Installed 3.5-ton R-454B Payne condenser. Installed Carrier evaporator coil and gas furnace with propane conversion. Installed new surge protector for the condenser. Installed new secondary drain pan for the evaporator coil. Built and installed new extended supply plenum. Built and installed new return plenum. Cut in new supply and return for the master bedroom, with new buckets and new 9 inch flex duct on both. Sealed all duct work connections with mastic/hardcast. Installed new gas pipe and flue pipe connections for the gas furnace. Rebuilt primary condensation drain, added SS2 and SS3 safety switches. Added insulation to the secondary drain pipe. Pressure tested system with nitrogen and pulled vacuum. Cleared primary drain with co2 and primed trap with water. Installed Ecobee Pro thermostat. Installed wire junction box for the outdoor condensing units. Weighed in 2lb 9oz of R-454b refrigerant. Adjusted gas pressures for propane operati