OB448A-1.qxp 07.5.14 4:20 PM Page 1 Revision A: • MS-A•WA- 1 have been added. 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 - 1 1 Outdoor unit service manual MU-A•WA Series (OB449) CONTENTS 1. TECHNICAL CHANGES ····································2 2. PART NAMES AND FUNCTIONS······················3 3. SPECIFICATION·················································5 4.
OB448A-1.qxp 07.5.14 4:20 PM Page 2 Revision A : • MS-A•WA- 1 have been added. Remote controller has been changed. 1 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 ➔ MS-A09WA MS-A12WA ➔ MS-A12WA - 1 1 1.Remote controller has been changed. • Temperature indication function (_F/_C) has been added. (Refer to 11-8.
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OB448A-1.qxp 07.5.14 4:20 PM Page 4 MS-A09WA MS-A12WA ACCESSORIES MS-A09/12WA MS-A09/12WA- 1 Installation plate 1 1 2 Installation plate fixing screw 4 o 25 mm 8 5 3 Remote controller holder 1 1 4 Fixing screw for 3 3.5 o 1.
OB448A-1.qxp 07.5.14 4:20 PM 3 Page 5 SPECIFICATION Model Item Indoor unit model External finish Power supply V, phase, Hz Max.-fuse size (time delay)/ Disconnect switch A Min. circuit ampacity A Fan motor F.L.A Airflow Low—Med.—High COOL Dry (Wet) CFM Moisture removal pt./h Sound level Low-Med.-High dB(A) Cond. drain connection O.D. in. W in. Dimensions D in. H in. Weight Ib. Remote controller Control voltage (by built-in transformer) MS-A12WA MS-A12WA MS-A09WA MS-A09WA White 115, 1, 60 15 1.2 0.
Page 6 OUTLINES AND DIMENSIONS Unit : inch MS-A09WA MS-A12WA Conduit plate(MS-A•WA- is excluded.) 7/16x13/16 Oblong hole 7/16x1 Oblong hole 2-3/16 7/8 hole 7/8 6-1/8 2-3/16 6-1/8 13-3/16 1-3/4 12-5/8 Wall hole [2-9/16 Air in 8-1/4 3/16 Installation plate 11-3/4 { 2-1/8 24-9/16 Liquid line [1/4 19-11/16 Gas line [3/8 16-15/16 Insulation [1-3/8 O.D [3/4 I.D Drain hose [5/8 (Connected part O.
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OB448A-1.qxp 07.5.14 4:21 PM 7 Page 8 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 ➔ 1-second Set time : 3-minute ➔ 3-second (It takes 3 minutes for the compressor to start operation. However, the starting time is shortened by short circuit of JPG and JPS.) 7-2. P.C.
OB448A-1.qxp 07.5.14 4:21 PM Page 9 7-3. 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. The “AUTO RESTART FUNCTION” sets to work the moment power has restored after power failure. Then, the unit will restart automatically. Operation 1 If the main power has been cut, the operation settings remain.
OB448A-1.qxp 07.5.14 4:21 PM Page 10 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. 3) If the electronic control P.C.
OB448A-1.qxp 07.5.14 4:21 PM Page 11 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. 1.
OB448A-1.qxp 07.5.14 4:21 PM Page 12 2. Indoor unit failure mode table Left lamp of OPERATION INDICATOR lamp Not lighted Abnormal point (Failure mode) Detection method Correspondence Normal – – 1-time flash every 0.5-second Room temperature thermistor The room temperature thermistor short or open circuit is detected every 8 seconds during operation. Refer to the characteristics of the room temperature thermistor (8-7.). 2-time flash 2.
OB448A-1.qxp 07.5.14 4:21 PM Page 13 8-3. Instruction of troubleshooting Start Indoor unit operates. Outdoor unit doesn't operate. Indoor unit doesn't receive the signal from remote controller. Outdoor unit operates when the EMERGENCY OPERATION switch is pressed. Outdoor unit doesn't operate when the EMERGENCY OPERATION switch is pressed. Indoor unit operates when EMERGENCY OPERATION switch is pressed. Indoor unit doesn't operate when EMERGENCY OPERATION switch is pressed.
OB448A-1.qxp 07.5.14 4:21 PM Page 14 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. Lighted OPERATION INDICATOR No.
