Abstract: A fluid flow control valve for use, in particular, in a heating and cooling system for a building, enables change-over of interconnections between ducts connected to rooms of the building and to the exterior and ducts connected to a heat recovery module for adapting the system to summer or winter operation. The control valve has a member rotatable about a predetermined axis of rotation between first and second positions, stationary first ducts distributed around the axis, flexible second ducts for communication with respective ones of the first ducts, the second ducts each having an end secured to the rotary member for movement therewith from one to another of the first ducts, and seals for sealing the second ducts to the first ducts.