Mitsubishi Electric M Z-C NA Series Service Manual Download Page 31

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The unit cannot be operated with the remote controller.

Also, OPERATION INDICATOR lamp does not light up by pressing the emergency operation switch.

Check of indoor electronic control P.C. board and indoor fan motor

Yes

*1. The fan motor connector's lead wire is red, whereas is black.

*2. Connect "+" of the tester to fan motor connector's lead
wire, and "-" to lead wire, otherwise the resistance cannot be
measured properly.

Yes

*1, *2

Does the unit operate with the remote controller?
Does OPERATION INDICATOR lamp light up by
pressing the emergency operation switch?

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.

Turn OFF the power supply.
Measure the resistance of the horizontal vane
motor coil and the vertical vane motor coil.
Refer to 9-5.

Turn OFF the power supply.
Measure the resistance between CN211
and of the indoor fan motor connector.

Short/ open circuit:
Replace the indoor fan motor.

Short/ open circuit:
Replace the horizontal vane motor, the vertical
vane motor coil and the indoor electronic
control P.C. board.

Turn OFF the power supply.
Check both “parts side” and “pattern
side” of the indoor electronic control P.C.
board visually.

Replace the varistor (NR11) and fuse (F11).

Are the varistor (NR11) burnt
and the fuse (F11) blown?

Be sure to check both the fuse
and the varistor in any case.

Yes

Is the fuse (F11) blown only?

Yes

Is the resistance 1MΩ

or more?

Measure the resistance between
(+) and (-) of the indoor fan
motor connector (to CN211 on the
indoor electronic control P.C. board).

Replace the fuse (F11).

Replace the fuse (F11) and the indoor fan motor.

Is the resistance
approximately 4

Ω

Measure the cement resistance R111 on
the indoor electronic control P.C. board.

Replace the indoor electronic control P.C. board.

Replace the indoor electronic control P.C. board
and the indoor fan motor.

Yes

CN211

Fuse (F11)

VARISTOR (NR11)

Indoor electronic

control P.C. Board

CN151

C111

R111

OBH802B

Summary of Contents for M Z-C NA Series

Page 1: ... AND FUNCTIONS 3 3 SPECIFICATION 4 4 OUTLINES AND DIMENSIONS 6 5 WIRING DIAGRAM 7 6 REFRIGERANT SYSTEM DIAGRAM 9 7 SERVICE FUNCTIONS 10 8 MICROPROCESSOR CONTROL 13 9 TROUBLESHOOTING 22 10 DISASSEMBLY INSTRUCTIONS 37 OBH802 REVISED EDITION A is void Revision B MLZ KP09 12 18NA2 U1 have been added Models MLZ KP09NA U1 MLZ KP09NA2 U1 MLZ KP12NA U1 MLZ KP12NA2 U1 MLZ KP18NA U1 MLZ KP18NA2 U1 ...

Page 2: ...er turn off the power supply breaker and pull the power plug Discharge the capacitor before the work involving the electric parts Precautions during the repair service Do not perform the work involving the electric parts with wet hands Do not pour water into the electric parts Do not touch the refrigerant Do not touch the hot or cold areas in the refrigeration cycle When the repair or the inspecti...

Page 3: ...crew for 4 х 16 mm 2 Remote controller 1 Remote controller holder 1 Fixing screw for 3 5 x 16 mm Black 2 INDOOR UNIT MLZ KP09NA MLZ KP12NA MLZ KP18NA MLZ KP09NA2 MLZ KP12NA2 MLZ KP18NA2 Display section Horizontal vane Vertical vane Air outlet Air ﬁlter Air purifying ﬁlter Air inlet Air cleaning ﬁlter Anti Allergy Enzyme filter option Intake grille Safety strings Spec name plate Open the display co...

