Abstract: A heat exchange apparatus having a first header for receiving fluid from a source, flexible thin-walled tubular plastic heat exchange elements defining a plurality of passages through a heat exchange zone and second header means for receiving fluid from said plastic heat exchange elements after passing through said heat exchange zone. Support elements are provided, supporting and rigidifying the flexible thin-walled tubular plastic heat exchange member. The plastic heat exchange element defining said plurality of passages is radially expandable by pressure of fluid from said source to avoid scale formation.