Mitsubishi Electric Mr.Slim MSH24WN User manual

SERVICE MANUAL
CONTENTS
1. FEATURES·························································3
2. PART NAMES AND FUNCTIONS······················4
3. SPECIFICATION·················································6
4. DATA···································································8
5. OUTLINES AND DIMENSIONS ·······················13
6. WIRING DIAGRAM ··········································15
7. REFRIGERANT SYSTEM DIAGRAM··············16
8. MICROPROCESSOR CONTROL ····················17
9. SERVICE FUNCTIONS ····································29
10. TROUBLESHOOTING······································31
11. DISASSEMBLY INSTRUCTIONS·····················44
12. PARTS LIST······················································48
13. OPTIONAL PARTS ······················BACK COVER
Wireless type
Models
MSH24WN (W) ·MUH24WN
SPLIT-TYPE, HEAT PUMPAIR CONDITIONERS
The Slim Line.
From Mitsubishi Electric.
L
I
S
T
E
D
CUS
INDOOR UNIT
Indication of model name
MSH24WN
OUTDOOR UNIT
Indication of model name
MUH24WN
Remote
controller
TM
Revision:
●PARTS LIST have been partially modified.
●Please void OB310.
No. OB310
REVISED EDITION-A
OB310--1.qxp 04.1.13 9:47 AM Page 1

Revision:
• Parts No. has been changed due to the color change of outdoor unit parts. WHITE➔NEW WHITE (Brighter)
• Capillary tubes have been added to parts list.
CAPILLARY TUBE (TAPER PIPE)
[0.17X[0.12X11-13/16
CAPILLARY TUBE (TAPER PIPE)
[0.17X[0.12X1-31/32
E02 785 936
E02 529 936
Part number
Part name
Model
MUH24WN
MUH24WN
Page
51
51
OB310--1.qxp 04.1.13 9:47 AM Page 2

3
LCD wireless
remote controller
“I FEEL CONTROL” IN OUR LCD WIRELESS REMOTE CONTROLLER WITH ON/OFF PROGRAM TIMER
Mitsubishi Electric’s new wireless remote controller incorporates a number of advanced features that provide even greater con-
trol and ease-to-use. It has a liquid crystal display which indicates such information as mode, fan speed and temperature
selected as well as the programmed ON/OFF timer. It is also equipped with “I Feel Control”, a unique Mitsubishi Electric fea-
ture that allows the user to adjust the temperature to exactly the level he or she wants simply by tapping the button that
describes present conditions : “Too Cool” or “Too Warm”. The optimum temperature set this way is then memorized for immedi-
ate recall whenever the air conditioner is used again.
Select desired air flow direction.
REMOTE-CONTROL OPERATION MODE
Using the remote controller, you can select from five airflow set-
tings to match room layout and the location of people. Also, you
can set the vane to swing automatically.
AUTO-RESTART FUNCTION
The auto-restart function restarts the equipment when power is
restored following an outage automatically. Operation resumes in
the mode in which the equipment was running immediately before
the outage.
HIGH PERFORMANCE ROTARY COMPRESSOR
The advanced design of Mitsubishi Electric’s powerful and energy
efficient rotary compressor results in lower operating costs and
longer service life.
SWING
MSH24WN
Model 22,000 Btu/h
Cooling capacity
23,600 Btu/h
Heating capacity
10.0
SEER 6.8/5.9
HSPF(44/55)
SWING
FEATURES
1
MSH24WN
MUH24WN
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4
PART NAMES AND FUNCTIONS
2
INDOOR UNIT
MSH24WN
Installation plate
Installation plate fixing screw 4 x 25 mm(0.16 x 0.98 in.)
Remote controller holder
Fixing screw for 33.5 x 16 mm(0.14 x 0.63 in.) (Black)
Battery (AAA) for remote controller
Wireless remote controller
Felt tape (Used for left or left-rear piping)
1
7
1
2
2
1
1
1
2
3
4
5
6
7
MSH24WN
ACCESSORIES
Grille
Air inlet
Remote control
receiving section
Horizontal vane
Remote controller
Deodorizing filter (option)
(Gray sponge type)
Air cleaning filter (option)
(White bellows type)
Air filter
Vertical vane
Operation section
(When the grille is opened)
Display section
Operation indicator lamp
Receiving section
Emergency operation switch
Front panel
Operation Indicator
OUTDOOR UNIT
MUH24WN
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5
REMOTE CONTROLLER
MSH24WN
ON/OFF
TOO
COOL
PM
AM
TOO
WARM
ON/OFF
FAN
TOO
WARM TOO COOL
VANE
MODE
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
VANE button
(Horizontal vane button)
CLOCK SET button
LONG button
WIDE VANE button
(Vertical vane button)
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6
SPECIFICATION
3
NOTE : Test conditions are based on ARI 210/240.
