Where should the controls, combustion air inlets, and draft hoods for duct furnaces be located?

• A. Inside the ducts
• B. Near the furnace
• C. On top of the furnace
• D. Outside of ducts

Answer: (D)

The controls, combustion air inlets, and draft hoods for duct furnaces should be located outside of the ducts. This positioning is crucial for several reasons.

First, having these components outside the ducts allows for easier access to the controls for monitoring and adjustments, which is essential for safe and efficient operation. It enables operators to make necessary changes without having to reach deep into the ductwork, enhancing safety and convenience.

Additionally, placing combustion air inlets outside the ducts ensures the furnace receives an ample supply of fresh air, needed for efficient combustion. If these inlets were placed inside the ducts, they could potentially draw in air that is already heated or contaminated, leading to inefficient combustion and potentially dangerous situations.

Using draft hoods outside of ducts also aids in ensuring proper ventilation and exhaust of combustion gases, keeping the system in compliance with safety standards. Therefore, the positioning of these components plays a vital role in maintaining the furnace's efficiency, safety, and functionality.