What symptoms are likely to result from a dirty evaporator in an air conditioning system?

A dirty evaporator in an air conditioning system can impede the heat exchange process, leading to insufficient absorption of heat from the indoor air. This scenario often results in low suction pressure and low discharge pressure.

When the evaporator coils are clogged with dirt and debris, they can't efficiently absorb heat, which means less refrigerant evaporates within the coils. A decrease in the evaporating refrigerant reduces the pressure on the suction side of the system because there is not enough heat transfer occurring. Consequently, this can also lead to lower discharge pressure, as the compressor works less efficiently due to the reduced flow of refrigerant.

In contrast, options that describe high pressures or inconsistent temperature control may indicate other issues but are not directly linked to a dirty evaporator. For example, high suction and discharge pressures typically arise from problems like overcharging or system blockage elsewhere. Thus, focusing on the effects of a dirty evaporator leads to the conclusion that low pressures are expected due to the decreased efficiency of heat exchange.