Page 4: ...32 27 47 41 36 29 Heating dB A 37 34 29 26 40 36 32 26 48 42 37 26 Cond drain connection O D in Ø1 26 mm Dimensions W in 43 3 8 D 14 3 16 H 7 5 16 Weight Ib 34 External finish White Control voltage by built in transformer 12 24 V DC NOTE Test conditions are based on ARI 210 240 1 Multi connection Specifications and rated conditions of main electric parts Model Item MLZ KP09NA MLZ KP12NA MLZ KP18NA...

Page 5: ...325 13 6 21 7 Wet MLZ KP12NA MLZ KP12NA2 HEAT Dry 332 13 9 22 1 COOL Dry 350 14 6 23 3 Wet MLZ KP18NA MLZ KP18NA2 HEAT Dry 403 16 9 26 7 COOL Dry 417 17 5 27 6 Wet 2 OPERATION The operating range of the outdoor unit depends on the connected outdoor unit Mode Condition Intake air temperature F Indoor Outdoor DB WB DB WB Cooling Standard temperature 80 67 95 Maximum temperature 90 73 115 Minimum tem...

Page 6: ...6 4 OUTLINES AND DIMENSIONS Unit inch INDOOR UNIT MLZ KP09NA MLZ KP12NA MLZ KP18NA MLZ KP09NA2 MLZ KP12NA2 MLZ KP18NA2 OBH802B ...

Page 7: ...FUSE T3 15AL250V DRAIN PUMP FLOAT SENSOR FS DP HORIZONTAL VANE MOTOR VERTICAL VANE MOTOR TERMINAL BLOCK MV1 MV2 F11 TB RELAY X11 ROOM TEMP THERMISTOR SYMBOL SYMBOL MF FAN MOTOR RT11 R111 NAME NAME t t t FS A disconnect should be required by local code Se procurer un sectionneur conforme aux réglementations locales NOTES 1 About the outdoor side electric wiring refer to the outdoor unit electric wi...

Page 8: ...CK MV1 MV2 F11 TB RELAY X11 ROOM TEMP THERMISTOR SYMBOL SYMBOL MF FAN MOTOR RT11 R111 NAME NAME A disconnect should be required by local code Se procurer un sectionneur conforme aux réglementations locales REMARQUES 1 Pour le câblage électronique côté extérieur se reporter au schéma d entretien du câblage électronique de l appareil extérieur 2 Utiliser des fils d alimentation en cuivre 3 Les symbo...

Page 9: ...Indoor coil thermistor RT12 main Indoor heat exchanger Flared connection Room temperature thermistor RT11 Indoor coil thermistor RT13 sub Flared connection Refrigerant flow in cooling Refrigerant flow in heating Refrigerant pipe Ø1 2 Ø12 7 with heat insulator Refrigerant pipe Ø1 4 Ø6 35 with heat insulator Indoor coil thermistor RT12 RT14 RT15 main INDOOR UNIT Unit inch mm MLZ KP09NA MLZ KP12NA ML...

Page 10: ...the remote controller for 2 seconds to enter the pairing mode 2 Press button again and assign a number to each remote controller Each press of button advances the number in the following order 1 2 3 4 3 Press button to complete the pairing setting After the setting turn ON the power supply and with the remote controller headed towards the indoor unit press the STOP OPERATE OFF ON button If 1 or 2 ...

Page 11: ...usly at restart Therefore the special counter measures are required to prevent the main voltage drop or the rush of the starting current by adding to the system that allows the units to start one by one C111 JR77 IC101 How to disable AUTO RESTART FUNCTION Turn off the main power for the unit Cut the jumper wire to JR77 on the indoor electronic control P C board Refer to 9 7 Operation If the main p...

Page 12: ... Electrical cover 1 Electrical cover 2 Electronic control P C board Slide switch SW3 Normal Up Increase airflow volume 7 4 P C BOARD MODIFICATION FOR CHANGING AIRFLOW VOLUME How to change Slide switch SWV1 setting Factory setting is normal 1 Make sure that the breaker for air conditioner is turned OFF 2 Remove the electrical cover 1 and 2 of the indoor unit 3 Slide out the electronic control P C b...

