A heat exchanger having an arrangement of heat transfer surfaces and a pair of vertical steam/water separators structurally interconnected to one another to provide an integral support structure for the heat exchanger. The structural interconnection includes upper and lower structural members extending between the pair of vertical steam/water separators. The upper and lower structural members include headers, and an arrangement of heating surface which extends between and is fluidically connected to the headers. A structural support framework surrounds the heat exchanger for bottom support thereof, the framework providing structural support and rigidity for the heat exchanger and a means by which the heat exchanger can be picked up and lifted for placement at a desired location.