Mitsubishi Electric MUFZ-KJ-NAHZ Series Service Manual Download Page 1

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INDOOR UNIT

SERVICE MANUAL

Models

MFZ-KJ09NA

MFZ-KJ12NA

MFZ-KJ15NA

MFZ-KJ18NA

NOTE:

• This service manual describes technical data of the indoor units.
• RoHS compliant products have <G> mark on the spec name plate.
For servicing of RoHS compliant products, refer to the RoHS Parts List.

No. OBH752

REVISED EDITION-B

PARTS CATALOG (OBB752)

Outdoor unit service manual
MUFZ-KJ•NAHZ Series (OBH753)
MXZ-C•NA, MXZ-C•NAHZ Series

(OBH702, OCH573)

CONTENTS

1. TECHNICAL CHANGES ··································· 3

2. PART NAMES AND FUNCTIONS ····················· 4

3. SPECIFICATION ················································ 5

4. OUTLINES AND DIMENSIONS ························ 7

5. WIRING DIAGRAM ············································ 8

6. REFRIGERANT SYSTEM DIAGRAM ··············· 9

7. SERVICE FUNCTIONS ··································· 10

8. MICROPROCESSOR CONTROL ··················· 12

9. TROUBLESHOOTING ····································· 21

10. DISASSEMBLY INSTRUCTIONS ···················· 36

OBH752 REVISED EDITION-A is void.

Revision B:

• 4. OUTLINES AND DIMENSIONS has been

modified.

INDOOR UNIT

Summary of Contents for MUFZ-KJ-NAHZ Series

Page 1: ...752 REVISED EDITION B PARTS CATALOG OBB752 Outdoor unit service manual MUFZ KJ NAHZ Series OBH753 MXZ C NA MXZ C NAHZ Series OBH702 OCH573 CONTENTS 1 TECHNICAL CHANGES 3 2 PART NAMES AND FUNCTIONS 4 3 SPECIFICATION 5 4 OUTLINES AND DIMENSIONS 7 5 WIRING DIAGRAM 8 6 REFRIGERANT SYSTEM DIAGRAM 9 7 SERVICE FUNCTIONS 10 8 MICROPROCESSOR CONTROL 12 9 TROUBLESHOOTING 21 10 DISASSEMBLY INSTRUCTIONS 36 OB...

Page 2: ...ed of Correct refrigerant is specified in the manuals and on the spec labels provided with our products We will not be held responsible for mechanical failure system malfunction unit breakdown or accidents caused by failure to follow the instructions Revision A 3 SPECIFICATION and 4 OUTLINES AND DIMENSIONS have been modified Revision B 4 OUTLINES AND DIMENSIONS has been modified 2 ...

Page 3: ...3 1 TECHNICAL CHANGES MFZ KJ09NA U1 MFZ KJ12NA U1 MFZ KJ15NA U1 MFZ KJ18NA U1 1 New model 2 ...

Page 4: ...e filter option LU OWHU 1DQR SODWLQXP OWHU Panel Front panel Horizontal vane Vertical vane 0XOWL ÀRZ YDQH ACCESSORIES MFZ KJ09NA MFZ KJ12NA MFZ KJ15NA MFZ KJ18NA Drain hose 1 Remote controller holder 1 Fixing screw for 3 5 x 16 mm Black 2 Pipe cover 1 Band 2 Battery AAA for remote controller 2 Indoor unit mounting bracket 1 Fixing screw for 4 x 25 mm 5 Wood screw for the indoor unit xation 4 Washe...

Page 5: ...ht Ib 33 External nish White Control voltage by built in transformer 12 24 VDC NOTE Test conditions are based on ARI 210 240 Indoor model MFZ KJ09NA MFZ KJ12NA MFZ KJ15NA MFZ KJ18NA Power supply V phase Hz 208 230 1 60 Max fuse size time delay Disconnect switch A 15 20 AirÀow Super High High Med Low Quiet COOL Dry Wet CFM 275 251 208 173 138 234 213 177 147 117 374 328 282 237 198 318 279 240 201 ...

Page 6: ...t 366 17 8 26 2 MFZ KJ18NA HEAT Dry 470 22 9 33 3 COOL Dry 491 23 9 34 8 Wet 417 20 3 29 7 2 Multi connection Model Mode Function AirÀow CFM Air speed ft s Coverage ft MFZ KJ09NA MFZ KJ12NA HEAT Dry 343 16 7 24 5 COOL Dry 275 13 4 19 8 Wet 234 11 4 16 9 MFZ KJ15NA MFZ KJ18NA HEAT Dry 470 22 9 33 3 COOL Dry 374 18 2 26 7 Wet 318 15 5 22 8 2 OPERATION Mode Condition Intake air temperature F Indoor O...

