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Signs of Cracked Furnace Heat Exchanger

Although a furnace has many parts and seems like a complicated piece of equipment, there are only really three primary components: the blower, the burner, and the furnace heat exchanger.

The furnace heat exchanger works in harmony with the burner to produce heat which is blown throughout your home. The heat exchanger also has another important job which is filtering out any toxic byproducts of combustion out of the heating system through your system’s flue.

When a problem develops in your furnace heat exchanger it can lead to a dangerous situation as toxic gases and fumes may be able to escape. This makes it very important to be able to detect when there is a problem with your heat exchanger.

  • Excess of residue/sediment – If your furnace is working correctly it will burn cleanly and not leave behind much residue. If you are seeing an excessive amount of residue left over in your furnace’s cabinet then this may be an indication of a crack in the furnace heat exchanger.
  • Excess of corrosion – A furnace does not use water in any way during the heating process, so if you are seeing corrosion and rust on your furnace unit, it’s crucial that you contact a professional to make sure that components like the furnace heat exchanger have not also experienced and corrosion or rust.
  • Appearance of flame – If a flame is both safe and healthy it would burn steadily and have a blue colour. If the flame burns in an orange or yellow colour and dances around instead of burning steadily then there is a good chance that there is a crack in your furnace heat exchanger. In this situation it would be in your best interest to call for help as soon as possible.
  • Strong odor – If you have a damaged furnace heat exchanger it can release an odor which smells similar to formaldehyde. A common misconception would be that this odor is the smell of carbon monoxide, but this is not true as carbon monoxide is odourless, although this odor can lead to serious headaches.


A cracked or broken heat exchanger is not a problem to be taken lightly as it can lead to some very dangerous situations. If you are experiencing any problems with your home’s heating system such as a cracked heat exchanger you should contact a professional to evaluate the situation and provide you with the best solution possible.

DeMark Home Ontario is here to do just that, we pride ourselves on our ability to provide our customers with the best possible solutions to their heating and cooling needs.


Call DeMark Home Ontario today at 647-847-2998 or fill out our online request form and one of our friendly staff will be in contact with you shortly

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