❈1 : Rating conditions(cooling) — Indoor : 80˚FDB, 67˚FWB, Outdoor : 95˚FDB, (75˚FWB)
(heating) — Indoor : 70˚FDB, 60˚FWB, Outdoor : 47˚FDB, 43˚FWB
❈2 : (heating) — Indoor : 70˚FDB, 60˚FWB, Outdoor : 17˚FDB, 15˚FWB
❈3 : (cooling) — Indoor : 80˚FDB, 67˚FWB, Outdoor : 82˚FDB, 65˚FWB
Operating Range
Item Model
Capacity
Power
consumption
EER [SEER]
HSPF IV(V)
COP
INDOOR UNIT MODEL
External finish
Power supply
Max. fuse size (time delay)/ Disconnect switch
Min. circuit ampacity
Fan motor
Auxiliary heater
Airflow Low—Med.—High
Moisture removal
Sound level Low-Med.-High
Cond. drain connection O.D.
Dimensions
Weight
OUTDOOR UNIT MODEL
External finish
Power supply
Max. fuse size (time delay)
Min. circuit ampacity
Fan motor
Compressor
Refrigerant control
Sound level
Defrost method
Dimensions
Weight
REMOTE CONTROLLER
Control voltage (by built-in transformer)
REFRIGERANT PIPING
Pipe size
(Min. wall thickness)
Connection method
Between the indoor
& outdoor units
Refrigerant charge (R22)
Refrigerating oil (Model)
Btu/h
Btu/h
Btu/h
W
W
A
A
F.L.A
A(kW)
CFM
CFM
pt./h
dB(A)
in.
in.
in.
in.
Ib.
A
A
F.L.A
R.L.A
L.R.A
dB(A)
in.
in.
in.
Ib.
in.
in.
ft.
ft.
lb.
oz.
MSH24WN
22,000
23,600
13,500
2,220
2,230
1,730
9.9 (10.0)
6.8 (5.9)
3.10
MSH24WN
White
115V 60Hz 1[
15
1.1
0.82
–
431-491-565
402(346)-484(417)-565(487)
7.3
39-43-47
5/8
43-5/16
8-15/16
12-13/16
40
MUH24WN
Munsell 5Y 7/1
208/230V 60Hz 1[3 wires
25
22
0.87
PH33NPBT
C-R 0.84 C-S 2.09
16
58
Linear expansion valve
55
Reverse cycle
34-1/4
11-5/8
33-1/2
154
Wireless type
12V DC
Not supplied (optional parts)
3/8 (0.0285)
5/8 (0.0315)
Flared
Flared
Max. 25
Max. 50
4 Ib. 0 oz.
27.9 (MS32N1)
❈1❈3
❈1
❈1
❈2
❈1❈1
❈2
Cooling
Heating 47
Heating 17
Cooling
Heating 47
Heating 17
Cooling
Heating
Heating
HEAT Dry
COOL Dry(Wet)
W
D
H
Model
Winding resistance (at 68˚F) Ω
W
D
H
Liquid
Gas
Indoor
Outdoor
Height difference
Piping length
❈1
Cooling
Heating
Maximum
Minimum
Maximum
Minimum
Indoor intake air temperature
95˚FDB, 71˚FWB
67˚FDB, 57˚FWB
80˚FDB, 67˚FWB
70˚FDB, 60˚FWB
Outdoor intake air temperature
115˚FDB
67˚FDB
75˚FDB, 65˚FWB
17˚FDB, 15˚FWB
OB310--1.qxp 04.1.13 9:47 AM Page 6

7
Indoor
unit
w Max. Height
difference 25ft. Outdoor unit
Refrigerant Piping
Max.length
A
w Height difference should be within
25ft. regardless of which unit,
indoor or outdoor position is high.
MAX. HEIGHT DIFFERENCE
Outside
diameter Minimum
Wall
thickness Outside
diameter Minimum
Wall
thickness
MSH24WN MUH24WN
Additional piping
Max. length : ft.