Page 7: ...7 4 OUTLINES AND DIMENSIONS MFZ KJ09NA MFZ KJ12NA MFZ KJ15NA MFZ KJ18NA Unit inch 2 ...

Page 8: ...8 MFZ KJ09NA MFZ KJ12NA MFZ KJ15NA MFZ KJ18NA 5 WIRING DIAGRAM 2 ...

Page 9: ...ared connection Room temperature thermistor RT11 Indoor coil thermistor RT12 RT14 RT15 main RT13 sub Flared connection Refrigerant flow in cooling Refrigerant flow in heating Refrigerant pipe 3 8 9 52 MFZ KJ09 12 1 2 12 7 MFZ KJ15 18 with heat insulator Refrigerant pipe 1 4 6 35 with heat insulator Distributor 2 ...

Page 10: ...EXCLUSIVELY FOR A PARTICULAR INDOOR UNIT A maximum of 4 indoor units with wireless remote controllers can be used in a room To operate the indoor units individually with each remote controller assign a number to each remote controller according to the number of the indoor unit This setting can be set only when all the following conditions are met The remote controller is powered OFF Weekly timer i...

Page 11: ...all the compressors may flow simultaneously at restart Therefore the special counter measures are required to prevent the main voltage drop or the rush of the starting cur rent by adding to the system that allows the units to start one by one 7 3 AUTO RESTART FUNCTION When the indoor unit is controlled with the remote controller the operation mode the set temperature and the fan speed are memorize...

Page 12: ...e the lid down to open the remote controller Slide it down further to get to the weekly timer buttons WEEKLY TIMER set buttons TIME TIMER set buttons FORWARD button BACKWARD button RESET button SMART SET button SLEEP button VANE CONTROL button POWERFUL button INDOOR UNIT DISPLAY SECTION Operation Indicator lamp The operation indicator at the right side of the indoor unit indicates the operation st...

Page 13: ...ed control works the same way as that in COOL mode 8 1 3 However in AUTO setting the fan speed changes 8 3 FAN OPERATION 1 Press STOP OPERATE OFF ON button OPERATION INDICATOR lamp of the indoor unit turns on with a beep tone 2 Select FAN mode with OPERATION SELECT button 3 Select the desired fan speed When AUTO it becomes Low Only indoor fan operates Outdoor unit does not operate NOTE Temperature...

Page 14: ...the other operating mode COOL ļ HEAT and becomes a state of standby NOTE 3 At the beginning of AUTO mode the air flow direction and the fan speed are set to AUTO and the air outlet selection is set to 2 FLOW 8 6 AUTO VANE OPERATION 1 Horizontal vane Horizontal vane Multi flow vane 1 Vane motor drive These models are equipped with a stepping motors for the horizontal vanes The rotating direction sp...

Page 15: ...dby In the following cases the horizontal vane returns to the closed position a When STOP OPERATE OFF ON button is pressed POWER OFF b When the operation is stopped by the emergency operation c When ON TIMER is ON standby 7 Dew prevention During COOL or DRY operation with the vane angle at Angle 3 or 4 when the compressor cumulative operation time exceeds 1 hour the vane angle automatically change...

Page 16: ...s longer the set time increases decreases by 10 minutes c Press the CLOCK set button 2 Press STOP OPERATE OFF ON button to start the air conditioner 3 Set the time of timer ON timer setting a Press ON TIMER button during operation b Set the time of the timer using TIME SET buttons and OFF timer setting a Press OFF TIMER button during operation b Set the time of the timer using TIME SET buttons and...

Page 17: ...et temperature cannot be set to 50 F 10 C The weekly timer operation and SMART SET operation cannot be used together Make sure that the current time and day are set correctly 1 Press button to enter the weekly timer setting mode 2 Press and buttons to select setting day and number 3 Press and buttons to set ON OFF time and temperature E g ON AM 6 00 and 75 F 24 C are selected Pressing selects ON O...

Page 18: ...y or number 3 Press button to exit the weekly timer setting NOTE When all days of the week are selected to view the settings and a different setting is included among them will be displayed 5 Press button to turn the weekly timer ON lights When the weekly timer is ON the day of the week whose timer setting is complete will light Press button again to turn the weekly timer OFF goes out NOTE The sav...

