A system supports an outlet, within a storage silo, of a pneumatic conveyor. The outlet comprises a horizontal section, a vertical section, and an elbow interconnecting the sections. The system comprises a vertical support for suspending and centering the outlet, and a horizontal support for selectively supporting the outlet upon the silo floor. The horizontal support has clamp assemblies mounted on the horizontal section, and sets of removable support legs respectively attachable to the clamp assemblies. The horizontal support also has elbow clamp assemblies adjacent the elbow, and an elbow brace and a subframe each interconnecting the elbow clamp assemblies. Each of the support legs has a locking pin for locking that leg in a deployed position, and a storing hole for placing that leg in a stored position. The system further comprises a deflector, and sets of stanchions therefor respectively attached to the clamp assemblies of the horizontal support.