What could cause an A/C system to freeze up?

Low refrigerant levels or poor airflow can lead to an A/C system freezing up primarily due to the drop in pressure within the evaporator coil. When refrigerant levels are low, there isn’t enough refrigerant to absorb heat effectively. This can cause the evaporator coil to operate at too low a temperature, leading to ice formation.

Similarly, when there is poor airflow, perhaps due to a dirty filter, blocked ducts, or an obstructed blower fan, the warm air that should be passing over the evaporator coil is insufficient. Without this warm air, the coil does not receive the heat it needs to prevent freezing, causing frost or ice to accumulate.

These two factors create a cycle where reduced heat exchange continues to exacerbate the freezing issue, leading to a malfunctioning air conditioning system that may even shut down due to the ice blockage. Understanding these dynamics is crucial for diagnosing and maintaining an efficiently operating A/C system.