Mitsubishi Electric MSH-A18ND User manual

CONTENTS
1. TECHNICAL CHANGES ····································2
2. PART NAMES AND FUNCTIONS······················2
3. SPECIFICATION·················································4
4. OUTLINES AND DIMENSIONS ·························5
5. WIRING DIAGRAM ············································6
6. REFRIGERANT SYSTEM DIAGRAM················7
7. SERVICE FUNCTIONS ······································8
8. TROUBLESHOOTING······································10
9. DISASSEMBLY INSTRUCTIONS ····················18
10. PARTS LIST······················································20
11. RoHS PARTS LIST···········································23
SPLIT-TYPE, HEAT PUMPAIR CONDITIONERS
Outdoor unit service manual
MUH-A·ND Series (OB428)
MSH-A18ND
MSH-A24ND
TM
Wireless type
Models
MSH-A18ND -
MSH-A24ND - S1
S1
SERVICE MANUAL
INDOOR UNIT No. OB427
REVISED EDITION-B
Please void OB427 REVISED EDITION-A.
Revision B:
•Remote controller model has been changed.
•RoHS PARTS LIST has been added.
NOTE:
This service manual describes technical data of the indoor units.
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).
OB427B-1.qxp 07.5.16 3:30 PM Page 1

TECHNICAL CHANGES
2
1
PART NAMES AND FUNCTIONS
2
INDOOR UNIT
Grille
Air inlet
Remote controller
Remote control
receiving section
Air cleaning filter
(White bellows type)
Horizontal vane
Vertical vanes
Catechin air filter
(When the grille is opened)
Operation section Display section
Emergency operation switch
Operation indicator lamp
Remote control
receiving section
Front panel
MSH-A18ND
MSH-A24ND
MSH-18TN - ➔MSH-A18ND -
MSH-24TN - ➔MSH-A24ND -
1. Model name has been changed.
2. Grille design has been changed.
3. Unit size has been changed.(W 1,015a o H 320a o D 190a➔W 1,100a o H 325a o D 258a)
4. Electricity receiving unit has been changed from indoor unit to outdoor unit.
S1S1
S1S1
ACCESSORIES
1
2
3
4
5
6
7
8
Installation plate
Installation plate fixing screw 4 o25 mm
Remote controller holder
Fixing screw for 3o3.5 o1.6 mm (Black)
Battery (AAA) for remote controller
Wireless remote controller
Air cleaning filter
Felt tape (Used for left or left-rear piping)
1
7
1
2
2
1
2
1
MSH-A18ND
MSH-A24ND
Revision A:
•Parts No. of 10.PARTS LIST has been revised.
Revision B:
•Remote controller model has been changed. (KP0A ➔KM04A)
Both remote controllers can be used as alternative.
•RoHS PARTS LIST has been added.
OB427B-1.qxp 07.5.17 7:35 AM Page 2

REMOTE CONTROLLER
MSH-A18ND
MSH-A24ND
3
ON/OFF
TOO
COOL
PM
AM
TOO
WARM
ON/OFF
FAN
TOO
WARM TOO COOL
VANE
MODE
ECONO COOL
STOP
START
HR.
MIN.
WIDE VANE
LONG
I FEEL COOL
HEAT
DRY
PM
CLOCK
AM
RESET CLOCK
Open the front lid.
Signal transmitting section
Operation display section
OPERATE /STOP
(ON /OFF) button
TEMPERATURE buttons
OPERATION SELECT button
FAN SPEED CONTROL button
OFF-TIMER button
HR. button
MIN. button
(TIME SET button)
ON-TIMER button
RESET button
ECONO COOL button
VANE button
(Horizontal vane button)
CLOCK SET button
LONG button
WIDE VANE button
(Vertical vane button)
Indication of remote controller
model is on back.
OB427B-1.qxp 07.5.16 3:30 PM Page 3

