SiUS181631EA Troubleshooting for FFQ SeriesTroubleshooting 2155.8 Signal Transmission Error (Between Indoor Unit andRemote Controller)Error Code U5Method of ErrorDetectionIn case of controlling 1 indoor unit with 2 remote controllers, check the system using microcomputerif signal transmission between indoor unit and remote controller (main and sub) is normal.Error DecisionConditionsNormal transmission does not continue for specified period.SupposedCauses Connection of 2 main remote controllers (when using 2 remote controllers) Defective indoor unit PCB Defective remote controller Signal transmission error caused by noiseTroubleshootingNote: For the way to change MAIN/SUB setting of remote controllers, refer to pages 148 and 149.CautionBe sure to turn off the power switch before connecting or disconnectingconnectors, or parts may be damaged.Are bothremote controllers set toMAIN?Do theservice monitors of allthe indoor unitsblink?Doesoperation returnto normal when thepower is turned offmomentarily?NONOYESYESNOReplace the indoor unitPCB (control PCB).Set one remote controller toSUB; turn the power supplyoff once and then back on.When using both wired andwireless remote controllers for1 indoor unit, make sure to setthe wireless remote controllerto SUB.There is possibility ofmalfunction caused by noise.Check the surrounding areaand turn on again.There is possibility ofmalfunction caused by noise.Check the surrounding areaand turn on again.NormalNormalNO NOUsing2 remote controllersfor 1 indoor unit?YES YESYESReplace the remote controller.Return to normal?Return to normal? NOReplace the indoor unit PCB.YES(R24057)
