1.
The first place to look is the thermostat. It may sound simple, but check to see that it is turned on. All modern thermostats have an on/off switch, but they are not clearly labeled with an “on” position. The “on” position is labeled “heat” or “cool.” Obviously you want to make sure the switch is in the “heat” position. If you have a programmable thermostat, be sure you bypass the program by adjusting the temperature number and pressing the “hold” button. If the heater still does not come on you’ll want to check to see if your thermostat has a replaceable battery and check it.