If a 5-year-old natural gas furnace has wavering burner flames, what is the technician likely to suspect?

In the context of a 5-year-old natural gas furnace with wavering burner flames, the suspicion of a faulty heat exchanger is concerning. The heat exchanger is crucial for transferring heat from the combustion gases to the air circulating through the home. If the heat exchanger is compromised, it can lead to issues with combustion efficiency and gas flow.

Wavering flames typically indicate that there is an irregular combustion process occurring, which can happen if the heat exchanger is malfunctioning. This may cause backdrafting or improper venting, resulting in unstable flame characteristics. Furthermore, a faulty heat exchanger can also lead to safety hazards, such as carbon monoxide leaks.

While the other answers might suggest related issues, they typically do not result in wavering flames as distinctly as a malfunctioning heat exchanger. For example, a faulty thermostat would likely cause temperature inconsistencies, a dirty air filter typically leads to airflow issues more indirectly affecting furnace efficiency, and an improper gas supply could lead to a different pattern of flame appearance.

Overall, suspicion towards the heat exchanger is warranted due to its direct impact on flame stability and safety in the combustion process of a gas furnace.