Is Rust on a Furnace a Problem?
Is Rust on a Furnace a Problem?

January 05, 2015


When there is a problem with the furnace, most homeowners will take any steps necessary to prevent replacing it. Often, you don’t need to replace the entire heating unit for a small repair, as only that single part will need repair or replacement from a heating technician. You want to hold onto your older unit as long as possible and a technician can sometimes help you to do just that. But unfortunately, when it comes to rust, there may be too much at stake to hold onto the furnace for too long.

Rust occurs when water, oxygen, and iron react together to form a visible red oxide. All three must be present in order for iron oxide to form, but water is usually the catalyst that finally allows the reaction to take place. Eventually, iron oxide will turn into rust that flakes off and disintegrates from the metal substance, corroding the metal until it becomes brittle.

Rust can occur on a furnace for a couple of reasons. For one, many air handlers contain a coil that can collect condensation as moist air from the indoors blows over it. If there is not adequate drainage to rid the air handler of this excess moisture, it may drip onto the furnace, creating conditions for rust to occur. Another common reason for corrosion happens in the flue pipe, the part that helps combustion gases to vent outdoors. Water vapor is created during combustion and it may damage the vent pipe. The water vapor may affect other portions of your furnace as well.

Unfortunately, rust can be bad news for your furnace. If the unit becomes too rusted, it’s no longer structurally sound and cannot be trusted to contain the poisonous gases created as a byproduct of combustion. As it corrodes, rust can flake off and interfere with the burners, or it may flake off from the heat exchanger which could give gas a chance to leak into the home. However, if it’s only the flue pipe or a very small component that has rusted, you may only have to worry about that part.

Bronco Plumbing Heating and Air can make the repair or replacement process easier by giving you plenty of options and keeping you informed about the damage. Call our friendly technicians today when you need to repair your heater in Sacramento.