Mitsubishi Electric MS-GH13VA User manual

Models
MS-GH13VA -KU1 ,KU2 ,KU2 U
MS-GH18VA -KU1 ,KU2 ,KU2 U
MS-GH24VA -KU1
MS-GH30VA -KU1
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 ·············9
7. SERVICE FUNCTIONS······························ 10
8. MICROPROCESSOR CONTROL ················ 12
9. TROUBLESHOOTING······························· 19
10. DISASSEMBLY INSTRUCTIONS················· 33
Outdoor unit service manual
MU-GH∙VA Series (OBH665)
INDOOR UNIT
PARTS CATALOG (OBB664)
NOTE:
RoHS compliant products have <G> mark on the spec name plate.
TM
SERVICE MANUAL
No. OBH664
REVISED EDITION-B
OBH664 REVISED EDITION-A is void.
Revision B:
•MS-GH13/18VA- KU2 Uhave been
added.

2
MS-GH13VA - KU1
MS-GH18VA - KU1
MS-GH24VA - KU1
MS-GH30VA - KU1
1. New model
MS-GH13VA- KU1 MS-GH13VA- KU2
MS-GH18VA- KU1 MS-GH18VA- KU2
1. The model name has been changed so as to correspond to standard.
2. Remote controller has been changed.
MS-GH13VA- KU2 MS-GH13VA- KU2 U
MS-GH18VA- KU2 MS-GH18VA- KU2 U
1. The model name has been changed so as to correspond to standard.
2. Remote controller has been changed. (The setting temperature range has been changed.)
TECHNICAL CHANGES
1
Use the specified 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.
Revision A:
•MS-GH13/18VA- KU2 have been added.
Revision B:
•MS-GH13/18VA- KU2 Uhave been added.
OBH664B

3
ACCESSORIES
PART NAMES AND FUNCTIONS
2
Model MS-GH13VA
Installation plate 1
Installation plate fixing screw 4 × 25 mm 5
Remote controller holder 1
Fixing screw for 3.5 × 16 mm (Black) 2
Battery (AAA) for remote controller 2
Wireless remote controller 1
Felt tape (For left or left-rear piping) 1
MS-GH13VA
Air filter
(Nano platinum filter)
Front panel
Air cleaning filter
(Electrostatic anti-allergy
enzyme filter, option)
Operation indicator lamp
Remote control receiving section
Emergency operation switch (E.O. SW)
Horizontal vane
Air outlet Heat exchanger
Display section
Air inlet
Remote controller
OBH664B

4
ACCESSORIES
MS-GH18VA MS-GH24VA MS-GH30VA
Horizontal vane
Air outlet
Air filter
(Nano platinum filter)
Air inlet
Front panel
Air cleaning filter
(Electrostatic anti-allergy
enzyme filter, option)
Remote controller
Display section
Heat exchanger
Operation indicator lamp
Remote control receiving section
Emergency operation switch
(E.O.SW)
Model MS-GH18VA MS-GH24VA
MS-GH30VA
Installation plate 1
Installation plate fixing screw 4 × 25 mm 7
Remote controller holder 1
Fixing screw for 3.5 × 16 mm (Black) 2
Battery (AAA) for remote controller 2
Wireless remote controller 1
Felt tape (For left or left-rear piping) 1
OBH664B

5
SPECIFICATION
3
Indoor model MS-GH13VA MS-GH18VA MS-GH24VA MS-GH30VA
Function Cooling
Power supply Single phase 220 - 230 - 240 V, 50 Hz
Electrical
data
Running current A 0.22 0.30 0.42
Power input W 43 39 51
Fan motor
Model RC4V18-FA RC0J56-AF
Current A 0.22 0.30 0.42
Dimensions W × H × D mm 798 x 295 x 232 1,100 x 325 x 238
Weight kg 916
Special remarks
Air direction 5
Airflow
Super High (POWERFUL)
m3/h
624 1,086 1,086 1,206
High 558 870 990 1,122
Med. 396 762 834 1,014
Low 288 642 714 882
Sound level
Super High (POWERFUL)
dB (A)
44 45 48 50
High 40 42 45 47
Med. 33 38 41 43
Low 26 34 37 39
Fan speed
Super High (POWERFUL)
rpm
1,100 1,100 1,100 1,200
High 1,000 920 1,020 1,130
Med. 770 800 890 1,040
Low 610 720 790 930
Fan speed regulator 4
Remote controller model
KU1 : KM12A KU1 : KM12B
KM12B
KU2 : KM15D KU2 : KM16A
KU2 U: KM17A KU2 U: KM17C
NOTE: Test conditions are based on ISO 5151.
Cooling: Indoor Dry-bulb temperature 27 Wet-bulb temperature 19
Outdoor Dry-bulb temperature 35 Wet-bulb temperature 24
Indoor-Outdoor piping length: 5 m
OBH664B

