What maintenance practice helps prevent coil freeze-up in an evaporator?

Proper airflow across the coils is crucial for the effective operation of an evaporator in a refrigeration system. When the airflow is optimal, it ensures that the refrigerant inside the evaporator coils absorbs sufficient heat from the surrounding air. If airflow is restricted or inadequate, the evaporator cannot effectively transfer heat. As a result, the temperature of the refrigerant may drop too low, leading to coil freeze-up due to excessive moisture freezing on the coils.

Regularly checking and maintaining this airflow involves ensuring that air filters are clean, fans are functioning correctly, and there are no obstructions to airflow. By maintaining proper airflow, the evaporator operates efficiently, minimizing the risk of low temperatures causing frost or ice accumulation, which can impair performance and lead to breakdowns.

In contrast, cleaning the evaporator coils annually might help with general performance but is not sufficient by itself to prevent freeze-up without ensuring satisfactory airflow. Replacing the thermal expansion valve and increasing the refrigerant charge may address specific issues related to flow and pressure but does not directly influence the airflow, which is critical to preventing coil freeze-up.