Final answer:
The line from the external equalizer is installed in refrigeration and air conditioning systems, providing a pressure signal to the thermostatic expansion valves from the suction line near the evaporator outlet.
Step-by-step explanation:
The line from the external equalizer is commonly installed in refrigeration and air conditioning systems that use thermostatic expansion valves (TXVs). This line is connected to the suction line near the evaporator outlet and its main purpose is to provide a pressure signal to the TXV, ensuring that the valve adjusts the flow of refrigerant properly to match the current load conditions. This set-up helps maintain the efficiency of the cooling system and prevents issues like coil frosting or reduced cooling capacity.
The external equalizer line is therefore installed between the outlet of the evaporator and the TXV. It's important for it to be installed properly to ensure the correct functioning of the refrigeration or air conditioning system.