6
Unit: mm
OUTLINES AND DIMENSIONS
4
211.5
231.5
253
21.5
155 155
80
80 225 225
3
5232
56
69
798
785 6.5
130619
50
295
50
42
56
43
42
8
100
107
112
45
56
69
33861
212.5
254
41
42
315 84
11×26 Oblong hole 11×20 Oblong hole
Installation plate
Indoor unit
Wall hole ø65
Air in
Air out
Installation plate
Piping
Drain hose
159
19
58
MS-GH13VA
Piping
Insulation ø35 O.D
Liquid line ø7 - 0.5 m (Flared connection ø6.35)
Gas line ø9.52 - 0.43 m (Flared connection: ø9.52)
Drain hose Insulation ø28 O.D Connected part ø16 O.D
Unit: mm
1090 5
1100
45 238.5
258.5
3
280
225 225
129
239.5
281
44
49.5 500.5 439.5
199.5199.5 110.5
65
63 76 843 181
65
65 30
63
65
67
63
325
3
100
125
160
110
( 70° )
238
5
210
21.5
184
12
Piping
Insulation Ø 50 O.D
Liquid line
Ø 9.52 - 0.5m (Flared connection Ø 6.35)
Gas line
Ø 12 - 0.43m (Flared connection Ø 15.88)
Drain hose Inslation
Ø 28 Connected part Ø 16 O.D
Piping
Insulation Ø 50 O.D
Liquid line
Ø 9.52 - 0.5m (Flared connection Ø 6.35)
Gas line
Ø 12 - 0.45m (Flared connection Ø 12.7)
Drain hose Inslation
Ø 28 Connected part Ø 16 O.D
Air out
Piping
Drain hose
11×26 Oblong hole 11×20 Oblong hole
Installation plate
Indoor unit
Wall hole Ø 75
Air in Installation plate
MS-GH18VA
MS-GH24VA
159
19
58
Piping
Insulation Ø 50 O.D
Liquid line
Ø 9.52 - 0.5m (Flared connection Ø 9.52)
Gas line
Ø 12 - 0.43m (Flared connection Ø 15.88)
Drain hose Inslation
Ø 28 Connected part Ø 16 O.D
MS-GH30VA
MS-GH18VA MS-GH24VA MS-GH30VA
OBH664B

7
WIRING DIAGRAM
5
MS-GH13VA- KU1
MS-GH13VA- KU2 ,KU2 U
OBH664B

8
MS-GH18VA- KU1 MS-GH24VA MS-GH30VA
MS-GH18VA- KU2 ,KU2 U
OBH664B

9
Unit: mm
REFRIGERANT SYSTEM DIAGRAM
6
MS-GH13VA
Indoor
heat
exchanger
Flared connection
Room temperature
thermistor
RT11
Flared connection
Refrigerant pipe 6.35
(with heat insulator)
Indoor coil
thermistor
RT12
Refrigerant flow in cooling
Refrigerant pipe 9.52
(with heat insulator)
Indoor
heat
exchanger
Flared connection
Room temperature
thermistor
RT11
Flared connection
Refrigerant pipe ø12.7 (MS-GH18VA)
ø15.88 (MS-GH24/30VA)
(with heat insulator)
Refrigerant pipe ø6.35 (MS-GH18/24VA)
ø9.52 (MS-GH30VA)
(with heat insulator)
Indoor coil
thermistor
RT12
Refrigerant flow in cooling
MS-GH18VA MS-GH24VA MS-GH30VA
OBH664B

