Large scale field erected air cooled industrial steam condenser. A bottom bonnet runs along the bottom length of the heat exchanger bundle for delivering steam to the bottom end of the condenser tubes and for receiving condensate formed in those same tubes. The tops of the tubes are connected to a top bonnet. Uncondensed steam and non-condensables flow into the top bonnet from the condenser tubes. Each cell of the ACC is fed by steam distribution manifold suspended from and directly below the bundle support framework.