Gas Heat ESCO Practice Exam

A "spud" or burner orifice:

1. controls air flow to the burner

2. ignites the gas

3. meters gas to the burner

4. regulates water flow

The correct answer is: meters gas to the burner

A "spud," also known as a burner orifice, is integral to the operation of a gas burner. Its primary function is to meter gas to the burner, which means it controls the flow of gas that reaches the burner assembly. By restricting or allowing the appropriate amount of gas, the spud helps ensure that the burner operates efficiently, delivering the optimal amount of fuel for combustion and resulting in effective heating. The correct functioning of the spud is critical because it affects the air-fuel ratio, which directly influences combustion efficiency and emissions. If too much gas flows through, it can lead to incomplete combustion, while too little gas may result in insufficient heating. While controlling airflow, igniting gas, and regulating water flow are significant aspects of gas combustion systems, they are not the primary role of the spud. Airflow is typically managed by different components, ignition is achieved by spark or pilot systems, and water flow would pertain to hydronic systems rather than gas burners.