10
7-1. TIMER SHORT MODE
For service, the following set time can be shortened by bridging JPG and JPS on the electronic control P.C. board.
(Refer to 9-7.)
Set time: 3 minutes 3 seconds (It takes 3 minutes for the compressor to start operation. However, the starting time is
shortened by bridging 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:
NOTE: For modification, take out the
batteries and press the
OPERATE/STOP (ON/OFF)
(MS-GH13/18/24/30VA- KU1 )/
STOP/OPERATE (OFF/ON)
(MS-GH13/18VA- KU2 ,KU2
U)button
2 or 3 times at first.
After modification, put back
the batteries then press the
RESET button.
J2
J1
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 is turned OFF, or the power supply is shut down.
Please conduct the above setting once again after the power has been restored.
SERVICE FUNCTIONS
7
MS-GH13VA MS-GH18VA MS-GH24VA MS-GH30VA
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.
OBH664B

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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. “AUTO RESTART FUNCTION” automatically starts operation
in the same mode just before the shutoff of the main power.
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 disable “AUTO RESTART FUNCTION”
Turn off the main power for the unit.
Solder the jumper wire to JR07 on the indoor electronic control P.C. board (MS-GH13VA).
Cut the jumper wire to JR77 on the indoor electronic control P.C. board (MS-GH18/24/30VA). (Refer to 9-7.)
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 can-
celled.
• 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
Indoor electronic
control P.C. board
111NCA01NC 151NC 211NC
MS-GH13VA MS-GH18/24/30VA
CN111
CN112
CN152
CN10A
Indoor electronic
control P.C. board
JR77
CN151
OBH664B

12
WIRELESS REMOTE CONTROLLER
MICROPROCESSOR CONTROL
8
NOTE: Last setting will be stored after the unit is turned OFF with the remote controller. Indoor unit receives the signal of the
remote controller with beeps.
Signal transmitting section
Operation display section
Temperature buttons
OPERATE/STOP
(ON/OFF) button
Indication of
remote controller
model is on back
TIME SET buttons
FORWARD button
BACKWARD button
VANE CONTROL button
OFF-TIMER button
RESET button
FAN SPEED CONTROL button
OPERATION SELECT button
ECONO COOL button ON-TIMER button
CLOCK button
POWERFUL COOL button
MS-GH13VA- KU1
NOTE: Last setting will be stored after the unit is turned OFF with the remote controller. Indoor unit receives the signal of the
remote controller with beeps.
MS-GH13VA- KU2 ,KU2 U
Signal transmitting section
Operation display section
Temperature buttons
STOP/OPERATE
(OFF/ON) button
Indication of
remote controller
model is on back
TIME SET buttons
FORWARD button
BACKWARD button
VANE CONTROL button
OFF-TIMER button
RESET button
FAN SPEED CONTROL button
OPERATION SELECT button
ECONO COOL button ON-TIMER button
CLOCK button
POWERFUL COOL button
OBH664B

13
NOTE: Last setting will be stored after the unit is turned OFF with the remote controller. Indoor unit receives the signal of the
remote controller with beeps.
MS-GH18VA- KU1 MS-GH24VA MS-GH30VA
Signal transmitting section
Operation display section
Temperature buttons
OPERATE/STOP
(ON/OFF) button
Indication of
remote controller
model is on back
LONG
TIME SET buttons
FORWARD button
BACKWARD button
VANE CONTROL button
(Horizontal vane button)
OFF-TIMER button
LONG button
RESET button
FAN SPEED CONTROL button
OPERATION SELECT button
ECONO COOL button
WIDE VANE button
(Vertical vane button)
ON-TIMER button
CLOCK SET button
POWERFUL COOL button
NOTE: Last setting will be stored after the unit is turned OFF with the remote controller. Indoor unit receives the signal of the
remote controller with beeps.
MS-GH18VA- KU2 ,KU2 U
Signal transmitting section
Operation display section
Temperature buttons
STOP/OPERATE
(OFF/ON) button
Indication of
remote controller
model is on back
LONG
TIME SET buttons
FORWARD button
BACKWARD button
VANE CONTROL button
(Horizontal vane button)
OFF-TIMER button
LONG button
RESET button
FAN SPEED CONTROL button
OPERATION SELECT button
ECONO COOL button
WIDE VANE button
(Vertical vane button)
ON-TIMER button
CLOCK SET button
POWERFUL COOL button
OBH664B

