Nest Themostat Wiring

[htcn]

 

I have a Honeywell thermostat connected with only 2 wires and a jumper which control AC & furnace. I installed the Gen 3 Learning Thermostat by connected red wire (C) to RH and white wire (C) to W1. However, only the heating option displayed on the thermostat but no option for cooling. Would anyone please assist? Thanks

 

[jay-0-1-kay]

Looks like you might need a C-wire adapter. The bottom left corner reads, "SOME SYSTEMS REQUIRE A C WIRE FOR REDLINK - SEE INSTRUCTIONS FOR DETAILS." I would try finding the instructions for your device if you don't already have them handy and see what it has to say about that 👍

[htcn]

Thank you for your response. However, when I connected the white wire to C terminal (just like my current wiring) and the red wire to RH, I got the message there no heating and cooling detected. I switched back to my old thermostat and both heating and cooling are working. I can definitely switch back to the Nest thermostat if I can find the solution.

[EdwardT]

Hi folks,

@jay-0-1-kay, thanks for the help!

@htcn, thanks for reaching out. I'm sorry to hear that you're having an issue with your Nest Thermostat. The terminal that handles cooling on your Nest Thermostat is the Y terminal, and if there's no wire connected to it, it's not going to detect your cooling system. Could you check the control board of your HVAC system so we could check the labels of the wires?

Looking forward to your response.

Thanks,

Edward

[aatienza]

Hey folks,

Appreciate the help, Edward. 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,

Archie

[aatienza]

Hey folks,

Just checking in to make sure that you've seen our responses. Please let me know if you have other questions or concerns as I will be locking this in 24 hours if I won't hear back from you again. Feel free to start a new thread and we'll be happy to help.

Thanks,

Archie