Mitsubishi Electric Mr. Slim MS-A09WA User manual

SERVICE MANUAL
CONTENTS
1. TECHNICAL CHANGES ··································· 2
2. PART NAMES AND FUNCTIONS····················· 3
3. SPECIFICATION················································ 5
4. OUTLINES AND DIMENSIONS ························ 6
5. WIRING DIAGRAM············································ 7
6. REFRIGERANT SYSTEM DIAGRAM ··············· 7
7. SERVICE FUNCTIONS ····································· 8
8. TROUBLESHOOTING······································· 9
9. DISASSEMBLY INSTRUCTIONS···················· 21
10. PARTS LIST····················································· 24
10-1. PARTS LIST············································· 24
10-2. RoHS PARTS LIST ·································· 27
11. MICROPROCESSOR CONTROL···················· 30
Models
MS-A09WA
MS-A09WA - 1
MS-A12WA
MS-A12WA - 1
NOTE:
RoHS compliant products have <G> mark on the spec name plate.
For servicing of RoHS compliant products, refer to the RoHS PARTS
LIST (RoHS compliant).
INDOOR UNIT
Outdoor unit service manual
MU-A•WA Series (OB449)
Revision C:
• TEST POINT DIAGRAM AND VOLTAGE has
been corrected. (8-7)
Please void OB448 REVISED EDITION-B.
No. OB448
REVISED EDITION-C

MS-A09WA MS-A09WA -1
MS-A12WA MS-A12WA -1
1. Remote controller has been changed.
• Temperature indication function (°F/°C) has been added. (Refer to 11-8.)
Models Remote controller Temperature indication
MS-A09/12WA KM06C °F
MS-A09/12WA- 1KM07L °F/°C
• Timer indication has been changed. (AM/PM indication)
2. Conduit plate has been removed.
3. Conduit cover, terminal block cover and terminal block holder have been changed.
2
1TECHNICAL 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.)
Revision A :
• MS-A•WA-1have been added.
Remote controller has been changed.
Revision B :
• SPECIFICATION has been corrected.
Powerful has been added. (Airflow ,Sound level)
Revision C:
• TEST POINT DIAGRAM AND VOLTAGE has been corrected. (8-7)

3
PART NAMES AND FUNCTIONS
2
MS-A09WA
MS-A12WA
Line flow fan
Air outlet
Vertical vane
Air inlet
Display section
Front panel
Panel
Heat exchanger
Horizontal vane
Operation section
(When the front panel is opened)
Remote controller
Remote control
receiving section
Catechin air filter
Air cleaning filter
(Anti-Allergy Enzyme
Filter, Blue bellows
type)
Emergency operation switch
Operation Indicator
lamp

4
ACCESSORIES
MS-A09WA
MS-A12WA
MS-A09/12WA MS-A09/12WA- 1
Installation plate 1 1
Installation plate fixing screw 4 × 25 mm 8 5
Remote controller holder 1 1
Fixing screw for 3.5 × 1.6 mm (Black) 2 2
Battery (AAA) for remote controller 2 2
Wireless remote controller 1 1
Felt tape (Used for left or left-rear piping) 1 1
Conduit plate 1 —

5
SPECIFICATION
3
Model MS-A09WA MS-A12WA
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 A15
Min. circuit ampacity A 1.2
Fan motor F.L.A 0.95
Airflow
Low–Med.–High–Powerful
COOL
Dry (Wet) CFM 183 - 261 - 335 - 367 (162 - 233 - 300 - 328)
222 - 286 - 406 - 446
(198 - 254 - 363 - 399)
Moisture removal pt./h 2.7 3.2
Sound level
Low–Med.–High–Powerful dB(A) 26 - 32 - 40 - 42 33 - 38 - 45 - 47
Cond. drain connection O.D. in. 5/8
Dimensions
W
in.
30-11/16
D 8-1/4
H 11/-3/4
Weight Ib. 23
Remote controller Wireless type
Control voltage (by built-in transformer) 115 VAC
NOTE : Test conditions are based on ARI 210/240
1 : Rating conditions (cooling) — Indoor : 80˚FDB, 67˚FWB, Outdoor : 95˚FDB, (75˚FWB) Rated frequency : 60Hz
Operating Range
Indoor intake air temperature Outdoor intake air temperature
Cooling Maximum 95˚FDB, 71˚FWB 115˚FDB
Minimum 67˚FDB, 57˚FWB 67˚FDB

