Mitsubishi Electric MU24WN Service Manual Download Page 15

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REFRIGERANT SYSTEM DIAGRAM

Indoor

heat

exchanger

Outdoor

heat

exchanger

Flared connection

Room temperature
thermistor
RT11

Indoor coil
thermistor
RT13(sub)

Discharge
temperature
thermistor
RT62

Flared connection

Stop valve

Stop valve
(with service port)

Capillary tube
O.D.0.14

I.D.0.09

1-31/32

Refrigerant flow in cooling

Compressor

Refrigerant pipe

[

5/8

(with heat insulator)

Refrigerant pipe

[

3/8

(with heat insulator)

Indoor coil
thermistor
RT12(main)

LEV

Strainer

Accumulator

Ambient
temperature
thermistor
RT63

Strainer

#50

Capillary tube
O.D.0.16

I.D.0.09

7-7/8

(Upper path)

Capillary tube
O.D.0.16

I.D.0.09

3-15/16

(Lower path)

SERVICE
PORT

FUSIBLE
PLUG

#100

MS24WN

INDOOR UNIT

OUTDOOR UNIT

MU24WN

Unit: inch

OB311--1.qxp 04.1.13 9:53 AM Page 15

Summary of Contents for MU24WN

Page 1: ... 25 10 TROUBLESHOOTING 27 11 DISASSEMBLY INSTRUCTIONS 40 12 PARTS LIST 44 13 OPTIONAL PARTS BACK COVER Wireless type Models MS24WN W MU24WN The Slim Line From Mitsubishi Electric LIST ED C US Remote controller TM SPLIT TYPE AIR CONDITIONERS INDOOR UNIT Indication of model name MS24WN OUTDOOR UNIT Indication of model name MU24WN Revision PARTS LIST have been partially modified Please void OB311 No ...

Page 2: ...en changed due to the color change of outdoor unit parts WHITE NEW WHITE Brighter Capillary tube has been added to parts list CAPILLARY TUBE TAPER PIPE 0 14X 0 09X1 31 32 E02 784 936 Part number Part name Model MU24WN Page 47 ...

Page 3: ...perature set this way is then memorized for immedi ate recall whenever the air conditioner is used again Select desired air flow direction REMOTE CONTROL OPERATION MODE Using the remote controller you can select from five airflow set tings to match room layout and the location of people Also you can set the vane to swing automatically SWING AUTO RESTART FUNCTION The auto restart function restarts ...

Page 4: ...t tape Used for left or left rear piping 1 7 1 2 2 1 1 1 2 3 4 5 6 7 MS24WN ACCESSORIES Grille Air inlet Remote control receiving section Horizontal vane Remote controller Deodorizing filter option Gray sponge type Air cleaning filter option White bellows type Air filter Vertical vane Operation section When the grille is opened Display section Operation indicator lamp Receiving section Emergency o...

Page 5: ... CLOCK FAN Open the front lid Signal transmitting section Operation display section OPERATE STOP ON OFF button TEMPERATURE buttons OPERATION SELECT button FAN SPEED CONTROL button OFF TIMER button HR button MIN button TIME SET button ON TIMER button RESET button VANE button Horizontal vane button CLOCK SET button LONG button WIDE VANE button Vertical vane button ...

Page 6: ...NG Pipe size Min wall thickness Connection method Between the indoor outdoor units Refrigerant charge R22 Refrigerant oil Model FAN Dry COOL Dry Wet W D H Model Winding resistance at 68 F Ω W D H Liquid Gas Indoor Outdoor Height difference Piping length Btu h W A A F L A CFM CFM pt h dB A in in in in lb A A F L A R L A L R A dB A in in in lb in in ft ft oz 22 800 2 170 10 5 10 5 MS24WN White 115V ...

Page 7: ...nit Outdoor unit MAX HEIGHT DIFFERENCE Outside diameter Minimum Wall thickness Outside diameter Minimum Wall thickness MS24WN MU24WN Additional piping Max length ft A 50 Gas Piping size in Length of connecting pipe in Liquid Indoor unit Outdoor unit Model Gas Liquid 0 0 Gas Liquid 16 15 16 19 11 16 5 8 3 8 0 0315 0 0285 MAX REFRIGERANT PIPING LENGTH MAX HEIGHT DIFFERENCE ...

Page 8: ... 17 8 SHC 10 4 12 3 13 6 TPC 2 50 2 41 2 30 IWB F 75 85 95 105 115 MS24WN 208V 230V Notes 1 IWB Intake air wet bulb temperature TC Total Capacity x103 Btu h SHC Sensible Heat Capacity x103 Btu h TPC Total Power Consumption kW 2 SHC is based on 80 F of indoor intake air DB temperature 4 2 PERFORMANCE CURVE MS24WN MU24WN 16 18 20 22 24 26 28 30 65 70 75 80 85 90 95 100 105 110 115 1 4 1 6 1 8 2 0 2 ...

