Which condition could lead to flooding in the evaporator?

Improper thermal bulb installation can lead to flooding in the evaporator because the thermal bulb is responsible for regulating the refrigerant flow through the evaporator. If it is not installed correctly, the bulb may not accurately sense the temperature of the refrigerant or may not function properly. This can result in the refrigerant not evaporating fully or at the right pace, leading to an excess buildup of liquid refrigerant in the evaporator. Such flooding can cause inefficiencies in the cooling process, leading to improper temperature control and potentially damaging the system.

In contrast, other conditions, while they may impact system performance, do not specifically create a situation where flooding in the evaporator is likely to occur. For instance, high outside temperatures can lead to increased cooling load and may cause overall system strain, but they do not directly affect the refrigerant's phase change in the evaporator as an improperly installed thermal bulb would. Compressor overloading might lead to other issues like high pressure or system failure, but it doesn’t directly cause flooding either. Insufficient airflow can reduce the efficiency of heat exchange but does not directly correlate with the proper functioning of the thermal bulb. Hence, improper thermal bulb installation is the most direct cause of flooding in the evaporator.