A system attachable to a refrigeration circuit, the system comprising: a recovery pump attachable to the refrigeration circuit to remove refrigerant therefrom, the recovery pump including a pump, an electric motor for driving the pump, a battery pack for providing power to the electric motor, and a recovery pump controller for controlling the operation of the electric motor, the recovery pump controller having a first communication interface; and an accessory attachable to the refrigeration circuit concurrently with the recovery pump, the accessory including a sensor for detecting a characteristic value of the refrigeration circuit, and an accessory controller electrically connected with the sensor to receive a signal therefrom corresponding with the characteristic value of the refrigeration circuit, the accessory controller having a second communication interface to communicate the signal to the recovery pump controller via the first and second communication interfaces (58, 84), wherein the recovery pump controller is operable to control the operation of the electric motor based upon the signal received from the accessory, and wherein the system is configured such that the pump is operable in a fluid removal state, in which the pump removes the refrigerant from the refrigeration circuit when the electric motor is activated, and in a fluid supply state, in which the pump supplies the refrigerant to the refrigeration circuit when the electric motor is activated. a recovery pump attachable to the refrigeration circuit to remove refrigerant therefrom, the recovery pump including a pump, an electric motor for driving the pump, a battery pack for providing power to the electric motor, and a recovery pump controller for controlling the operation of the electric motor, a pump, an electric motor for driving the pump, a battery pack for providing power to the electric motor, and a recovery pump controller for controlling the operation of the electric motor, the recovery pump controller having a first communication interface; and an accessory attachable to the refrigeration circuit concurrently with the recovery pump, the accessory including a sensor for detecting a characteristic value of the refrigeration circuit, and an accessory controller electrically connected with the sensor to receive a signal therefrom corresponding with the characteristic value of the refrigeration circuit, the accessory controller having a second communication interface to communicate the signal to the recovery pump controller via the first and second communication interfaces (58, 84), a sensor for detecting a characteristic value of the refrigeration circuit, and an accessory controller electrically connected with the sensor to receive a signal therefrom corresponding with the characteristic value of the refrigeration circuit, the accessory controller having a second communication interface to communicate the signal to the recovery pump controller via the first and second communication interfaces (58, 84), wherein the recovery pump controller is operable to control the operation of the electric motor based upon the signal received from the accessory, and wherein the system is configured such that the pump is operable in a fluid removal state, in which the pump removes the refrigerant from the refrigeration circuit when the electric motor is activated, and in a fluid supply state, in which the pump supplies the refrigerant to the refrigeration circuit when the electric motor is activated. operable in a fluid removal state, in which the pump removes the refrigerant from the refrigeration circuit when the electric motor is activated, and in a fluid supply state, in which the pump supplies the refrigerant to the refrigeration circuit when the electric motor is activated.