SiBE041029EB TroubleshootingService Diagnosis 624.7 Low-voltage Detection or Over-voltage DetectionError Code U2Method of ErrorDetectionLow-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.Error DecisionConditionsLow-voltage detection: The voltage detected by the DC voltage detection circuit is below 150 ~ 200 V (depending onthe model). The compressor stops if the error occurs, and restarts automatically after 3-minute standby.Over-voltage detection: An over-voltage signal is fed from the over-voltage detection circuit to the microcomputer. The compressor stops if the error occurs, and restarts automatically after 3-minute standby.SupposedCauses 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 Short circuit inside the fan motor winding Noise Momentary drop of voltage Momentary power failure Defective outdoor unit PCB
