Completed homecare visit today in single gas system in attic. Inspected ductwork, filter, flushed drain line and tested heating operation. Checked gas pressures and adjusted to manufacture specifications. Tested electrical components, took amp draws and verified system operation from thermostat. Inspected outdoor unit electrical, refrigerant levels and checked condenser coil overall condition. System is zoned with a 14" and 8" damper for one zone and a 12" damper for upstairs. The 14" damper is getting stuck, not opening all the way once it closes. Zoning system is missing D.A.T.S., discharge air temperature sensor, and missing a bypass damper. Return ductwork is undersized with 920cfm but 3 ton system requires 1200 cfm. Total repairs listed as follows, installation of 12" bypass damper, discharge air temperature sensor, 14" damper replacement and adding a 12" return to ductwork. Inadequate flood protection on attic system. System is operational at time of service.