14
Operation Indicator lamp
The operation indicator at the right side of the indoor unit indicates the operation state.
•The following indication applies regardless of shape of the indication.
Indication Operation state Room temperature
The unit is operating to
reach the set temperature
About 2°C or more away
from set temperature
The room temperature is
approaching the set tem-
perature
About 1 to 2°C from set
temperature
INDOOR UNIT DISPLAY SECTION
Lighted
Blinking
Not lighted
8-1. COOL ( ) OPERATION
(1) Press OPERATE/STOP (ON/OFF) (MS-GH13/18/24/30VA- KU1 )/ STOP/OPERATE (OFF/ON) (MS-GH13/18VA- KU2 ,
KU2 U)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 16 - 31°C (MS-GH13/18/24/30VA- KU1 , MS-GH13/18VA- KU2 )/ 20°C - 31°C (MS-GH13/18VA- KU2 U).
1. Coil frost prevention
When the temperature of indoor heat exchanger becomes too low, the coil frost prevention mode works.
The indoor fan operates at the set speed and the compressor stops. This mode continues until the temperature of indoor
heat exchanger rises.
8-2. DRY ( ) OPERATION
(1) Press OPERATE/STOP (ON/OFF) (MS-GH13/18/24/30VA- KU1 )/STOP/OPERATE (OFF/ON) (MS-GH13/18VA- KU2 ,
KU2 U)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. Coil frost prevention
Coil frost prevention works the same way as that in COOL mode. (8-1.1.)
8-3. FAN ( )OPERATION
(1) Press OPERATE/STOP (ON/OFF) (MS-GH13/18/24/30VA- KU1 )/ STOP/OPERATE (OFF/ON) (MS-GH13/18VA- KU2 ,
KU2 U)button. OPERATION INDICATOR lamp of the indoor unit turns ON with a beep tone.
(2) Select FAN mode with OPERATION SELECT button.
(3) Select the desired fan speed. When AUTO, it becomes Low. Only indoor fan operates. Outdoor unit does not operate.
Mode
COOL mode of
"I FEEL CONTROL"
DRY mode of
"I FEEL CONTROL"
Initial room temperature
25 or more
more than 13 ,
less than 25
8-4. “I FEEL CONTROL” ( ) OPERATION
(1) Press OPERATE/STOP (ON/OFF) (MS-GH13/18/24/30VA- KU1 )/ STOP/OPERATE (OFF/ON) (MS-GH13/18VA- KU2 ,
KU2 U)button on the remote controller. OPERATION INDICATOR lamp of the indoor unit turns ON with a beep tone.
(2) Select “I FEEL CONTROL” mode with the OPERATION SELECT
button.
(3) The operation mode is determined by the room temperature at
start-up of the operation.
• Once the mode is fixed, the mode does not change by room temperature afterwards.
• Under ON-TIMER ( ) operation, mode is determined as follows:
When the system is stopped by the remote controller, and restarted within 2 hours in “I FEEL CONTROL” ( ) mode,
the system operates in previous mode automatically regardless of the room temperature.
OBH664B

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Previous operation
COOL mode of
“I FEEL CONTROL”
or COOL mode
Restart
COOL mode of
“I FEEL CONTROL”
Operation timer chart
Example
When the system is restarted after 2 hours and more, the operation mode is determined by the room temperature at
start-up of the operation.
Operation time chart
Example
Previous operation
COOL mode of
“I FEEL CONTROL”
or COOL mode
Restart
COOL or DRY mode of
“ I FEEL CONTROL” that
determined by room
temperature at start-up
of the operation.
(4) The initial set temperature is decided by the initial room temperature.
1
Mode Initial room temperature
26 °C or more 24 °C
Initial room temperature
minus 2 °C
25 °C to 26 °C
Initial set temperature
DRY mode of
“I FEEL CONTROL”
COOL mode of
“I FEEL CONTROL”
more than 13 °C, less than 25 °C
Initial room temperature
minus 2 °C
1 When the system is restarted with the remote controller, the system operates with the previous set temperature regard-
less of the room temperature at restart.
The set temperature is calculated by the previous set temperature.
(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 TOO WARM or TOO COOL button is pressed, the indoor unit receives the signal and emits a beep tone.
Fuzzy control
When TOO COOL or TOO WARM button is pressed, the microprocessor changes the set temperature, considering the
room temperature, the frequency of pressing TOO COOL or TOO WARM button and the user’s preference to heat or
cold. So this is called “Fuzzy control” and it works only in “I FEEL CONTROL” mode.
In DRY mode of “I FEEL CONTROL”, the set temperature does not change.
… To raise the set temperature 1 ~ 2
… To lower the set temperature 1 ~ 2
OBH664B