A
50
GasPiping size : in. Length of connecting pipe : in. Liquid Indoor unit Outdoor unit
Model
Gas :
Liquid : 0 0
Gas :
Liquid :16-15/16
19-11/16
[ 5/8 [ 3/8
0.0315 0.0285
MAX. REFRIGERANT PIPING LENGTH
OB310--1.qxp 04.1.13 9:47 AM Page 7

8
DATA
4
Model Refrigerant piping length (one way)
1.0
25ft. (std.)
0.954
40ft.
0.923
50ft.
MSH24WN
2) COOLING CAPACITY CORRECTIONS
3) HEATING CAPACITY
(208V/ 230V)
Model
Indoor air Outdoor intake air WB temperature(˚F)
75
70
65
TC
13.7
14.5
14.9
TPC
1.66
1.61
1.54
TC
17.1
17.7
18.5
TPC
1.95
1.91
1.84
TC
20.4
20.9
21.6
TPC
2.17
2.12
2.06
TC
23.0
23.6
24.3
TPC
2.29
2.23
2.17
TC
23.7
24.3
25.0
TPC
2.32
2.27
2.21
TC
26.9
27.5
28.1
TPC
2.41
2.36
2.32
IDB
(˚F)15 25 35 43 45 55
MSH24WN
NOTE: 1. IDB : Intake air dry-bulb temperature
TC : Total Capacity (x103 Btu/h)
TPC : Total Power Consumption (kW)
2. Above data is for heating operation without any frost.
4-1. PERFORMANCE DATA
1) COOLING CAPACITY
MSH24WN MUH24WN
Model
Indoor air Outdoor intake air DB temperature(˚F)
71
67
63
TC
27.0
25.5
24.0
SHC
13.4
16.1
18.3
TPC
1.98
1.86
1.78
TC
25.2
23.8
22.2
SHC
12.5
15.0
17.0
TPC
2.16
2.05
1.96
TC
23.7
22.0
20.7
SHC
11.7
13.9
15.8
TPC
2.33
2.22
2.12
TC
22.0
20.5
18.8
SHC
10.9
12.9
14.4
TPC
2.45
2.35
2.26
TC
20.2
18.8
17.2
SHC
10.1
11.9
13.1
TPC
2.55
2.46
2.35
IWB
(˚F)75 85 95 105 115
MSH24WN
(208V/ 230V)
NOTE 1. IWB : Intake air wet-bulb temperature
TC : Total Capacity (x103 Btu/h), SHC : Sensible Heat Capacity (x103 Btu/h)
TPC : Total Power Consumption (kW)
2. SHC is based on 80˚F of indoor intake air DB temperature.
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9
4-2. PERFORMANCE CURVE
MSH24WN
MUH24WN
16
18
20
22
24
26
28
30
65 70 75 80 85 90 95 100 105 110 115
1.6
1.8
2.0
2.2
2.4
2.6
15 20 25 30 35 40 45 50 55 60
1.6
1.8
2.0
2.2
2.4
2.6
10
12
14
16
18
20
22
24
26
28
30
71
67
63
71
67
63
65
70
75
75
70
65
Total power consumption (kW) Total capacity ( ✕10 Btu/h)
Outdoor intake air DB temperature (°F)
Indoor intake air WB temperature (°F)
Indoor intake air WB temperature (°F)
Cooling
SHF at rating condition = 0.63
= 487CFM
= 0.19
Airflow
Bypass Factor
Total power consumption (kW) Total capacity ( ✕10 Btu/h)
Outdoor intake air WB temperature (°F)
Indoor intake air DB temperature (°F)
Indoor intake air DB temperature (°F)
Heating
= 565CFM
Airflow
208V/230V
208V/230V
208V/230V
208V/230V
OB310--1.qxp 04.1.13 9:47 AM Page 9

10
Data is based on the condition of indoor humidity 50%.
Air flow should be set to High speed.
4-3. Condensing pressure
MSH24WN
(Cooling)
Data is based on the condition of outdoor humidity 75%.
Air flow should be set to High speed.
Data is for heating operation without any frost.
