Why does a general inspection stop short of confirming a heat exchanger is intact?

A heat exchanger is the metal barrier separating combustion gases from the air blown into the house, and a crack in it can put carbon monoxide into the living space. It is also almost entirely concealed: the exchanger sits within the furnace cabinet with only small portions visible through the burner opening or the blower compartment, and the surfaces where cracks typically form are not among them. Confirming integrity requires dismantling the furnace, or specialized methods such as combustion analysis, tracer gas or a camera — all outside a visual inspection. So the inspector observes what is visible, watches the flame for disturbance when the blower starts, notes corrosion or soot, and reports any indication for HVAC evaluation. Reporting the limitation matters as much as reporting the observations, because a client may otherwise assume the exchanger was cleared.

Most of the heat exchanger is concealed within the cabinet and cannot be seen without dismantling. Confirming integrity requires methods outside a visual inspection, so the inspector observes indicators and reports the limitation.

Heat exchangers separate combustion products from circulating air. They are largely concealed, and assessment requires dismantling or specialized techniques such as combustion analysis. General inspections report visible indicators and the limitation.

You Can See a Sliver of it, and cracks do not form on the sliver. Report the indicators and say what you could not examine.

Watch the flame when the blower starts. A flame that rolls, flutters or changes character is a classic indicator worth reporting even though it is not proof.

• •Implying the heat exchanger was cleared by silence
• •Attempting to assess the exchanger by looking through the burner opening
• •Failing to report flame disturbance as an indicator