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8-5. AUTO VANE OPERATION
1. Horizontal vane
(1) Vane motor drive
These models are equipped with a stepping motor for the horizontal vane. The rotating direction, speed, and angle of
the motor are controlled by pulse signals (approximately 12 V) transmitted from indoor microprocessor.
(2) The horizontal vane angle and mode change as follows by pressing VANE CONTROL button.
1
AUTO 1 2 3 4 5 SWING
(3) Positioning
To confirm the standard position, the vane moves until it touches the vane stopper. Then the vane is set to the
selected angle.
Confirming of standard position is performed in the following cases:
(a) When the operation starts or finishes (including timer operation).
(b) When the test run starts.
(4) VANE AUTO ( ) mode
In VANE AUTO mode, the microprocessor automatically determines the vane angle to make the optimum room tem-
perature distribution.
Vane angle is fixed to Angle 1.
(7) SWING ( ) mode
By selecting SWING mode with VANE CONTROL button, the horizontal vane swings vertically.
(8) ECONO COOL ( ) operation (ECONOmical operation)
When ECONO COOL button is pressed in COOL mode, set temperature is automatically set 2°C higher.
Also the horizontal vane swings in various cycles.
SWING operation makes you feel cooler than set temperature. So, even though the set temperature is higher, the
air conditioner can keep comfort. As a result, energy can be saved.
To cancel this operation, select a different mode or press one of the following buttons in ECONO COOL
operation:ECONO COOL, VANE CONTROL, LONG or POWERFUL COOL button.
(5) STOP (operation OFF) and ON TIMER standby
In the following cases, the horizontal vane returns to the closed position.
(a) When OPERATE/STOP (ON/OFF) (MS-GH13/18/24/30VA- KU1 )/ STOP/OPERATE (OFF/ON)
(MS-GH13/18VA- KU2 , KU2 U)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 4 or 5 when the compressor cumulative operation time
exceeds 1 hour, the vane angle automatically changes to Angle 1 for dew prevention.
(9) POWERFUL ( ) operation
The air conditioner automatically adjusts the fan speed and the set temperature, and operates the POWERFUL
mode.
The POWERFUL mode is cancelled automatically 15 minutes after operation starts. To cancel this operation manu-
ally, select a different mode or press one of the following buttons: POWERFUL, OPERATE/STOP (ON/OFF)
(MS-GH13/18/24/30VA- KU1 )/ STOP/OPERATE (OFF/ON) (MS-GH13/18VA- KU2 , KU2 U), ECONO COOL, or
FAN SPEED CONTROL button
OBH664B

