AC on instead of heat

[aq123]

We had to reset our Nest because it wouldn't connect to our new WIFI after reseting the Nest and the router. Now, the AC turns on instead of the heat. I saw someone had said to switch the heat pump wire from O to B and it didn't work. I switched it back now to see if that helps. We never had this issue before with our thermostat.

[Orcharddr]

I’m having the same issue.  Don’t have a heat pump.  Just started doing this, working fine for last 8 months.

[luciaaa]

Hi, there! 

Thank you for your post in the community. I apologize for the inconvenience of your thermostat cooling instead of heating. I understand how important it is to maintain the correct temperature. I'm happy to assist you.

@aq123, I appreciate you taking the time to adjust the O/B orientation. Thank you, @Orcharddr, for informing me that your system is not a heat pump system. Could you please confirm if it's a conventional system?

To ensure the most accurate troubleshooting steps, please answer the following question:

• What type of thermostat do you have?
• Would you mind sharing a picture of your wiring configuration?
• When was the last maintenance check for your HVAC system?
• Have there been any recent changes or upgrades to your HVAC system?
• Does the issue happen with heating only, cooling only, or both?
• Are there any error messages?
• Is this the first time you're activating heating since the season changed?

In the meantime, ensure wires are fully inserted: The wires may not be making a proper connection with the terminals. Make sure at least ¼ to ½ inch of the copper wire is exposed, straightened, and fully inserted into each of the required connectors. If necessary, strip and re-insert the wires.

Please keep me posted.

Best regards,

Ana