Page 9: ... at High MU24WN 70 75 80 85 90 95 100 104 F 40 50 60 70 80 90 100 70 75 80 85 90 95 100 104 F 160 180 200 220 240 260 280 300 86 80 75 70 Condensing pressure Outdoor ambient temperature PSIG 86 80 75 70 Indoor DB temperature Indoor DB temperature PSIG 68 Suction pressure Outdoor ambient temperature 68 ...

Page 10: ... 9 36 8 30 0 67 0 71 250 71 174 115 48 158 25 4 Ib 5 oz 80 67 51 50 1 280 487 Wet 95 750 820 1 589 1 765 Capacity SHF Input INDOOR UNIT MODEL Power supply Input Fan motor current OUTDOOR UNIT MODEL Power supply Input Comp current Fan motor current Condensing pressure Suction pressure Discharge temperature Condensing temperature Suction temperature Comp shell bottom temp Ref pipe length Refrigerant...

Page 11: ...ature Maximum temperature Minimum temperature Maximum humidity DB F 80 95 67 WB F 67 71 57 Indoor 78 DB F 95 115 67 WB F Outdoor Condition Intake air temperature The air coverage range is the figure up to the position where the air speed is 1 ft sec when air is blown out horizontally from the unit properly at the High speed position The coverage range should be used only as a general guideline sin...

Page 12: ... 6 13 16 16 5 16 16 5 16 3 16 8 7 8 8 15 16 9 15 16 31 1 8 2 3 16 42 1 16 43 5 16 12 13 16 Air out Air in Insulation 1 1 8 Drain hose 5 8 Connected part O D Liquid line 3 8 19 11 16 Gas line 3 4 16 15 16 Insulation 1 15 16 O D 1 1 4 I D Installation plate Wall hole 2 15 16 Wireless remote controller Installation plate Indoor unit ...

Page 13: ...9 16 1 9 16 1 1 16 Terminal block for indoor and outdoor unit connection Terminal block for power line Handle for moving 7 1 18 20 5 8 17 3 8 17 17 32 17 23 32 18 7 18 21 3 4 33 1 2 1 9 16 2 3 8 20 5 8 Service panel Refrigerant pipe flared connection 5 8 Refrigerant pipe flared connection 3 8 Knock out hole for front piping refrigerant drainage and wiring 1 5 8 1 3 4 4 1 8 1 5 16 Bottom piping hol...

Page 14: ...2 RT63 SR61 TB1 SYMBOL C1 C2 DSAR F61 LEV MC NAME NAME NAME COMPRESSOR CAPACITOR OUTDOOR FAN CAPACITOR SURGE ABSORBER FUSE 3 15A EXPANSION VALVE COIL COMPRESSOR INNER PROTECTOR OUTDOOR FAN MOTOR INNER PROTECTOR VARISTOR DISCHARGE TEMPERATURE THERMISTOR AMBIENT TEMPERATURE THERMISTOR SOLID STATE RELAY TERMINAL BLOCK TERMINAL BLOCK TRANSFORMER COMPRESSOR AUXILIARY RELAY COMPRESSOR CONTACTOR SG79J606...

Page 15: ...y tube O D 0 14 I D 0 09 1 31 32 Refrigerant flow in cooling Compressor Refrigerant pipe 5 8 with heat insulator Refrigerant pipe 3 8 with heat insulator Indoor coil thermistor RT12 main LEV Strainer Strainer Accumulator Ambient temperature thermistor RT63 Strainer 50 Capillary tube O D 0 16 I D 0 09 7 7 8 Upper path Capillary tube O D 0 16 I D 0 09 3 15 16 Lower path SERVICE PORT SERVICE PORT FUS...

Page 16: ...tate INDOOR UNIT DISPLAY SECTION The following indication applies regardless of shape of the indicator MS24WN MU24WN Initial room temperature more than 55 F less than 77 F COOL mode of I FEEL CONTROL DRY mode of I FEEL CONTROL WIRELESS REMOTE CONTROLLER ON OFF FAN TOO WARM TOO COOL VANE MODE STOP START HR MIN WIDE VANE LONG I FEEL COOL DRY PM CLOCK AM RESET CLOCK OPERATION SELECT button FAN SPEED ...