Page 19: ...ns to the previous settings SLEEP operation is also cancelled when the FAN button is pressed or the operation mode is changed NOTE SLEEP operation and SMART SET operation cannot be set at same time 8 10 SMART SET OPERATION 1 How to set SMART SET operation 1 Press STOP OPERATE OFF ON button 2 Select COOL HEAT or ECONO COOL mode 3 Press SMART SET button 4 Set the temperature fan speed and airÀow dir...

Page 20: ...the case that 2 FLOW operation is selection by the remote controler The coil frost prevention works even in the test run or the emergency operation In the test run or emergency operation the horizontal vane operates in VANE AUTO mode Emergency operation continues until EMERGENCY OPERATION switch is pressed once or twice or the unit receives any signal from the remote controller In the latter case ...

Page 21: ...dge of the board with care NOT to apply stress on the components 4 When connecting or disconnecting the connectors hold the connector housing DO NOT pull the lead wires 3 Troubleshooting procedure 1 Check if the OPERATION INDICATOR lamp on the indoor unit is flashing ON and OFF to indicate an abnormality To make sure check how many times the OPERATION INDICATOR lamp is flashing ON and OFF before s...

Page 22: ...r units The units do not operate and the operation indicator lamp flashes as shown in the figure below when the total capacity of the indoor units exceed the capacity of the outdoor unit Do not connect the indoor units beyond the outdoor unit capacity When operating the 2 or more indoor units connected to a multi system outdoor unit set all the indoor units to the same operation mode If the COOL a...

Page 23: ...s ON for 3 seconds without beep The outdoor unit is abnormal The indoor unit is abnormal Check the blinking pattern and identify the abnormal point by referring to the indoor unit failure mode table Refer to indoor unit service manual Make sure to check at least 2 consecutive blinking cycles 2 Releasing the failure mode recall function Release the failure mode recall function by the following proc...

Page 24: ...FF Serial signal error The serial signal from the outdoor unit is not received for a maximum of 6 minutes 1 time flash every 0 5 second Refer to the characteristics of the room temperature thermistor 9 7 Room temperature thermistor The room temperature thermistor short or open circuit is detected every 8 seconds during operation Not lighted Normal Left lamp of OPERATION INDICATOR lamp 13 time flas...

Page 25: ...r Left lamp 3 time flash Cause Indoor unit 7URXEOH RI indoor fan motor Left lamp 5 time flash Cause Outdoor unit 2XWGRRU power system abnormality Left lamp 6 time flash Cause Outdoor unit 7URXEOH RI thermistor in outdoor unit Left lamp 7 time flash Cause Outdoor unit 7URXEOH RI outdoor control system Check room temperature thermistor and indoor coil thermis tor Refer to 9 7 Test point diagram and ...

Page 26: ...Room tempera ture thermistor Left lamp flashes 2 time flash 2 5 second OFF The indoor coil or the room temperature thermistor is short or open circuit 5HIHU WR WKH FKDUDFWHULVWLFV RI indoor coil thermistor and the room temperature thermistor on 9 7 Left lamp flashes 3 time flash 2 5 second OFF 7KH URWDWLRQDO IUHTXHQF IHHGEDFN VLJQDO LV not emitted during the indoor fan operation 5HIHU WR RZ WR FKH...

Page 27: ...0 C Color of the lead wire 51 RWKHU RQH Horizontal vane motor MV2 BACK Measure the resistance between the terminals with a tester Part temperature 50 F 86 F 10 C 30 C Check 9 6 Check of indoor fan motor and Check of indoor electronic control P C board and indoor fan motor Normal 51 RWKHU RQH Color of the lead wire Normal 51 RWKHU RQH Color of the lead wire OPERATION INDICATOR Not lighted Blinking ...

Page 28: ...ait 5 seconds or more and then press EMERGENCY OPERATION switch Measure the supply voltage as follows within 12 seconds after EMER GENCY OPERATION switch is pressed If more than 12 seconds passes turn OFF the power supply and turn it ON again then measure the voltage Indoor electronic control P C board 1 Measure the voltage between CN211 and 2 Measure the voltage between CN211 and If more than 12 ...

Page 29: ...a number of remote controller Refer to 7 2 Check if the unit operates with the remote controller Does the unit operate with the remote controller Yes No OK Measure the voltage between display receiver P C board connector CN301 and when the remote controller button is pressed Is the voltage approximately 4 VDC 5 VDC No Yes Replace the indoor electronic control P C board 1 Look at the image of the s...

Page 30: ... Be sure to check both the fuse and the varistor in any case Is the fuse F11 blown only Measure the resistance between CN211 and of indoor fan motor connector 1 2 Yes Is the resistance 1Mȍ or more Replace the fuse F11 and the indoor fan motor 3 No Replace the fuse F11 3 Measure the resistance of resis tor R111 on the indoor electronic control P C board Is the resistance of resistor R111 approxi ma...