SPECIFICATION
4
3
Indoor model
Function
Power supply
Air flow
(High/Med./Low)
Running current
Power input
Power factor
Model
Current
Winding
resistance (at 20:)
Dimensions WOHOD
Weight
Air direction
Sound level (High/Med./Low)
Fan speed (High/Med./Low)
Fan speed regulator
Remote controller model
K/h
A
W
%
A
"
mm
kg
dB
rpm
Single phase
220V, 60Hz
768/642/516
0.28
60
97
RC4N32-AA
0.28
WHT-BLK 205.5
BLK-RED 217.6
1,100O325O258
16
5
42/37/32
1,070/920/780
3
KP0A, KM04A
Cooling Heating Cooling
954/822/684
1,280/1,130/970
Heating
954/834/726
1,280/1,150/1,020
Single phase
220V, 60Hz
0.37
81
99
RC4V40-AA
0.37
WHT-BLK 138.2
BLK-RED 159.0
1,100O325O258
16
5
47/42/37
3
KP0A, KM04A
Electrical
data
Fan
motor
Special
remarks
Capacity
MSH-A18ND MSH-A24ND
NOTE: Test conditions are based on ISO 5151.
Cooling : Indoor DB27°C WB19°C Heating : Indoor DB20°C WB 15.5°C
Outdoor DB35°C WB(24°C) Outdoor DB 7°C WB 6°C
Indoor-Outdoor piping length : 5m
Test conditions are based on SSA 356/366.
Cooling : Indoor DB29°C WB19°C Heating : Indoor DB21°C
Outdoor DB46°C WB24°C Outdoor DB 7°C WB 6°C
Indoor-Outdoor piping length : 7.5m
OB427B-1.qxp 07.5.16 3:30 PM Page 4

5
OUTLINES AND DIMENSIONS
4
258
162
19
58
47
7.5
315
255.547
2.5
98 173
98 173414.5 414.5
5
253
791
56
1068
1100
325
Air out
Air in
Insulation [28
Drain hose [16
(Connected part O.D)
Installation plate
Wall hole [75
Wireless remote controller
Installation plate Indoor unit
{
Liquid line [6.35-0.5m
Gas line [12-0.43m
Insulation [50 O.D
[32 I.D
{
Liquid line [9.52-0.5m
Gas line [12-0.43m
Insulation [50 O.D
[32 I.D
for MSH-A18ND
for MSH-A24ND
INDOOR UNIT
MSH-A18ND
MSH-A24ND Unit: mm
OB427B-1.qxp 07.5.16 3:30 PM Page 5

6
WIRING DIAGRAM
5
MSH-A18ND
INDOOR UNIT
1.About the outdoor side electric wiring, refer to the outdoor unit electric wiring diagram for servicing.
2.Use copper conductors only. (For field wiring)
3.Symbols below indicate. : Connector
: Terminal block
NOTES:
SYMBOL
C11
F11
HIC1
MF
NAME
INDOOR FAN CAPACITOR
FUSE (3.15A)
DC/DC CONVERTER
FAN MOTOR (INNER PROTECTOR)
SYMBOL
MV1
MV2
NR11
RT11
NAME
VANE MOTOR (HORIZONTAL)
VANE MOTOR (VERTICAL)
VARISTOR
ROOM TEMPERATURE THERMISTOR
SYMBOL
RT12
SR141
TB
NAME
INDOOR COIL THERMISTOR
SOLID STATE RELAY
TERMINAL BLOCK
RT11
RT12
BLK
GRY
YLW
BRN
WHT
RED
MF
SR141
CN
121
CN
112
CN
111
C11
CN211
HIC1
151
CN
MV2 MV2 MV1
15
NR11
ELECTRONIC CONTROL P.C. BOARD
F11
220V~
BRN
CN201
12V
TO OUTDOOR
UNIT
CONNECTING
GRN/YLW
BLU
RED
CN
101
CN
102
DISPLAY
P.C.BOARD RECEIVER P.C.BOARD REMOTE
CONTROLLER
TAB12
TB
33
3
3
N
2
2
3
13
1
4
INDOOR UNIT
BLK
GRY
YLW
BRN
WHT
RED
MF
3
SR141
4
3
1
1
4
2
3
CN
121
C11
HIC1
MV1
RT13
CN112
151
CN
MV2
15
RT12
RT11
111
CN
CN211
NR11
ELECTRONIC CONTROL P.C. BOARD
F11
220V~
BRN
CN201
12V
TO OUTDOOR
UNIT
CONNECTING
MV2
BLU
RED
CN
101
CN
102
DISPLAY
P.C.BOARD RECEIVER P.C.BOARD REMOTE
CONTROLLER
33
TAB12
TB
3
N
2
1
2
3
GRN/YLW
1.About the outdoor side electric wiring, refer to the outdoor unit electric wiring diagram for servicing.
2.Use copper conductors only. (For field wiring)
3.Symbols below indicate. : Connector
: Terminal block
NOTES:
SYMBOL
SR141
TB
SYMBOL
MV2
NR11
RT11
RT12
RT13
SYMBOL
C11
F11
HIC1
MF
MV1
INDOOR FAN CAPACITOR
FUSE (3.15A)
DC/DC CONVERTER
INDOOR FAN MOTOR (INNER PROTECTOR)
VANE MOTOR (HORIZONTAL)
VANE MOTOR (VERTICAL)
VARISTOR
ROOM TEMPERATURE THERMISTOR
INDOOR COIL THERMISTOR (MAIN)
INDOOR COIL THERMISTOR (SUB)
SOLID STATE RELAY
TERMINAL BLOCK
NAME NAME NAME
MSH-A24ND
OB427B-1.qxp 07.5.16 3:30 PM Page 6

