Upon arrival system not operational; tripping on high limit after 10 minutes. Had 93 degree air coming back through the return from the Barometric bypass. Found one return duct pinched around joist. Also found zone 1 damper motor stuck closed causing higher static pressure and more heat gain in bypass. Opened stuck zone damper. Adjusted 2 return ducts for better airflow, increased CFM from 1480 to 1930. Return air temp. Now 82 degrees. System is currently operational. Disconnected both zone motors for temporary operation. Need to remove bypass. Replace zone board and damper motors.