MSH24WN
(Heating)
68 70 75 80 85 90 95 100 104(°F)
40
50
60
70
80
90
100
Suction pressure
Outdoor ambient temperature
68 70 75 80 85 90 95 100 104(°F)
140
160
180
200
220
240
260
280
300
(PSIG)
Condensing pressure
Outdoor ambient temperature
Indoor DB temperature (°F)
86
80
75
70
Indoor DB temperature (°F)
(PSIG)
86
80
75
70
5 10152025303540455055606570(°F)
140
160
180
200
220
240
260
280
300
320
340
Indoor DB temperature(°F)
75
70
65
75
70
65
(PSIG)
Condensing pressure
Outdoor ambient temperature
(PSIG)
Suction pressure
Outdoor ambient temperature
5 10152025303540455055606570(°F)
10
20
30
40
50
60
70
80
90
Indoor DB temperature (°F)
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4-4. STANDARD OPERATION DATA
11
Capacity
SHF
Input
Indoor unit
Power supply
Input
Fan motor current
Aux. heater current
Outdoor unit
Power supply
Input
Comp. current
Fan motor current
Condensing pressure
Suction pressure
Discharge temperature
Condensing temperature
Suction temperature
Comp. shell bottom temp
Ref. pipe length
Refrigerant charge (R22)
Intake air temperature
Discharge air temperature
Fan speed (High)
Airflow (High)
Intake air temperature
Fan speed
Airflow
Unit
Btu / h
—
kW
kW
A
A
kW
A
A
PSIG
PSIG
˚F
˚F
˚F
˚F
ft.
—
˚F
˚F
˚F
˚F
rpm
CFM
˚F
˚F
rpm
CFM
Heating
23,600
–
2.23
2.159
9.65 / 8.56
250
56
185
115
35
167
70
60
109
–
1,280
565(Dry)
47
43
DB
WB
DB
WB
DB
WB
Item
Model
Total
Electrical
circuit
Refrigerant
circuit
Indoor
unit
Outdoor
unit
Cooling
22,000
0.63
2.22
2.149
9.60 / 8.52
257
73
180
116
52
163
80
67
53
51
1,280
487(Wet)
95
–
MSH24WN
115V 60Hz 1[
0.071
0.62
–
MUH24WN
208/230V 60Hz 1[
0.67/0.71
25
4 lb. 0 oz.
750/820
1,589/1,765
MSH24WN
POWER SUPPLY ✻ Control voltage
Power supply voltage to
serial signal circuit is 12V
DC.
Voltage between 11- and
33+ on in-out terminal
block will be 12V DC
peak voltage.
MSH24WN
INDOOR UNIT
OUTDOOR UNIT
115V 60Hz 1[, 2 wires
208/230V 60Hz 1[,
2 wires
SIGNAL
WIRE
2 wires
12V DC
INDOOR UNIT
OUTDOOR UNIT
208/230V
60Hz 1[,
3 wires
115V 60Hz 1[,
2wires
SIGNAL WIRE
2 wires 12V DC
•Both wirings can be applied.
115V
Disconnect switch
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12
4-5. OPERATING RANGE
(1) POWER SUPPLY
Indoor unit
Outdoor unit
Rating
115V 60Hz 1[
208/230V 60Hz 1[
Guaranteed Voltage
MSH24WN
MUH24WN
Model
Min. 103V Max. 127V 115V
Min. 198V Max. 253V
208V 230V
(2) OPERATION
78% —
Function
Cooling
Heating
Standard temperature
Maximum temperature
Minimum temperature
Maximum humidity
Standard temperature
Maximum temperature
Minimum temperature
DB (˚F)
80
95
67
70
80
70
WB (˚F)
67
71
57
60
67
60
Indoor
DB (˚F)
95
115
67
47
75
17
WB (˚F)
—
—
—
43
65
15
Outdoor
Condition
Intake air
temperature
4-6. OUTLET AIR SPEED AND COVERAGE RANGE
Model
MSH24WN
Mode
HEAT
COOL
565
565
487
Air flow
(CFM) Air speed (ft./sec.) Coverage range (ft.)
Function
Dry
Dry
Wet
20.1
20.1
17.2
34.2
34.2
29.4
4-7. ADDITIONAL REFRIGERANT CHARGE (R22(oz.))
MSH24WN MUH24WN
Outdoor unit
precharged
(up to 25ft.)
4 lb. 0 oz.
25ft.
0
30ft.
1.61
35ft.
3.22
Refrigerant piping length (one way)
40ft.
4.83
45ft.
6.44
50ft.
8.05
Model
CALCULATION : Xoz. = 1.61/ 5oz./ft. x (Additional Piping Length-25) ft.
●The air coverage range is the figure up to the position where the air speed is 1 ft./sec., when air is blown out
horizontally from the unit properly at the High speed position.
The coverage range should be used only as a general guideline since it varies according to the size of the room and furniture
arranged inside the room.
