SPLIT-TYPE AIR CONDITIONERS Please void OB448. INDOOR UNIT No. OB448 SERVICE MANUAL REVISED EDITION-A Wireless type Models MS-A09WA MS-A09WA - MS-A12WA MS-A12WA - Outdoor unit service manual MU-A•WA Series (OB449) CONTENTS 1. TECHNICAL CHANGES ····································2 2. PART NAMES AND FUNCTIONS······················3 3. SPECIFICATION·················································5 4.
Revision A : • MS-A•WA- have been added. Remote controller has been changed. TECHNICAL CHANGES MS09TW MS-A09WA MS12TN MS-A12WA 1.Indoor fan motor has been changed. 2.Signal of remote controller has been changed. (It is not available for conventional models.) MS-A09WA...
PART NAMES AND FUNCTIONS MS-A09WA MS-A12WA Air inlet Heat exchanger Front panel Panel Air cleaning filter (Anti-Allergy Enzyme Filter, Blue bellows type) Catechin air filter Air outlet Vertical vane Horizontal vane Remote controller Line flow fan Display section Operation section...
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MS-A09WA MS-A12WA ACCESSORIES MS-A09/12WA MS-A09/12WA- Installation plate Installation plate fixing screw 4 o 25 mm Remote controller holder Fixing screw for 3 3.5 o 1.6 mm (Black) Battery (AAA) for remote controller Wireless remote controller Felt tape (Used for left or left-rear piping)
SPECIFICATION Model MS-A12WA MS-A09WA Item Indoor unit model MS-A09WA MS-A12WA External finish White Power supply V, phase, Hz 115, 1, 60 Max. fuse size (time delay)/ Disconnect switch Min. circuit ampacity Fan motor 0.95 0.95 F.L.A Airflow Low—Med.—High 335(300)-261(233)-183(162) 406(363)-286(254)-222(198)
SERVICE FUNCTIONS MS-A09WA MS-A12WA 7-1. TIMER SHORT MODE For service, set time can be shortened by short circuit of JPG and JPS the electronic control P.C. board. The time will be shortened as follows. (Refer to 8-7.) Set time : 1-minute...
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. TROUBLESHOOTING MS-A09WA MS-A12WA 8-1. Cautions on troubleshooting 1. Before troubleshooting, check the following 1) Check the power supply voltage.
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3. Troubleshooting procedure 1) First, check if the OPERATION INDICATOR lamp on the indoor unit is flashing on and off to indicate an abnormality. To make sure, check how many times the abnormality indication is flashing on and off before starting service work. 2) Before servicing check that the connector and terminal are connected properly.
8-2. 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 (8-4.) disappears, the memorized failure details can be recalled. This mode is very useful when the unit needs to be repaired for the abnormality which doesn't recur.
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2. Indoor unit failure mode table Left lamp of OPERATION Abnormal point Detection method Correspondence INDICATOR lamp (Failure mode) Not lighted Normal – – The room temperature thermistor short or Room temperature Refer to the characteristics of the room 1-time flash open circuit is detected every 8 seconds thermistor temperature thermistor (8-7.).
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8-3. Instruction of troubleshooting Start Indoor unit Indoor unit OPERATION INDICATOR operates. doesn't receive lamp on the indoor unit is Outdoor unit the signal from flashing on and off.w doesn't remote controller. operate. w If flashing of operation indicator lamp cannot be checked, it can be checked Outdoor unit Indoor unit...
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8-4. Troubleshooting check table Before taking measures, make sure that the symptom reappears for accurate troubleshooting. When the indoor unit has started operation and the following detection method has detected an abnormality (the first detection after the power ON), the indoor electronic control P.C. board turns OFF the indoor fan motor with OPERATION INDICATOR lamp flashing.
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8-5. Trouble criterion of main parts MS-A09WA MS-A12WA Part name Check method and criterion Figure Room temperature Measure the resistance with a tester. (Part temperature 50˚F ~ 86˚F) thermistor(RT11) Indoor coil thermistor Refer to 8-7. "Test point diagram and voltage", the chart of thermistor.
8-6. Troubleshooting flow When OPERATION INDICATOR lamp flashes 3-time. Indoor fan does not operate. Check of indoor fan motor The indoor fan motor error has occurred, and the indoor fan doesn't operate. Turn OFF the power supply. Pay careful attention to the high voltage on the fan motor connector CN211.
Indoor unit operates by pressing EMERGENCY OPERATION switch, but does not operate with the remote controller. Check of remote controller and receiver P.C. board wCheck if the remote controller is exclusive for this air conditioner. Switch ON the remote controller. Is LCD display on the remote con- Replace the batteries.
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The unit does not operate with the remote controller. Also, OPERATION INDICATOR lamp does not light up by pressing EMERGENCY OPERATION switch. Check of indoor electronic control P.C. board and indoor fan motor Turn OFF the power supply. Measure the resistance between CN211 3 Remove indoor fan motor connector CN211 and Short/open circuit: and 4 of the indoor fan motor connector.
Electromagnetic noise enters into TV sets or radios Is the unit grounded? Ground the unit. Is the distance between the Extend the distance between antennas and the indoor the antennas and the indoor unit within 9.91ft., or is the unit, and/or the antennas and distance between the the outdoor unit.
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8-7. Test point diagram and voltage MS-A09WA MS-A12WA Indoor electronic control P.C. board Power supply input Varistor (NR11) 115V AC Fuse(F11) 250V 3.15A Cement resistor (R111) Indoor fan motor (CN211) 1325V DC 3(-) Fiducial terminal of cathode side on measur-...
2Pull the terminal while pull out the terminal pushing the locking slowly. Locking lever lever. Connector MS-A09WA MS-A12WA OPERATING PROCEDURE PHOTOS 1. Removing the panel Photo 1 (1) Remove the horizontal vane. (2) Remove the screw caps of the panel.
