Vented wall furnaces must be located such that any door swing does not come closer than how many inches to any air inlet or outlet?

Vented wall furnaces need to be positioned in a way that ensures safe and efficient operation, particularly regarding airflow. The requirement that no door swing comes closer than 12 inches to any air inlet or outlet is established to prevent potential obstruction of air circulation. This distance helps avoid situations where a door could inadvertently block or disrupt the airflow needed for proper combustion and ventilation.

When air inlets are obstructed, it can lead to inefficient furnace operation, increased energy costs, and even safety hazards, such as carbon monoxide buildup. Proper clearance, in this case, 12 inches, ensures that air can flow freely, maintaining optimal performance and safety of the vented wall furnace.