What purpose does an equalizer line serve on a thermal expansion valve (TEV)?

The equalizer line on a thermal expansion valve (TEV) plays a critical role in maintaining proper refrigerant flow through the system and ensuring efficient operation of the refrigeration cycle. Its primary purpose is to compensate for the pressure drop that occurs across the evaporator coil.

When refrigerant passes through the evaporator, it absorbs heat and changes from a liquid to a gas. This process can create a pressure differential between the inlet and the outlet of the evaporator coil. The equalizer line connects the evaporator outlet to the TEV, allowing the valve to sense the lower pressure at the outlet. By doing so, it adjusts the opening of the TEV to ensure that the flow of refrigerant matches the evaporator load. This regulation is essential for optimizing the performance of the system, as it prevents issues like flooding or starving the evaporator, leading to inefficient operation or potential damage.

The other choices do not accurately describe the function of the equalizer line. While overheating prevention, measuring refrigerant flow, and improving compressor efficiency are important aspects of a refrigeration system, they do not directly relate to the specific purpose of the equalizer line in compensating for pressure drops across the evaporator coil.