INDOOR UNIT No. OBH780 SERVICE MANUAL Models MSZ-DM50VA MSZ-DM60VA MSZ-DM71VA Outdoor unit service manual MUZ-DM·VA Series (OBH781) 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 ·····················8 6.
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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.
PART NAMES AND FUNCTIONS MSZ-DM50VA Front panel Air inlet Air lter Air cleaning lter [Silver- ionized air purifier filter, option] Horizontal vane Air outlet Heat exchanger Display section Remote control Remote controller receiving section Operation indicator lamp Emergency operation switch...
NOISE CRITERIA CURVES MSZ-DM50VA FUNCTION SPL(dB(A)) LINE FAN SPEED Test conditions Cooling : Dry-bulb temperature 27°C Wet-bulb temperature 19°C COOLING Heating : Dry-bulb temperature 20°C Super High HEATING INDOOR UNIT WALL NC-70 0.8m NC-60 MICROPHONE NC-50 NC-40 NC-30 NC-20 NC-10...
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MSZ-DM60VA MSZ-DM71VA 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 4000 8000 BAND CENTER FREQUENCIES, Hz...
SERVICE FUNCTIONS MSZ-DM50VA MSZ-DM60VA MSZ-DM71VA 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.)
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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.
MICROPROCESSOR CONTROL MSZ-DM50VA MSZ-DM60VA MSZ-DM71VA 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.
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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.
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(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.
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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.
TROUBLESHOOTING MSZ-DM50VA MSZ-DM60VA MSZ-DM71VA 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.
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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.
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NOTE : Blinking patterns of this mode differ from the ones of 2. Table of indoor unit failure mode recall function TROUBLESHOOTING CHECK TABLE (10-4.). Upper lamp of OP- Abnormal point ERATION INDICA- Condition Remedy (Failure mode) TOR lamp Not lit Normal —...
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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 fl ashing on and off. remote controller.
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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 Blinking Not lit...
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fi rst has manual. setting not operate. the priority. 10-5. TROUBLE CRITERION OF MAIN PARTS MSZ-DM50VA MSZ-DM60VA MSZ-DM71VA Part name Check method and criterion Figure Measure the resistance with a tester. Room temperature thermistor (RT11) Refer to 10-7.
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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.
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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.
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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.
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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...
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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.
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10-7. TEST POINT DIAGRAM AND VOLTAGE MSZ-DM50VA 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 V DC (+)3-6 V DC 15 V DC...
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MSZ-DM60VA MSZ-DM71VA 1. Indoor power P.C. board 12 V DC 5 V DC Connector to indoor electronic Indoor terminal block Indoor terminal block control P.C. board (CN20A) connecting (TAB2) connecting (TAB1) Connector to Terminal block (CN201) Fuse (F11) T3.15AL250V Varistor (NR11) Connector to Indoor fan motor (CN211) Reactor (L111)
Locking lever lever. Connector 11-1. MSZ-DM50VA NOTE: Turn OFF the power supply before disassembly. OPERATING PROCEDURE PHOTOS 1. Removing the panel (1) Remove the screw caps on the panel and remove the Photo 1 screws of the panel.
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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...
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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.
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(Figure 1). Figure 1 Indoor coil thermistor 4 mm Water cover Screws of the motor bed MSZ-DM50VA Screws of the left side of the heat exchanger OBH780...
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11-2. MSZ-DM60VA MSZ-DM71VA NOTE: Turn OFF the power supply before disassembly. OPERATING PROCEDURE PHOTOS 1. Removing the panel (1) Remove the screw caps on the panel and remove the Photo 1 screws of the panel. (2) Pull the panel slightly toward you, and then remove the panel by pushing it upward.
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OPERATING PROCEDURE PHOTOS 2. Removing the indoor power P.C. board and the Photo 2 electrical box Water cover (1) Remove the panel. (Refer to 1.) Remove the right cor- ner box. Screws of the earth plate (2) Disconnect the following connectors: Screw of the <Indoor electronic control P.C.
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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. Indoor electronic (2) Disconnect the following connectors: control P.C. board <Indoor electronic control P.C.
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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 water cover, the electrical box and the nozzle assembly.