Mitsubishi Electric MFZ-KJ25VE-E2 Service Manual

Mitsubishi Electric MFZ-KJ25VE-E2 Service Manual

Split-type air conditioners


Quick Links

• 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 ···················· 33
Revision B:
and MFZ-KJ50VE-
have been added.
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-E2

  • Page 1: Table Of Contents

  • Page 2: Technical Changes

    Use the specifi ed refrigerant only Never use any refrigerant other than that specified. Doing so may cause a burst, an explosion, or fire when the unit is being used, serviced, or disposed 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.
  • 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) Emergency operation switch Remote control receiving section...
  • Page 4: Specification

    SPECIFICATION Indoor model MFZ-KJ25VE MFZ-KJ35VE MFZ-KJ50VE Power supply Single phase 230 V, 50 Hz Cooling Power input Heating Cooling 0.14 0.20 Running current Heating 0.17 0.34 Model RC0J30-KX RC0J40-PA Cooling 0.14 0.20 Current Heating 0.17 0.34 Dimensions W × H × D 750 ×...
  • Page 5: Noise Criteria Curves

    NOISE CRITERIA CURVES MFZ-KJ25VE MFZ-KJ35VE FAN SPEED FUNCTION SPL(dB(A)) LINE FAN SPEED FUNCTION SPL(dB(A)) LINE COOLING COOLING Super High Super High HEATING HEATING NC-70 NC-70 NC-60 NC-60 NC-50 NC-50 NC-40 NC-40 NC-30 NC-30 NC-20 NC-20 NC-10 NC-10 1000 2000 4000 8000 1000 2000...
  • 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 Flared connection Refrigerant pipe 6.35...
  • 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 bridging 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 Operation display section VANE CONTROL button i-save 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 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 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 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 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 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 OPERATION INDICATOR Lighted Blinking Not lighted Abnormal Operation indicator lamp Symptom Condition Remedy point Right lamp flash When the operation mode of the each indoor Outdoor unit MXZ type • Select the same operation mode unit is differently set to COOL (includes DRY) operates but Operation for all the units.
  • Page 24 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 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 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. Was the indoor unit ever connected to the Multi (MXZ) series and operated (turned on)? The connection information to the Multi series is stored in the indoor unit.
  • Page 29 MXZ Type Turn OFF the power supply. Is there rated voltage in the power supply? Check the power supply. Turn ON the power supply. Is there rated voltage between outdoor terminal block S1 and S2? Check the wiring. Press EMERGENCY OPERATION switch once. Does the left lamp of the OPERATION INDICATOR lamp light up? <Confi...
  • Page 30 Turn ON the power supply. LED indication for communication status Communication status is indicated by the LED. Is there rated voltage Check the power supply Unit status between outdoor Blinking: normal communication and correct the problem. terminal block S1 and S2 ? Lighted: abnormal communication or not connected Not lighted: The outdoor P.C.
  • Page 31 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 32 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", (R111)
  • Page 33: Disassembly Instructions

    DISASSEMBLY INSTRUCTIONS <"Terminal with locking mechanism" Detaching points> The terminal which has the locking mechanism can be detached as shown below. There are two types (refer to (1) and (2)) 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.
  • Page 34 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 35 How to remove the multi-flow Horizontal vane (back) vane and the horizontal vanes Horizontal vane (front) Unit body (1) Removing the horizontal vane (front/back) (1)-1. See the figure below and push to open the indicated Multi-flow vane 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.
  • Page 36 OPERATING PROCEDURE PHOTOS Photo 9 5. Removing the horizontal vane motor (1) Remove the panel. (Refer to 1.) Screws of the nozzle (2) Remove the screws of the horizontal vane motor sup- port and pull out the horizontal vane motor support from the nozzle.
  • Page 37 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 38 HEAD OFFICE: TOKYO BLDG., 2-7-3, MARUNOUCHI, CHIYODA-KU, TOKYO 100-8310, JAPAN Copyright 2013 MITSUBISHI ELECTRIC CORPORATION Distributed in Jan. 2014. No. OBH666 REVISED EDITION-B Distributed in Oct. 2013. No. OBH666 REVISED EDITION-A New publication, effective Jan. 2014 Distributed in Jun. 2013. No. OBH666 Specifications are subject to change without notice.
  • Page 39 Related Links Model Number: MFZ-KJ25VE MFZ-KJ25-50 Declaration of Conformity MFZ-KJ25-50VE Installation Manual (JG79A762H01) MFZ-KJ25-50VE Instruction Book (JG79A955H01) MFZ-KJ25-50VE Parts Catalogue (OBB666B) MFZ-KJ25-50VE Service Manual (OBH666B)

Table of Contents