The subject of the work is the design of the machine for heat recovery device automatic assembling. The material of the heat recovery unit is polypropylene plate. The device is designed for assembling plate heat recovery unit of maximum dimensions 2050x2050x800 mm. It was found that such machine for heat recovery unit assembling does not exist in the market. Devices that can be used as partial solutions for individual systems are found. By creating goals for product development, functional decomposition and morphological matrix, the guidelines for the design of the machine are settled and complete solutions in the form of concepts are offered. The device consists of a material supply system, the pick and place positioning system, automated adhesive system and plate suppression system. The machine is fully automated and with the possibility of assembling two heat recovery units at the same time, speeds up the production process. Through concept evaluation and techno-economic analysis, the final design of the machine is given. The design of the machine is made by using standard assemblies and calculations of non-standard parts. 3D CAD model of the machine is made with all necessary technical documentation.