A vented wall furnace must be located so that a door cannot swing within how many inches of the air inlet or outlet?

• A. 6 inches
• B. 9 inches
• C. 12 inches
• D. 15 inches

Answer: (C)

A vented wall furnace must be installed at a distance where the swinging of a door cannot interfere with air movement, specifically within a certain number of inches from the air inlet or outlet. The requirement to maintain a distance of 12 inches is crucial for ensuring safety and efficiency. If a door were to swing too close to the air inlet or outlet, it could obstruct the flow of air, leading to potential malfunction or safety hazards.

This specific distance helps to ensure that the furnace operates effectively without the risk of blocked airflow, which is essential for maintaining proper combustion and ventilation. Additionally, this separation minimizes the risk of doors inadvertently damaging the venting system or creating a hazardous situation that could arise from improper air circulation. The other options present distances that are either too short or do not meet the standard requirements typically outlined in gas appliance installation codes.