A control system, for controlling a closed-circuit respirator breathing gas circuit, includes a temperature sensor, a temperature-reading unit and with a control unit. The temperature sensor is configured to send a temperature signal in the presence of a corresponding temperature polling. The temperature signal indicates the temperature currently present in an area surrounding the temperature sensor. The temperature-reading unit is arranged in the closed-circuit respirator at a spaced location from the breathing gas circuit and the temperature sensor, and is configured to trigger the temperature polling at the temperature sensor by sending a polling signal, and to receive the temperature signal sent by the temperature sensor. The control unit is signal connected to the temperature-reading unit and is configured to determine the temperature indicated by the temperature signal in the area surrounding the temperature sensor and to output a control signal as a function of this temperature.