Page 17: ...om temperature TOO COOL TOO WARM 2 Time control When the three conditions as follows have been satisfied for 1 hour and 45 minutes compressor stops for 3 minutes a Compressor has been continuously operating b Indoor fan speed is Low or Med c Room temperature is below 79 F When compressor stops the accumulated time is cancelled and when compressor restarts time counting starts from the beginning Ti...

Page 18: ... temperature thermistor RT62 becomes 212 F or less the compressor is turned ON 8 1 2 DRY mode of I FEEL CONTROL The system for dry operation uses the same refrigerant circuit as the cooling circuit The compressor and the indoor fan are controlled by the room temperature By such controls indoor flow amounts will be reduced in order to lower humidity without much room temperature decrease 1 Indoor f...

Page 19: ... or TOO COOL button to select the desired temperature The setting range is 59 89 F w Indoor fan continues to operate regardless of thermostat s OFF ON at set speed w Coil frost prevention is as same as COOL mode of I FEEL CONTROL High Med Low High 8 5 FAN MOTOR CONTROL 1 Rotational frequency feedback control The indoor fan motor is equipped with a rotational frequency sensor and outputs signal to ...

Page 20: ... FAN operation Vane angle is fixed to Angle 1 Vane angle is fixed to Angle 4 6 Dew prevention During COOL or DRY operation at Vane Angle 4 or 5 when the compressor cumulative operation time exceeds 1 hour the vane angle automatically changes to Angle 1 for dew prevention 7 SWING MODE By selecting SWING mode with the VANE button the horizontal vane swings vertically The remote controller displays 8...

Page 21: ...he vane moves right and left in the width of Angle 4 repeatedly 5 WIDE MODE By selecting WIDE mode with the WIDE VANE button indoor fan speed becomes faster than setting fan speed on the remote controller W The remote controller displays W Indoor fan speed becomes faster than setting fan speed on the remote controller even when or is selected 8 7 TIMER OPERATION 1 How to set the timer 1 Press OPER...

Page 22: ...egardless of shape of the indicator Press once Cool Press once again Stop PROGRAM TIMER Example 1 The current time is 8 00 PM The unit turns off at 11 00 PM and on at 6 00 AM The OFF timer and ON timer can be used in combination and display shows the order of the OFF timer and ON timer operation Example 2 The current time is 11 00 AM The unit turns on at 5 00 PM and off at 9 00 PM PM AM PM PM NOTE...

Page 23: ...ower than target one LEV is corrected in closed direction when the discharge temperature is higher than target one LEV is corrected in opening direction At thermostat OFF Opening in stop 150 pulse LEV is set to the initial opening after about 3 minutes passed At thermostat ON Same as the starting of compressor operation At remote controller OFF Opening in stop 150 pulse LEV is set so that the open...

Page 24: ...ion mode or the unit status as follows Tb F 171 144 136 COOL Normal COOL RT is less than 4deg or RT is 4deg or more and less than 6deg COOL RT is 6deg or more NOTE Target discharge temperature Tb Operation mode NOTE When the discharge temperature Ta is 122 F or less on the cool operation LEV opening is set in 54 pulse When this state continues for 20 minutes the compressor is stopped and restarts ...

Page 25: ...TOP ON OFF button twice or 3 times at first After finish remodelling put back the batteries then press the RESET button The P C board has the print J1 and J2 Solder J1 and J2 according to the number of indoor unit as shown in Table 1 After modification press the RESET button How to set the remote controller exclusively for particular indoor unit After you turn the breaker ON the first remote contr...

Page 26: ...ditions approximately after 3 minutes NOTE The operation settings are memorized when 10 seconds have passed after the indoor unit was operated with the remote controller If the main power is turned off or a power failure occurs while AUTO START STOP timer is active the timer setting is cancelled If the unit has been off with the remote controller before power failure the auto restart function does...

Page 27: ...n abnormality To make sure check how many times the abnormality indication is flashing on and off before starting service work 2 Before servicing check that the connector and terminal are connected properly 3 If the electronic control P C board is supposed to be defective check the copper foil pattern for disconnection and the components for bursting and discoloration 4 When troubleshooting refer ...

Page 28: ...Cause Outdoor unit Trouble of thermistor in outdoor unit 7 time flash Cause Outdoor unit Trouble of outdoor control system Refer to F How to check mis wiring When outdoor unit doesn t oper ate on page 35 Refer to A Check of indoor fan motor on page 31 Refer to H Check of outdoor thermistor on page 36 Replace the deicer P C board 10 time flash Cause Outdoor unit Trouble of low discharge temperature...

