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SPLIT-TYPE AIR CONDITIONERS
OUTDOOR UNIT
SERVICE MANUAL
No. OBH686
HFC
utilized
R410A
Models
MUZ-HE09NA
MUZ-HE12NA
MUZ-HE15NA
MUZ-HE18NA
MUZ-HE24NA
Indoor unit service manual
MSZ-HE•NA Series (OBH685)
CONTENTS
MUZ-HE09NA
MUZ-HE12NA
MUZ-HE15NA
1. TECHNICAL CHANGES ··································· 2
2. PART NAMES AND FUNCTIONS ····················· 3
3. SPECIFICATION ················································ 4
4. OUTLINES AND DIMENSIONS ························ 7
5. WIRING DIAGRAM·········································· 10
6. REFRIGERANT SYSTEM DIAGRAM ············· 13
7. DATA ································································ 16
8. ACTUATOR CONTROL ··································· 30
9. SERVICE FUNCTIONS ··································· 31
10. TROUBLESHOOTING ····································· 31
11. DISASSEMBLY INSTRUCTIONS ···················· 52
NOTE:
RoHS compliant products have <G> mark on the spec name plate.
PARTS CATALOG (OBB686)
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.
1
TECHNICAL CHANGES
MUZ-HE09NA
MUZ-HE12NA
MUZ-HE15NA
MUZ-HE18NA
MUZ-HE24NA
1. New model
OBH686
2
2
PART NAMES AND FUNCTIONS
MUZ-HE09NA MUZ-HE12NA MUZ-HE15NA
Air inlet
(back and side)
Piping
Drain hose
Air outlet
Drain outlet
MUZ-HE18NA
Air inlet
(back and side)
Piping
Drain hose
Air outlet
Drain outlet
MUZ-HE24NA
Air inlet
(back and side)
Piping
Drain hose
Air outlet
Drain outlet
OBH686
3
3
SPECIFICATION
Outdoor unit model
Capacity
Rated (Minimum~Maximum)
MUZ-HE09NA
Cooling 1
Btu/h
Heating 47 1
Btu/h
Cooling 1
W
Heating 47 1
W
EER 1 [SEER] 2
Cooling
HSPF IV 3
Heating
COP
Heating 1
Power supply
V , phase , Hz
Max. fuse size (time delay)
A
Min. circuit ampacity
A
Fan motor
F.L.A
Model
R.L.A
Compressor
L.R.A
Power consumption
Rated
Refrigeration oil
(Model)
MUZ-HE15NA
MUZ-HE18NA
14,000
17,200
9,000
12,000
( 3,800 ~ 10,000 ) ( 3,800 ~ 12,200 ) ( 3,100 ~ 16,000 ) ( 3,700 ~ 18,000 )
18,000
18,000
10,900
12,200
( 4,500 ~ 11,800 ) ( 5,500 ~ 14,500 ) ( 4,800 ~ 18,500 ) ( 3,500 ~ 20,900 )
750
1,210
1,170
1,640
900
990
1,600
1,590
12.0 [ 18.0 ]
9.9 [ 18.0 ]
12.0 [ 18.0 ]
10.5 [ 18.0 ]
8.5
3.55
3.61
3.30
3.32
208/230 , 1 , 60
15
12
14
0.50
0.93
KNB073FQDHC KNB092FQAHC
SNB130FQBHT
6.6
7.4
10.0
8.2
9.3
12.5
L
MUZ-HE12NA
0.32 (NEO22)
Refrigerant control
Sound level 1
Cooling
Heating
dB(A)
dB(A)
Linear expansion valve
49
51
Reverse cycle
31-1/2
11-1/4
21-5/8
77
80
Munsell 3Y 7.8/1.1
Wireless type
12 - 24
Not supplied
1/4 (0.0315)
46
50
Defrost method
Dimensions
W
D
H
Weight
External finish
Remote controller
Control voltage (by built-in transformer)
Refrigerant piping
Refrigerant pipe size Liquid
(Min. wall thickness) Gas
Indoor
Connection method
Outdoor
Between the indoor & Height difference
outdoor units
Piping length
Refrigerant charge (R410A)
in.
in.
in.
Ib.
66
VDC
in.
in.
0.45 (NEO22)
3/8 (0.0315)
33-1/16
13
33-7/16
119
1/2 (0.0315)
Flared
Flared
ft.
ft.
40
65
1 lb. 12 oz.
2 lb. 9 oz.
NOTE: Test conditions are based on AHRI 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
OBH686
54
56
4
50
100
3 lb. 7 oz.
Outdoor unit model
Capacity
Rated (Minimum~Maximum)
Cooling 1
Btu/h
Heating 47 1
Btu/h
Cooling 1
W
Heating 47 1
W
EER 1 [SEER] 2
Cooling
HSPF IV 3
Heating
COP
Heating 1
Power supply
V , phase , Hz
Max. fuse size (time delay)
A
Min. circuit ampacity
A
Fan motor
F.L.A
Model
R.L.A
Compressor
L.R.A
Power consumption
Rated
Refrigeration oil
(Model)
Refrigerant control
Sound level 1
Cooling
Heating
Defrost method
Dimensions
W
D
H
Weight
External finish
Remote controller
Control voltage (by built-in transformer)
Refrigerant piping
Refrigerant pipe size Liquid
(Min. wall thickness) Gas
Indoor
Connection method
Outdoor
Between the indoor & Height difference
outdoor units
Piping length
Refrigerant charge (R410A)
L
MUZ-HE24NA
22,500
(8,200 ~ 22,500)
26,600
(7,500 ~ 30,000)
2,620
2,150
8.6 [18.0]
8.5
3.62
208/230 , 1 , 60
20
17.1
0.93
SNB172FQKMT
12.9
16.1
0.40 (FV50S)
Linear expansion valve
55
55
Reverse cycle
in.
33-1/16
in.
13
in.
34-5/8
Ib.
119
Munsell 3Y 7.8/1.1
Wireless type
VDC
12-24
Not supplied
in.
3/8 (0.0315)
in.
5/8 (0.0315)
Flared
Flared
ft.
50
ft.
100
4 lb. 3 oz.
dB(A)
dB(A)
NOTE: Test conditions are based on AHRI 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
OBH686
5
Test condition
2, 3
ARI
Mode
Indoor air condition (°F)
Dry bulb
Wet bulb
Test
Outdoor air condition (°F)
Dry bulb
Wet bulb
"A-2" Cooling Steady State
at rated compressor Speed
80
67
95
(75)
"B-2" Cooling Steady State
at rated compressor Speed
80
67
82
(65)
SEER "B-1" Cooling Steady State
(Cooling) at minimum compressor Speed
80
67
82
(65)
"F-1" Cooling Steady State
at minimum compressor Speed
80
67
67
(53.5)
"E-V" Cooling Steady State
at Intermediate compressor Speed 4
80
67
87
(69)
"H1-2" Heating Steady State
at rated compressor Speed
70
60
47
43
"H3-2" Heating
at rated compressor Speed
70
60
17
15
HSPF
"H0-1" Heating Steady State
(Heating)
at minimum compressor Speed
70
60
62
56.5
"H1-1" Heating Steady State
at minimum compressor Speed
70
60
47
43
"H2-V" Heating
at Intermediate compressor Speed 4
70
60
35
33
4: At Intermediate compressor Speed
= ("Cooling rated compressor speed" - "minimum compressor speed") / 3 + "minimum compressor speed".
3-1. OPERATING RANGE
(1) POWER SUPPLY
Rated voltage
Outdoor unit
Guaranteed voltage (V)
208/230 V
1 phase
60 Hz
Min. 187
208
230
Max. 253
(2) OPERATION
Intake air temperature (°F)
Mode
Condition
Standard temperature
Maximum temperature
Cooling
Minimum temperature
Maximum humidity
Standard temperature
Heating Maximum temperature
Minimum temperature
OBH686
Indoor
Outdoor
DB
80
90
67
WB
67
73
57
DB
95
115
14
60
67
60
47
75
-4
78 %
WB
—
—
—
—
70
80
70
6
43
65
-5
4
OUTLINES AND DIMENSIONS
Unit: inch
MUZ-HE09NA MUZ-HE12NA MUZ-HE15NA
REQUIRED SPACE
*1 4 in. or more when front
and sides of the unit are clear
Drain hole ø1-5/8
Air out
. or
13-9/16
11/16
Air in
12 ~ 12-3/4
Air in
Clear *1
1-3/4
15-3/4
4 in
4 in
. or
mo
re
1-9/16
2- 3/8
2
re *
mo
. or
29/32
11-1/4
17/32
*2 When any 2 sides of left, right
and rear of the unit are clear
11-29/32
6-23/32
19-11/16
31-1/2
OBH686
Liquid pipe
Gas pipe
5-7/8
2
11-1/32
13/32
21-5/8
handle
5-15/16
14
8 in
13/16 Oval hole
7/8
e
mor
2-23/32
7
:1/4 (flared)
:3/8 (flared) (HE09/12)
1/2 (flared) (HE15)
in.
or m
ore
Unit: inch
MUZ-HE18NA
*1 20 in. more when front
and sides of the unit are clear
11-25/32
2-19/32
Air in
1-9/16
re
r mo
.o
4 in
2
Drain 3 holes
ø1-5/16
1-11/32
20-9/32
Clear *1
REQUIRED SPACE
4 in
. or
14-3/16
13
Air in
mo
re
2
Air out
19-11/16
33-1/16
4-3/8 × 13/16 slot
n. o
20 i
re *
r mo
14
or m
*2 When any 2 sides of left, right
and rear of the unit are clear
3-3/16
8-11/32
8
2-9/16
3-9/16
35°
30°
16-15/16
33-7/16
4-25/32
OBH686
in.