7
REFRIGERANT SYSTEM DIAGRAM
6
Refrigerant flow in cooling
Refrigerant flow in heating
Strainer
#50
MSH-A18ND
INDOOR UNIT
Indoor
heat
exchanger
Room temperature
thermistor
RT11
Refrigerant pipe [12.7
(with heat insulator)
Flared connection
Flared connection
Indoor coil
thermistor
RT12
Refrigerant pipe [6.35
(with heat insulator)
Distributor
Strainer
#50
MSH-A24ND
INDOOR UNIT
Indoor
heat
exchanger
Room temperature
thermistor
RT11
Refrigerant pipe [15.88
(with heat insulator)
Flared connection
Flared connection
Refrigerant pipe [6.35
(with heat insulator)
Distributor
Unit:mm
Indoor coil
thermistor
RT12(main)
Indoor coil
thermistor
RT13(sub)
OB427B-1.qxp 07.5.16 3:30 PM Page 7

8
SERVICE FUNCTIONS
7
When the indoor unit is controlled with the remote controller, the operation mode, 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. However if the unit is operated in “I FEEL CONTROL”mode before power
failure, the operation is not memorized. In “I FEEL CONTROL”mode, the operation is decided by the initial room tempera-
ture.
7-3. AUTO RESTART FUNCTION
7-1. TIMER SHORT MODE
For service, set time can be shortened by short circuit of JPG and JPS on the electronic control P.C. board.
The time will be shortened as follows.
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.)
MSH-A18ND
MSH-A24ND
Table 1
No. 1 unit
No. 2 unit
No. 3 unit
No. 4 unit
1 unit operation
No modification
–
–
–
2 units operation
Same as at left
Solder J1
–
–
3 units operation
Same as at left
Same as at left
Solder J2
–
4 units operation
Same as at left
Same as at left
Same as at left
Solder both J1 and J2
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 :
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 2 or 3 times at first.
After modification, put back the batteries then press the RESET button.
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 only accepts 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.
Remote controller model : KP0A
Remote controller model : KM04A
J2
J1 J1
J2
OB427B-1.qxp 07.5.16 3:30 PM Page 8

9
How to release “AUTO RESTART FUNCTION”
1Turn off the main power for the unit.
2Pull out the electronic control P.C. board, the receiver P.C.
board and the display P.C.board. (Refer to 9-2.)
3Solder jumper wire to JR07 on the indoor
electronic control P.C. board. (Refer to 8-6.)
JR07
IC152
CN151
CN112
CN111
CN121
SW1
IC101
RA102
C11
CN201
CN211
TAB12
Operation
1If the main power has been cut, the operation settings remain.
2After 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.)
NOTE
•The operation settings are memorized when 10 seconds have passed after the remote controller 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 appliances 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.
OB427B-1.qxp 07.5.16 3:30 PM Page 9

10
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 mis-wiring.
2. Take care of the following during servicing
(1) Before servicing the air conditioner, be sure to first turn off the remote controller to stop the main unit, 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
components.
(4) When connecting or disconnecting the connectors, hold the housing of the connector. DO NOT pull the lead wires.
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 discolouration.
(4) When troubleshooting, refer to 8-2. and 8-3.
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.
1Remove the front lid and insert batteries.
Then reattach the front lid.
Lead wiring Housing point
MSH-A18ND
MSH-A24ND
RESET button
2Press the RESET button with tip end of ball point
pen or the like, and then use the remote controller.
NOTE : If the RESET button is not pressed, the remote controller may not operate correctly.
Insert the negative pole
of the batteries first.
Check if the polarity of
the batteries is correct.
OB427B-1.qxp 07.5.16 3:30 PM Page 10