Installed 5 ton R-454B Carrier condenser and evaporator coil. Installed vertical Carrier gas furnace with propane conversion. Installed new disconnect box and high voltage wiring for the condenser. Installed new plywood overlay and filter base for the furnace to sit on, with 20x25 filter. Installed all new flue pipe up to the roof. New gas connections for the furnace. Installed Ecobee pro thermostat. Built and installed new extended supply plenum. Cleaned out the return chase. Sealed all connections with mastic / hardcast. Pressure tested system with nitrogen and pulled vacuum. Adjusted gas pressures for propane operation. Charged AC with R-454B refrigerant.