Liquid:1/4(flared)
Gas :1/2(flared)
ore
MUZ-HE24NA
Unit: inch
*1 20 in. or more when front
and sides of the unit are clear
Clear *1
REQUIRED SPACE
16-7/16
Air in
Drain hole
1-9/16
1-5/8
4 in
mo
ore
or m
re
13
2
14-3/16
. or
.
4 in
ore
Air out
2-holes 13/32 13/16
6-7/8
20
19-11/16
33-1/16
i
rm
n. o
*2
14
in.
or
mo
re
*2 When any 2 sides of left, right
and rear of the unit are clear
3-3/16
4-5/16
Service panel
35
17-25/32
34-5/8
Liquid refrigerant pipe joint
Refrigerant pipe (flared) Ø 3/8
6-1/2
3-29/32
44
Gas refrigerant pipe joint
Refrigerant pipe (flared) Ø 5/8
7-11/16
OBH686
9
5
WIRING DIAGRAM
MUZ-HE09NA MUZ-HE12NA
MUZ-HE15NA
OBH686
10
MUZ-HE18NA
OBH686
11
MUZ-HE24NA
OBH686
12
6
REFRIGERANT SYSTEM DIAGRAM
Unit: inch
MUZ-HE09NA
Refrigerant pipe ø3/8
(with heat insulator)
4-way valve
Muffler
Stop valve
(with service port)
Outdoor
heat
exchanger
Muffler
Discharge
temperature
thermistor
Service port
RT62
Compressor
Service port
Flared connection
Outdoor heat
exchanger
temperature
thermistor
RT68
Ambient
temperature
thermistor
RT65
Defrost
thermistor
RT61
Flared connection
Refrigerant pipe ø1/4
(with heat insulator)
Strainer
#100
Capillary tube
O.D. 0.118 × I.D. 0.079
× 9-7/16
LEV
(ø3.0 × ø2.0 × 240)
R.V. coil
heating ON
cooling OFF
Stop valve
(with strainar)
Refrigerant flow in cooling
Refrigerant flow in heating
MUZ-HE12NA MUZ-HE15NA
Refrigerant pipe ø3/8 (HE12NA)
Refrigerant pipe ø1/2 (HE15NA)
(with heat insulator)
Muffler
Stop valve
(with service port)
Flared connection
4-way valve
Discharge
temperature
thermistor
RT62
Outdoor
heat
exchanger
Muffler
Service port
Compressor
Service port
Flared connection
Refrigerant pipe ø1/4
(with heat insulator)
OBH686
Defrost
thermistor
RT61
Capillary tube
O.D. 0.118 × I.D. 0.079
LEV
× 9-7/16
(ø3.0 × ø2.0 × 240)
Stop valve
(with strainar)
Outdoor heat
exchanger
temperature
thermistor
RT68
Capillary tube
O.D. 0.118 × I.D. 0.071
× 23-5/8
(ø3.0 × ø1.8 × 600) (×2)
Ambient
temperature
thermistor
RT65
Strainer
#100
R.V. coil
heating ON
cooling OFF
Refrigerant flow in cooling
Refrigerant flow in heating
13
Unit: inch
MUZ-HE18NA
Muffler
4-way valve #100
Refrigerant pipe ø1/2
(with heat insulator)
Stop valve
(with service port)
Service port
Flared connection
Service port
Discharge
temperature
thermistor
RT62
Defrost
thermistor
RT61
Outdoor
heat
exchanger
Ambient
temperature
thermistor
RT65
Compressor
Outdoor heat
exchanger
temperature
thermistor
RT68
Flared connection
LEV
Receiver
Refrigerant pipe ø1/4
(with heat insulator)
Stop valve
(with strainar)
Strainer
#100
R.V. coil
heating ON
cooling OFF
Capillary tube
O.D. 0.142 × I.D. 0.094
× 1-31/32
(ø3.6×ø2.4×50)
Refrigerant flow in cooling
Refrigerant flow in heating
MUZ-HE24NA
Refrigerant pipe ø5/8
(with heat insulator)
Muffler
4-way valve #100
Service
port
Stop valve
(with service port)
Flared connection
Discharge
temperature
Service thermistor
RT62
Defrost
thermistor
RT61
port
Outdoor
heat
exchanger
Ambient
temperature
thermistor
RT65
Compressor
Outdoor heat
exchanger
temperature
thermistor
RT68
Flared connection
Strainer
#100
Stop valve
Refrigerant pipe ø3/8
(with heat insulator)
OBH686
LEV
Strainer
#100
Capillary tube
O.D.0.157 × I.D.0.094
× 3-15/16
(ø4.0×ø2.4×100)
14
R.V. coil
heating ON
cooling OFF
Refrigerant flow in cooling
Refrigerant flow in heating
MAX. REFRIGERANT PIPING LENGTH and MAX. HEIGHT DIFFERENCE
Refrigerant piping: ft.
Max. Length
Max. Height difference
A
B
Model
40
Piping size O.D: in.
Gas
Liquid
3/8 (HE09/12)
1/2 (HE15)
1/4
MUZ-HE09/12/15NA
65
MUZ-HE18NA
100
50
1/2
MUZ-HE24NA
100
50
5/8
3/8
Indoor
unit
Max. Height
difference
B
Max. Length
A
Outdoor unit
ADDITIONAL REFRIGERANT CHARGE (R410A: oz.)
NOTE: Refrigerant piping exceeding 25 ft. requires additional refrigerant charge according to the calculation.
Model
MUZ-HE09NA
MUZ-HE12NA
MUZ-HE15NA
Outdoor unit
precharged
Refrigerant piping length (one way): ft.
40
50
60
25
30
0
1.62
65
1 lb. 12 oz.
2 lb. 9 oz.
4.86
8.10
11.34
12.96
Calculation: X oz. = 1.62/5 oz. / ft. × (Refrigerant piping length (ft.) - 25)
Model
MUZ-HE18NA
Outdoor unit
precharged
3 lb. 7 oz.
25
0
30
1.08
Refrigerant piping length (one way): ft.
40
50
60
70
80
3.24
5.40
7.56
9.72
11.88
90
14.04
100
16.20
Calculation: X oz. = 1.08/5 oz. / ft. × (Refrigerant piping length (ft.) - 25)
NOTE: Refrigerant piping exceeding 33 ft. requires additional refrigerant charge according to the calculation.
Model
MUZ-HE24NA
Outdoor unit
precharged
4 lb. 3 oz.
33
0
40
4.14
Refrigerant piping length (one way): ft.
