Industrial Maintenance Technician Practice Test 2025 – 400 Free Practice Questions to Pass the Exam

An iced evaporator often indicates a dirty filter, which can restrict airflow to the system. When the airflow is diminished, the evaporator coil doesn't receive enough warm air to absorb heat effectively. This leads to the refrigerant inside the coil not being able to evaporate properly, causing the temperature to drop below freezing. As the moisture in the air passes over the cold coil, it can freeze on the surface, resulting in icing.

Factors like strong limit switches, proper airflow, or high refrigerant levels do not directly correlate with the condition of an iced evaporator. A strong limit switch typically indicates that the system is operating correctly in terms of safety controls, while proper airflow would help prevent icing in the first place. High refrigerant levels can lead to other issues, but they do not typically cause ice buildup on the evaporator coils directly like a dirty filter does. Therefore, identifying a dirty filter is crucial for diagnosing the icing issue.