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13
OUTLINES AND DIMENSIONS
5
MSH24WN
INDOOR UNIT
Unit: inch
6-3/8
3/4
2-5/16
1-7/8
5/16
12-3/8
10-1/161-7/8
1/8
3-7/8
3-7/8
6-13/16
6-13/16
16-5/16 16-5/16
3/168-7/8
8-15/16
9-15/16
31-1/8
2-3/16
42-1/16
43-5/16
12-13/16
Air out
Air in
Insulation [1-1/8
Drain hose [5/8
(Connected part O.D)
{
Liquid line [3/8 19-11/16
Gas line [3/4 16-15/16
Insulation [1-15/16 O.D
[1-1/4 I.D
Installation plate
Wall hole [2-15/16
Wireless remote controller
Installation plate Indoor unit
OB310--1.qxp 04.1.13 9:47 AM Page 13

14
MUH24WN
OUTDOOR UNIT
413/32
39-3/8
For 10 units or less
7-7/8
Outdoor Unit-Necessary surrounding clearance
(Concentrated installation) The upper side must be open.
Outdoor Unit-Necessary surrounding clearance
7-7/8
13/32
13/32
13/32
Note:Allow adequate
upper clearance
5-29/32
19-11/16
19-11/16
Service space
Front opening
R13/16
R13/16
1 max.
Standard bolt length
2-9/16
Front right piping holes-
detail figures
3-1/8
11/16
1/2
R1/4
15/16
1-5/16
Side air intake
9/32 15/16 11-5/8
Outlet guide
installation hole
11-7/8
Air intake
Air intake
Air outlet
34-1/4
7-9/32 7-9/32
19-11/16
13
14-1/4 11/16
9/16
1-9/16 1-1/16
Terminal block for indoor and outdoor unit connection
Terminal block for power line
Handle for moving
7-1/18 20-5/8
17-3/8
17-17/32
17-23/32
18-7/18
21-3/4
33-1/2
1-9/16 2-3/8 20-5/8
Service panel
Refrigerant-pipe flared
connection [5/8
Refrigerant-pipe flared
connection [3/8
Knock out hole
for front piping
(refrigerant,drainage
and wiring)
1-5/8
1-3/4
4-1/8
1-5/16
Bottom
piping hole
2-U-shaped
notched
holes
Drain hole [1-5/16
Drain hole [1-5/16
2-1/2o7/8 Oval holes
(standard bolt M10)
Handle for moving
A
Handle
for moving
5-7/16
3-3/4 Rear piping hole
Rear fresh
air intake
A
Knock out hole
for right piping
(refrigerant,drainage
and wiring)
4-3/4
1-3/4
2-1/16
Knock out holes for
power line 2-[1-1/16
2-3/8
NOTE: Do not wire12V DC and
115V AC in same conduit hole.
Conduit hole
Unit: inch
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15
WIRING DIAGRAM
6
MSH24WN
MUH24WN
MODEL WIRING DIAGRAM
MODEL WIRING DIAGRAM
INDOOR UNIT
OUTDOOR UNIT
TAB12
POWER
FROM OUTDOOR
UNIT
CONNECTING
WIRES
TO OUTDOOR
UNIT
CONNECTING
WIRE
SUPPLY
115V
1 phase
60Hz
CN201 RT13
121
CN
CN211
CN112
TO OUTDOOR
UNIT
CONNECTING
WIRES
12V DC
3
F11
VLT
1-
3+
15
3
REMOTE
CONTROLLER
MV2 MV2 MV1
BLK
GRY
TRANS
HIC1
C11
N
L1
BLK
ORN
WHT
BRN
YLW
RED
ELECTRONIC CONTROL P.C. BOARD
NR11
RED
MF
RT12
CN
151 CN
101
3
DISPLAY
P.C.BOARD RECEIVER P.C.BOARD
CN
102
SR141 1
3
4
4
3
2
1
RT11
111
CN
1
2
3
4
TB
w
()
wA disconnect may be required by local code.
