Mitsubishi Electric MFZ-KJ25VE Service Manual

Mitsubishi Electric MFZ-KJ25VE Service Manual

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• 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.
1. TECHNICAL CHANGES ··································· 2
2. PART NAMES AND FUNCTIONS ····················· 3
3. SPECIFICATION ················································ 4
4. NOISE CRITERIA CURVES ······························ 5
5. OUTLINES AND DIMENSIONS ························ 6
6. WIRING DIAGRAM ············································ 7
8. SERVICE FUNCTIONS ····································· 9
9. MICROPROCESSOR CONTROL ····················11
10. TROUBLESHOOTING ····································· 18
11. DISASSEMBLY INSTRUCTIONS ···················· 31
Revision A:
has been added.
Please void OBH666.
No. OBH666
Outdoor unit service manual
MUFZ-KJ•VE Series (OBH667)
MUFZ-KJ•VEHZ Series (OBH668)


Table of Contents

Summary of Contents for Mitsubishi Electric MFZ-KJ25VE

  • Page 1: Table Of Contents

    Please void OBH666. SPLIT-TYPE AIR CONDITIONERS INDOOR UNIT No. OBH666 SERVICE MANUAL REVISED EDITION-A Models MFZ-KJ25VE MFZ-KJ35VE MFZ-KJ50VE Outdoor unit service manual MUFZ-KJ•VE Series (OBH667) MUFZ-KJ•VEHZ Series (OBH668) CONTENTS 1. TECHNICAL CHANGES ··································· 2 2. PART NAMES AND FUNCTIONS ····················· 3 3.
  • Page 2: Technical Changes

    Revision A: • MFZ-KJ50VE- has been added. TECHNICAL CHANGES MFZ-KJ25VE- MFZ-KJ35VE- MFZ-KJ50VE- 1. New model With the horizontal vanes and the multi-flow vane, air blows to the expanded vertical area using only one fan. These models are compatible with the outdoor units with low standby power control.
  • Page 3: Part Names And Functions

    PART NAMES AND FUNCTIONS MFZ-KJ25VE MFZ-KJ35VE MFZ-KJ50VE Air outlet Horizontal vane Vertical vane Multi-flow vane Fan guard Air cleaning filter (Anti-Allergy Enzyme Filter) Panel Front panel Air filter (Nano platinum filter) Display and operation section (When the front panel is opened)
  • Page 4: Specification

    Heating: Indoor Dry-bulb temperature 20°C Outdoor Dry-bulb temperature 7°C Wet-bulb temperature 6°C 1 Measured under rated operating frequency. Specifications and rating conditions of main electric parts Model MFZ-KJ25VE MFZ-KJ35VE MFZ-KJ50VE Item Fuse (F11) T3.15AL250V Horizontal vane motor (Front) (MV1) 12 VDC 250 Ω...
  • Page 5: Noise Criteria Curves

  • Page 6: Outlines And Dimensions

  • Page 7: Wiring Diagram

  • Page 8: Refrigerant System Diagram

    REFRIGERANT SYSTEM DIAGRAM MFZ-KJ25VE Unit: mm MFZ-KJ35VE MFZ-KJ50VE Refrigerant pipe 9.52 (MFZ-KJ25/35) 12.7 (MFZ-KJ50) (with heat insulator) Indoor coil Indoor thermistor heat RT12 (main) exchanger Flared connection Distributor Indoor coil thermistor RT14, RT15 (main) RT13 (sub) Room temperature thermistor RT11...
  • Page 9: Service Functions

    SERVICE FUNCTIONS MFZ-KJ25VE MFZ-KJ35VE MFZ-KJ50VE 8-1. TIMER SHORT MODE • For service, the following set time can be shortened by short circuiting the timer short mode point on the electronic control P.C. board. (Refer to 10-7.) • The set time for the ON/OFF timer can be reduced to 1 second for each minute.
  • Page 10 8-3. AUTO RESTART FUNCTION When the indoor unit is controlled with the remote controller, the operation mode, the set temperature, and the fan speed are memorized by the indoor electronic control P.C. board. “AUTO RESTART FUNCTION” automatically starts operation in the same mode just before the shutoff of the main power. Operation If the main power has been cut, the operation settings remain.
  • Page 11: Microprocessor Control

