Gas Fitter Test 2025 – 400 Free Practice Questions to Pass the Exam

Flue gases begin to condense when the temperature drops below the dew point, which is the temperature at which water vapor in the gases turns into liquid. Typically, for natural gas combustion, this condensation occurs around 130°F. However, various factors such as the composition of the gas, flue gas mixture, and the presence of other components can influence this temperature slightly.

Choosing 127°F reflects an understanding that this range is close to the average temperature where condensation might initiate under typical conditions. Recognizing the precise nature of flue gas behavior is essential for gas fitters, as it helps prevent issues like corrosive damage in flue systems, ensuring longer-lasting equipment and safer operation.

Understanding that while other temperatures are close, the selection of 127°F is supported by established engineering and gas fitting principles, evidencing a practical grasp of the nuances involved in gas fitting practices.