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OPERATING PROCEDURE PHOTOS 2. Removing the electronic control P.C. board, the Photo 4 power monitor receiver P.C. board, SW P.C. board and the terminal block (1) Remove the horizontal vane, the panel (Refer to 1.) and the corner box. (2) Remove the screw of the conduit cover, and conduit cover. (See Photo 2.
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OPERATING PROCEDURE PHOTOS Photo 7 4. Removing the horizontal vane motor unit (1) Remove the horizontal vane and the panel. (Refer to 1.) (2) Remove the screws of the horizontal vane motor unit, and pull out the horizontal vane motor unit. (See Photo 7.) Screws of the (3) Disconnect the connector from the horizontal vane motor horizontal vane...
PARTS LIST 10-1. PARTS LIST (non-RoHS compliant) MS-A09WA MS-A12WA 1. INDOOR UNIT STRUCTURAL PARTS 2. ACCESSORY AND REMOTE CONTROLLER (See 10-5.) 1. INDOOR UNIT STRUCTURAL PARTS Q'ty/unit Symbol Part No. Part name in Wiring Remarks MS-A09WA MS-A12WA Diagram E02 A32 234...
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MS-A09WA MS-A12WA 3. INDOOR UNIT ELECTRICAL PARTS AND FUNCTIONAL PARTS Q'ty/unit Symbol Part No. in Wiring Remarks Part name MS-A09WA MS-A12WA Diagram E02 751 509 BEARING MOUNT E02 001 504 SLEEVE BEARING E02 897 702 DRAIN HOSE E02 A49 235 NOZZLE ASSEMBLY UP &...
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MS-A09WA MS-A12WA 4. INDOOR UNIT HEAT EXCHANGER Q'ty/unit Symbol in Wiring Part No. Part name Remarks MS-A09WA MS-A12WA Diagram E02 A49 620 INDOOR HEAT EXCHANGER INDOOR HEAT EXCHANGER E02 A50 620 {3/8 UNION (GAS) E02 151 666 {1/2 E02 155 666...
10-2. RoHS PARTS LIST (RoHS compliant) MS-A09WA MS-A12WA 1. INDOOR UNIT STRUCTURAL PARTS 2. ACCESSORY AND REMOTE CONTROLLER (See 10-5.) 1. INDOOR UNIT STRUCTURAL PARTS Q'ty/unit Symbol MS-A09WA MS-A12WA Part No. Part name in Wiring Remarks Diagram E12 A32 234...
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MS-A09WA MS-A12WA 3. INDOOR UNIT ELECTRICAL PARTS AND FUNCTIONAL PARTS Q'ty/unit Symbol in Wiring Part No. Part name MS-A09WA MS-A12WA Remarks Diagram BEARING MOUNT E12 751 509 E12 001 504 SLEEVE BEARING E12 897 702 DRAIN HOSE E12 A49 235 NOZZLE ASSEMBLY UP &...
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MS-A09WA MS-A12WA 4. INDOOR UNIT HEAT EXCHANGER Q'ty/unit Symbol in Wiring Part No. Part name Remarks MS-A09WA MS-A12WA Diagram E12 A49 620 INDOOR HEAT EXCHANGER INDOOR HEAT EXCHANGER E12 A50 620 {3/8 UNION (GAS) E12 151 666 {1/2 E12 155 666...
MICROPROCESSOR CONTROL MS-A09WA MS-A12WA WIRELESS REMOTE CONTROLLER Signal transmitting section Operation display section ON/OFF (operate/ stop) button VANE button (Horizontal vane button) Fan speed control button Temperature buttons Off-timer button Operation select button ECONO COOL button On-timer button TIME set buttons...
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11-1. COOL ( ) OPERATION (1) Press OPERATE/STOP(ON/OFF) button. OPERATION INDICATOR lamp of the indoor unit turns on with a beep tone. (2) Select COOL mode with OPERATION SELECT button. (3) Press TEMPERATURE buttons (TOO WARM or TOO COOL button)to select the desired temperature. The setting range is 61 ~ 88°F.
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(5) TEMPERATURE buttons In “I FEEL CONTROL” ( ) mode, set temperature is decided by the microprocessor based on the room temperature. In addition, set temperature can be controlled by TOO WARM or TOO COOL buttons when you feel too cool or too warm. Each time the TOO WARM or TOO COOL button is pressed, the indoor unit receives the signal and emits a beep tone.
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(8) To change the airflow direction not to blow directly onto your body. To change the air When to use this function? COOL/DRY flow direction Pressing and holding Use this function if you don’t The air conditioner starts the want the air from the indoor cooling or drying operation VANE CONTROL unit to blow directly onto your...
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11-6. TIMER OPERATION 1. How to set the timer (1) Press OPERATE/STOP (ON/OFF) button to start the air conditioner. (2) Check that the current time is set correctly. NOTE : Timer operation will not work without setting the current time. Initially “0:00” blinks at the current time display of TIME MONITOR, so set the current time correctly with CLOCK SET button.
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11-7. EMERGENCY/TEST OPERATION In case of test run operation or emergency operation, use EMERGENCY OPERATION switch on the front of the indoor unit. Emergency operation is available when the remote controller is missing, has failed or the batteries of the remote controller run down.
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HEAD OFFICE: TOKYO BLDG., 2-7-3, MARUNOUCHI, CHIYODA-KU, TOKYO 100-8310, JAPAN C C Copyright 2006 MITSUBISHI ELECTRIC ENGINEERING CO.,LTD Distributed in May 2007. No. OB448 REVISED EDITION-A 7 New publication, effective May 2007 Distributed in Mar. 2006. No. OB448 7 Specifications subject to change without notice.