Nest 3rd Gen Thermostat not working on heat or cooling

[RB7X]

Hi Folks,

I just had a Nest Learning 3rd Gen installed in my mom’s house, and the unit is acting strange. It looks like the fan is blowing, but the A/C is buzzing on the outside condenser, trying to kick on, and on the other end, when I try the heat, the furnace kicks on, then stops, then kicks on again and stops. I had an electrician wire the unit, but he must have done it wrong. I attached pics of my old thermostat wiring vs. how it's wired currently with the Nest. Can anyone help me troubleshoot this? Any ideas. I appreciate your help and guidance! 

https://photos.app.goo.gl/XURUY2hx9jrR94Lr6 https://photos.app.goo.gl/hRp7zeXEgJE3WjH8A 

[virnab]

Hi RB7X,

Thank you for posting in the community.

I understand you're looking for help with your mom's new Nest Learning Thermostat 3rd gen. I know how concerning it may be when a new installation isn't working as it should, especially with the A/C unit buzzing and the furnace short-cycling. I appreciate you providing the photos; they are very helpful.

To help me get to the bottom of this, please answer the following questions:

• Does the thermostat screen indicate that it's actively calling for heating or cooling?
• When was the last time your HVAC system was serviced and cleaned?
• Is this the first time you're calling for cooling this year?
• Do you see a power error code on your thermostat?
• When did you install the thermostat?
• Could you please send a photo of the physical wiring on the backplate of the thermostat? (You can see the wires by gently pulling the thermostat display off the wall.)

Please keep me posted.

Best regards,

Virna