Heat exchanger
The metal partition in a fuel-burning furnace that transfers heat to the air stream while keeping combustion gases separate from it.
What is Heat exchanger?
The heat exchanger is what keeps carbon monoxide out of the air being distributed through the home. When it cracks, combustion gases can enter the supply air. Because most of the exchanger is not visible without disassembly, a general home inspection cannot certify one as sound, and inspectors should say so rather than implying a clean bill of health. Indicators that warrant referral include flame disturbance when the blower starts, soot, rust flakes in the burner compartment, a persistent CO alarm, and the age of the equipment. Evaluation is an HVAC contractor's job, typically with a camera or a combustion analyser.