Nest Thermonstat won't turn on AC anymore after factory reset. Only blows hot air.

[gb1123]

Hello! I recently bought a home and the previous owners installed a Nest Thermostat. In order for me to take control  of the Nest and add it to my account, I needed to factory reset it. After resetting the Nest, the AC will not blow cold air. Only hot air is coming out of my vents even with the temp set over 10 degrees lower than the houses current temp.

Note: the Nest had been working perfectly over the past several months, even up the the minuet before reset, but after the reset the issue started. No wires were changed and no breakers were flipped.

Any help or insight would be greatly appreciated
Thank you!

[gb1123]

Additional info:
Model: Nest Learning Thermostat, 3rd generation
Wires:

 

Wires Detected:

 

[ovidioj · Accepted solution]

Hello @gb1123,

Thanks for posting in the community. 
I understand the frustration of encountering unexpected heating and cooling behavior after resetting your Nest thermostat. I also appreciate the information you have provided.

To effectively troubleshoot this issue, please provide the following information:

• What type of Nest thermostat do you have?
• Are there any error messages? If so, what are they exactly?
• When was the last maintenance check for your HVAC system?
• Does the problem occur only during heating, cooling, or both?
• Has there been any recent changes or upgrades to your HVAC system?

While I gather more information, you can try the following:

1. On your thermostat, go to the Settings Nest settings icon.
2. Select Equipment.
3. Select Continue and then Continue.
4. Select Heat Pump.
5. The Nest thermostat defaults to an O setting for heat pumps. 
6. If the O option is highlighted, select B, or vice versa.
7. If the B option is highlighted, select O, or vice versa. 
8. To make sure the issue is resolved, test your heating and cooling again.

Please keep me posted. Thank you. 

Regards, 
Jorge

[gb1123]

Hello @ovidioj!

Swapping from O to B solved the issue. The air is now blowing cool again. 

Thank you so much.

[ovidioj]

Hi @gb1123,

Thanks for your reply.
I'm glad to hear that swapping from O to B resolved the issue and your Nest thermostat is now functioning correctly. I appreciate your effort.

Please don't hesitate to reach out if you encounter any further problems or have other questions. I'm here to assist you.

All the best, 
Jorge