A refrigerant handling system that includes a compressor for pumping refrigerant through the system, and an evaporator connected to the compressor inlet for ensuring that refrigerant fed to the compressor inlet is in vapor phase. A flow control device is coupled to the inlet of the evaporator for controlling flow of refrigerant to the evaporator, and comprises a thermostatic expansion valve having first and second pressure inputs, and valve elements for controlling flow of refrigerant through the valve to the evaporator as a function of a pressure differential between the pressure inputs. A first bulb containing refrigerant is sealingly coupled to the first pressure input of the valve, and is positioned so as to supply a first control pressure to the valve as a function of vapor pressure of refrigerant in the bulb at the temperature of refrigerant entering the evaporator. A second bulb containing the same type of refrigerant is sealingly coupled to the second pressure input of the valve, and is positioned to supply a control pressure to the second valve input as a function of vapor pressure of refrigerant at the temperature of refrigerant exiting the evaporator.