Mitsubishi MSH-24NV Service Manual Page 1

SERVICE MANUALFLOOR AND CEILING TYPE AIR CONDITIONERSCONTENTS1. TECHNICAL CHANGES ····································22. PART NAMES AND FUNCTIONS····

10Dry Bulb temperature (˚C)202530Relative humidity (%)506070OUTDOOR LOW PRESSURE AND OUTDOOR UNIT CURRENTCOOL operation1 Both indoor and outdoor units

11MICROPROCESSOR CONTROL8WIRELESS REMOTE CONTROLLERMCFH-24NV - MUCFH-24NV -EBEBOnce the operation mode are set, the same operation modecan be repeat

12w1 After the system restarts by the remote controller, the system operates with the previous set temperature regardless ofthe initial set temperatur

13NOTE : Coil frost prevention during COOL mode of “I FEEL CONTROL”There are two types of controls in coil frost prevention as follows.1 Temperature c

14— HEAT mode of “I FEEL CONTROL” —1. Indoor fan speed control(1) Followings are the fan speed in AUTO.Room temperature minus set temperature: 2 degre

152. High pressure protectionDuring heating operation, the outdoor fan motor is controlled by the indoor coil thermistor RT12 temperature for excess r

16NOTE ● When the indoor coil thermistor reads above 18°C, indoor fan operates at Very Low for 30 seconds.● When the indoor coil thermistor reads 18

178-2. COOL ( )OPERATION(1) Press OPERATE/STOP button.OPERATION INDICATOR lamp of the indoor unit turns on with a beep tone.(2) Select COOL mode.(

188-5. AUTO VANE OPERATION(1) Vane motor driveThis series is equipped with a stepping motor for the vane. The rotating direction, speed, and angle of

198-6. TIMER OPERATION1. How to set the timer (1) Press OPERATE/STOP button to start the air conditioner.(2) Check that the current time is set correc

TECHNICAL CHANGES21PART NAMES AND FUNCTIONSINDOOR UNITMCFH-24NV -EB(When installed on the floor)(When the air inlet grille is opened.)Deodorizing fil

208-7. EMERGENCY-TEST OPERATIONWhen the remote controller is missing, has failed or the batteries run down, press the EMERGENCY OPERATION switch on th

21SERVICE FUNCTIONS9MCFH-24NV -EB9-1. TIMER SHORT MODEFor service, set time can be shortened by short circuit of JPG and JPS on the electronic contro

229-3. COMPULSORY DEFROSTING MODE FOR SERVICEBy short circuit of the connector JPG1 and R871 on the outdoor deicer P.C. board, defrosting mode can be

23TROUBLESHOOTING10MCFH-24NV - MUCFH-24NV -EBEB10-1. Cautions on troubleshooting10-1-1. Before troubleshooting, check the followings: 1) Check the p

24StartIndoor unit operates.Outdoor unit doesn't operate.Indoor unit doesn't receive the signal from remote controller.Indoor unit operates

2510-2-1. Troubleshooting check tableOPERATIONINDICATORlampBefore taking measures, make sure that the symptom reappears, for accurate troubleshooting.

26Measure the resistance between the terminals with a tester.(Coil wiring temperature10°C ~ 30°C)Compressor(MC)Room temperaturethermistor (RT11)10-2-2

27YesYesCheck of indoor fan motorAIndoor unit operates by pressing the EMERGENCY OPERATION switch, but doesn’t operate with the remote con-troller.Rep

Trouble of the indoor electroniccontrol P.C. board.Replace the varistor.Replace the fuse.28Check of indoor electronic control P.C. boardCThe unit does

29Check of outdoor unitECompressor and / or outdoor fan motor doesn’t stop.Check of R.V. coilFAfter 30 seconds, does compressor stop?NoYesIs there 220

3RESETCLOCKgMCFH-24NV -EBOUTDOOR UNITMUCFH-24NV -EBAir inletAir outletOB266--1.qxp 01.4.13 10:31 AM Page 3

