What symptoms can a dirty evaporator cause in an air conditioning system?

A dirty evaporator can significantly impact an air conditioning system's performance, primarily due to its role in the heat exchange process. When the evaporator coil is dirty, it creates an insulating layer that reduces the coil's ability to absorb heat from the indoor air. This reduced heat absorption can lead to several issues within the system.

One of the symptoms of a dirty evaporator is low suction pressure. With insufficient heat absorption, the refrigerant in the evaporator does not evaporate adequately, resulting in a decreased pressure in the suction line. This is indicative that the refrigerant is not absorbing enough heat to transition fully from liquid to gas.

In addition to low suction pressure, a dirty evaporator may also cause low discharge pressure. This occurs because the compressor is working inefficiently; it is not able to draw in enough vaporized refrigerant, leading to lower pressures overall. The reduced volume and energy of the refrigerant returning to the compressor can hinder its ability to function properly, leading to both pressures being affected negatively.

Therefore, a dirty evaporator is characterized by low suction pressure and low discharge pressure, aligning with the dynamics of heat exchange in air conditioning systems and the operational impacts of a dirty coil.