Why is my Furnace not coming on?

Your furnace not coming on during the winter can be a scary thing. I know this can be alarming especially if it occurs during a cold night. Remember preventive maintenance can greatly reduce your chance for these stressful break downs. If you are a part of our preventive maintenance program we typically will come out in the Fall months to ensure your furnace is prepared for the cold before it even arrives. Things do happen so if you find yourself in this situation I always recommend calling a professional. If that’s not an option at the time here are some potential causes and ways to fix it.

  • Check your thermostat: Open the thermostat and gently blow out any dust or debris. Ensure it’s level and firmly attached, and that all wires are connected and secure. Then set the temperature five degrees higher than the room temperature and see if the furnace turns back on.
  • Check your Filters: Most people do not realize dirty filters can cause furnace problems. Excess dust and dirt can restrict airflow. If the filter becomes to clogged it can cause the heat exchanger to overheat and shut off too quickly. You will find this is most likely the issue if the blower is running but no heat is coming out.
  • Faulty or dirty ignitor/sensor: I find this is typically the most common cause when your furnace is not working. Normally the furnace is notified by the thermostat to click on, the ignitor then will get hot. This then triggers the process of igniting the gas and blowing hot air. If you have a faulty or dirty sensor the furnace will not be able to go through this process. If this is the issue it is best to call a licensed HVAC professional.