Gas furnaces have many components, and it can be easy to get confused about terms like “flame sensor” and “pilot assembly” and be unclear about just how critical a part is to your furnace’s ability to function. For simplicity’s sake, let us state for the record that without a heat exchanger, you don’t have a furnace. While other components are also very important to the function of your heater, and all problems should be addressed promptly by qualified technicians, a cracked heat exchanger is an emergency causing not only heating failure but also serious safety hazards.
So we’d like to help you understand what a heat exchanger is, how it works, why it might crack, and what to do if it does so that you can navigate that situation with the seriousness it requires.