SiBE041012_A TroubleshootingService Diagnosis 1204.26 Low-voltage Detection or Over-voltage DetectionRemoteControllerDisplayU2Method ofMalfunctionDetection+ Indoor UnitEvaluation of zero-cross detection of power supply by the indoor unit PCB.+ Outdoor UnitLow-voltage detection:An abnormal voltage drop is detected by the DC voltage detection circuit.Over-voltage detection:An abnormal voltage rise is detected by the over-voltage detection circuit.MalfunctionDecisionConditions+ Indoor UnitThere is no zero-cross detection in approximately 10 seconds.+ Outdoor UnitLow-voltage detection: The voltage detected by the DC voltage detection circuit is below 150 ~ 180 V (depending onthe model).Over-voltage detection: An over-voltage signal is fed from the over-voltage detection circuit to the microcomputer.(The voltage is over 400 V.) If the error repeats, the system is shut down. Reset condition: Continuous run for about 11 minutes (50 class: 5 minutes) without anyother errorSupposedCauses Power supply voltage is not as specified. Defective DC voltage detection circuit Defective over-voltage detection circuit Defective PAM control part Disconnection of compressor harness Noise Momentary fall of voltage Momentary power failure Defective indoor unit PCB
