Built and installed 3 new supply plenums in Bull head T shape. Installed zoning damper in each plenum. Built and installed new return air plenum. Attached existing flex duct and sealed all connections with mastic/hardcast. Installed new 2 stage 3 zone control board and rewired. Cleared primary drain with CO2 and primed trap with water. Tested operation of system and the new zoning equipment. Everything is working at completion of service.