Cracked Heat Exchanger

Cracked Heat Exchanger

What is a Furnace Heat Exchanger?

A furnace’s heat exchanger is a set of tubes or coils that are looped repeatedly through the air flow inside your furnace for the purpose of heating air. Simply put, the furnace heat exchanger is the part of your furnace that actually heats the air. What shape these coils take is dependent on what model of furnace you have, as well as what type of fuel that your furnace uses for combustion.

Is a Cracked Heat Exchanger Dangerous?

Yes, a cracked or damaged furnace heat exchanger is a major danger to you and your family. Remember that your furnace is burning some type of material in order to generate heat, but this process should be taking place inside your furnace’s heat exchanger itself. If your heat exchanger is cracked or damaged, dangerous gasses can leak into your home, including carbon monoxide – aka “the silent killer.”

Why Do Heat Exchangers Crack?

Cracks in metal surfaces are caused by stress and flexing of the metal. Each time your furnace heats up and cools down, this cycle will naturally cause the metal surfaces to contract and expand, applying more stress to the metal and ultimately resulting in a crack or failure of the heat exchanger. This is a natural process that happens to every furnace over time and the rate at which it happens to yours just depends on how the unit is maintained. A heat exchanger can fail for many different reasons; over firing of the gas pressure, lack of maintenance (filter replacement), improper combustion air, and the age and life expectancy of the heat exchanger itself.

Second Opinion?

If you trust that the contractor has done a proper diagnostic and provided sufficient proof that your heat exchanger has cracked or failed, then you may not require a second opinion. However, if the contracting company and technician do not show or explain their findings, (for example, the crack itself, the c/o reading in your home, or the c/o in the exhaust) then it may be in your best interest to get a second opinion. Sometimes a technician that does not have a trained eye can prematurely jump to the conclusion that the furnace is unsafe and the gas needs to be shut off. In some circumstances, the furnace could just be over firing, lacking combustion air, or not be draining the condensation from the secondary heat exchanger.

I get asked the question all the time, “should we repair or replace the furnace?” I try and educate the homeowner as much as I can so they can make an informed decision. If the system is over 10 years old, I just don’t see using good money to chase bad money. You pay for the repair and then a few months later or the next season the blower motor or circuit board goes and then your into another costly repair. For the most part, a new furnace comes with a 10 year parts warranty. Most contractors offer a 10 year labour warranty provided you have annual maintenance (also known as a ‘Tune-up’) which will prevent you not being back in this situation 10-12 years from now.

Chris Martin
Service Manager
Martino HVAC