    MICROPROCESSOR CONTROL MFZ-KJ25VE MFZ-KJ35VE MFZ-KJ50VE WIRELESS REMOTE CONTROLLER Signal transmitting section Distance of signal : About 6 m Beep(s) is (are) heard from the indoor unit when the signal is received. FAN SPEED CONTROL button OPERATION SELECT button ECONO COOL button...
  • Page 12 9-2. DRY ( ) OPERATION (1) Press OPERATE/STOP (ON/OFF) button. OPERATION INDICATOR lamp of the indoor unit turns on with a beep tone. (2) Select DRY mode with OPERATION SELECT button. (3) The set temperature is determined from the initial room temperature. 1.
  • Page 13 9-6. 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, speed, and angle of the motor are controlled by pulse signals (approximately 12 V) transmitted from indoor microprocessor. (2) The horizontal vane angle and mode change as follows by pressing VANE CONTROL ( ) button.
  • Page 14 (6) STOP (operation OFF) and ON TIMER standby In the following cases, the horizontal vane returns to the closed position. (a) When OPERATE/STOP (ON/OFF) 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 changes to Angle 1 for dew prevention.
  • Page 15: Weekly Timer Operation

    9-8. WEEKLY TIMER OPERATION • A maximum of 4 ON or OFF timers can be set for individual days of the week. • A maximum of 28 ON or OFF timers can be set for a week. 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 •...
  • Page 16 (4) Press button to complete and transmit the weekly timer setting. which was blink- ing goes out, and the current time will be displayed. NOTE: • Press button to transmit the setting information of weekly timer to the indoor unit. Point the remote controller toward the indoor unit for 3 seconds.
  • Page 17 9-10. EMERGENCY/TEST OPERATION In the case of test run operation or emergency operation, use Operation mode COOL/HEAT EMERGENCY OPERATION switch on the right side of the indoor unit. Set temperature 24°C Emergency operation is available when the remote controller is miss- Fan speed Medium ing or has failed, or when the batteries in the remote controller are...
  • Page 18: Troubleshooting

    TROUBLESHOOTING MFZ-KJ25VE MFZ-KJ35VE MFZ-KJ50VE 10-1. CAUTIONS ON TROUBLESHOOTING 1. Before troubleshooting, check the following 1) Check the power supply voltage. 2) Check the indoor/outdoor connecting wire for miswiring. 2. Take care of the following during servicing 1) Before servicing the air conditioner, be sure to turn OFF the main unit first with the remote controller, and then after confirming the horizontal vane is closed, turn OFF the breaker.
  • Page 19: Indoor Unit

    10-2. FAILURE MODE RECALL FUNCTION Outline of the function This air conditioner can memorize the abnormal condition which has occurred once. Even though OPERATION INDICATOR lamp indication listed on the troubleshooting check table (10-4.) disappears, the memorized failure details can be recalled. This mode is very useful when the unit needs to be repaired for the abnormality which does not recur.
  • Page 20: Indoor Unit

    2. Indoor unit failure mode table NOTE: Blinking patterns of this mode differs from the ones of Troubleshooting check table (10-4.). Left lamp of Right lamp of Abnormal point OPERATION OPERATION Condition Remedy (Failure mode) INDICATOR lamp INDICATOR lamp Not lighted Not lighted Normal –...
  • Page 21: Indoor Unit

    10-3. INSTRUCTION OF TROUBLESHOOTING Start Indoor unit Indoor unit does Indoor unit operates. OPERATION INDICATOR operates. not receive Outdoor unit does lamp on the indoor unit is Outdoor unit the signal from not operate normally. flashing ON and OFF. does not remote controller.
  • Page 22: Indoor Unit

    10-4. TROUBLESHOOTING CHECK TABLE Before taking measures, make sure that the symptom reappears for accurate troubleshooting. When the indoor unit has started operation and detected an abnormality of the following condition (the first detection after the power ON), the indoor fan motor turns OFF and OPERATION INDICATOR lamp flashes. OPERATION INDICATOR Lighted Blinking...
  • Page 23 10-5. TROUBLE JUDGEMENT CRITERIA OF MAIN PARTS MFZ-KJ25VE MFZ-KJ35VE MFZ-KJ50VE Part name Check method and criteria Figure Room temperature thermistor (RT11) Measure the resistance with a tester. Indoor coil thermistor Refer to 10-7. "Test point diagram and voltage", "Indoor electronic control (RT12 (MAIN 1), RT13 (SUB) P.C.
  • Page 24: Troubleshooting Flow

