Where is the convection section located in a heater?

• A. Below the radiant tubes
• B. Above the radiant tubes
• C. Inside the combustion chamber
• D. Adjacent to the feed

Answer: (B)

The main idea here is that heat transfer to the water continues after the flame’s direct heat, in a section designed for convection. In a typical heater layout, the radiant tubes sit closest to the flame and soak up heat directly. Above them, the convection section provides a second pass where the hot combustion products flow over many tubes, giving up more heat as they rise and cool. This placement uses the natural buoyancy of the hot gases and gives a larger surface area for heat transfer without mixing with the combustion chamber or the water inlet. So the convection section is located above the radiant tubes.