50
60
70
80
10.06
15.98
21.90
27.82
90
33.74
100
39.66
Calculation: X oz. = 2.96/5 oz. / ft. × (Refrigerant piping length (ft.) - 33)
OBH686
15
7
DATA
7-1. PERFORMANCE DATA
1) COOLING CAPACITY
MUZ-HE09NA MUZ-HE12NA MUZ-HE15NA MUZ-HE18NA MUZ-HE24NA
Indoor air
Model
MUZ-HE09NA
MUZ-HE12NA
MUZ-HE15NA
MUZ-HE18NA
MUZ-HE24NA
IWB (˚F)
71
67
63
71
67
63
71
67
63
71
67
63
71
67
63
TC
11.0
10.4
9.8
14.7
13.9
13.1
17.2
16.2
15.3
21.1
20.0
18.7
27.6
26.1
24.5
75
SHC
7.6
8.6
9.4
9.4
10.7
11.8
11.1
12.7
13.9
12.2
14.2
15.8
17.0
19.6
21.7
TPC
0.67
0.63
0.60
1.08
1.02
0.97
1.04
0.98
0.94
1.46
1.38
1.31
2.33
2.20
2.10
TC
10.3
9.7
9.1
13.7
13.0
12.1
16.0
15.1
14.1
19.7
18.6
17.4
25.8
24.3
22.7
Outdoor intake air DB temperature (˚F)
85
95
105
SHC TPC TC SHC TPC TC SHC
7.1 0.73 9.7 6.6 0.79 9.0 6.2
8.0 0.69 9.0 7.4 0.75 8.4 6.9
8.7 0.66 8.5 8.1 0.72 7.7 7.3
8.7 1.18 12.9 8.2 1.27 12.0 7.6
10.0 1.12 12.0 9.2 1.21 11.2 8.6
10.9 1.07 11.3 10.2 1.16 10.3 9.3
10.4 1.14 15.1 9.7 1.23 14.0 9.1
11.8 1.08 14.0 10.9 1.17 13.0 10.2
12.9 1.04 13.2 12.0 1.12 12.0 10.9
11.4 1.60 18.5 10.7 1.72 17.2 9.9
13.2 1.52 17.2 12.2 1.64 16.0 11.4
14.7 1.45 16.2 13.6 1.57 14.7 12.4
15.9 2.55 24.2 14.9 2.75 22.5 13.9
18.2 2.42 22.5 16.9 2.62 20.9 15.7
20.1 2.32 21.1 18.7 2.50 19.2 17.0
NOTE: 1. IWB: Intake air wet-bulb temperature
TC: Total Capacity (×103 Btu/h)
SHC: Sensible Heat Capacity (×103 Btu/h)
TPC: Total Power Consumption (kW)
2. SHC is based on 80˚F of indoor Intake air DB temperature.
2) COOLING CAPACITY CORRECTIONS
Model
MUZ-HE09NA
MUZ-HE12NA
MUZ-HE15NA
MUZ-HE18NA
MUZ-HE24NA
OBH686
Refrigerant piping length (one way: ft.)
25 (std.)
40
65
100
1.0
0.954
0.878
—
1.0
0.954
0.878
0.771
16
TPC
0.83
0.80
0.77
1.34
1.28
1.23
1.29
1.24
1.19
1.81
1.74
1.67
2.90
2.78
2.67
TC
8.3
7.7
7.0
11.0
10.3
9.4
12.9
12.0
10.9
15.8
14.7
13.4
20.7
19.2
17.6
115
SHC
5.7
6.3
6.7
7.0
7.9
8.5
8.3
9.3
10.0
9.1
10.4
11.3
12.8
14.4
15.5
TPC
0.86
0.83
0.80
1.39
1.34
1.28
1.35
1.30
1.24
1.89
1.82
1.74
3.01
2.91
2.78
3) HEATING CAPACITY
Indoor air
Model
MUZ-HE09NA
MUZ-HE12NA
MUZ-HE15NA
MUZ-HE18NA
MUZ-HE24NA
IDB (˚F)
75
70
65
75
70
65
75
70
65
75
70
65
75
70
65
5
TC
4.8
5.2
5.5
5.4
5.8
6.1
7.9
8.6
9.0
7.9
8.6
9.0
11.7
12.6
13.3
TPC
0.53
0.51
0.49
0.58
0.56
0.53
0.94
0.90
0.86
0.94
0.90
0.86
1.27
1.21
1.16
15
TC TPC
6.3 0.67
6.7 0.65
6.9 0.62
7.1 0.74
7.5 0.71
7.7 0.68
10.4 1.19
11.1 1.15
11.3 1.10
10.4 1.18
11.1 1.14
11.3 1.10
15.4 1.60
16.4 1.55
16.8 1.48
Outdoor intake air WB temperature (˚F)
25
35
43
TC TPC TC TPC TC TPC
7.9 0.79 9.4 0.88 10.6 0.92
8.2 0.77 9.6 0.86 10.9 0.90
8.6 0.74 10.0 0.83 11.2 0.88
8.8 0.87 10.6 0.97 11.9 1.01
9.2 0.85 10.8 0.94 12.2 0.99
9.6 0.82 11.2 0.92 12.6 0.97
13.1 1.40 15.6 1.56 17.6 1.64
13.5 1.37 15.9 1.52 18.0 1.60
14.1 1.32 16.5 1.48 18.5 1.56
13.1 1.39 15.6 1.55 17.6 1.63
13.5 1.36 15.9 1.51 18.0 1.59
14.1 1.31 16.5 1.47 18.5 1.55
19.3 1.88 23.0 2.10 25.9 2.20
20.0 1.84 23.5 2.04 26.6 2.15
20.9 1.77 24.3 1.99 27.4 2.10
45
TC TPC
11.0 0.94
11.2 0.92
11.6 0.89
12.3 1.03
12.6 1.01
12.9 0.98
18.1 1.66
18.5 1.63
19.1 1.58
18.1 1.65
18.5 1.62
19.1 1.57
26.7 2.24
27.4 2.19
28.2 2.13
55
TC TPC
12.4 0.97
12.7 0.95
13.0 0.94
13.9 1.07
14.2 1.05
14.5 1.03
20.5 1.73
21.0 1.70
21.4 1.66
20.5 1.72
21.0 1.69
21.4 1.65
30.3 2.32
31.0 2.28
31.7 2.24
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.
How to operate with fixed operational frequency of the compressor.
1. Press the EMERGENCY OPERATION switch on the front of the indoor unit, and select either EMERGENCY COOL
mode or EMERGENCY HEAT mode before starting to operate the air conditioner.
2. The compressor starts with operational frequency.
3. The fan speed of the indoor unit is High.
4. This operation continues for 30 minutes.
5. In order to release this operation, press the EMERGENCY OPERATION switch twice or once, or press any button on
the remote controller.
OBH686
17
7-2. PERFORMANCE CURVE
Cooling
Capacity correction factors
Indoor air Wet-bulb temperature
difference (°F)
Cooling capacity (at Rated frequency)
1.5
Indoor intake air WB
temperature( F)
1.4
1.3
1.2
79
1.1
75
1.0
0.9
14
23
32
41
50
59
68
77
86
95
104
72
68
64
113
Outdoor intake air DB temperature(°F)
0.9
71
67
63
0.8
0.7
0.6
0.5
0.4
65
B
e air W
r intak
Indoo
rature
tempe
(°F)
75
85
95
105
Outdoor intake air DB temperature (°F)
115
Total power consumption
(kW)
MUZ-HE15NA
1.4
71
67
63
1.2
1.1
0.9
0.8
65
1.5
SHF at rating condition = 0.74
Airflow = 367 CFM
71
67
63
1.4
1.3
1.2
1.1
1.0
0.9
65
75
85
95
105
Outdoor intake air DB temperature (°F)
)
re (°F
peratu
B tem
e air W
r intak
Indoo
75
85
95
105
Outdoor intake air DB temperature (°F)
115
2.0
Total power consumption
(kW)
SHF at rating condition = 0.75
Airflow = 634 CFM
B
e air W
r intak
Indoo
71
67
63
1.8
1.6
1.4
1.2
1.0
65
rature
tempe
75
85
95
105
Outdoor intake air DB temperature (°F)
(°F)
115
18
)
re (°F
peratu
B tem
e air W
r intak
Indoo
71
67
63
75
85
95
105
Outdoor intake air DB temperature (°F)
OBH686
115
SHF at rating condition = 0.71
Airflow = 498 CFM
MUZ-HE24NA
3.1
2.9
2.7
2.5
2.3
2.1
1.9
1.7
1.5
1.3
65
F)
ture (°
mpera
B te
e air W
r intak
Indoo
MUZ-HE18NA
SHF at rating condition = 0.8
Airflow = 498 CFM
1.3
1.0
Total power consumption
(kW)
1.0
MUZ-HE12NA
SHF at rating condition = 0.82
Airflow = 367 CFM
Total power consumption
(kW)
Total power consumption
(kW)
MUZ-HE09NA
115
Heating
Heating capacity (at Rated frequency)
59
68
79
Capacity correction factor
Indoor air Dry-bulb temperature
difference (°F)
1.3
1.2
1.1
1.0
0.9
e
tak
r in
oo
d
n
I
0.8
e(
tur
era
p
tem
DB
air
F)
0.7
0.6
0.5
0.4
-4
5
14
23
32
41
50
Outdoor intake air WB temperature (°F)
59
Total power consumption
(kW)
MUZ-HE09NA
Airflow = 413 CFM
1.1
75
70
65
0.9
0.7
0.5
0.3
take air
Indoor in
0
F)
rature (°
DB tempe
10
20
30
40
50
60
Outdoor intake air WB temperature (°F)
70
Total power consumption
(kW)
MUZ-HE12NA
1.2
1.1
1.0
0.9
0.8
0.7
0.6
0.5
0.4
Airflow = 413 CFM
75
70
65
take air
Indoor in
0
F)
rature (°
DB tempe
10
20
30
40
50
60
Outdoor intake air WB temperature (°F)
70
Total power consumption
(kW)
MUZ-HE15NA
Airflow = 463 CFM
2.1
75
70
65
1.8
1.5
1.2
0.9
0.6
take
Indoor in
0
re (°F)
mperatu
air DB te
10
20
30
40
50
60
Outdoor intake air WB temperature (°F)
70
This value of frequency is not the same as the actual frequency in operating. Refer to 7-5 and 7-6 for the relationships
between frequency and capacity.
