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Mitsubishi Electric MSZ-DM25VA Service Manual
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Mitsubishi Electric MSZ-DM25VA Service Manual

Split-type air conditioner
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See also: Installation Manual

INDOOR UNIT

SERVICE MANUAL

Models
MSZ-DM25VA
MSZ-DM35VA
MSZ-DM25VA
MSZ-DM35VA
NOTE:
RoHS compliant products have
<G> mark on the spec name plate.
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E1
ER1
,
-
E1
ER1
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CONTENTS
1. TECHNICAL CHANGES ······························3
2. PART NAMES AND FUNCTIONS ··················4
3. SPECIFICATION ········································5
4. NOISE CRITERIA CURVES ··························6
5. OUTLINES AND DIMENSIONS ·····················7
6. WIRING DIAGRAM ·····································8
7. REFRIGERANT SYSTEM DIAGRAM ·············9
8. SERVICE FUNCTIONS ······························ 10
9. MICROPROCESSOR CONTROL ················ 12
10. TROUBLESHOOTING ······························· 16
11. DISASSEMBLY INSTRUCTIONS ················· 28
PARTS CATALOG (OBB750)
No. OBH750
Outdoor unit service manual
MUZ-DM·VA Series (OBH751)
MXZ-DM•VA Series (OBH739)

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Summary of Contents for Mitsubishi Electric MSZ-DM25VA

  • Page 1: Table Of Contents

    INDOOR UNIT No. OBH750 SERVICE MANUAL Models MSZ-DM25VA MSZ-DM35VA Outdoor unit service manual MUZ-DM·VA Series (OBH751) MXZ-DM•VA Series (OBH739) CONTENTS 1. TECHNICAL CHANGES ······························3 2. PART NAMES AND FUNCTIONS ··················4 3. SPECIFICATION ········································5 4. NOISE CRITERIA CURVES ··························6 5. OUTLINES AND DIMENSIONS ·····················7 6.
  • Page 2 Use the specif 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: Technical Changes

    TECHNICAL CHANGES MSZ-DM25VA - MSZ-DM35VA - 1. New model OBH750...

  • Page 4: Part Names And Functions

    PART NAMES AND FUNCTIONS MSZ-DM25VA MSZ-DM35VA Front panel Air inlet Air filter Air cleaning filter (Silver-ionized air purifier filter) Horizontal vane Air outlet Heat exchanger Display section Remote control Remote controller receiving section Operation indicator lamp Emergency operation switch ACCESSORIES Installation plate Installation plate f xing screw 4 ×...

  • Page 5: Specification

    SPECIFICATION Indoor model MSZ-DM25VA MSZ-DM35VA Power supply Single phase 230 V, 50 Hz Breaker Capacity Cooling 1,020 Power input 1 (Total) Heating Cooling Running current 1 (Total) Heating Cooling Power factor 1 (Total) Heating Starting current 1 (Total) Model RC0J40-EF Cooling 0.19...

  • Page 6: Noise Criteria Curves

    NOISE CRITERIA CURVES MSZ-DM25VA MSZ-DM35VA 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...

  • Page 7: Outlines And Dimensions

    OUTLINES AND DIMENSIONS MSZ-DM25VA MSZ-DM35VA Unit: mm 11×26 Oblong hole 11×20 Oblong hole Installation plate 80.5 80.5 Indoor unit 61.5 59.5 Wall hole Ø65 Air in Installation plate Piping Drain hose Air out Insulation Ø35 O.D Liquid line Ø7.0 - 0.39m (Flared connection Ø6.35) Gas line Ø9.52 - 0.34m (Flared connection Ø9.52)

  • Page 8: Wiring Diagram

    WIRING DIAGRAM MSZ-DM25VA - MSZ-DM35VA - OBH750...

  • Page 9: Refrigerant System Diagram

    REFRIGERANT SYSTEM DIAGRAM MSZ-DM25VA MSZ-DM35VA Unit: mm Refrigerant pipe ø9.52 (with heat insulator) Indoor coil Indoor thermistor heat RT12 exchanger Flared connection Indoor coil thermistor RT13 Room temperature thermistor RT11 Flared connection Refrigerant pipe ø6.35 (with heat insulator) Refrigerant flow in cooling...

  • Page 10: Service Functions

    SERVICE FUNCTIONS MSZ-DM25VA MSZ-DM35VA 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.) Set time : 3-minute → 3-second (It takes 3 minutes for the compressor to start operation. However, the starting time is shortened by bridging the timer short mode point.)
  • Page 11 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.

  • Page 12: Microprocessor Control

    MICROPROCESSOR CONTROL MSZ-DM25VA MSZ-DM35VA WIRELESS REMOTE CONTROLLER Signal transmitting section Operation display section STOP/OPERATE (OFF/ON) button Fan speed control button Temperature buttons ECONO COOL button Operation select button Vane control button Timer mode select button Time set buttons RESET button NOTE : Last setting will be stored after the unit is turned OFF with the remote controller.
  • Page 13 9-2. DRY ( ) OPERATION (1) Press STOP/OPERATE/ (OFF/ON) 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 14 (5) STOP (operation OFF) and ON TIMER standby 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. (6) Dew prevention During COOL or DRY operation with the vane angle at Angle 3 ~ 5 when the compressor cumulative operation time exceeds 1 hour, the vane angle automatically changes to Angle 2 for dew prevention.
  • Page 15 9-6. EMERGENCY/TEST OPERATION In the case of test run operation or emergency operation, use EMERGENCY OPERATION switch on the right side of the indoor unit. Emergency operation is available when the remote controller is missing or has failed, or when the batteries in the remote controller are running down.

