NATE Air Conditioning and Heat Pumps Practice Exam

When air flow through an electric heater is insufficient, the technician should observe that the heater elements glow red or orange. This phenomenon occurs because inadequate airflow prevents the heat generated by the heating elements from being properly distributed throughout the system. As a result, the elements themselves can become excessively hot, causing them to emit a visible glow. In a well-functioning electric heater, the airflow plays a crucial role in removing heat from the heating elements and delivering it to the intended space. When this airflow is compromised, such as by blockage or insufficient ventilation, the heat builds up, causing the elements to reach high temperatures. Observing the elements glowing red or orange is an indication that they are overheating due to the lack of adequate air movement. While fusible links may also glow if they are heating excessively, it is specifically the heater elements that will show visible signs of overheating due to poor airflow. The other choices related to voltage readings are less likely to directly relate to airflow issues; higher or lower voltage readings can indicate other electrical issues unrelated to airflow, making them less relevant to this specific problem.