No. The heat exchangers are installed during ongoing operation. If necessary, the dry weather flow is guaranteed by means of water retention, i.e. a bypass is laid during the installation period allowing work to continue without disruption. The need for and extent of water retention measures are determined as part of the obligatory sewer inspection during the project planning phase. Guaranteeing uninterrupted operation of the sewer during installation is a major factor in the success of the technology. Otherwise, it would not be approved.