Page 13: ... perature About 2 to 4 F 1 to 2 C from set temperature Standby mode Refer to multi system operation Lit Blinking Not lit Signal transmitting section Battery replacement indicator Operation display section Temperature buttons STOP OPERATE OFF ON button Indication of remote controller model is on back FAN SPEED CONTROL button OPERATION SELECT button ECONO COOL button CLOCK SET button WEEKLY TIMER se...

Page 14: ... on with a beep tone 2 Select HEAT mode with OPERATION SELECT button 3 Press TEMPERATURE buttons TEMP or button to select the desired temperature The setting range is 50 F 10 C and 61 88 F 16 31 C 1 Cold air prevention control When the compressor is not operating or is starting and the temperature of indoor heat exchanger and or the room tem perature is low or when defrosting is being done the ind...

Page 15: ...door microprocessor 2 The horizontal vane angle and mode change as follows by pressing VANE CONTROL button NOTE The setting when the higher airflow is preferred in the Airflow direction 1 The angle of airflow direction 1 can be slightly heightened by changing SWV1 to up Refer to 7 5 P C BOARD MODIFICATION FOR CHANGING AIRFLOW DIRECTION ADJUSTMENT However it may cause the dirt on the ceiling Factor...

Page 16: ...tects water level above fixed point during a HEAT operation b emergency HEAT operation c standby when during multi system operation d standby when ON timer is set e operation STOP Drain pump operates in conditions 1 or 2 Operation stop condition Condition other than 1 or 2 indicated above 2 Float sensor Float moves with the up and down of water surface inside the drain pan and judges water level F...

Page 17: ... timer setting a Press OFF TIMER button during operation b Set the time of the timer using TIME SET buttons and Each time FORWARD button is pressed the set time increases by 10 minutes each time BACKWARD but ton is pressed the set time decreases by 10 minutes 2 To release the timer To release ON timer press ON TIMER button To release OFF timer press OFF TIMER button TIMER is cancelled and the disp...

Page 18: ...temperature blinks Pressing selects the day of the week to be set Pressing selects the setting number E g Mon Tue Sun and 1 are selected All days can be selected NOTE The simple ON OFF timer setting is available while the weekly timer is on In this case the ON OFF timer has priority over the weekly timer the weekly timer operation will start again after the simple ON OFF timer is complete When the...

Page 19: ...timer setting mode blinks 2 Press or buttons to view the setting of the particular day or number 3 Press button to exit the weekly timer setting 4 Press button to complete and transmit the weekly timer setting which was blink ing goes out and the current time will be displayed 8 10 SMART SET OPERATION 1 How to set SMART SET operation 1 Press STOP OPERATE OFF ON button 2 Select COOL or HEAT mode 3 ...

Page 20: ... for the operation running when SLEEP button is pressed It will change to the set temperature for SLEEP operation in about 30 minutes Pressing SLEEP button again returns the operation to the previous settings is pressed is pressed For about 30 minutes Set temperature for the operation before SLEEP operation Set temperature for SLEEP operation Set temperature for the operation before SLEEP operatio...

Page 21: ...VANE AUTO mode Emergency operation continues until the emergency operation switch is pressed once or twice or the unit receives any signal from the remote controller In the latter case normal operation will start NOTE Do not press the emergency operation switch during normal operation 8 13 3 MINUTE TIME DELAY OPERATION When the system turns OFF compressor will not restart for 3 minutes as 3 minute...

Page 22: ...larity of the batteries is correct Press RESET button with a fine tipped object and then use the remote controller Remove the front lid and insert batteries Then reattach the front lid NOTE 1 If RESET button is not pressed the remote controller may not operate correctly 2 This remote controller has a circuit to automatically reset the microprocessor when batteries are replaced This function is equ...

