When motorized dampers are provided in combustion air ducts, they shall be ______ to prevent operation of the burner when the dampers are not the fully open position.

When motorized dampers are provided in combustion air ducts, they shall be ______ to prevent operation of the burner when the dampers are not the fully open position.

• A. arranged
• B. connected
• C. installed
• D. electrically interlocked

Answer: (D)

The important idea here is tying the burner’s ability to operate to the position of the combustion-air damper through an electrical safety interlock. When a motorized damper is in the combustion air duct, the burner control is designed so that the damper must be fully open before the burner can be energized. This electrical interlock ensures the burner cannot start if there isn’t adequate combustion air, and it will trip or shut the burner off if the damper closes during operation. This arrangement protects against incomplete combustion and the buildup of dangerous gases by guaranteeing that sufficient air is actually available for proper burning. The other terms describe general states or arrangements without guaranteeing this safety function; they don’t ensure the burner is prevented from firing unless the damper is fully open.

The important idea here is tying the burner’s ability to operate to the position of the combustion-air damper through an electrical safety interlock. When a motorized damper is in the combustion air duct, the burner control is designed so that the damper must be fully open before the burner can be energized. This electrical interlock ensures the burner cannot start if there isn’t adequate combustion air, and it will trip or shut the burner off if the damper closes during operation.

This arrangement protects against incomplete combustion and the buildup of dangerous gases by guaranteeing that sufficient air is actually available for proper burning. The other terms describe general states or arrangements without guaranteeing this safety function; they don’t ensure the burner is prevented from firing unless the damper is fully open.