17
2. Vertical vane (MS-GH18/24/30VA)
(1) Vane motor drive
These models are equipped with a stepping motor for the vertical vane. The rotating direction, speed, and angle of
the motor are controlled by pulse signals (approximately 12 V) transmitted from microprocessor.
(2) The vertical vane angle and mode change as follows by pressing WIDE VANE CONTROL button.
(3) Positioning
To confirm the standard position, the vane moves until it touches the vane stopper. Then the vane is set to the select-
ed angle.
(SWING)
123 456
Confirming of standard position is performed in the following cases:
(a) OPERATE/STOP (ON/OFF) (MS-GH13/18/24/30VA- KU1 )/ STOP/OPERATE (OFF/ON) (MS-GH13/18VA- KU2 ,
KU2 U)button is pressed (POWER ON).
(b) SWING is started.
(4) SWING ( ) MODE
By selecting SWING mode with WIDE VANE button, the vertical vane swings horizontally. The remote controller
displays “ ”. Swing mode is cancelled when WIDE VANE button is pressed once again.
(5) WIDE MODE ( )
By selecting WIDE mode with WIDE VANE button, indoor fan speed becomes faster than setting fan speed on the
remote controller ( ). The remote controller displays “ ”.
Indoor fan speed becomes faster than setting fan speed on the remote controller even when or is selected.
1. How to set the time
(1) 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 button.
How to set the current time
(a) Press the CLOCK button.
(b) Press the TIME SET buttons ( and ) to set the current time.
• Each time FORWARD button ( ) is pressed, the set time increases by 1 minute, and each time BACKWARD
button ( ) is pressed, the set time decreases by 1 minute.
• Pressing those buttons longer, the set time increases/decreases by 10 minutes.
(c) Press the CLOCK button.
(2) Press OPERATE/STOP (ON/OFF) (MS-GH13/18/24/30VA- KU1 )/STOP/OPERATE (OFF/ON) (MS-GH13/18VA-
KU2 , KU2 U)button to start the air conditioner.
(3) Set the time of timer.
ON timer setting
(a) Press ON TIMER button( ) during operation.
(b) Set the time of the timer using TIME SET buttons ( and ).
OFF timer setting
(a) Press OFF TIMER button ( ) during operation.
(b) Set the time of the timer using TIME SET buttons ( and ).
Each time FORWARD button ( ) is pressed, the set time increases by 10 minutes: each time BACKWARD but-
ton ( ) is pressed, the set time decreases by 10 minutes.
8-6. TIMER OPERATION
COOL / DRY
Fan speed : Faster
Solid arrow : When the LONG mode is used.
Dotted arrow : When the LONG mode is not used.
( 10 ) LONG MODE ( ) (MS-GH18/24/30VA)
By pressing LONG button indoor fan speed becomes faster than setting fan speed on the remote controller, and the
horizontal vane moves to the position for LONG mode. The remote controller displays “ ”. To cancel this opera-
tion, press one of the following buttons: LONG, VANE CONTROL, or ECONO COOL (during cool mode). In the fol-
lowing example, the vertical vane is set to (front.).
OBH664B

18
(Example 1) The current time is 8:00 PM.
The unit turns off at 11:00 PM, and on at 6:00 AM.
• OFF timer and ON timer can be used in combination. The set time that is reached first will operate first.
• “ ” and “ ” display shows the order of OFF timer and ON timer operation.
PROGRAM TIMER
(Example 2) The current time is 11:00 AM.
The unit turns on at 5:00 PM, and off at 9:00 PM.
NOTE: If the main power is turned OFF or a power failure occurs while ON/OFF timer is active, the timer setting is can-
celled. As these models are equipped with an auto restart function, the air conditioner starts operating with timer
cancelled when power is restored.
8-7. 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 miss-
ing or has failed, or when the batteries in the remote controller are
running down. The unit will start and OPERATION INDICATOR lamp
will light up.
The first 30 minutes of operation is the test run operation. This opera-
tion is for servicing. The indoor fan runs at High speed and the tem-
perature control does not work.
After 30 minutes of test run operation, the system shifts to
EMERGENCY COOL MODE with a set temperature of 24°C. The fan
speed shifts to Med.
The coil frost prevention works even in the test run or the emergency
operation.
In the test run or emergency operation, the horizontal vane operates in
VANE AUTO ( ) mode.
Emergency operation continues until EMERGENCY OPERATION
switch is pressed again or the unit receives any signal from the remote
controller. In the latter case, normal operation will start.
NOTE: Do not press EMERGENCY OPERATION switch during normal operation.
Operation mode COOL
Set temperature 24°C
Fan speed Med.
Horizontal vane Auto
The operation mode is indicated by the
Operation Indicator lamp as following
Operation Indicator lamp
EMERGENCY COOL