OBH686
19
Total power consumption
(kW)
MUZ-HE18NA
Airflow = 512 CFM
2.0
75
70
65
1.8
1.6
1.4
1.2
0.8
re (°F)
mperatu
air DB te
take
Indoor in
1.0
0
10
20
30
40
50
60
Outdoor intake air WB temperature (°F)
70
Total power consumption
(kW)
MUZ-HE24NA
Airflow = 738 CFM
2.5
2.1
75
70
65
1.7
1.3
take
Indoor in
0.9
0.5
0
re (°F)
mperatu
air DB te
10
20
30
40
50
60
Outdoor intake air WB temperature (°F)
70
This value of frequency is not the same as the actual frequency in operating. Refer to 7-5 and 7-6 for the relationships
between frequency and capacity.
7-3. CONDENSING PRESSURE
Cooling
Data is based on the condition of indoor humidity 50 %.
Air flow should be set to High speed.
MUZ-HE09NA
(PSIG)
200
400
rature (°F)
Indoor DB tempe
°F)
oor
Ind
75
80
te
DB
85
(
ture
era
mp
320
75
70
160
140
90
95
120
68 70
100 105(°F)
Outdoor ambient temperature
OBH686
80
180
360
280
68 70
86
86
80
75
70
Suction pressure
Condensing pressure
(PSIG)
440
75
80
85
90
95
Outdoor ambient temperature
20
100 105(°F)
MUZ-HE12NA
(PSIG)
190
86
80
75
70
380
340
ture
a
per
D
oor
Ind
75
80
)
(°F
m
B te
300
260
68 70
86
170
Suction pressure
Condensing pressure
(PSIG)
420
85
D
oor
Ind
75
mp
B te
150
80
°F)
re (
tu
era
70
130
95
90
110
68 70
100 105(°F)
Outdoor ambient temperature
75
80
85
90
95
100 105(°F)
Outdoor ambient temperature
MUZ-HE15NA
(PSIG)
200
86
80
75
70
400
360
320
or
ndo
°F)
re (
atu
er
mp
te
DB
86
180
Suction pressure
Condensing pressure
(PSIG)
440
Indoor DB
)
temperature (°F
80
75
160
70
140
I
280
68 70
75
80
85
90
95
120
68 70
100 105(°F)
75
Outdoor ambient temperature
80
85
90
95
100 105(°F)
Outdoor ambient temperature
MUZ-HE18NA
)
390
350
or
o
Ind
DB
(°F
310
270
68 70
80
75
70
130
75
80
85
90
95
100
68 70
100 105(°F)
m
B te
D
oor
Ind
75
80
85
atu
per
90
95
Outdoor ambient temperature
21
°F)
re (
115
Outdoor ambient temperature
OBH686
86
145
r
pe
tem
re
atu
(PSIG)
160
86
80
75
70
Suction pressure
Condensing pressure
(PSIG)
430
100 105(°F)
MUZ-HE24NA
(PSIG)
480
390
B
rD
o
do
)
°F
e(
ur
rat
e
mp
te
In
360
86
170
Suction pressure
Condensing pressure
450
420
(PSIG)
180
86
80
75
70
330
300
160
80
150
75
140
70
130
Indoor DB temperature (°F)
120
270
68 70
75
80
85
95
90
110
68 70
100 105(°F)
75
Outdoor ambient temperature
80
85
90
95
Outdoor ambient temperature
Heating
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.
MUZ-HE09NA
(PSIG)
370
(PSIG)
210
75
70
65
or
ndo
m
B te
r
atu
per
320
D
I
295
270
58Hz
245
220
5
15
25
35
185
F)
e (°
Suction pressure
Condensing pressure
345
45
55
65
160
135
oor
Ind
DB
er
mp
°F)
re (
atu
te
110
58Hz
85
75(°F)
60
5
Outdoor ambient temperature
OBH686
75
70
65
15
25
35
45
55
Outdoor ambient temperature
22
65
75(°F)
100 105(°F)
MUZ-HE12NA
(PSIG)
460
(PSIG)
Suction pressure
Condensing pressure
)
°F
e(
r
atu
er
380
340
B
rD
oo
Ind
p
tem
185
75
70
65
420
58Hz
300
260
75
70
65
210
160
°F)
re (
atu
r
e
mp
B te
or D
o
d
In
135
110
58Hz
85
5
15
25
35
45
55
60
75(°F)
65
5
15
Outdoor ambient temperature
25
35
45
55
65
75(°F)
Outdoor ambient temperature
MUZ-HE15NA
(PSIG)
(PSIG)
440
404
re
atu
per
tem
B
D
oor
Ind
368
185
(
332
160
ture
a
per
m
B te
135
)
(°F
D
oor
Ind
110
54Hz
296
260
75
70
65
°F)
Suction pressure
Condensing pressure
210
75
70
65
54Hz
85
5
15
25
35
45
55
60
75(°F)
65
5
15
Outdoor ambient temperature
25
35
45
55
65
75(°F)
Outdoor ambient temperature
MUZ-HE18NA
(PSIG)
500
(PSIG)
75
70
65
475
)
425
re
atu
r
pe
400
B
D
or
(°F
tem
o
Ind
185
Suction pressure
Condensing pressure
450
375
75
70
65
210
)
160
ra
135
or
o
nd
DB
pe
e
r
tu
(°F
m
te
I
110
350
58Hz
325
300
5
15
25
35
45
55
65
75(°F)
60
Outdoor ambient temperature
OBH686
58Hz
85
5
15
25
35
45
55
Outdoor ambient temperature
23
65
75(°F)
MUZ-HE24NA
(PSIG)
450
(PSIG)
210
75
70
65
425
°
e(
tur
a
er
or
o
Ind
350
DB
tem
170
)
p
375
190
Suction pressure
Condensing pressure
400
F)
75
70
65
325
300
150
r
130
or
o
nd
DB
pe
re
u
at
(°F
m
te
I
110
90
58Hz
58Hz
275
250
70
5
15
25
35
45
55
65
75(°F)
50
Outdoor ambient temperature
OBH686
5
15
25
35
45
55
Outdoor ambient temperature
24
65
75(°F)
7-4. STANDARD OPERATION DATA
Model
MSZ-HE09NA
Item
Total
Capacity
MSZ-HE12NA
Unit
Cooling
Heating
Cooling
Heating
Btu/h
9,000
10,900
12,000
14,400
SHF
-
0.82
—
0.77
—
Input
kW
0.750
0.900
1.210
0.990
Rated frequency
Hz
59.5
77.5
69.0
77.0
Indoor unit
MSZ-HE09NA
MSZ-HE12NA
Refrigerant circuit
Electrical circuit
Power supply (V, Phase, Hz)
Input
Fan motor current
0.022
0.023
0.022
0.023
A
0.24/0.22
0.25/0.23
0.24/0.22
0.25/0.23
MUZ-HE09NA
MUZ-HE12NA
Power supply (V, phase, Hz)
208/230, 1, 60
Input
kW
0.728
0.877
1.188
0.967
Comp. current
A
3.32/3.00
3.66/3.31
4.39/3.97
5.41/4.89
Fan motor current
A
0.27/0.24
0.30/0.27
0.34/0.31
0.31/0.28
Condensing pressure
PSIG
389
331
389
397
Suction pressure
PSIG
151
103
133
104
Discharge temperature
°F
154
152
163
162
Condensing temperature
°F
115
103
115
116
Suction temperature
°F
59
39
56
35
Comp. shell bottom temp
°F
151
149
158
158
Ref. pipe length
ft.
Refrigerant charge (R410A)
-
Discharge air temperature
DB
80
2 lb. 9 oz.