Page 29: ... discharge temperature has been 122 F or less on cool operation or is 120 F or less on heat operation for 20 minutes Abnormal point Outdoor unit does not operate Room tempera ture thermistor 2 time flash 2 5 second OFF Detect Indoor coil room temperature thermistor short or open circuit every 8 seconds during operation Refer to the characteristics of main indoor coil thermistor sub indoor coil the...

Page 30: ...efore measurement hold the thermistor with your hands to warm it up Part temperature 32 F 104 F Normal 120 k 800k Abnormal Open or short circuit Normal 5 k 60 k Abnormal Open or short circuit Motor part Sensor part Measure the resistance between the terminals with a tester Part temperature 50 F 86 F Measure the voltage power ON Color of lead wire BRN YLW YLW GRY Abnormal Remain 0V or 5V Normal 4 5...

Page 31: ...ssing the EMERGENCY OPERATION switch but doesn t operate with the remote controller Turn on a radio to AM and press switch on the remote controller Is noise heard from radio Are there any fluorescent lights of inverter or rapid start type within the range of 1m Measure the voltage between receiver P C board connector CN301 No 1 and No 3 when remote controller button is pressed Is the voltage appro...

Page 32: ... C board Is winding resistance of fan motor 0 Is winding resistance of vane motor 0 No Yes Replace the vane motor Turn OFF the power supply Turn OFF the power supply No Yes Yes Is varistor NR11 burnt Replace the varistor Yes Turn OFF the power supply Remove indoor fan motor connector CN211 and vane motor connector CN151 from the indoor electronic control P C board and turn ON the power supply No N...

Page 33: ... outdoor electronic control P C board w1 Replace the outdoor electronic control P C board No Yes No Is there 208 230V AC between 1 L1 on the compressor contactor 52C and L2 on the outdoor terminal block No No Make the connection of wiring correct Yes Yes Yes Is there 208 230V AC between CN711 2 3 on the outdoor electronic control P C board w1 Operate the unit in COOL mode by pressing the EMERGENCY...

Page 34: ...OL mode by pressing the EMERGENCY OPERATION switch 4 Operate the unit for 1 minute or more and stop it by pressing the EMERGENCY OPERATION switch again Ok No After 30 seconds does outdoor fan motor stop Yes Ok No Is there 208 230V AC between 2 T1 on the compressor contactor 52C and L2 on the outdoor terminal block Yes Replace the compressor contactor 52C No Make the connection of wiring correct Re...

Page 35: ...isplays all signs Before the unit resumes normal operation Release the checking mode by pressing the RESET button on the remote controller and then send the unit signal to stop operation Turn OFF the power supply to indoor outdoor units Get indoor terminal blocks 1 1 and 3 3 opened and reconnect indoor outdoor wiring Is the power voltage to terminal blocks of indoor outdoor units normal Does the O...

Page 36: ...EV and feel it vibrate Does the resistance of LEV coil have the characteristics No Yes Yes Yes No LEV CN724 WHT RED RED ORN YLW BRN BRN BLU Resistance 30 3 37 0 Characteristics of LEV coil No Properly fix LEV coil to the body Replace the outdoor electronic control P C board NOTE After check of LEV do the undermentioned operations 1 Turn OFF the power supply of the unit and turn ON again 2 Press th...

Page 37: ...main Timer short mode point JPS JPG Refer to page 25 Emergency operation switch 12V DC Indoor coil thermistor RT12 main RT13 sub Room temperature thermistor RT11 32 F 50 68 86 104 122 140 Room temperature thermistor RT11 Auto restart function Solder the Jumper wire or the Resistor 220Ω to the JR07 Refer to page 26 Indoor coil thermistor RT13 sub R132 Receiver P C board Varistor NR11 ...

Page 38: ...00 200 300 400 500 600 700 800 900 Ambient temperature thermistor RT63 0 10 20 30 40 50 60 70 80 90 100 Resistance k 4 14 32 50 68 86 104 Temperature F CN662 1 2 Discharge temperature thermistor RT62 Refer to page 36 CN662 3 4 Ambient temperature thermistor RT63 Refer to page 36 LEV connector CN724 Fan motor connector CN711 CN7301 3 208 230V AC Refer to page 33 Refer to page 33 J101 J401 ...

Page 39: ...O or set speed AUTO or set speed AUTO or set speed links with 52C CONTACTOR AUTO or set speed MODE THERMOSTAT 52C CONTACTOR INDOOR FAN SPEED COOL COOL mode of I FEEL CONTROL DRY DRY mode of I FEEL CONTROL ON AUTO or set speed OFF for 5 min After that OFF is prolonged until indoor coil thermistor reads termination temperature AUTO or set speed RELAY OPERATION MS24WN NOTE Once the compressor is OFF ...

