Carrier 40MBQB09D-3 Service Manual

Also see for 40MBQB09D--3: Service manual Owner's manual

Contents

33DIAGNOSIS AND SOLUTION (CONT)Inverter compressor drive error diagnosis and solution (P4)Error Code P4Malfunction decision conditionsAn abnormal inverter compressor drive is detected by a special detection circuit,including communication signal detection, voltage detection, compressor rotation speedsignal detection.Supposed causes Wiring mistake; IPM malfunction; outdoor fan ass'y faulty Compressor malfunction; Outdoor PCB faultyFig. 43 – TroubleshootingMain Parts CheckTemperature sensor checkingDisconnect the temperature sensor from PCB, measure the resistance value with a tester.Fig. 44 – TesterTemperature Sensors.Room temp.(T1) sensor,Indoor coil temp.(T2) sensor,Outdoor coil temp.(T3) sensor,Outdoor ambient temp.(T4) sensor,Compressor discharge temp.(T5) sensor.Measure the resistance value of each winding by using the multi−meter.