The method to unlock a thermostat varies depending on the brand and model of the thermostat. For example, to unlock a Honeywell thermostat, you would need to enter the menu and enter your unit’s key code. For a Nest thermostat, you can unlock it by entering a four-digit PIN code on the thermostat or using the app.
You can find specific instructions on how to unlock your thermostat by referring to the owner’s manual or by visiting the manufacturer’s website.