Help! Wiring problems Nest thermostat

[Jmawet]

 

Hello! I’m trying to install a new nest thermostat but it will not turn on at all. I’ve done as much research as i can but I’m stumped. I know i have a red wire, w wite, and g wite in my old thermostat. The blue and yellow wires were not used. My old thermostat also required aa batteries to work which i thought was weird. I tried using all 5 wires in the new nest, wondering if the blue wire was a common wire to power the new nest but it still didn’t work. 

see the three Photos below. One is the wiring of my old thermostat ( without blue and yellow) , one is the wiring with the new nest all 5 wires, abs then a page from my hvac manual explaining the wires. 

any help here wiukd be greatly appreciated!!

 

 

[CoolingWizard]

Did you use the  Nest online configuration tool when you set up your Nest thermostat?  Since your old thermostat was not using Y1 or C, you have a heating only system.  So you will use Rh, W1, and G only. 

Ken, The AC Cooling Wizard 

[Patrick_Caezza]

The first thing to do is remove the yellow and blue wire from the Nest. The Nest can tell when a wire is inserted and will try to configure it and fail.

Could you look in the furnace and see where the thermostat wires are connected?

You'll probably see the blue wire is just hanging loose. Connect it to the C terminal on the control board terminal.

Return to your thermostat and reconnect the blue wire to the C terminal.

Revove the Nest thermostat from the Mest App.

Do a reset to Factory Defaults

1. Press your thermostat ring to open the Quick View menu.
2. Choose Settings .
3. Turn the ring to Reset and press to select.
4. Select All Settings

Set up the thermostat again.

[Jmawet · Accepted solution]

Thanks so much. The blue wire was not connected to the furnace. Once I connected that everything started working. Thanks again for all your help!

[Jeran]

Thank you for helping out on this thread, CoolingWizard and Patrick_Caezza!

Hey there Jmawet,

I'm glad to hear you were able to resolve this wiring issue! In that case, do you have any more questions or need any additional help? If not, I'll go ahead and lock this thread in 24 hours.

Best regards,
Jeran