Page 23: ...te controller the set temperature is displayed with the remote controller headed towards the indoor unit Press the emergency operation switch so that the memorized abnormal condition is deleted 4 Release the failure mode recall function according to Releasing the failure mode recall function men tioned above Yes Blinks No OFF NOTE 1 Make sure to release the failure mode recall function after it is...

Page 24: ...s of normal or abnormal 2 short beeps are emitted as the signal is received Does OPERATION INDICATOR lamp on the indoor unit blink at the interval of 0 5 seconds Blinks The outdoor unit is abnormal Beeps are emitted at the same timing as the blinking of OPERATION INDICATOR lamp 2 Deleting the memorized abnormal condition Repair the failure parts With the remote controller headed towards the indoor...

Page 25: ...nal error When the serial signal from the out door unit is not received for a maxi mum of 6 minutes Refer to 9 6 How to check miswir ing and serial signal error 5 time blink 2 5 second OFF Not lit Drain pump Float sensor Float sensor is open Float sensor detects abnormal water level Check the float sensor and the drain pump Check the connectors of float sensor and the drain pump Refer to 9 6 Check...

Page 26: ...Outdoor unit Trouble of thermistor in outdoor unit Left lamp 7 time blink Cause Outdoor unit Trouble of outdoor control system Refer to 9 6 How to check miswiring and serial signal error when outdoor unit does not work Check room temperature thermistor and indoor coil thermis tor Refer to 9 7 Test point diagram and voltage Refer to 9 6 Check of indoor fan motor Refer to How to check the inverter c...

Page 27: ...efer to the characteristics of indoor coil thermistor and the room temperature thermistor on 9 7 Left lamp blinks 3 time blink 2 5 second OFF When the rotational frequency feedback signal is not emitted during the indoor fan operation Refer to 9 6 Check of indoor fan motor Indoor unit and outdoor unit do not operate Indoor unit and outdoor unit do not operate Left lamp blinks 5 time blink 2 5 seco...

Page 28: ...N PARTS MLZ KP09NA MLZ KP12NA MLZ KP18NA MLZ KP09NA2 MLZ KP12NA2 MLZ KP18NA2 YLW YLW RED YLW YLW ROTOR Part name Figure Check method and criteria Indoor fan motor Measure the resistance with a tester Part temperature 50 F 86 F 10 C 30 C Normal 8 kΩ 20 kΩ Room temperature thermistor RT11 Indoor coil thermistor RT12 RT14 RT15 MAIN RT13 SUB Horizontal vane motor MV1 Measure the resistance between the...

Page 29: ...ration switch is pressed If more than 12 seconds passes by turn OFF the power supply and turn ON it again then measure the voltage 1 Measure the voltage between CN211 and 2 Measure the voltage between CN211 and The indoor fan motor error has occurred and the indoor fan repeats 12 second ON and 30 second OFF 3 times and then stops Measure the voltage between CN211 and while the fan motor is rotatin...

Page 30: ... a filter on receiving part Replace the receiver P C board Assign 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 receiver P C board connector CN301 and when the remote controller button is pressed Is the voltage approximately 4 V DC 5 V DC No Yes Replace the indo...

Page 31: ...e resistance between CN211 and of the indoor fan motor connector Short open circuit Replace the indoor fan motor Short open circuit Replace the horizontal vane motor the vertical vane motor coil and the indoor electronic control P C board Turn OFF the power supply Check both parts side and pattern side of the indoor electronic control P C board visually Replace the varistor NR11 and fuse F11 Are t...

Page 32: ...e the operation starts No Yes No Yes Yes No No Yes No Yes As for outdoor unit refer to outdoor unit service manual Turn OFF the power supply Turn ON the power supply Is there 208 230 V AC between outdoor terminal block S1 and S2 Does the left lamp of OPERATION INDICATOR lamp light up Confirmation of the power supply to the indoor unit Press the emergency operation switch once Check the power suppl...

