When installing air supply duct, how far should it be placed above the burner?

When installing air supply duct above a burner, it is essential for safety and efficiency to position it at a distance that prevents combustion issues and ensures proper air intake. The correct distance of twelve inches above the burner is specified in safety standards to avoid interference with the burner operation. This distance helps to prevent the potential for overheating of the ductwork, which could lead to structural damage or fire hazards. Furthermore, maintaining this space allows for adequate airflow to the burner, ensuring optimal combustion and minimizing the risks associated with inadequate ventilation.

This standard is part of best practices in HVAC installation, emphasizing the balance between safety and performance in heating systems.