DEICER P.C.BOARD
FROM INDOOR UNIT
CONNECTING WIRES
12V DC
TO INDOOR UNIT
CONNECTING
WIRES
115V
1 phase 60Hz
BLK
RED
FROM INDOOR UNIT
CONNECTING WIRE
BLK
BLK
RED
RED
GROUND
GRN/YLW
RED
BLU
VLT
BLU
7
POWER
SUPPLY
208/230V
1 phase 60Hz
BLK
WHT
CN721
152C 2
RED C2
ORN
CN730
A2 A1
BLU
52C
WHT
C1 RED
BLK
S
C
R
NR61
5
3
BLU
T61
CN661
RT61
X52X62
X62
1
2
3
21S4
ORN
SR61
COM NO
F61
TAB52
X52
1
CN711
CN724
CN662
6
MF
RT62 RT63
123
21
BLK
WHT
ORN
RED
3456
LEV
NO
COM
TB2
3
TB1
L1
N
L2
1
N
L1
DSAR
-
+
MC
NOTE: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;
: Terminal block, : Connector
SYMBOL
RT12
RT13
SR141
TB
SYMBOL
MV1
MV2
NR11
RT11
SYMBOL
C11
F11
HIC1
MF
NAME NAME NAME
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
SG79J618H02
SYMBOL
T61
X52
X62
21S4
52C
SYMBOL
NR61
RT61
RT62
RT63
SR61
TB1
TB2
SYMBOL
C1
C2
DSAR
F61
LEV
MC
MF
NAME NAME NAME
COMPRESSOR CAPACITOR
OUTDOOR FAN CAPACITOR
SURGE ABSORBER
FUSE(3.15A)
EXPANSION VALVE COIL
COMPRESSOR(INNER PROTECTOR)
OUTDOOR FAN MOTOR(INNER PROTECTOR)
VARISTOR
DEFROST THERMISTOR
DISCHARGE TEMPERATURE THERMISTOR
AMBIENT TEMPERATURE THERMISTOR
SOLID STATE RELAY
TERMINAL BLOCK
TERMINAL BLOCK
TRANSFORMER
COMPRESSOR AUXILIARY RELAY
R.V. COIL RELAY
R.V. COIL
COMPRESSOR CONTACTOR
SG79J604H02
NOTE:1. About the indoor side electric wiring, refer to the indoor unit electric wiring diagram for servicing.
2. Use copper conductors only.(For field wiring)
3. Symbols below indicate;
: Terminal block, : Connector
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16
REFRIGERANT SYSTEM DIAGRAM
7
MSH24WN MUH24WN
INDOOR UNIT OUTDOOR UNIT
Indoor
heat
exchanger
Outdoor
heat
exchanger
Flared connection
Room temperature
thermistor
RT11
Indoor coil
thermistor
RT13(sub)
Defrost
thermistor
RT61
Discharge
thermistor
RT62
Flared connection
Stop valve
Stop valve
(with service port)
Capillary tube
O.D. 0.17✕I.D. 0.12✕1-31/32 Refrigerant flow in cooling
Compressor
Muffler
4-way valve
Refrigerant flow in heating
Refrigerant pipe [5/8
(with heat insulator)
Refrigerant pipe [3/8
(with heat insulator)
Indoor coil
thermistor
RT12(main)
LEV R.V. coil
heating ON
cooling OFF
Strainer
#100
Check
valve
Accumulator
SERVICE
PORT
SERVICE
PORT
FUSIBLE
PLUG
Ambient
temperature
thermistor
RT63
Capillary tube
O.D. 0.17✕I.D. 0.12✕11-13/16
Strainer
#100
Strainer
#100
Strainer
#50
Unit: inch
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17
MICROPROCESSOR CONTROL8
lighted
not lighted
Approx. 4-F
or more
Difference
between target
temperature
and room
temperature
Approx. 4-F
or less
This shows that the
air conditioner is
operating to reach
the target temperature.
Please wait unit the
target temperature is
obtained.
This shows that the
room temperature is
approaching the
target temperature.
Operation stateIndication
Operation Indicator
Operation Indicator lamp
The operation indicator at the right side of the indoor
unit indicates the operation state.
INDOOR UNIT DISPLAY SECTION
• The following indication applies regardless of shape
of the indicator.
WIRELESS REMOTE CONTROLLER
Mode
COOL mode of
"I FEEL CONTROL"
DRY mode of
"I FEEL CONTROL"
HEAT mode of
"I FEEL CONTROL"
Initial room temperature
77-F or more
73-F to 77-F
less than 73-F
MSH24WN MUH24WN
ON/OFF
FAN
TOO
WARM TOO COOL
VANE
MODE
STOP
START
HR.
MIN.
WIDE VANE
LONG
I FEEL COOL
HEAT
DRY
PM
CLOCK
AM
RESET CLOCK
OPERATION SELECT button
FAN SPEED CONTROL button
OFF-TIMER button
HR. button
MIN. button
(TIME SET button)
ON-TIMER button
RESET button
VANE button
(Horizontal vane button)
CLOCK SET button
LONG button
WIDE VANE button
(Vertical vane button)
ON/OFF
TOO
COOL
PM
AM
TOO
WARM
Signal transmitting section
Operation display section
OPERATE /STOP
(ON /OFF)button
TEMPERATURE buttons
Once the operation mode is set, the same operation mode
can be repeated by simply turning the OPERATE/STOP
(ON/OFF) button ON.