70
80
70
°F
67
60
67
60
DB
°F
60
97
56
108
WB
Fan speed (High)
Intake air temperature
°F
25
1 lb. 12 oz.
WB
Airflow (High)
Outdoor unit
kW
Outdoor unit
Intake air temperature
Indoor unit
208/230, 1, 60
DB
58
—
55
—
1,020
1,040
1,020
1,040
CFM
367 (Wet)
413
367 (Wet)
413
°F
95
47
95
47
°F
—
43
—
43
Fan speed
rpm
800
850
900
860
Airflow
CFM
1151
1225
1229
1172
OBH686
WB
°F
rpm
25
Model
MSZ-HE15NA
Item
Total
Capacity
MSZ-HE18NA
Unit
Cooling
Heating
Cooling
Heating
Btu/h
14,000
18,000
17,200
18,000
SHF
-
0.78
—
0.71
—
Input
kW
1.170
1.600
1.640
1.590
Rated frequency
Hz
55.5
74.0
83.0
84.0
Indoor unit
MSZ-HE15NA
MSZ-HE18NA
Electrical circuit
Power supply (V, Phase, Hz)
208/230, 1, 60
Input
Fan motor current
Refrigerant circuit
0.030
0.043
0.039
0.50/0.45
0.35/0.32
0.43/0.39
0.40/0.36
MUZ-HE15NA
MUZ-HE18NA
Power supply (V, phase, Hz)
208/230, 1, 60
Input
Fan motor current
kW
1.127
1.570
1.597
1.551
A
4.86/4.40
7.38/6.67
6.97/6.29
8.36/7.55
A
0.33/0.30
0.34/0.31
0.80/0.72
0.64/0.59
Condensing pressure
PSIG
400
431
376
458
Suction pressure
PSIG
139
99
117
102
Discharge temperature
°F
164
179
177
184
Condensing temperature
°F
117
122
112
127
Suction temperature
°F
57
31
59
33
Comp. shell bottom temp
°F
148
165
164
170
Ref. pipe length
ft.
Refrigerant charge (R410A)
-
Intake air temperature
Indoor unit
0.043
A
Outdoor unit
Comp. current
Discharge air temperature
3 lb. 7 oz.
DB
°F
80
70
80
70
°F
67
60
67
60
DB
°F
60
114
56
117
WB
°F
57
—
54
—
rpm
1,280
1,140
1,280
1,240
CFM
498 (Wet)
463
498 (Wet)
512
°F
95
47
95
47
Fan speed (High)
Intake air temperature
25
2 lb. 9 oz.
WB
Airflow (High)
Outdoor unit
kW
DB
°F
—
43
—
43
Fan speed
rpm
910
900
780
740
Airflow
CFM
1,243
1,229
1,730
1,659
OBH686
WB
26
Model
MSZ-HE24NA
Item
Electrical circuit
Total
Capacity
Refrigerant circuit
Heating
22,500
26,600
-
0.75
—
Input
kW
2.620
2.150
Rated frequency
Hz
66.5
82.0
Indoor unit
MSZ-HE24NA
Power supply (V, Phase, Hz)
208/230, 1, 60
Input
Fan motor current
kW
0.058
A
0.56/0.51
Outdoor unit
MUZ-HE24NA
Power supply (V, phase, Hz)
208/230, 1, 60
Input
Fan motor current
kW
2.562
2.092
A
7.01/6.34
9.59/8.67
A
1.61/1.05
1.13/1.02
Condensing pressure
PSIG
395
405
Suction pressure
PSIG
141
102
Discharge temperature
°F
158
Condensing temperature
°F
171
115
Suction temperature
°F
52
33
Comp. shell bottom temp
°F
140
148
Ref. pipe length
ft.
25
Refrigerant charge (R410A)
-
4 lb. 3 oz.
Intake air temperature
Indoor unit
Cooling
SHF
Comp. current
Discharge air temperature
DB
°F
80
70
WB
°F
67
60
DB
°F
56
111
WB
°F
53
—
Fan speed (High)
rpm
Airflow (High)
Outdoor unit
Unit
Btu/h
Intake air temperature
DB
CFM
634 (Wet)
738
°F
95
47
°F
—
43
Fan speed
rpm
840
810
Airflow
CFM
1,769
1,701
OBH686
WB
1,300
27
7-5. CAPACITY AND INPUT CORRECTION BY INVERTER OUTPUT FREQUENCY
MUZ-HE09NA
Correction of Cooling capacity
Capacity correction factors
1.5
1.5
Correction of Cooling total input
1.5
Correction of Heating capacity
1.0
1.0
1.0
0.5
0.5
0.5
0.5
0
50
100(Hz)
0
MUZ-HE12NA
Correction of Cooling capacity
Capacity correction factors
1.5
50
100(Hz)
0
50
100
150(Hz)
1.5
Correction of Cooling total input
1.5
Correction of Heating capacity
0
50
100
150(Hz)
The operational frequency of compressor
2.0
Correction of Heating total input
1.5
1.0
1.0
1.0
1.0
0.5
0.5
0.5
0.5
0
50
100(Hz)
0
50
100(Hz)
0
50
100
150(Hz)
The operational frequency of compressor The operational frequency of compressor The operational frequency of compressor
MUZ-HE15NA
Correction of Cooling capacity
1.5
Capacity correction factors
Correction of Heating total input
1.5
1.0
The operational frequency of compressor The operational frequency of compressor The operational frequency of compressor
2.0
Correction of Cooling total input
1.5
Correction of Heating capacity
1.5
0
50
100
150(Hz)
The operational frequency of compressor
2.0
Correction of Heating total input
1.5
1.0
1.0
1.0
1.0
0.5
0.5
0.5
0
50
100(Hz)
0.5
0
50
100(Hz)
0
50
100
150(Hz)
The operational frequency of compressor The operational frequency of compressor The operational frequency of compressor
MUZ-HE18NA
1.5
Capacity correction factors
2.0
Correction of Cooling capacity
1.5
Correction of Cooling total input
1.5
Correction of Heating capacity
0
50
100
150(Hz)
The operational frequency of compressor
2.0
Correction of Heating total input
1.5
1.0
1.0
1.0
1.0
0.5
0.5
0.5
0.5
0
50
100(Hz)
0
50
100(Hz)
0
50
100
150(Hz)
The operational frequency of compressor The operational frequency of compressor The operational frequency of compressor
OBH686
28
0
50
100
150(Hz)
The operational frequency of compressor
MUZ-HE24NA
Capacity correction factors
1.5
Correction of Cooling capacity
1.5
Correction of Cooling total input
1.5
Correction of Heating capacity
1.5
1.0
1.0
1.0
1.0
0.5
0.5
0.5
0.5
0
50
100(Hz)
0
50
100(Hz)
0
50
100(Hz)
The operational frequency of compressor The operational frequency of compressor The operational frequency of compressor
0
Correction of Heating total input
50
100 (Hz)
The operational frequency of compressor
7-6. HOW TO OPERATE FIXED-FREQUENCY OPERATION (Test run operation)
1. Press EMERGENCY OPERATION switch to start COOL or HEAT mode (COOL: Press once, HEAT: Press twice).
2. Test run operation starts and continues to operate for 30 minutes.
3. Compressor operates at rated frequency in COOL mode or 58 Hz in HEAT mode.
4. Indoor fan operates at High speed.
5. After 30 minutes, test run operation finishes and EMERGENCY OPERATION starts (operation frequency of compressor varies).
6. To cancel test run operation (EMERGENCY OPERATION), press EMERGENCY OPERATION switch or any button on
remote controller.
OBH686
29
8
ACTUATOR CONTROL
MUZ-HE09NA MUZ-HE12NA MUZ-HE15NA MUZ-HE18NA MUZ-HE24NA
8-1. OUTDOOR FAN MOTOR CONTROL
The fan motor turns ON/OFF, interlocking with the compressor.
[ON] The fan motor turns ON 5 seconds before the compressor starts up.
[OFF] The fan motor turns OFF 15 seconds after the compressor has stopped running.
5 seconds
15 seconds
ON
Compressor
OFF
ON
Outdoor fan
motor
OFF
8-2. R.V. COIL CONTROL
Heating . . . . . . . . . . . . . . . . . ON
Cooling . . . . . . . . . . . . . . . . . OFF
Dry . . . . . . . . . . . . . . . . . . . . OFF
NOTE: The 4-way valve reverses for 5 seconds right before start-up of the compressor.
