Heat exchanger

The heat exchanger assembly (14), and especially for a motor vehicle heating system (10) with a burner (12), has a fluid flow zone (30) enclosed by a housing structure (26,28) and a sensor (34) system to register the fluid temperature. The sensor system has at least one temperature sensor (36,38), embedded at least partially into the plastics housing material. The heat exchanger assembly (14), and especially for a motor vehicle heating system (10) with a burner (12), has a fluid flow zone (30) enclosed by a housing structure (26,28) and a sensor (34) system to register the fluid temperature. The sensor system has at least one temperature sensor (36,38), embedded at least partially into the plastics housing material. One sensor can be wholly encapsulated in the housing material, and the other sensor projects into the fluid flow zone at a measurement section (40).