    10-6. TROUBLESHOOTING FLOW A Check of indoor fan motor The indoor fan motor error has occurred, and the indoor fan does not operate. Turn OFF the power supply. Pay enough attention to the high voltage on the fan motor connector. Turn ON the power supply, wait 5 seconds or more, and then press EMERGENCY OPERATION switch.
  • Page 25 Check of remote controller, display receiver P.C. board and indoor control P.C. board Check if the remote controller is exclusive for this air conditioner. Press OPERATE/STOP (ON/OFF) button on the remote controller. 1 Look at the image of the signal transmitting section of the remote controller through the monitor of a digital camera or a camera phone.
  • Page 26 Check of indoor electronic control P.C. board and indoor fan motor Turn OFF the power supply. Remove indoor fan motor connector CN211 Measure the resistance of indoor fan and vane motor connector CN151 from the Short circuit: motor. indoor electronic control P.C. board and turn Replace the indoor fan motor.
  • Page 27: Indoor Unit

    How to check miswiring and serial signal error MUFZ-KJ25/35 Turn OFF the power supply. Is there rated voltage in the Check the power supply. power supply? Turn ON the power supply. Is there rated voltage between Check the wiring. outdoor terminal block S1 and S2? Press EMERGENCY OPERATION switch once.
  • Page 28: Indoor Unit

    MUFZ-KJ50 Turn the power supply OFF. NOTE: Refer to the indoor unit service manual. Is there rated voltage in the power supply? Check the power supply. Check for incorrect indoor-outdoor connecting wiring. • Turn OFF inverter-controlled lighting equipment. • Turn OFF the power supply and then turn ON again. •...
  • Page 29: Indoor Unit

    Electromagnetic noise enters into TV sets or radios Is the unit earthed? Earth the unit. Is the distance between the Extend the distance between antennas and the indoor the antennas and the indoor unit within 3 m, or is the unit, or the antennas distance between the and the outdoor unit.
  • Page 30 10-7. TEST POINT DIAGRAM AND VOLTAGE MFZ-KJ25VE MFZ-KJ35VE MFZ-KJ50VE Indoor electronic control P.C. board FUSE (F11) T3.15AL250V Varistor (NR11) Serial signal input (CN202) JR05 Modification JR06 point for Power supply (CN201) individual input 230 VAC operation (Refer to 8-2.) To disable "Auto Resistor restart function",...
  • Page 31: Disassembly Instructions

    Locking lever lever. Connector 11-1. MFZ-KJ25VE MFZ-KJ35VE MFZ-KJ50VE NOTE: Turn OFF power supply before disassembly. OPERATING PROCEDURE PHOTOS 1. Removing the panel Photo 1 (1) Push down the tabs on the both sides of the unit.
  • Page 32 OPERATING PROCEDURE PHOTOS 3. Removing the electronic control P.C. board and Photo 4 the display receiver P.C. board (1) Remove the panel. (Refer to 1.) Earth wire connect to (2) Remove the electrical box. (Refer to 2.) the heat exchanger (3) Remove the earth wire connected to the electronic control P.C.
  • Page 33 OPERATING PROCEDURE PHOTOS Photo 9 4. Removing the nozzle assembly (1) Remove the panel. (Refer to 1.) Screws of the nozzle (2) Rotate the display receiver P.C. board holder to the right side and disconnect the vane motor relay con- nector.
  • Page 34 OPERATING PROCEDURE PHOTOS 7. Removing the line flow fan and the indoor fan Photo 13 Screw of the line flow fan motor (1) Remove the panel. (Refer to 1.) (2) Remove the electrical box. (Refer to 2.) (3) Remove the nozzle. (Refer to 4.) (4) Disengage the water cover from the catches.
  • Page 35 OBH666A...
  • Page 36 HEAD OFFICE: TOKYO BLDG., 2-7-3, MARUNOUCHI, CHIYODA-KU, TOKYO 100-8310, JAPAN Copyright 2013 MITSUBISHI ELECTRIC CORPORATION Distributed in Oct. 2013. No. OBH666 REVISED EDITION-A New publication, effective Oct. 2013 Distributed in Jun. 2013. No. OBH666 Specifications are subject to change without notice.

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