Page 33: ...m emergency COOL operation Measure the voltage between CN1N1 and Yes Yes No No Is there 208 230 V AC between CN1N1 and Is there large amount of water in drain pan 1 Refer to 9 5 when float sensor can be checked Yes Replace the indoor electronic control P C board Replace the indoor electronic control P C board Replace the indoor electronic control P C board Check power supply voltage No Replace the...

Page 34: ... strength or the installation condition combination of specific 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 Layout ...

Page 35: ...GND High voltage DC 0 or 15 V DC 5 V DC GND Timer short mode point 2 points Refer to 7 1 SWV1 Changing air flow direction Refer to 7 5 CN151 Vane motor connector Receiver P C board Factory setting Do not change the setting ON OFF 1 2 3 4 5 6 SW101 CN105 Connector to optional interface Modifica tion point for individual operation Refer to 7 2 Indoor coil ther mistor RT13 SUB CN113 Indoor coil ther ...

Page 36: ...DC 0 or 15 V DC 5 V DC GND Timer short mode point 2 points Refer to 7 1 SWV1 Changing air flow direction Refer to 7 5 CN151 Vane motor connector Receiver P C board Factory setting Do not change the setting ON OFF 1 2 3 4 5 6 SW101 CN105 Connector to optional interface Modifica tion point for individual operation Refer to 7 2 Indoor coil ther mistor RT13 SUB CN113 Indoor coil ther mistor RT15 MAIN ...

Page 37: ...ng mechanism can be detached as shown below There are 2 types of the terminal with locking mechanism The terminal without locking mechanism can be detached by pulling it out Check the shape of the terminal before detaching Detaching method of the terminal with locking mechanism Connector Sleeve Locking lever MLZ KP09NA MLZ KP12NA MLZ KP18NA MLZ KP09NA2 MLZ KP12NA2 MLZ KP18NA2 NOTE Turn OFF the pow...

Page 38: ...t fits closely with the ceiling surface Loosely fasten with the provided fixing screws at 4 places on the left and right side Figure 6 5 Tighten the fixing screws at 2 places in the middle and the fixing screw in the center Figure 6 6 Tighten the fixing screws at 4 places on the left and right sides NOTE Make sure there are no gaps between the indoor unit and the grille or between the grille and t...

Page 39: ...d right sides Check after installing 1 Check that there are no gaps between the indoor unit and the grille or between the grille and the ceiling surface NOTE If there are any gaps the wind may come in and it may cause water to drip 2 Check that the screw cap is installed 3 Check that the left and right side panels are installed securely 4 Check that the emergency operation switch is installed secu...

Page 40: ...nd 5 Disconnect the connectors of the horizontal and vertical vane motors 6 Remove the indoor coil thermistors main and sub 7 Remove the drain cover 3 fixing screws 8 Remove the pipe band 9 Remove the heat exchanger 6 fixing screws 10 Remove the stabilizer 2 fixing screws 5 Removing the horizontal and vertical vane motors 1 Remove the grille 2 Remove the drain pan 3 Remove the horizontal vane 4 Re...

Page 41: ...trings to the tabs on the side plate of indoor heat exchanger 9 Remove the indoor heat exchanger 6 fixing screws and slide it downward 10 Remove the stabilizer 2 fixing screws 11 Partially slide the indoor electric control P C board out 12 Disconnect the connector CN211 of indoor fan motor 13 Remove the motor band 2 fixing screws Figure 6 14 Remove the indoor fan motor and line flow fan No need to...

Page 42: ...KU TOKYO 100 8310 JAPAN Copyright 2018 MITSUBISHI ELECTRIC CORPORATION Issued Apr 2022 No OBH802 REVISED EDITION B Issued Mar 2019 No OBH802 REVISED EDITION A Published Mar 2018 No OBH802 Made in Japan Specifications are subject to change without notice ...

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