Question
I don't know what heats the walls of a firebox, but i know that it is either air or water!
Nearly always, it is hot gases that flow in the air box of a fireplace that heats the walls. Water would be dangerous, as if it boiled, pressures would rupture the walls.
Nearly always, it is hot gases that flow in the air box of a fireplace that heats the walls. Water would be dangerous, as if it boiled, pressures would rupture the walls.