A system supply airflow check is used primarily to diagnose which issue?

A system supply airflow check is primarily used to diagnose humidity problems because airflow plays a crucial role in the dehumidification process in air conditioning systems. Proper airflow across the evaporator coil is necessary for effective heat exchange, which includes the removal of moisture from the air. If the airflow is insufficient, it can lead to high humidity levels in the conditioned space, as the system won't adequately dehydrate the air.

When airflow is restricted or improper, it can cause a range of issues that affect both comfort and system performance. For instance, inadequate airflow can prevent the evaporator coil from reaching the appropriate temperature necessary for optimal dehumidification, resulting in excess humidity. Therefore, conducting a supply airflow check helps technicians identify and rectify airflow issues, ultimately addressing humidity concerns effectively.

The other issues mentioned are typically related to other factors, such as the performance of specific components rather than airflow itself.