G2 Gas Fitter Practice Exam 2025 - Free Gas Fitter Practice Questions and Study Guide

A glow bar used for burner ignition indicates that the appliance is equipped with a hot surface igniter. This component is designed to heat up to a high temperature when electric current passes through it, creating enough heat to ignite the gas in the burner.

Hot surface igniters are typically made from materials that can withstand high temperatures, allowing them to glow red or orange when activated. Once the gas ignites, the heat from the burning gas will keep the igniter warm, and it usually plays a critical role in ensuring a safe and efficient ignition process in gas appliances.

In contrast, other components listed, such as flame sensors, thermocouples, and energized spark plugs, serve different functions. For instance, flame sensors verify the presence of a flame, thermocouples measure temperature and can shut off the gas flow if no heat is detected, and energized spark plugs generate a spark to ignite the gas, rather than using heat from a glowing element. Understanding the function of each component helps clarify why a glow bar specifically refers to a hot surface igniter in this context.