The suction line should be sized so that the maximum pressure drop equals a saturation temperature drop of how many degrees Fahrenheit?

The correct choice of a 2-degree Fahrenheit saturation temperature drop for sizing the suction line is based on industry standards that help ensure efficient system performance. This guideline helps maintain refrigerant capacity and minimizes the potential for issues like compressor flooding or decreased cooling effectiveness.

A 2-degree drop is considered optimal because it strikes a balance between minimizing pressure loss and ensuring that the refrigerant remains in a gaseous state, which is critical for proper compressor operation. If the pressure drop were to exceed this threshold, it could indicate that the suction line may be oversized, leading to inefficiencies or poor system operation.

Sizing the suction line to maintain this specific pressure drop helps ensure that the refrigerant's flow remains adequate for heat transfer while preventing excessive energy consumption. This ensures the equipment operates within its designed parameters, optimizing performance and prolonging the lifespan of the system. Therefore, a 2-degree Fahrenheit drop is a standard practice widely accepted within the HVAC industry for maintaining system reliability and efficiency.