The heat exchangers are installed in accordance with the relevant requirements of the regulator, DWA (German Association for Water Management, Wastewater and Waste). The requirements are defined in DWA leaflet 114. The heat exchanger modules are not concreted in, for example; they are fixed with “hold-down devices”. Hold-down devices are brackets which are fixed in the sewer wall with an HKD expansion anchor. The maximum bore depth is 40 mm, bore diameter 12 mm. The anchor is screwed in flush, using countersunk screws (DIN 7991 M10x25). All fixing elements are made in 1.4404 quality to avoid interactions. The elements and connecting parts are protected from dirt and damage by deflector plates. These deflector plates and the cladding of the forward and return flow pipes are also made from 1.4404 steel. The transition areas from the sewer bottom to the first element and from the last element are each protected by run-up and discharge ramps so that no coarse matter can get stuck. The ramps are also made from 1.4404 steel.
