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

A loose thermocouple could cause the pilot light to extinguish when the pilot button is released because the thermocouple is responsible for detecting the heat from the flame. When the pilot light is on, the thermocouple generates a small voltage that keeps the gas valve open. If the thermocouple is not secured properly, it may not receive adequate heat from the pilot flame once the button is released, causing the gas valve to close and the pilot light to go out.

In contrast, factors such as low gas pressure or a dirty pilot orifice might lead to difficulties in maintaining the flame, but they wouldn't directly relate to the behavior observed specifically upon releasing the pilot button. Excessive gas flow could result in an unmanageable pilot flame or cause other operational issues, but the immediate effect of extinguishing upon button release is closely linked to the thermocouple's functionality. Understanding these relationships is crucial for troubleshooting and ensuring safe operation of gas appliances.