Troubleshooting for Outdoor Unit SiEBE18-526296 Troubleshooting7.3 Actuation of Low Pressure SwitchRemoteControllerDisplayE4ApplicableModelsAII outdoor unit modelsMethod ofMalfunctionDetectionMalfunctionDecisionConditionsError is generated when the low pressure is dropped under specific pressure.SupposedCauses Abnormal drop of low pressure Defect of low pressure sensor Defect of outdoor unit PCB Stop valve is not opened.Troubleshooting∗1: Voltage measurement point∗2: Refer to pressure sensor, pressure / voltage characteristics table on P328.(Q0423)CautionBe sure to turn off power switch before connect or disconnect connector,or parts damage may be occurred.Is the malfunctiondue to abnormal drop of lowpressure?Measurethe voltage (VL)of X45A pin No. (2) - (3)of outdoor PCB (A1P).∗1Is the relationshipbetween lowvoltage and VLnormal?∗2Out of gas, refrigerant systemclogging, wiring and piping wrongconnection, stop valve closed,electronic expantion valve fullyclose malfunction.Replace the low pressure sensor.Replace outdoor unit PCB A1P.NONOYESYESIs stop valve opened? Open stop valve.NOYESOutdoor unit PCB A1PGNDLow pressure sensor(Q0424)RedBlackWhite4321+5VX45A(blue)MicrocomputerA/D input*2 Measure voltage (DC) within this space
