A steam cooking system includes a first steam cooking cavity, a second steam cooking cavity and a steam generator. The steam generator includes a steam outlet for selectively feeding steam to one or both of the first steam cooking cavity and the second steam cooking cavity, the outlet selectively connectable to feed steam to the first steam cooking cavity and/or the second steam cooking cavity via a valved fluid path. The valved fluid path includes a main supply valve, a first valve and a second valve configured and controllable to assure that the steam generator outlet is always connect to atmosphere by one or more paths.
