Built and installed new supply plenums for zoning system with 16x16 dampers. Installed new zone control board. Installed Solaris Ionizer system in the supply plenums. Cut back some of the old flex duct and replaced with new sections. Sealed all ductwork connections with mastic / hardcast. Installed new black metal gas pipe and gas flex coming out of the furnace to fix gas leak. Tested operation of the system and new zoning equipment. Everything is working at completion of service.