what does rust on furnace mean?
Rust in your furnace is more common than you might think. Rust is the result of oxidation that occurs when metal, oxygen, and water mix. The great danger of rust to metal is that it eats away at the metal and eventually causes it to crumble and flake away.ou donât want this to occur to your furnace, especially along the heat exchangers: if cracks occur in a heat exchanger because of the weakening effect of rust, it can lead to dangerous carbon monoxide leaks.