Installed 3 ton Carrier straight electric R-454B system, vertical air handler with electric heat kit. Installed new disconnect box and wiring for the condenser. Leveled new condenser on new pad. Installed new plywood platform for the air handler to sit on. Rebuilt primary drain line and installed new safety switches. Built and installed extended supply plenum. Installed Ecobee pro thermostat. Attached existing flex to new plenum and sealed all connections with mastic/hardcast. Pressure tested system with nitrogen and pulled vacuum. Charged the system with R-454B refrigerant. Cleared primary drain with CO2 and primed trap with water. Tested heating and cooling operation. Everything is working at completion of service.