G2 Gas Fitter Practice Exam

The expanding pilot is designed specifically to burn at low turndown rates, which means it can operate efficiently with minimal fuel when there is no call for heat. However, when there is a demand for heat, such as when a thermostat or control system signals for increased heating, the expanding pilot responds by allowing more fuel flow. This characteristic makes it particularly well-suited for systems that require flexibility in fuel delivery based on varying heating demands. In contrast to the expanding pilot, other types of pilots serve different functions. A proved pilot is used to ensure that the flame is continuously monitored for safety, while a flame safety pilot generally works in conjunction with safety systems to prevent gas flow if the flame is lost. Variable duty pilots can modulate fuel flow but may not specifically focus on the low turndown feature combined with temperature demand. The functionality and design of the expanding pilot align with the requirements for responding dynamically to heating demands, making it the appropriate choice for this question.