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A Furnace Can Corrode: What This Means

old-furnace-in-basementPeople think of corrosion and rust as something that only occurs with an appliance that uses water. A water heater or a boiler might rust, but why would a gas furnace? It doesn’t sound like it should happen.

But it can and it does. It’s something you may find happening to your furnace at some point. Why does it happen, and what does it mean for the furnace when corrosion starts? We’ll explain more, as well as tell you what you should do about it.

Why a furnace might corrode

Furnaces are often housed in a single cabinet with the air conditioning system. The AC coils are at the top the cabinet and the furnace’s heat exchanger and the gas burners are below, and both share the same air handler. It’s possible for water to fall out of the air conditioner’s condensate pan because of loose parts or a clog in the drain line forcing an overflow. The water can fall into the furnace and cause corrosion in the heat exchanger. If you do notice water dripping from the cabinet, it’s probably because of the AC. The air conditioner needs to be repaired, and the technicians can also check on the furnace to see that there’s no corrosion danger.

However, this isn’t the primary reason a furnace may corrode. Usually, it happens because of poor venting of the combustion gases the furnace uses to heat the air. The reaction of the combustion gases with the metal inside the heat exchanger can cause the metal of the exchanger to corrode. If the combustion gas isn’t venting properly out the flue, the process of corrosion will speed up. But even the best venting furnace may have corrosion begin after so many years of combustion gas vapor in contact with metal. Once a gas furnace is more than 15 years old, corrosion is more likely.

Corrosion is a serious problem

If you do notice corrosion anywhere on your furnace, shut off the gas and contact a professional to check on the system. It might seem as if a few spots of rust are no big deal, but the concern is corrosion along the heat exchanger. Corrosion weakens metal, and this can allow the heat exchanger to crack and toxic combustion gases to seep into the air being blown into the house.

A cracked heat exchanger must be remedied immediately. In most cases, it’s less expensive to install a new furnace rather than replace the cracked heat exchanger. A corroding furnace is often already quite old, making the choice to replace it much easier.

Only call licensed professionals for the job

Working with a gas furnace without a license is illegal in most jurisdictions, and for good reason: the hazards from toxic fumes and explosions make the work dangerous for anyone who doesn’t have proper training. If you notice corrosion on your furnace, call for furnace repair in Summit, NJ from our team. Our technicians are NATE-certified to ensure the job is done right and you and your family kept safe.

At Air Creations, Inc., “We Do It Right!” since 1987. We have 24-hour emergency service available for your heating needs.

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