<COOL>
<HEAT>
5 seconds
Compressor
ON
OFF
R.V.coil
ON
OFF
5 seconds
Outdoor fan ON
OFF
motor
8-3. RELATION BETWEEN MAIN SENSOR AND ACTUATOR
Sensor
Discharge temperature
thermistor
Indoor coil temperature
thermistor
Defrost thermistor
Fin temperature thermistor
Ambient temperature
thermistor
Outdoor heat exchanger temperature thermistor
OBH686
Purpose
Protection
Cooling: Coil frost prevention
Heating: High pressure protection
Heating: Defrosting
Protection
Cooling: Low ambient temperature operation
Cooling: Low ambient temperature operation
Cooling: High pressure protection
Compressor
LEV
○
○
○
○
○
○
○
○
○
30
○
○
○
○
○
Actuator
Outdoor fan
motor
○
○
○
○
○
R.V.coil
Indoor fan
motor
○
○
9
SERVICE FUNCTIONS
MUZ-HE09NA MUZ-HE12NA MUZ-HE15NA MUZ-HE18NA MUZ-HE24NA
9-1. CHANGE IN DEFROST SETTING
Changing defrost finish temperature
<JS> To change the defrost finish temperature, cut/solder the JS wire of the outdoor inverter P.C. board. (Refer to 10-6.1.)
Jumper
JS
Defrost finish temperature
MUZ-HE09
MUZ-HE12
MUZ-HE15
MUZ-HE18
MUZ-HE18/24
Soldered
(Initial setting)
41°F (5°C)
50°F (10°C)
41°F (5°C)
48°F (9°C)
50°F (10°C)
None
(Cut)
46°F (8°C)
55°F (13°C)
50°F (10°C)
64°F (18°C)
64°F (18°C)
9-2. PRE-HEAT CONTROL SETTING
PRE-HEAT CONTROL
When moisture gets into the refrigerant cycle, it may interfere the start-up of the compressor at low outside temperature.
The pre-heat control prevents this interference. The pre-heat control turns ON when the discharge temperature thermistor
is 68°F (20°C) or below. When pre-heat control turns ON, compressor is energized. (About 50 W)
Pre-heat control setting
<JK> ON: To activate the pre-heat control, cut the JK wire of the inverter P.C. board. (Refer to 10-6.1.)
OFF: To deactivate the pre-heat control, solder JK wire of the inverter P.C. board. (Refer to 10-6.1.)
NOTE: When the inverter P.C. board is replaced, check the Jumper wires, and cut/solder them if necessary.
10
TROUBLESHOOTING
MUZ-HE09NA MUZ-HE12NA MUZ-HE15NA MUZ-HE18NA MUZ-HE24NA
10-1. 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, 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 electrical parts, be careful of the residual voltage of smoothing capacitor.
4) When removing the electronic control P.C. board, hold the edge of the board with care NOT to apply stress on the
components.
5) When connecting or disconnecting the connectors, hold the housing of the connector. DO NOT pull the lead wires.
<Incorrect>
<Correct>
Lead wiring
Housing point
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) Refer to 10-2. and 10-3.
OBH686
31
10-2. 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 (10-3.) disappears, the memorized failure details
can be recalled.
1. Flow chart of failure mode recall function for the indoor/outdoor unit
Operational procedure
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 buttons.
Press OPERATE/STOP (ON/OFF) button of the remote controller (the set temperature
is displayed) with the remote controller headed towards the indoor unit. 1
Does the 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 the upper
lamp of OPERATION INDICATOR lamp. 2
1. Regardless of normal or abnormal condition, a short
beep is emitted once the signal is received.
Indoor unit is normal.
But the outdoor unit might be abnormal because there are some abnormalities that can not be recalled with this way.
Check if outdoor unit is abnormal according to the detailed outdoor unit
failure mode recall function. (Refer to 10-2.2)
No
(OFF)
Yes
(Blinks)
Judgment of indoor/outdoor abnormality
Before blinking, does the upper lamp of OPERATION INDICATOR lamp stay ON for 3 seconds?
Stays ON for 3 seconds (without beep):
The outdoor unit is abnormal.
No
Yes
The outdoor unit is abnormal.
Check the blinking pattern, and identify the abnormal point by referring to
outdoor unit failure mode table. (Refer to 10-2.3)
Make sure to check at least two consecutive blinking cycles. 3
The indoor unit is abnormal.
Check the blinking pattern, and identify the abnormal point by referring to indoor
unit failure mode table. (Refer to indoor unit service manual.)
2
Make sure to check at least two consecutive blinking cycles.
Releasing the failure mode recall function
Release the failure mode recall function by the following procedures.
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) 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.
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:
Blinking at 0.52.5-second OFF second interval
Blinking at 0.52.5-second OFF second interval
ON
OFF
Beeps
Repeated cycle
Beeps
Repeated cycle
Beeps
Repeated cycle
3.Blinking pattern when the outdoor unit is abnormal:
Blinking at 0.52.5-second OFF
3-second ON
second interval
2.5-second OFF
3-second ON
Blinking at 0.5second interval
ON
OFF
No beep
Repeated cycle
OBH686
Beeps
No beep
Repeated cycle
32
Beeps
Repeated cycle
2. Flow chart of the detailed outdoor unit failure mode recall function
Operational procedure
The outdoor unit might be abnormal.
Check if outdoor unit is abnormal according to the following procedures.
Make sure that the remote controller is set to the failure mode recall function.
With the remote controller headed towards the indoor unit, press TOO
COOL or TOO WARM button to adjust the set temperature to 77°F (25°C).
1
Does the upper lamp of OPERATION INDICATOR
lamp on the indoor unit blink at the interval of 0.5
seconds?
Blinks: The outdoor unit is abnormal. Beep is emitted
at the same timing as the blinking of the upper
lamp of OPERATION INDICATOR lamp. 2
Yes
(Blinks)
1. Regardless of normal or abnormal condition, 2 short
beeps are emitted as the signal is received.
No
(OFF)
The outdoor unit is abnormal.
Check the blinking pattern, and identify the abnormal point by referring to
outdoor unit failure mode table (10-2.3.).
Make sure to check at least two consecutive blinking cycles. 2
The outdoor unit is normal.
Releasing the failure mode recall function
Release the failure mode recall function by the following procedures.
Turn OFF the power supply and turn it ON again.
Press RESET button of the remote controller.
Release the failure mode recall function according to the left mentioned procedure.
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" (10-2.1.).
Press OPERATE/STOP (ON/OFF) 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.
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 outdoor unit is abnormal:
2.5-second OFF
ON
OFF
OBH686
3-second ON
No beep
Repeated cycle
Blinking at 0.5second interval
2.5-second OFF
Beeps
3-second ON
No beep
Repeated cycle
33
Blinking at 0.5second interval
Beeps
Repeated cycle
3. Outdoor unit failure mode table
OPERATION
Abnormal point
INDICATOR
(Failure mode / protection)
upper lamp
(Indoor unit)
OFF
None (Normal)
2-time flash Outdoor power system
2.5 seconds
OFF
3-time flash
2.5 seconds
OFF
—
—
Discharge temperature
thermistor
Defrost thermistor
1-time flash every
2.5 seconds
Fin temperature thermistor
3-time flash
2.5 seconds OFF
4-time flash
2.5 seconds OFF
2-time flash
2.5 seconds OFF
P.C. board temperature
thermistor
Ambient temperature
thermistor
Outdoor heat exchanger
temperature thermistor
(MUZ-HE24)
4-time flash
2.5 seconds
OFF
LED indication
(Outdoor P.C. board)
Overcurrent
11-time flash
2.5 seconds OFF
Condition
—
—
Overcurrent protection cut-out operates • Reconnect connectors.
• Refer to 10-5. "How
3 consecutive times within 1 minute
to check inverter/
after the compressor gets started.
compressor".
• Check the stop valve.
• Refer to 10-5. "Check
Thermistor shorts or opens during
compressor running.
of outdoor thermistors".
Defective outdoor
thermistors can be
identified by checking
the blinking pattern of
LED.
Large current flows into intelligent
power module/ power module 1.
12-time flash
Compressor synchronous
abnormality (Compressor start- 2.5 seconds OFF
up failure protection)
Waveform of compressor current is
distorted.
5-time flash
2.5 seconds
OFF
Discharge temperature
Temperature of discharge temperature
thermistor exceeds 241°F (116°C),
compressor stops.
Compressor can restart if discharge
temperature thermistor reads 212°F
(100°C) or less 3 minutes later.
