How serious is a crack on heat exchanger of your furnace?
So what is the big deal if your furnace has a crack on the heat exchanger?
First let me explain how the heat exchanger works. The heat exchanger is metal chamber where hot gasses flow inside the cambers or tubes. As the hot gasses flow through, air flows on the outside of those chambers to pick up the heat and distribute it through the home.
A crack in the heat exchanger will allow those gasses to escape into the air causing carbon monoxide to enter your home.
I recommend having your furnace inspected on an annual basis by a qualified HVAC company and to have a carbon monoxide detector installed in your home to warn you of any potential risks.