OB448A-1.qxp 07.5.14 4:21 PM Page 15 8-5. Trouble criterion of main parts MS-A09WA MS-A12WA Part name Room temperature thermistor(RT11) Indoor coil thermistor (RT12) Indoor fan motor(MF) Horizontal vane motor(MV) Check method and criterion Figure Measure the resistance with a tester. (Part temperature 50˚F ~ 86˚F) Refer to 8-7. "Test point diagram and voltage", the chart of thermistor. Check 8-6. A. Measure the resistance between the terminals with a tester.
OB448A-1.qxp 07.5.14 4:21 PM Page 16 8-6. Troubleshooting flow When OPERATION INDICATOR lamp flashes 3-time. Indoor fan does not operate. A 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.
OB448A-1.qxp 07.5.14 4:21 PM Page 17 Indoor unit operates by pressing EMERGENCY OPERATION switch, but does not operate with the remote controller. B 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 controller visible? No Replace the batteries. (Refer to 8-1.4.) (not clear) Yes Remove the batteries, then set them back and press RESET button. (Refer to 8-1.4.
OB448A-1.qxp 07.5.14 4:21 PM Page 18 The unit does not operate with the remote controller. Also, OPERATION INDICATOR lamp does not light up by pressing EMERGENCY OPERATION switch. C Check of indoor electronic control P.C. board and indoor fan motor Turn OFF the power supply. Remove indoor fan motor connector CN211 and vane motor connector CN151 from the indoor electronic control P.C. board and turn ON the power supply. Measure the resistance between CN211 3 and 4 of the indoor fan motor connector.
OB448A-1.qxp 07.5.14 4:21 PM Page 19 D Electromagnetic noise enters into TV sets or radios No Is the unit grounded? Ground the unit. Yes Is the distance between the antennas and the indoor unit within 9.91ft., or is the distance between the antennas and the outdoor unit within 9.91ft.? Extend the distance between the antennas and the indoor unit, and/or the antennas and the outdoor unit. Yes No Is the distance between the TV sets or radios and the indoor unit within 3.28ft.
OB448A-1.qxp 07.5.14 4:21 PM Page 20 8-7. Test point diagram and voltage MS-A09WA MS-A12WA Indoor electronic control P.C. board Power supply input 115V AC } Varistor (NR11) Fuse(F11) 250V 3.15A Cement resistor (R111) Indoor fan motor (CN211) 1325V DC 3(-) Fiducial terminal of cathode side on measuring high-voltage DC 415V DC 5(+)3-6V DC 6(+)0V DC or 15V DC Release of Auto restart function Solder the Jumper wire to JR07 (Refer to 7-3.
OB448A-1.qxp 07.5.14 4:21 PM 9 Page 21 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. (1) Slide the sleeve and check if there is a locking lever or not.
OB448A-1.qxp 07.5.14 4:21 PM Page 22 OPERATING PROCEDURE PHOTOS 2. Removing the electronic control P.C. board, the power monitor receiver P.C. board, SW P.C. board and the terminal block Photo 4 (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. or Photo 3.) (3) Remove the indoor/outdoor connecting wire. (4) Remove the switch holder from the electrical cover. (See Photo 4.
OB448A-1.qxp 07.5.14 4:21 PM Page 23 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.) (3) Disconnect the connector from the horizontal vane motor unit. 5. Removing the indoor fan motor and the line flow fan (1) Remove the horizontal vane, the panel (Refer to 1.) and the corner box.
OB448A-1.qxp 07.5.14 4:21 PM 10 Page 24 PARTS LIST 10-1. PARTS LIST (non-RoHS compliant) MS-A09WA MS-A12WA 1. INDOOR UNIT STRUCTURAL PARTS 2. ACCESSORY AND REMOTE CONTROLLER 9 1 11 12 10 8 2 7 (See 10-5.) 3 4 5 6 1. INDOOR UNIT STRUCTURAL PARTS No. 1 2 3 4 5 6 7 8 9 10 Part No.
OB448A-1.qxp 07.5.15 10:34 AM Page 25 MS-A09WA MS-A12WA 3. INDOOR UNIT ELECTRICAL PARTS AND FUNCTIONAL PARTS 1 18 17 14 15 16 2 3 4 5 6 11 10 9 8 7 No. Part No. Part name Symbol in Wiring Diagram 12 Q'ty/unit MS-A09WA 1 E02 751 509 BEARING MOUNT 1 E02 001 504 SLEEVE BEARING 1 E02 897 702 DRAIN HOSE 1 E02 A49 235 NOZZLE ASSEMBLY MV 1 E02 897 303 VANE MOTOR UNIT (HORIZONTAL) 1 E02 913 040 HORIZONTAL VANE 1 E02 913 095 POWER MONITOR RECEIVER P.C.