  • Page 16: Troubleshooting

    TROUBLESHOOTING MSZ-DM25VA MSZ-DM35VA 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 and/or disconnect the power plug.
  • Page 17 10-2. FAILURE MODE RECALL FUNCTION Outline of the function This air conditioner can memorize the abnormal condition which has occurred once. Even though LED 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 18 2. Indoor unit failure mode table Upper lamp of OP- Abnormal point ERATION INDICA- Condition Remedy (Failure mode) TOR lamp Not lighted Normal — — The room temperature thermistor short or 1-time f ash every Room temperature Refer to the characteristics of the room temperature open circuit is detected every 8 seconds dur- 0.5-second thermistor...
  • Page 19 10-3. INSTRUCTION OF TROUBLESHOOTING Start Indoor unit operates. Indoor unit does Indoor unit oper- OPERATION INDICATOR Outdoor unit does not receive ates. lamp on the indoor unit is not operate normally. Outdoor unit the signal from f ashing on and off. does not operate.
  • Page 20 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 21 10-5. TROUBLE CRITERION OF MAIN PARTS MSZ-DM25VA MSZ-DM35VA Part name Check method and criterion Figure Measure the resistance with a tester. Room temperature thermistor (RT11) Refer to 10-7.

  • Page 22: 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 CN211. Turn ON the power supply, wait 5 seconds or more, and then press EMERGENCY OPERATION switch.
  • Page 23 B Check of remote controller and indoor electronic control P.C. board Check if the remote controller is exclusive for this air conditioner. Press STOP/OPERATE/ (OFF/ON) button on the remote controller. 1 Look at the image of the signal transmitting section of Is LCD display on the remote controller Replace the batteries.
  • Page 24 C Check of indoor P.C. board and indoor fan motor Turn OFF the power supply. Remove indoor fan motor connector CN211 from indoor power P.C. board and vane Measure the resistance of indoor fan Short circuit: motor connector CN151 from the indoor motor.
  • Page 25 D How to check miswiring and serial signal error Turn OFF the power supply. Is there rated voltage in the Check the power supply. power supply? 1. Turn ON the power supply. 2. Press the emergency operation switch. Has the relay 52C been turned on 3 minuets later ? [The relay will be turned on in 3 to 7 seconds by bridging the timer short mode point (Refer to 10-7.).] Initializing the determination of the power...
  • Page 26 E Electromagnetic noise enters into TV sets or radios Is the unit earthed? Earth the unit. Is the distance between the antennas Extend the distance between the antennas and and the indoor unit within 3 m, or is the the indoor unit, and/or the antennas and the distance between the antennas and the outdoor unit.
  • Page 27 10-7. TEST POINT DIAGRAM AND VOLTAGE MSZ-DM25VA MSZ-DM35VA 1. Indoor power P.C. board Connector to Fuse (F11) Terminal block T3.15AL250V Varistor (NR11) Resistor (R111) (CN201) Connector to Indoor fan motor (CN211) (+)0 or 15 VDC (+)3-6 VDC 15 VDC (-) GND...

  • Page 28: Disassembly Instructions

    Pull the terminal while pull out the terminal pushing the locking slowly. Locking lever lever. Connector 11-1. MSZ-DM25VA MSZ-DM35VA NOTE: Turn OFF the power supply before disassembly. OPERATING PROCEDURE PHOTOS 1. Removing the panel Photo 1 Front panel (1) Remove the screw caps on the panel and remove the screws of the panel.
  • Page 29 OPERATING PROCEDURE PHOTOS 2. Removing the indoor power P.C. board and the Photo 2 Earth wire electrical box (1) Remove the panel. (Refer to 1.) Remove the right corner box. (2) Disconnect the following connectors: <Indoor electronic control P.C. board> Screw of the CN151 (Vane motor) electrical cover...
  • Page 30 OPERATING PROCEDURE PHOTOS 3. Removing the indoor electronic control P.C. Photo 4 board Control P.C. board holder (Inside) (1) Remove the panel. (Refer to 1.) Remove the right corner Catch box. (2) Disconnect the following connectors: Indoor electronic <Indoor electronic control P.C. board> control P.C.
  • Page 31 OPERATING PROCEDURE PHOTOS 5. Removing the indoor fan motor, the indoor coil Photo 6 thermistor and the line flow fan (1) Remove the panel. (Refer to 1.) Remove the corner box. (2) Remove the control P.C. board holder, the electrical box and the nozzle assembly.
  • Page 32 Mount the clip-shape part on the marked position. Do not pull the lead wire when removing the indoor coil thermistor. HEAD OFFICE: TOKYO BLDG., 2-7-3, MARUNOUCHI, CHIYODA-KU, TOKYO 100-8310, JAPAN © Copyright 2015 MITSUBISHI ELECTRIC CORPORATION Distributed in Dec. 2015. No. OBH750 New publication, effective Dec. 2015 Made in Japan Specifications are subject to change without notice.

This manual is also suitable for:

Msz-dm35va

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