How Does a Secondary Heat Exchanger Work

The secondary heat exchanger is where the flue gas undergoes further heat exchange and water vapor forms. After exiting the primary heat exchanger, the burning gas proceeds to the secondary heat exchanger. As water is changed from a vapor to a liquid, it releases more heat into the secondary heat exchanger.

What is the function of the secondary heat exchanger?

As the combustion exhaust leaves the primary heat exchanger, it travels into a secondary heat exchanger where more heat is released from the flue gas and water vapor begins to form.

What does the secondary heat exchanger do in a condensing furnace?

With a condensing furnace, on the other hand, the combustion exhaust gases are also passed through a secondary heat exchanger that absorbs much of the remaining heat from the gases. As the gases cool, they condense to form water and carbon dioxide (which together form carbonic acid).