Question 132Refrigeration & AC - 1st Asst/Chief

The correct answer is C) temperature of the evaporator coil outlet. The pressure within the power element of a thermostatic expansion valve depends directly on the temperature of the refrigerant leaving the evaporator coil. This is because the power element contains a fluid that expands and contracts in response to changes in temperature, which in turn controls the opening of the valve to maintain the desired superheat at the evaporator outlet. The other options are incorrect because they do not directly determine the pressure in the power element. The compressor suction pressure (A) and the temperature in the box (B) can influence the operation of the thermostatic expansion valve, but they do not directly affect the pressure within the power element. The heat transferred from the saturated liquid in the evaporator (D) affects the evaporator coil temperature, but it is the resulting temperature at the evaporator outlet that determines the pressure in the power element.