Nest Triggering AC causing start stop rapidly

[Dr777]

4 days ago I moved into my new home and installed my nest leaning thermostat here, replacing the old thermostat. The wires used for the original thermostat are R (jumper to Rc), W, Y, and G. Additionally there are two wires not used that are wrapped around the cable. When I connected the Nest I connected the R to Rc, W to W1, Y to Y1, and G to G. The issue I am having is that sometimes once it reaches temp something in my HVAC will turn off then kick on and off rapidly, sounds awful for the unit like a limit switch being hit then a loud clunk sound.

Any idea what the cause of this could be?

[moralesvicente]

Hello Dr777, 

Thank you for reaching out to our community. I understand that you're encountering some difficulties after installing your Nest Learning Thermostat.

While your current wiring system is generally compatible with the Nest Thermostat, it's crucial to confirm if your HVAC system has a common wire (C) available. This wire provides constant power to the thermostat, ensuring optimal performance.

Please check the control board of your HVAC system for any unused wires. If you find any, please describe their colors or attach a photo for better clarity. This information will help us determine if they can be used to complete the installation.

For more detailed guidance on the common wire, please refer to this helpful article: Learn about the common or C wire.

Feel free to reply to this post with any additional questions or information. 

Best regards, 

Daniel