It is possible that the thermostat is bad. It could also be your mainboard problem. When the furnace is supposed to kick in but not, go to your furnace and open the cover. You should see a light on the mainboard. The number of flashing on the light tells you the problem. If the light tells there is no heat signal, it is probably the thermostat. Otherwise, it is most likely the mainboard problem. Replacing either is pretty easy to do. I had the same problem a few years ago. It turned to be the mainboard problem.
这个是thermostat问题吗？谢谢🙏
最好拍一个照片给我看看，和一般人相比我算是专家了。
I had the same problem a few years ago. It turned to be the mainboard problem.