STOP
Lighted
Not lighted
8-8. 3-MINUTE TIME DELAY OPERATION
When the system turns OFF, compressor will not restart for 3 minutes as 3-minute time delay function operates to protect
compressor from overload.
Emergency
operation switch
(E.O. SW)
2. To release the timer
To release ON timer, press ON TIMER button ( ).
To release OFF timer, press OFF TIMER button( ).
TIMER is cancelled and the display of set time disappears.
OBH664B

19
9-1. 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.
2) Be sure to turn OFF the power supply before removing the front panel, the cabinet, the top panel, and the P.C. board.
3) When removing the P.C. board, hold the edge of the board with care NOT to apply stress on the components.
4) When connecting or disconnecting the connectors, hold the connector housing. DO NOT pull the lead wires.
3. Troubleshooting procedure
1) 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 OPERATION INDICATOR lamp 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 9-2, 9-3 and 9-4.
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.
Lead wiring Connector housing
<Correct>
<Incorrect>
TROUBLESHOOTING
9
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.
3. Do not use the leaking batteries.
Press RESET button with a thin instrument, and
then use the remote controller.
Remove the front lid and insert batteries.
Then reattach the front lid.
MS-GH13VA MS-GH18VA MS-GH24VA MS-GH30VA
OBH664B

20
9-2. 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 (9-4.) disappears, the memorized failure details can
be recalled.
1. Flow chart of failure mode recall function for the indoor unit
Does upper lamp of OPERATION INDICATOR
lamp on the indoor unit blink at the interval of 0.5
seconds?
Blinks: Either indoor or outdoor unit is abnormal.
Beep is emitted at the same timing as the
blinking of upper lamp of OPERATION
INDICATOR lamp. 2
Indoor unit is normal.
But the outdoor unit might be abnormal because there are some abnor-
malities that cannot be recalled with this way.
The indoor unit is abnormal.
Check the blinking pattern, and identify the abnormal point by referring to the
table of indoor unit failure mode recall function. (Refer to 9-2.2)
Make sure to check at least 2 consecutive blinking cycles. 2
Releasing the failure mode recall function
Release the failure mode recall function by the following procedure.
Turn OFF the power supply and turn it ON again.
Press RESET button of the remote controller.
Repair the failure parts.
Deleting the memorized abnormal condition
After repairing the unit, recall the failure mode again according to "Setting up the failure mode recall
function" mentioned above.
Press OPERATE/STOP (ON/OFF) (MS-GH13/18/24/30VA- KU1 )/ STOP/OPERATE (OFF/ON) (MS-
GH13/18VA- KU2 , KU2 U)button of the remote controller (the set temperature is displayed) with
the remote controller headed towards the indoor unit.
Press EMERGENCY OPERATION switch so that the memorized abnormal condition is deleted.
Release the failure mode recall function according to "Releasing the failure mode recall function"
mentioned above.
Yes
(Blinks)
No
(OFF)
NOTE: 1. Make sure to release the failure mode recall function after it is set up, otherwise the unit cannot operate properly.
2. If the abnormal condition is not deleted from the memory, the last abnormal condition is kept memorized.
2. Blinking pattern when the indoor unit is abnormal:
ON
OFF
Beeps
Repeated cycle Repeated cycle
2.5-second OFF
Blinking at 0.5-
second interval
Beeps
Repeated cycle
2.5-second OFF
Blinking at 0.5-
second interval
Beeps
The cause of abnormality cannot be found because the abnormality does not recur.
Setting up the failure mode recall function
Turn ON the power supply.
<Preparation of the remote controller>
While pressing both OPERATION SELECT button and TOO COOL button on the
remote controller at the same time, press RESET button.
First, release RESET button.
Hold down the other two buttons for another 3 seconds. Make sure that the indicators
on the LCD screen shown in the right figure are all displayed. Then release the but-
tons.
Press OPERATE/STOP (ON/OFF) (MS-GH13/18/24/30VA- KU1 )/ STOP/OPERATE (
(OFF/ON) (MS-GH13/18VA- KU2 , KU2 U) button of the remote controller (the set
temperature is displayed) with the remote controller headed towards the indoor unit. 1
Operational procedure
1 Regardless of normal or abnormal condition,
a short beep is emitted once the signal is
received.
MS-GH18/24/30VAMS-GH13VA
OBH664B