Indoor unit receives the signal with a beep tone.
When the system turns off, 3-minute time delay will oper-
ate to protect system from overload and compressor will
not restart for 3 minutes.
8-1. “I FEEL CONTROL” ( ) OPERATION
(1) Press OPERATE/STOP (ON/OFF) 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 OPERA-
TION SELECT button.
(3) The operation mode is determined by the room tem-
perature at start-up of the operation.
Example
Previous operation
COOL mode of
“I FEEL CONTROL”
or COOL mode
• Once the mode is fixed, the mode does not change
by room temperature afterwards.
• Under the ON-TIMER ( ) operation, mode is
determined according to the room temperature at the
set time the operation starts.
• When the system is stopped on 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.
Example
Previous operation
COOL mode of
“I FEEL CONTROL”
or COOL mode
When the system is restarted after 2 hours and more,
the operation mode is determined by the room tempera-
ture at start-up of the operation.
Restart
COOL mode of
“I FEEL CONTROL”
Restart
COOL or DRY or
HEAT mode of “I
FEEL CONTROL”
that determined by
room temperature
at start-up of the
operation.
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18
Model
COOL mode of
"I FEEL CONTROL"
DRY mode of
"I FEEL CONTROL"
HEAT mode of
"I FEEL CONTROL"
Initial room temperature Initial set temperature
79-F
79-F or more
77-F to 79-F
less than 73-F
73-F to 77-F
75-F
Initial room temperature
minus 4-F
Initial room temperature
minus 4-F
❈1
(4) The initial set temperature is decided by the initial room temperature.
❈1 When the system is restarted with the remote controller, the system operates with the previous set temperature regard-
less of 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 the TOO WARM or TOO COOL button is pressed, the indoor unit receives the signal and emits a beep tone.
• Fuzzy control
When the 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
cool. So this is called “Fuzzy control”, and works only in “I FEEL CONTROL” mode.
In DRY mode of “I FEEL CONTROL”, the set temperature doesn’t change.
… To raise the set temperature 2~4 degrees(°F) … To lower the set temperature 2~4 degrees(°F)
TOO
COOL
TOO
WARM
1. Indoor fan speed control
Indoor fan operates at the set speed by FAN SPEED CONTROL button.
In AUTO the fan speed is as follows. Initial temperature difference Fan Speed
Room temperature minus set temperature : 3 degrees or more ·····························High
Room temperature minus set temperature : Between 2 and 3 degrees ··················Med.
Room temperature minus set temperature : less than 2 degree ····························· Low
8-1-1. COOL mode of “I FEEL CONTROL”
Difference between room
temperature and set temperature
during operation
2deg. 3deg. 4deg.
2. Coil frost prevention
① Temperature control
When the indoor coil thermistor RT12 or RT13 reads 30°F or below the coil frost prevention mode starts immediately.
However, the coil frost prevention doesn’t work for 5 minutes since the compressor has started.
The indoor fan operates at the set speed and the compressor stops for 5 minutes.
After that, if RT12 or RT13 still reads below 30°F this mode prolonged until the RT12 or RT13 still reads over 30°F.
② Time control
When the three conditions as follows have been satisfied for 1 hour and 45 minutes, compressor stops for 3 minutes.
a. Compressor has been continuously operating.
b. Indoor fan speed is Low or Med.
c. Room temperature is below 79°F.
When compressor stops, the accumulated time is cancelled and when compressor restarts, time counting starts from the
beginning.
Time counting also stops temporarily when the indoor fan speed becomes High or the room temperature exceeds
79°F. However, when two of the above conditions (b.and c.) are satisfied again. Time accumulation is resumed.
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19
Compressor
Outdoor fan OFF
ON
(continuously at set speed)
Indoor fan ON
ON
OFF
Operation chart
Example
3. Discharge temperature protection
The compressor is controlled by the temperature of discharge temperature thermistor RT62 for excess rise protection of
compressor discharge pressure.
• Compressor
When the temperature of discharge temperature thermistor RT62 goes to 248°F or more, the compressor is turned OFF.
After 3 minutes since the compressor has been turned OFF, if the temperature of discharge temperature thermistor RT62
becomes 212°F or less, the compressor is turned ON.
8-1-2. DRY mode of “I FEEL CONTROL”
The system for dry operation uses the same refrigerant circuit as the cooling circuit.
The compressor and the indoor fan are controlled by the room temperature.
