A common accessory added to multiple evaporator systems operating at different evaporating temperatures is the evaporator pressure regulator (EPR). It is a refrigerant flow control device that prevents the refrigerant pressure in an evaporator from operating below a minimum value. It is typically installed on those evaporators designed to
operate at a pressure higher than the evaporator with the lowest design operating pressure. The EPR will prevent these evaporators from operating at the lower operating pressure. It is normally installed in the suction line just after the outlet of these evaporators and upstream of any other suction line controls or accessories.