OB448A-1.qxp 07.5.15 10:34 AM Page 26 MS-A09WA MS-A12WA 4. INDOOR UNIT HEAT EXCHANGER 1 2 3 No. 1 2 3 Part No. E02 E02 E02 E02 E02 A49 A50 151 155 151 620 620 666 666 667 Part name Symbol in Wiring Diagram Q'ty/unit MS-A09WA INDOOR HEAT EXCHANGER INDOOR HEAT EXCHANGER UNION (GAS) UNION (GAS) UNION (LIQUID) Remarks MS-A12WA 1 1 1 1 1 1 {3/8 {1/2 {1/4 5. AIR CLEANING FILTER (ANTI-ALLERGY ENZYME FILTER) ● AIR CLEANING FILTER removes fine dust of 0.
OB448A-1.qxp 07.5.15 10:34 AM Page 27 10-2. RoHS PARTS LIST (RoHS compliant) MS-A09WA MS-A12WA 1. INDOOR UNIT STRUCTURAL PARTS 2. ACCESSORY AND REMOTE CONTROLLER 9 1 12 11 10 8 2 7 (See 10-5.) 3 4 5 6 No. 1 2 3 4 5 6 7 8 9 10 RoHS 1. INDOOR UNIT STRUCTURAL PARTS G G G G G G G G G G Part No.
OB448A-1.qxp 07.5.15 10:34 AM Page 28 MS-A09WA MS-A12WA 3. INDOOR UNIT ELECTRICAL PARTS AND FUNCTIONAL PARTS 1 19 18 16 17 15 2 3 4 5 6 12 11 7 10 No. RoHS 8 Part No.
OB448A-1.qxp 07.5.14 4:21 PM Page 29 MS-A09WA MS-A12WA 4. INDOOR UNIT HEAT EXCHANGER 1 2 No. 1 2 3 RoHS 3 G G G G G Part No. E12 E12 E12 E12 E12 A49 A50 151 155 151 620 620 666 666 667 Part name Symbol in Wiring Diagram INDOOR HEAT EXCHANGER INDOOR HEAT EXCHANGER UNION (GAS) UNION (GAS) UNION (LIQUID) Q'ty/unit MS-A09WA - 1 1 1 1 1 MS-A12WA 1 1 1 1 1 1 1 1 Remarks - 1 {3/8 {1/2 {1/4 5. AIR CLEANING FILTER (ANTI-ALLERGY ENZYME FILTER) ● AIR CLEANING FILTER removes fine dust of 0.
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OB448A-2.qxp 07.5.14 4:24 PM 11-1. COOL ( Page 31 ) 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. 1. Coil forest prevention When the temperature of indoor heat exchanger becomes too low, the coil frost prevention mode works.
OB448A-2.qxp 07.5.14 4:24 PM Page 32 (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.
OB448A-2.qxp 07.5.14 4:24 PM Page 33 (8) To change the airflow direction not to blow directly onto your body. To change the air flow direction Pressing and holding VANE CONTROL button for 2 seconds or more causes the horizontal vane to reverse and move to horizontal position. Horizontal position When to use this function? COOL/DRY Use this function if you don’t want the air from the indoor unit to blow directly onto your body.
OB448A-2.qxp 07.5.14 4:24 PM Page 34 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. How to set the current time (1) Press the CLOCK set button.
OB448A-2.qxp 07.5.14 4:24 PM Page 35 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. The unit will start and OPERATION INDICATOR lamp will light. The first 30 minutes of operation is the test run operation. This operation is for servicing.
OB448A-2.qxp 07.5.14 4:24 PM Page 36 TM HEAD OFFICE: TOKYO BLDG., 2-7-3, MARUNOUCHI, CHIYODA-KU, TOKYO 100-8310, JAPAN C Copyright 2006 MITSUBISHI ELECTRIC ENGINEERING CO.,LTD Distributed in May 2007. No. OB448 REVISED EDITION-A 7 Distributed in Mar. 2006. No. OB448 7 Made in Japan New publication, effective May 2007 Specifications subject to change without notice.
