What impact does reducing the airflow across the evaporator have on the system?

Reducing the airflow across the evaporator adversely affects the cooling efficiency of the system. The evaporator's primary function is to absorb heat from the indoor air, which cools the air as it passes over the evaporator coil. When airflow is reduced, less warm air is available for heat exchange, which results in a decrease in the amount of refrigerant evaporating in the coil.

As the evaporator becomes less effective at absorbing heat, the temperature and pressure of the refrigerant in the evaporator drop. This is because the evaporator coil experiences an increase in evaporating temperature, and less refrigerant vapor is produced, leading to a decrease in suction line pressure. Consequently, the system struggles to maintain stable operating conditions, leading to issues like frozen coils or reduced cooling capacity.

The reduced airflow can ultimately lead to other problems in the system, such as increased energy consumption, but the immediate and primary impact is the lowering of the suction line pressure as the system cannot maintain the required heat exchange efficiency.