6
4OUTLINES AND DIMENSIONS
MS-A12WA
Unit : inch
MS-A09WA
11-3/4
424-9/16
30-11/16
8-1/4 3/16
2-1/8
3/4
6-1/4
2-5/16
Air in
Air out
Installation plate
6-1/8 6-1/8
7/8
1-3/4
13-3/16 12-5/8
1-5/8 8-7/16
10-1/8
1-11/16
8-7/16
1/8 11-5/16
2-3/4
2-3/16
2-3/16 2-3/16
8-7/8 8-7/8
9/1610-3/4
9-3/16
Wall hole 2-9/16
Indoor unit
Installation plate
7/16x13/16 Oblong hole
7/16x1 Oblong hole
7/8
hole
Conduit plate(MS-A•WA- is excluded.)
3/4 I.D
Insulation 1-1/8
Drain hose 5/8
(Connected part O.D)
Liquid line 1/4 19-11/16
Gas line 3/8 16-15/16
Insulation 1-3/8 O.D
{

7
WIRING DIAGRAM
5
REFRIGERANT SYSTEM DIAGRAM
6
MS-A09WA
MS-A12WA
Indoor
heat
exchanger
Flared connection
Room temperature
thermistor
RT11
Flared connection
Refrigerant flow in cooling
Refrigerant pipe 3/8 (MS-A09)
1/2 (MS-A12)
(with heat insulator)
Refrigerant pipe 1/4
(with heat insulator)
Indoor coil
thermistor
RT12
Unit : inch
MS-A09WA
MS-A12WA

8
7SERVICE FUNCTIONS
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. BOARD MODIFICATION FOR INDIVIDUAL OPERATION
A maximum of 4 indoor units with wireless remote controllers can be used in a room.
In this case, to operate each indoor unit individually by each remote controller, P.C. boards of remote controller must be
modified according to the number of the indoor unit.
How to modify the remote controller P.C. board
Remove batteries before modification.
The board has a print as shown below :
Table 1
1 unit operation 2 units operation 3 units operation 4 units operation
No. 1 unit No modification Same as at left Same as at left Same as at left
No. 2 unit — Solder J1 Same as at left Same as at left
No. 3 unit — — Solder J2 Same as at left
No. 4 unit — — — Solder both J1 and J2
How to set the remote controller exclusively for particular indoor unit.
After you turn the breaker ON, the first remote controller that sends the signal to the indoor unit will be regarded as the remote
controller for the indoor unit.
The indoor unit will only accept the signal from the remote controller that has been assigned to the indoor unit once they are
set.
The setting will be cancelled if the breaker has turned off, or the power supply has shut down.
Please conduct the above setting once again after the power has restored.
The P.C. board has the print “J1” and “J2”. Solder “J1” and “J2” according to the number of indoor unit as shown in Table 1.
After modification, press the RESET button.
NOTE : For modification, take out
the batteries and press
the OPERATE/STOP(ON/
OFF)button twice or 3
times at first.
After finish modification,
put back the batteries then
press the RESET button.
J2
J1
MS-A09WA
MS-A12WA

9
TROUBLESHOOTING
8
8-1. 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 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.
2) Be sure to turn OFF the power supply before removing the front panel, the cabinet, the top panel, and the electronic
control P.C. board.
3) When removing the electronic control P.C. board, hold the edge of the board with care NOT to apply stress on the com-
ponents.
4) When connecting or disconnecting the connectors, hold the housing of the connector. DO NOT pull the lead wires.
MS-A09WA MS-A12WA
NOTE:
• The operation settings are memorized when 10 seconds have passed after the indoor unit was operated with the
remote controller.
• If main power is turned OFF or a power failure occurs while AUTO START/STOP timer is active, the timer setting is
cancelled.
• If the unit has been off with the remote controller before power failure, the auto restart function does not work as the
power button of the remote controller is off.
• To prevent breaker off due to the rush of starting current, systematize other home appliance not to turn on at the
same time.
• When some air conditioners are connected to the same supply system, if they are operated before power failure, the
starting current of all the compressors may flow simultaneously at restart.
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.
JR07
CN151 CN211CN112 CN1R1
BZ
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
If the main power has been cut, the operation settings remain.
After the power is restored, the unit restarts automatically according to the memory.
(However, it takes at least 3 minutes for the compressor to start running.)
How to release “AUTO RESTART FUNCTION”
Turn off the main power for the unit.
Solder the Jumper wire JR07 on the indoor electronic control P.C. board. (Refer to 8-7.)
Lead wiring Housing point

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) When the electronic control P.C. board seems to be defective, check the copper foil pattern for disconnection and the
components for bursting and discoloration.
4) When troubleshooting, refer to 8-2., 8-3. and 8-4.
4. How to replace batteries
Weak batteries may cause the remote controller malfunction.
In this case, replace the batteries to operate the remote controller normally.
RESET button
Insert the negative pole of the
batteries first. Check if the polarity
of the batteries is correct.
NOTE : 1. If RESET button is not pressed, the remote controller may not operate correctly.
2. This remote controller has a circuit to automatically reset the microcomputer when batteries are replaced.
This function is equipped to prevent the microcomputer from malfunctioning due to the voltage drop caused by the
battery replacement.
Press RESET button with tip end of ball point pen
or the like, and then use the remote controller.
Remove the front lid and insert batteries.
Then reattach the front lid.