Which of the following factors does NOT affect the capacity of a thermostatic expansion valve?

The correct answer indicates that the external equalizer does not affect the capacity of a thermostatic expansion valve. This is because the external equalizer primarily serves to balance the pressure in the system and allows the valve to maintain a consistent superheat setting by measuring the pressure downstream of the evaporator. It does not directly influence the overall capacity or flow rate that the valve can handle.

On the other hand, temperature difference, pressure settings, and compressor output all play critical roles in determining the capacity of the thermostatic expansion valve. The temperature difference directly affects the refrigerant’s vaporization process, influencing how much heat the refrigerant will absorb. Pressure settings are crucial since they dictate the performance characteristics of the entire refrigeration cycle, thereby impacting how the expansion valve regulates refrigerant flow. Finally, the compressor output is a vital factor, as it determines how much refrigerant is being pushed through the system at any given time. This output affects how the thermostatic expansion valve must modulate to maintain optimal system performance.