Page 31: ...second OFF and 0 8 second ON quick blinking 3 Yes No Lighted or not lighted Replace the inverter P C board 2 2 Be careful of the residual voltage of smoothing capacitor Is there amplitude of 10 to 20 VDC between the indoor terminal block S2 and S3 Con rmation of serial signal Yes Check the wiring If there are any error of the indoor outdoor connecting wire such as the damage of the wire intermedia...

Page 32: ...the wiring Press EMERGENCY OPERATION switch once Does the left lamp of the OPERATION INDICATOR lamp light up Con rmation of the power to the indoor unit Yes No Is serial signal error indicated 6 minutes later Yes No Is there any miswiring poor contact or wire disconnection of the indoor outdoor connect ing wire Yes Correct them No Turn OFF the power supply Check once more if the indoor outdoor con...

Page 33: ...ghted Lighted Blinking Turn ON the power supply C Turn OFF the power supply Remove the bridge between outdoor terminal block S2 and S3 Turn ON the power supply Is there amplitude of 10 to 20 VDC between outdoor terminal block S2 and S3 Confirmation of serial signal Is there rated voltage between indoor terminal block S1 and S2 Confirmation of power voltage Replace the indoor electronic control P C...

Page 34: ... eld strength or the installation condition combination of speci c conditions such as antennas or wiring Check the following before asking for service 1 Devices affected by the electromagnetic noise TV sets radios FM AM broadcast shortwave 2 Channel frequency broadcast station affected by the electromagnetic noise 3 Channel frequency broadcast station unaffected by the electromagnetic noise 4 Layo...

Page 35: ...aristor NR11 Indoor coil thermistor CN112 Indoor coil thermistor RT15 MAIN 3 Indoor coil thermistor RT14 MAIN 2 Indoor coil thermistor RT12 MAIN 1 Indoor coil thermistor RT13 SUB Serial signal input CN202 Connect to display receiver P C board CN1J1 Interface CN105 Indoor fan motor CN211 0 or 15 VDC 3 6 VDC 15 VDC GND high voltage DC 294 325 VDC Connector cable CN24 Timer short mode point 2 points ...

Page 36: ... Disconnect the following connectors on the electronic control P C board Fan motor connector CN211 Photo 5 Indoor coil thermistor connector CN112 Photo 5 9 Rotate the display receiver P C board holder to the right side and disconnect the vane motor relay con nector Photo 6 10 Disengage the electrical box from the upper catch and pull out the electrical box from the box 36 1 Slide the sleeve and ch...

Page 37: ...to 6 4 Removing the nozzle assembly 1 Remove the panel Refer to 1 2 Rotate the display receiver P C board holder to the right side and disconnect the vane motor relay con nector 3 Remove the fixed screws on the both sides of the nozzle 4 Disengage the catches on the nozzle from the box 5 Hold the both sides of the nozzle Rotate the nozzle toward you around the right and left ribs to remove it Phot...

Page 38: ...ach it from the rib on the multi flow vane Slide the vane shaft in arrow 2 direction and separate it from the unit body Multi flow vane 1 1 See the figure below and push to open the indicated places on the horizontal vanes between front and back with your fingers so that you can access 4 vane shafts positioned on the back of the horizontal vanes vane shafts on each horizontal vane 2 1 Open the hor...

Page 39: ...orizontal vane motor Connect the connectors to the horizontal vane motors by referring to the colors red and white noted on the vane motor support Photo 9 Photo 10 Photo 11 6 Removing the multi flow vane motor unit 1 Remove the panel Refer to 1 2 Disconnect the connector from the multi flow vane motor unit 3 Remove the screws of the multi flow vane motor unit and pull out the multi flow vane motor...

Page 40: ...bed together with the indoor fan motor and the motor band 8 Disengage the catches on the motor band and remove the motor band and pull out the indoor fan motor 9 Remove the screws fixing the both sides of the heat exchanger 10 Disengage the catch on the right side on the heat exchanger 11 Lift the heat exchanger and pull out the line flow fan upward Photo 16 Photo 13 Photo 14 Photo 15 Photo 17 40 ...

Page 41: ...41 2 ...

Page 42: ...sued May 2017 No OBH752 REVISED EDITION B Issued Mar 2016 No OBH752 REVISED EDITION A Published Feb 2016 No OBH752 Made in Japan HEAD OFFICE TOKYO BLDG 2 7 3 MARUNOUCHI CHIYODA KU TOKYO 100 8310 JAPAN Specifications are subject to change without notice ...

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