What occurs in the cooling mode if the prefilter of an electronic air cleaner gets plugged with dirt?

When the prefilter of an electronic air cleaner becomes clogged with dirt while the system is in cooling mode, it restricts the airflow across the cooling coil. This lack of adequate airflow can lead to a significant drop in the temperature of the coil because the air is not effectively being circulated through it. As the temperature of the coil drops excessively due to reduced airflow, moisture from the air can freeze on the coil, resulting in frost formation. This can further exacerbate airflow issues and may lead to system inefficiencies or even shutdown.

Frosting of the cooling coil is a common issue in HVAC systems when airflow is compromised, as it can impede the overall cooling capacity of the unit. Proper airflow is crucial for maintaining the necessary conditions for heat exchange, and any obstruction, such as a dirty prefilter, can create conditions that encourage frost buildup.