Installed 2.5 ton Payne R-454B system. Vertical gas furnace. Installed Ecobee lite thermostat. Installed new disconnect box for the condenser and new pad. Installed new plywood for the furnace to sit on. New gas pipe and flue pipe connections. Built and installed new extended supply plenum. Sealed all ductwork connections with mastic/hardcast. Rebuilt primary drain, added secondary safety switch. Found poly pipe drain broken and disconnected underneath the house. Installed all new drain pipe. Pressure tested system with nitrogen and pulled vacuum. Charged AC with R-454B refrigerant. Tested heating and cooling operation. Everything is working at completion of install.