By such controls, indoor flow amounts will be reduced in order to lower humidity without much room temperature
decrease.
2. The operation of the compressor and indoor/ outdoor fan
Compressor operates by room temperature control and time control.
Set temperature is controlled to fall 4°F from initial room temperature.
Indoor fan and outdoor fan operate in the same cycle as the compressor.
•When the room temperature is 73°F or over:
When the thermostat is ON, the compressor repeats 8 minutes ON and 3 minutes OFF.
When the thermostat is OFF, the compressor repeats 4 minutes OFF and 1 minute ON.
•When the room temperature is under 73°F.
When the thermostat is ON, the compressor repeats 2 minutes ON and 3 minutes OFF.
When the thermostat is OFF, the compressor repeats 4 minutes OFF and 1 minute ON.
1. Indoor fan speed control
Indoor fan operates at the set speed by FAN SPEED CONTROL button.
However, in AUTO fan operation, fan speed becomes Low.
Operation time chart
Example
Thermostat
Indoor fan
Outdoor fan
Compressor
ON
8 min. 1 min.4 min.
3 min.
ON
OFF
OFF
OFF
OFF
OFF
ON
ON
ON
ON
ON
ON
OFF
OFF
OFF
3. Coil frost prevention
• The operation is as same as coil frost prevention during COOL mode of “I FEEL CONTROL”.
• Indoor fan operates at the set speed and the compressor stops for 5 minutes, because protection(Coil frost
prevention) has the priority.
However, when coil frost prevention works while the compressor is not operating, it’s speed becomes Low.
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20
(4) Flow soft control
After the thermostat turns off, the indoor fan operates at Very Low.
NOTE : When the thermostat turns on, the fan operates at the set speed. Due to the cold air prevention control, the fan
does not start at set speed until the indoor coil thermistor RT12 reads 72°F or more.
<Time condition> <Indoor fan speed>
less than 2 minutes························Low
2 minutes to 4 minutes···················Med.
4 minutes or more··························High
The upper limit of the fan speed is the set speed.
If the thermostat turns off, this operation changes to flow soft control.
8-1-3. HEAT mode of “I FEEL CONTROL”
1. Indoor fan speed control
(1) In AUTO the fan speed is as follows.
Set temperature minus room temperature: 4 degrees or more················································· High
Set temperature minus room temperature: Between 2 and 4 degrees····································· Med.
Set temperature minus room temperature: less than 2 degree················································· Low
(2) Cold air prevention control
The fan runs at set speed when the indoor coil thermistor RT12 temperature exceeds 72°F. The fan operates Low when
the temperature of indoor coil thermistor RT12 is below 64°F. But the fan stops when the indoor fan operates at Very
Low and the room temperature is 59°F or less.
NOTE : If the temperature of RT12 reads from 64°F to 72°F at the air conditioner starting and also after defrosting, this
control works.
(3) Warm air control.
When compressor starts in heating operation or after defrosting, the fan changes the speed due to the indoor coil ther-
mistor RT12 temperature to blow out warm air.
After releasing of cold air prevention, when the indoor coil thermistor RT12 temperature is 99°F or above, the fan speed
shifts to the set speed, and when the fan speed is changed by the remote controller, the fan speed is the set speed.
When the indoor coil thermistor RT12 temperature is less than 99°F, the fan speed is controlled by time as below.
Difference between room
temperature and set temperature
during operation
2deg. 3deg. 7deg.
4deg.
Initial temperature difference Fan speed
Indoor coil thermistor
RT12 temperature
Released
Cold Air Prevention 64F-72F-
Fan speed
Set speed
Very Low or stop
NOTE : During the high pressure protection and for 10 seconds after high pressure protection, defrosting of outdoor heat
exchanger is not detected by the defrost thermistor RT61.
3. Discharge temperature protection
Discharge temperature protection is as same as during COOL mode of “I FEEL CONTROL”.
• Compressor
When the temperature of indoor coil thermistor RT12 goes to 167°F or more, the compressor is turned OFF.
3 minutes after the compressor is turned OFF and if the temperature of indoor coil thermistor RT12 becomes 167°F or
less, the compressor is turned ON.
2. High pressure protection
During heating operation, the outdoor fan and the compressor are controlled by the temperature of indoor coil thermistor
RT12 for excess rise protection of compressor discharge pressure.
• Outdoor fan
When the temperature of indoor coil thermistor RT12 goes to 131°F or more, the outdoor fan is turned OFF.
When the temperature of indoor coil thermistor RT12 becomes to 126°F or less, the outdoor fan is turned ON.
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