So, a qualified HVAC service technician has just delivered bad news: your furnace has a cracked heat exchanger. First, be glad you found out sooner rather than later, and before something far worse happened. You see, the heat exchanger plays a vital part in the heating process inside a gas-fired furnace. But, it’s also a critical safety component that can’t be ignored.
A heat exchanger receives both heat and toxic combustion gasses (including carbon monoxide) produced by the furnace burner flame. Heat energy is transferred through the exchanger into the HVAC system airflow that circulates through the house. The toxic gasses, conversely, are sealed out of the airflow by the heat exchanger and safely diverted up the furnace vent pipe into outdoor air.
Cracks in a furnace heat exchanger aren’t uncommon. Usual causes include:
- Age of the unit.
- Low airflow causing the heat exchanger to overheat.
- Rust and other internal deterioration.
- Furnace burner flame too hot.
What’s The Risk?
Most industry organizations including the American Gas Association state that any crack in a heat exchanger is unacceptable and replacement of the component—or purchase of a new furnace—are the only recommended safe options. Even tiny cracks in heat exchangers typically continue to expand under the stress of heating and cooling cycles and dangerous leakage eventually occurs. This could pose a clear safety hazard to all occupants in the house.
To Repair Or Replace?
Cost of replacing a cracked heat exchanger—usually the most expensive component in a furnace—is steep. In many cases, the repair will cost nearly as much as upgrading to a new furnace. Consider the age of your existing unit. If it’s more than 10 years old, replacing the heat exchanger rarely makes sound financial sense versus purchasing a new furnace. Also, consider that a new furnace will provide added benefits including improved energy efficiency, lower operating costs and better overall heating performance.
Contact the experts at Aggressive Mechanical for a professional opinion on what to do about a cracked heat exchanger in your furnace.