30How to check mis-wiring and serial signal error (when outdoor unit doesn’t work)GYesYes1. Turn OFF the power supply.2. Turn ON the power supply.3. P

31Check of outdoor thermistorMeasure resistance between CN 661 1 and 2.Measure resistance between CN 662 3 and 4.NoYesReplace the thermistor.Reconnect

32DE00R697BTo the indoorelectronic controlP.C.board CN113Indoor coil thermistor (RT12)Room temperature thermistor (RT11)RT11EMERGENCY OPERATION switch

33MUCFH-24NV -Outdoor deicer P.C. boardEBVaristor(NR62)Fuse 3.15A / 250VDefrostintervaltime shortpin(JPG1,R871)(Refer topage 22.)}12V DCJumper wire f

34DISASSEMBLY INSTRUCTIONS11”w” shows the terminals with a lock mechanism,so they cannot be removed when you pull thelead wire.Be sure to pull the wi

35OPERATING PROCEDURE PHOTOS3. Removing the indoor heat exchanger.(1) Remove the grill. (Refer to 1(1) (2))(2) Remove the screws on both side and in f

3611-2. MUCFH-24NV -OUTDOOR UNITEBOPERATING PROCEDURE PHOTOSPhoto 1Photo 2Photo 4Propellerfan nutValve bedSeparator support plateMotor supportPropel

37OPERATING PROCEDURE PHOTOSPhoto 5Photo 6Photo 7Stop valveHeat exchangerAccumulatorScrewsScrewsRearpanelSidepanelRear guard4. Removing the heat excha

38PARTS LIST12MCFH-24NV -12-1. INDOOR UNITSTRUCTURAL PARTSEBPart number that are circled is not shown in the illustration.No. Part No.Part name Remar

39MCFH-24NV- (WH)12-3. ACCESSORY ANDREMOTE CONTROLLER PARTSEB12111112E02 257 426E02 141 083REMOTE CONTROLLERREMOTE CONTROLLER HOLDER11Part numbers

4SPECIFICATION3Indoor modelFunctionPower supplyCapacityAir flow(High)DehumidificationPower outletRunning currentPower inputAuxiliary heaterPower facto

40MUCFH-24NV -12-4. OUTDOOR UNIT STRUCTURAL PARTS, ELECTRICAL PARTS AND FUNCTIONAL PARTSEB17299272615 20102585136216 2117432423281422121119131318OB266

41MUCFH-24NV -12-4. OUTDOOR UNIT STRUCTURAL PARTS, ELECTRICAL PARTS AND FUNCTIONAL PARTSEBE02 214 297E02 540 309E02 444 961E02 529 490E02 214

13OPTIONAL PARTS4213-1. REFRIGERANT PIPESThe air conditioner has flared connections its indoor and outdoor sides.Please use the optional extension pip

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New publication, effective Apr. 2001Specifications subject to change without notice.CCCopyright 2001 MITSUBISHI ELECTRIC ENGINEERING CO.,LTDDistribute

5(When installed on the floor)(When installed on the ceiling)50cm or more50cm or more50cm or more50cm or more100cm or more650616.580.8 906 112.8114161

6100 101000For 10 units or less200Outdoor Unit-Necessary surrounding clearance(Concentrated installation)The upper side must be open.Outdoor Unit-Nece

TRANSFORMERCONTACTORR.V. COIL RELAYR.V. COILCOMPRESSOR CONTACTORT61X52X6221S452VARISTORDEFROST TEMPERATURE THERMISTORAMBIENT TEMPERATURE THERMISTORS

REFRIGERANT SYSTEM DIAGRAM86ModelsA: Refrigerant piping Max.length 15mMax. Height difference *5mMAX. REFRIGERANT PIPING LENGTH & MAX. HEIGHT

9PERFORMANCE CURVES7The standard data contained in these specifications apply only to the operation of the air conditioner under normal condition.Oper