What is a typical cause of liquid slop over in an ammonia refrigeration system?

A typical cause of liquid slop over in an ammonia refrigeration system is overfeeding the liquid to a direct expansion (DX) evaporator. In a DX evaporator, the refrigerant absorbs heat from the surrounding area, causing it to evaporate. If too much liquid refrigerant is fed into the evaporator, it can cause the liquid to flood the evaporator coil rather than allowing it to completely vaporize. This flooding leads to a buildup of liquid refrigerant in the evaporator, resulting in liquid slop over into the suction line, impairing the system's efficiency and potentially damaging the compressor.

Proper feed rates and control of liquid refrigerant are crucial to ensuring that the evaporator operates correctly, allowing for optimal heat exchange and preventing issues such as slop over. The other options involve factors that can affect system performance but do not directly cause liquid slop over in the way that overfeeding does.