us know if you have any other questions or concerns as I will be locking this in 24 hours.

Thanks,
Mel

[PaulKahn]

I am constantly getting "batteries need replacing" about once a week.  I have R,W, Y and G wires connected, and a blue and brown one not connected.  The R and W show 24 volts, but the R and C do not read anything on my multimeter.    What do I do in my furnace to get the C wire connected?

[CoolingWizard]

Paul, the problem might be is at the HVAC equipment, the wire color connected to C in your HVAC equipment needs to be connected to the C connector in the thermostat backplate. 

Ken, AC Cooling Wizard

[Jhonleanmel]

Hey folks, 

Thanks again for helping here, @CoolingWizard. 
@claybur43204, I hope you've got the answer you're looking for. If you're still in need of any assistance, feel free to let us know. 

Best,
Mel