Page 40: ...anel Screws 1 Removing the front panel 1 Remove the screw caps of the front panel Remove the screws 2 Pull the panel down to your side slightly and unhook the catches at the top Screw of the electrical cover R L holder Receiver P C board 2 Removing the electronic control P C board the receiver P C board and the display P C board NOTE In case of removing only indoor electronic control P C board wor...

Page 41: ...outdoor unit con necting wire 11 Remove the lock nut from the connector of indoor outdoor connecting wire 12 Remove the screw fixing the electrical box remove the electrical box 5 Removing the line flow fan and the indoor fan motor 1 Remove the front panel Refer to 1 2 Remove the electrical box Refer to 3 3 Pull out the drain hose from the nozzle assembly remove the nozzle assembly 4 Remove the wa...

Page 42: ...Screws of the top panel Screw of the service panel Terminal blocks Compressor contactor Outdoor electronic control P C board Fan motor connector Relay panel Propeller nut Screws of the valve bed Screw of the separator support plate Screws of the motor support Propeller Screw of the side panel Screw of the side panel Screw of the separator Screws of the fan motor Lead clamps Screws of the cabinet D...

Page 43: ...ust be removed by up and down 2 Remove the screws of the side panel and the side panel Photo 4 3 Remove the screws of the rear guard and the rear guard 4 Remove the screws of the separator support plate and the separator support plate Photo 4 5 Remove the screws of the motor support and the motor support Photo 4 6 Remove the relay panel Photo 3 7 Remove the fan motor lead wire from lead clamps Pho...

Page 44: ...MP PANEL Symbol in Wiring Diagram Q ty unit Including No 4 5 6 4PCS SET 3PCS SET Remarks Part No NO Part Name 1 2 3 4 5 6 7 8 9 1 1 1 4 3 1 2 1 1 W 12 2 INDOOR UNIT HEAT EXCHANGER 2 4 5 7 6 1 10 8 11 12 3 CATCH SCREW CAP E02 527 620 E02 527 666 E02 527 667 INDOOR HEAT EXCHANGER UNION GAS UNION LIQUID 5 8 3 8 10 11 12 1 1 1 12 2 INDOOR UNIT HEAT EXCHANGER 12 1 INDOOR UNIT STRUCTURAL PARTS Part numb...

Page 45: ...ROOM TEMPERATURE THERMISTOR TERMINAL BLOCK INDOOR COIL THERMISTOR VANE MOTOR SUPPORT SET RIGHT VANE MOTOR SUPPORT SET LEFT Symbol in Wiring Diagram Q ty unit 3 15A RIGHT LEFT UP DOWN Remarks Part No NO Part Name F11 NR11 MF MV2 MV1 RT11 TB RT12 RT13 1 1 1 1 1 1 1 1 1 1 1 2 1 1 1 1 1 1 1 1 1 1 W RC4W33 Including RUBBER MOUNT AUTO RESTART Including No 16 Part numbers that are circled are not shown i...

Page 46: ...46 MU24WN 12 5 OUTDOOR UNIT STRUCTURAL PARTS ELECTRICAL PARTS AND FUNCTIONAL PARTS 1 3 5 30 2 28 27 10 7 25 6 11 31 8 4 2 13 22 14 26 24 29 9 23 16 15 12 21 20 B A 9 17 18 19 ...

Page 47: ...SOR RUBBER SET COMPRESSOR STOP VALVE LIQUID STOP VALVE GAS SERVICE PORT SERVICE PORT FUSIBLE PLUG SERVICE PANEL COVER PANEL TERMINAL BLOCK TERMINAL BLOCK OUTDOOR FAN CAPACITOR COMPRESSOR CONTACTOR COMPRESSOR CAPACITOR SURGE ABSORBER OUTDOOR ELECTRONIC CONTROL P C BOARD REAR PANEL REAR GUARD SIDE PANEL MOTOR SUPPORT FUSE CAPILLARY TUBE CAPILLARY TUBE CAPILLARY TUBE TAPER PIPE Symbol in Wiring Diagr...

Page 48: ...IZING FILTER every two weeks If the filter is particularly dirty clean the filter more often For cleaning soak the filter in warm water for a while and then wash and rinse it Dry the filter in the shade thoroughly When the filter color is still dark even after cleaning replace the filter with a new one Replace the filter at least once a year DEODORIZING FILTER and AIR CLEANING FILTER can be attach...

Page 49: ...3400 Lawrenceville Suwanee Road Suwanee Georgia 30024 Toll Free 800 433 4822 Toll Free Fax 800 889 9904 www mrslim com Specifications are subject to change without notice ...

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