6-time flash
2.5 seconds
OFF
High pressure
7-time flash
2.5 seconds
OFF
Fin temperature/ P.C. board
temperature
8-time flash
2.5 seconds
OFF
Outdoor fan motor
9-time flash
2.5 seconds
OFF
Nonvolatile memory data
—
—
7-time flash
2.5 seconds OFF
—
Power module
(MUZ-HE24NA)
10-time flash Discharge temperature
2.5 seconds
OFF
5-time flash
2.5 seconds OFF
6-time flash
2.5 seconds OFF
—
Remedy
Temperature of indoor coil thermistor
exceeds 158°F (70°C) in HEAT mode.
Temperature of outdoor heat exchanger
temperature thermistor exceeds 158°F
(70°C) in COOL mode.
Temperature of fin temperature
thermistor on the inverter P.C. board
exceeds 167 ~ 176°F (75 ~ 80°C), or
temperature of P.C. board temperature
thermistor on the inverter P.C. board
exceeds 158 ~ 167°F (70 ~ 75°C).
• Reconnect compressor
connector.
• Refer to 10-5. "How
to check inverter/
compressor".
• Check the stop valve.
• Reconnect compressor
connector.
• Refer to 10-5. "How
to check inverter/
compressor".
• Check the refrigerant
circuit and the
refrigerant amount.
• Refer to 10-5. "Check
of LEV".
• Check the refrigerant
circuit and the
refrigerant amount.
• Check the stop valve.
• Check around the
outdoor unit.
• Check the outdoor unit
air passage.
• Refer to 10-5. "Check
of outdoor fan motor".
Outdoor fan has stopped 3 times in a
• Refer to 10-5. "Check
row within 30 seconds after outdoor fan of outdoor fan motor".
start-up.
Refer to 10-5. "Check
of inverter P.C. board".
Nonvolatile memory data cannot be
• Replace the inverter
read properly.
P.C. board.
• Refer to 10-5. "How
The interphase short circuit occurs
to check inverter/
in the output of the intelligent power
compressor".
module (IPM)/power module (IPM) 1.
The compressor winding shorts circuit.
Temperature of discharge temperature • Refer to 10-5. "Check
of LEV".
thermistor has been 122°F (50°C) or
• Check the refrigerant
less for 20 minutes.
circuit and the
refrigerant amount.
NOTE: Blinking patterns of this mode differ from the ones of Troubleshooting check table (10-3.).
1
Intelligent power module: MUZ-HE24NA
Power module: Other models
OBH686
34
Indoor/
Outdoor unit
outdoor unit
failure mode
failure mode
recall function
recall function
—
—
○
○
○
○
—
○
—
○
—
○
—
○
—
○
—
○
○
○
—
○
OPERATION
Abnormal point
INDICATOR
(Failure mode / protection)
upper lamp
(Indoor unit)
11-time flash DC voltage
2.5 seconds
OFF
Each phase current of
compressor
12-time flash Overcurrent Compressor open2.5 seconds phase
OFF
14-time flash Stop valve (Closed valve)
2.5 seconds
OFF
4-way valve/
Pipe temperature
LED indication
(Outdoor P.C. board)
8-time flash
2.5 seconds OFF
9-time flash
2.5 seconds OFF
10-time flash
2.5 seconds OFF
Condition
DC voltage of inverter cannot be
detected normally.
Each phase current of compressor
cannot be detected normally.
Large current flows into intelligent
power module (IPM)/power module
(IPM) 1.
The open-phase operation of
compressor is detected.
The interphase short circuit occurs
in the output of the intelligent power
module (IPM)/power module (IPM) 1.
The compressor winding shorts circuit.
Remedy
• Refer to 10-5. "How
to check inverter/
compressor".
—
○
• Reconnect compressor
connector.
• Refer to 10-5. "How
to check inverter/
compressor".
—
○
○
○
14-time flash
2.5 seconds OFF
Closed valve is detected by compressor • Check the stop valve
current.
16-time flash
2.5 seconds OFF
The 4-way valve does not work
properly.
The indoor coil thermistor detects an
abnormal temperature.
• Check the 4-way valve.
• Replace the inverter
P.C. board.
NOTE: Blinking patterns of this mode differ from the ones of Troubleshooting check table (10-3.).
1
Intelligent power module: MUZ-HE24NA
Power module: Other models
OBH686
35
Indoor/
Outdoor unit
outdoor unit
failure mode
failure mode
recall function
recall function
10-3. TROUBLESHOOTING CHECK TABLE
No. Symptom
1
Outdoor
unit does
not operate.
2
3
Abnormal point/
Condition
Remedy
Condition
1-time flash every Outdoor power sys- Overcurrent protection cut-out operates 3 consecutive times with- • Reconnect connector of compressor.
2.5 seconds
tem
in 1 minute after the compressor gets started, or failure of restart • Refer to 10-5. "How to check inverter/
compressor".
of compressor has repeated 24 times.
• Check the stop valve.
Outdoor thermistors Discharge temperature thermistor, fin temperature thermistor, de- • Refer to 10-5. "Check of outdoor
frost thermistor, outdoor heat exchanger temperature thermistor, thermistors".
P.C. board temperature thermistor or ambient temperature thermistor shorts or opens during compressor running.
• Replace inverter P.C. board.
Outdoor control sys- Nonvolatile memory data cannot be read properly.
tem
(The upper lamp of OPERATION INDICATOR of the indoor unit
lights up or flashes 7 times.)
LED indication
Serial signal
6
6-time flash
2.5 seconds OFF
11-time flash
2.5 seconds OFF
14-time flash
2.5 seconds OFF
7
16-time flash
4-way valve/
2.5 seconds OFF Pipe temperature
4
5
'Outdoor
unit stops
8 and restarts 3
minutes
later' is
repeated.
9
10
11
12
Stop valve/
Closed valve
Outdoor unit
(Other abnormality)
• Refer to 10-2.2. "Flow chart of the detailed outdoor unit failure mode recall
function".
The 4-way valve does not work properly.
The indoor coil thermistor detects an abnormal temperature.
• Refer to 10-5. "Check of R.V. coil".
• Replace the inverter P.C. board.
• Check around the outdoor unit.
• Check the outdoor unit air passage.
• Refer to 10-5. "Check of outdoor fan
motor".
• Check the refrigerant circuit and the
refrigerant amount.
• Check the stop valve.
The waveform of compressor current is distorted.
8-time flash
Compressor syn2.5 seconds OFF chronous abnormality
• Reconnect connector of the compressor.
• Refer to 10-5. "How to check inverter/
compressor".
12-time flash
2.5 seconds OFF
13-time flash
15
2.5 seconds OFF
Outdoor 1-time flash
16 unit oper- 2.5 seconds OFF
ates.
3-time flash
2.5 seconds OFF
17
Each phase current
of compressor
DC voltage
Frequency drop by
current protection
Frequency drop by
high pressure protection
Frequency drop by
defrosting in COOL
mode
4-time flash
Frequency drop by
2.5 seconds OFF discharge temperature protection
Outdoor fan has stopped 3 times in a row within 30 seconds after • Refer to 10-5. "Check of outdoor fan
outdoor fan start-up.
motor.
• Refer to 10-5. "Check of inverter P.C.
board.
Each phase current of compressor cannot be detected normally. • Refer to 10-5. "How to check inverter/
compressor".
DC voltage of inverter cannot be detected normally.
• Refer to 10-5. "How to check inverter/
compressor".
Current from power outlet is nearing Max. fuse size.
The unit is normal, but check the following.
• Check if the indoor filters are clogged.
Temperature of indoor coil thermistor exceeds 131°F (55°C) in
•
Check if the refrigerant is short.
HEAT mode, compressor frequency lowers.
• Check if the indoor/outdoor unit air circulation is short cycled.
Indoor coil thermistor reads 46°F (8°C) or less in COOL mode,
compressor frequency lowers.
Temperature of discharge temperature thermistor exceeds 232°F • Check the refrigerant circuit and the
(111°C), compressor frequency lowers.
refrigerant amount.
• Refer to 10-5. "Check of LEV".
• Refer to 10-5. "Check of outdoor
thermistors".
NOTE: 1. The location of LED is illustrated at the right figure. Refer to 10-6.1.
2. LED is lighted during normal operation.
The flashing frequency shows the number of times the LED blinks after every 2.5-second OFF. Flashing
(Example) When the flashing frequency is “2”.
0.5-second ON
0.5-second ON
ON
OFF
• Reconnect connector of the compressor.
• Refer to 10-5. "How to check inverter/
compressor".
• Check the stop valve.
• Check the refrigerant circuit and the
refrigerant amount.
• Refer to 10-5. "Check of LEV".
Large current flows into intelligent power module/power module
1.
When overcurrent protection occurs within 10 seconds after
compressor starts, compressor restarts after 15 seconds
(MUZ-HE09/12/15/18NA).
