Fujitsu ARU7RLF Service Instruction

Also see for AGU12RLF: Design & technical manual Service manual Service instructions Service instructions Design & technical manual

Thermistor Characteristics (Rough value)If Thermistor is either open or shorted, replace it and reset the power.Detective Actuators:Indoor Unit Controller PCBHeat Exchanger (MID) ThermistorDetective details:Heat Exchanger (MID) thermistor is open or short is detected always.Forecast of Cause : 1. Connector failure connection 2. Thermistor failure 3. Controller PCB failureCheck Point 1 : Check connection of ConnectorCheck if connector is loose or removedCheck erroneous connectionCheck if thermistor cable is open>>Reset Power when reinstalling due to removed connector or incorrect wiring.OKCheck Point 2 : Remove connector and check Thermistor resistance value02-11Trouble shooting 8INDOOR UNIT Error Method:Indicate or Display:Indoor Heat Ex. Thermistor Error Refer to error code table.Resistance Value ( )Temperature (°F)31.79539.68649.762.9580.3103.3134.2176.0776859504132Resistance Value ( )Temperature (°F)17.120.925.6122113104OKCheck Point 3 : Check voltage of Controller PCB (DC5.0V)Make sure circuit diagram of each indoor unit and check terminal voltage at Thermistor (DC5.0V)Small size Wall mount circuit diagram(Connector connection)If the voltage does not appear, replace Controller PCB and execute the check operation again.H/E (MID) ThermistorRoom Temp. ThermistorRoom Temp. ThermistorH/E ThermistorDCCassette circuit diagram (Connector connection) Wall mount circuit diagram (Direct soldering to PCB)Duct circuit diagram (Connector connection)BLACKBLACK34CN4123412BLACKBLACKBLACKBLACKBLACKBLACK1212CN3CN1123123REDWHITEH/E ThermistorRoom Temp. ThermistorBLACKBLACK12121 12 2CN5CN8GRAYGRAY12CN7BLACKBLACK12121 12 2CN5CN8GRAYGRAY H/E (MID) ThermistorRoom Temp. ThermistorFloor circuit diagram (Connector connection and Direct soldering to PCB)BLACKBLACK121212CN3CN1GRAYGRAY H/E (MID) ThermistorRoom Temp. Thermistor