Responded to no heat call for 12-4 NG Gibson furnace. Diagnosed open limit/rollout switch fault with furnace sitting cold. Found main limit switch with abnormal resistance (4-5 ohms) showing signs of overheating, and capacitor measuring 2 μF despite 5 μF rating. Noted additional issues including oil-leaking blower motor, dirty blower wheel restricting airflow, evaporator coil buildup, and intermittent burner ignition. Assessment suggests oversized furnace (80,000 BTU) for the home's ductwork system.
