The invention relates to a condenser tumble dryer with a drum for articles to be dried, a drive motor for the drum, a process air duct, a process air blower, a heating and cooling system for the process air, a temperature sensor and a control device. The temperature sensor is an infrared telescope and is arranged to simultaneously measure heat radiation from at least two components of the condenser tumble dryer which are to be monitored. The invention also relates to a method for operating a condenser tumble dryer of said type.