Waste heat reuse system, in particular for a motor vehicle, with a feed pump

The system has a feed pump (1), and temperature sensors (Ta, Tg) for direct or indirect detection of a current working medium temperature. The sensors are attached to a control unit (S) for controlling a pump drive. A temperature threshold value is preset in the control unit, and compared with the temperature. The drive and a pump conveying unit are deactivated by the control unit during falling below the value. The drive and the conveying unit are switched on during exceeding the value or another temperature threshold value, which is defined high relative to the former threshold value. The pump drive is a mechanical pump drive. The working medium is water. An independent claim is also included for a method for operating a waste heat utilization system.