Installed zoned 4-ton R-454B Carrier Infinity system with gas furnace and evaporator coil in the attic. Installed Carrier Infinity thermostats. Installed new Infinity zone control board. Built and installed new supply plenum with 1 square zone damper and 1 round zone damper. Built and installed new return plenum with 2 - 20x25 Aprilaire media filters. Installed new secondary drain pan. Rebuilt primary condensation drain and added SS2 and SS3 safety switches. Installed new gas pipe and flue pipe connections for the furnace. Pressure tested system with nitrogen and pulled vacuum. Cleared primary drain with CO2 and primed trap with water. Charged AC with R-454B refrigerant according to Infinity thermostat. Tested heating and cooling operation of new system. Tested operation of zone control. Everything is working at completion of install.