A customer reports that their air conditioning system runs constantly but is not cooling adequately. When inspecting, you find the suction line is very cold and the compressor is sweating. What is a likely cause?

A likely cause for the air conditioning system running constantly without adequately cooling while exhibiting a very cold suction line and sweating compressor is a restriction of return air or a dirty evaporator.

When the evaporator coil becomes dirty or there is a restriction in the return air system, it can significantly hinder the airflow over the evaporator coil. This reduced airflow means that the coil does not effectively absorb heat from the air in the space, leading to inadequate cooling performance. The result is that the system may run continuously in an attempt to cool the indoor space, but without sufficient airflow, it cannot achieve the desired temperature.

In addition, the very cold suction line indicates that the refrigerant is absorbing heat, but with lack of airflow across the evaporator due to the restriction, it cannot transfer enough of that absorbed heat away, leading to the impression that the system is underperforming in terms of cooling. The sweating compressor can be a sign of temperature imbalance or the effect of the system trying to work harder under these conditions, leading to condensation.

Other potential causes, such as high refrigerant levels or a faulty thermostat, do not directly correlate with the symptoms observed in this scenario. A malfunctioning compressor may cause issues related to cooling, but would typically present with different