A "spud" or burner orifice is used to:

A "spud" or burner orifice is specifically designed to meter gas to the burner. This component plays a crucial role in controlling the flow and pressure of gas that enters the burner assembly. By accurately regulating the amount of gas delivered, it ensures the furnace operates efficiently and safely, providing the correct mixture for combustion. This is essential for maintaining the proper heating output and minimizing any risks of incomplete combustion, which can lead to carbon monoxide production or other hazardous conditions.

The metering function of the orifice allows technicians to modify the flow based on the specific requirements of the system, making it a fundamental part of gas burner operation. Understanding this role is critical for anyone working with gas furnaces, as it directly affects performance, efficiency, and safety.