3-time flash
Discharge tempera- Temperature of discharge temperature thermistor exceeds 241°F
2.5 seconds OFF ture overheat protec- (116°C), compressor stops. Compressor can restart if discharge
temperature thermistor reads 212°F (100°C) or less 3 minutes
tion
later.
4-time flash
Fin temperature /P.C. Temperature of fin temperature thermistor on the heat sink ex2.5 seconds OFF board temperature ceeds 167 ~ 176°F (75 ~ 80°C) or temperature of P.C. board temthermistor overheat perature thermistor on the inverter P.C. board exceeds 158 ~ 167°F
protection
(70 ~ 75°C).
5-time flash
High pressure pro- Temperature of indoor coil thermistor exceeds 158°F (70°C) in
2.5 seconds OFF tection
HEAT mode. Temperature of outdoor heat exchanger temperature thermistor exceeds 158°F (70°C) in COOL mode.
14
18
Outdoor unit is defective.
2-time flash
Overcurrent protec2.5 seconds OFF tion
10-time flash
Outdoor fan motor
2.5 seconds OFF
13
The communication fails between the indoor and outdoor unit for • Refer to 10-5. "How to check miswir3 minutes.
ing and serial signal error.
Closed valve is detected by compressor current.
• Check the stop valve.
2.5-second OFF
MUZ-HE24NA
LED
LED
2.5-second OFF
Flashing →
1
Intelligent power module: MUZ-HE24NA
Power module: Other models
OBH686
Inverter
P.C. board
(Parts side)
36
MUZHE09/12/15/18
NA
Abnormal point/
Condition
Condition
Low discharge tem- Temperature of discharge temperature thermistor has been
Outdoor 7-time flash
19 unit oper- 2.5 seconds OFF perature protection 122°F (50°C) or less for 20 minutes.
ates.
No. Symptom
8-time flash
PAM protection PAM:
2.5 seconds OFF Pulse Amplitude
Modulation
Zero cross detecting
circuit
9-time flash
Inverter check mode
2.5 seconds OFF
20
21
This is not malfunction. PAM protection
will be activated in the following cases:
1 Instantaneous power voltage drop
(Short time power failure)
2 When the power supply voltage is high.
The connector of compressor is disconnected, inverter check
mode starts.
• Check if the connector of the compressor is correctly connected. Refer to
10-5. "How to check inverter/compressor".
0.5-second ON
0.5-second ON
ON
2.5-second OFF
OBH686
• Refer to 10-5. "Check of LEV".
• Check the refrigerant circuit and the
refrigerant amount.
The overcurrent flows into IGBT (Insulated Gate Bipolar transistor: TR821) or the bus-bar voltage reaches 320 V or more, PAM
stops and restarts.
Zero cross signal for PAM control cannot be detected.
NOTE: 1. The location of LED is illustrated at the right figure. Refer to 10-6.1.
2. LED is lighted during normal operation.
The flashing frequency shows the number of times the LED blinks after every 2.5-second OFF. Flashing
(Example) When the flashing frequency is “2”.
OFF
Remedy
LED indication
Inverter
P.C. board
(Parts side)
MUZ-HE24NA
LED
LED
2.5-second OFF
Flashing →
37
MUZ-HE09/12/15/
18NA
10-4. TROUBLE CRITERION OF MAIN PARTS
MUZ-HE09NA MUZ-HE12NA MUZ-HE15NA MUZ-HE18NA MUZ-HE24NA
Part name
Defrost thermistor (RT61)
Fin temperature
thermistor (RT64)
Ambient temperature
thermistor (RT65)
Check method and criterion
Figure
Measure the resistance with a tester.
Refer to 10-6. “Test point diagram and voltage”, 1. “Inverter P.C.
board”, for the chart of thermistor.
Outdoor heat exchanger
temperature thermistor
(RT68)
Discharge temperature
thermistor (RT62)
Measure the resistance with a tester. Before measurement, hold the
thermistor with your hands to warm it up.
Refer to 10-6. “Test point diagram and voltage”, 1. “Inverter P.C.
board”, for the chart of thermistor.
Measure the resistance between terminals using a tester.
(Temperature: -4 ~ 104°F (-20 ~ 40°C))
Compressor
HE09
U-V
U-W
V-W
1.36 ~ 1.93
Normal (Ω)
HE12
HE15/18
1.52 ~ 2.17
0.78 ~ 1.11
WHT
W
HE24
0.83 ~ 1.18
Measure the resistance between lead wires using a tester.
(Temperature: -4 ~ 104°F (-20 ~ 40°C))
Outdoor fan motor
Color of lead wire
RED – BLK
BLK – WHT
WHT – RED
R. V. coil (21S4)
Normal (Ω)
HE15
HE09/12
28 ~ 40
RED BLK
V
WHT
U
RED BLK
W
HE18/24
11 ~ 16
V
U
Measure the resistance using a tester.
(Temperature: 14 ~ 104°F (-10 ~ 40°C))
Normal (kΩ)
0.97 ~ 1.38
OBH686
37 ~ 54
38
LEV
RED
ORN
BLU
Normal (Ω)
YLW
Expansion valve coil
(LEV)
Color of lead wire
WHT – RED
RED – ORN
YLW – BRN
BRN – BLU
WHT
BRN
Measure the resistance using a tester.
(Temperature: 14 ~ 104°F (-10 ~ 40°C))
10-5. TROUBLESHOOTING FLOW
A How to check inverter/compressor
Disconnect the connector between compressor
and the intelligent power module (IPM)/power
module (IPM) 1.
See 10-5.
Check the voltage between terminals.
Are the voltages balanced?
Yes
No
Replace the inverter P.C. board.
See 10-5.
Check the compressor.
“Check of open phase”.
“Check of compressor”.
B Check of open phase
● With the connector between the compressor and intelligent power module/power module 1 disconnected, activate the inverter and check if the inverter is normal by measuring the voltage balance between the terminals.
Output voltage is 50 - 130 V. (The voltage may differ according to the tester.)
<< Operation method>>
Start cooling or heating operation by pressing EMERGENCY OPERATION switch on the indoor unit. (TEST RUN OPERATION: Refer to 7-6.)
<<Measurement point>>
at 3 points
BLK (U) - WHT (V)
Measure AC voltage between the lead wires at 3 points.
BLK (U) - RED (W)
WHT(V) - RED (W)
NOTE: 1. Output voltage varies according to power supply voltage.
2. Measure the voltage by analog type tester.
3. During this check, LED of the inverter P.C. board flashes 9 times. (Refer to 10-6.1.)
C Check of compressor
Refer to 10-5. “Check of compressor
winding”.
Is the compressor normal?
Yes
No
Refer to 10-5. “Check of compressor
operation time”.
Does the compressor operate continuously?
Yes
No
Replace the compressor.
Refer to 10-5.
“Check of compressor start failure”.
OK.
1
Intelligent power module: MUZ-HE24NA
Power module: Other models
OBH686
39
D Check of compressor winding
● Disconnect the connector between the compressor and intelligent power module/power module 1, and measure the resistance between the compressor terminals.
<<Measurement point>>
At 3 points
BLK - WHT
BLK - RED
Measure the resistance between the lead wires at 3 points.
WHT - RED
1
<<Judgement>>
Intelligent
power module: MUZ-HE24NA
Refer to 10-4.
Power
module:
Other models
0[Ω] ················· Abnormal [short]
Infinite [Ω] ········ Abnormal [open]
NOTE: Be sure to zero the ohmmeter before measurement.
E Check of compressor operation time
● Connect the compressor and activate the inverter. Then measure
the time until the inverter stops due to over current.
<<Operation method>>
Start heating or cooling operation by pressing EMERGENCY
OPERATION switch on the indoor unit.
(TEST RUN OPERATION: Refer to 7-6.)
<<Measurement>>
Measure the time from the start of compressor to the stop of
compressor due to overcurrent.
<<Judgement>>
0 second
Compressor starts
1 second
Abnormal
(IPM failure)
(Compressor winding short)
2 seconds
Abnormal
(Compressor lock out)
(Starting defect)
10 seconds
Abnormal
(Poor contact)
(Inverter P.C. board defect)
(Disconnected connector)
Abnormal
(Refrigerant circuit defect)
(Closed valve)
10 minutes
F Check of compressor start failure
Normal
Confirm that 1~4 is normal.
• Electrical circuit check
1. Contact of the compressor connector
2. Output voltage of inverter P.C. board and balance of them (See 10-5. )
3. Direct current voltage between DB61(+) and (-) (MUZ-HE09/12/15/18NA)/
JP715(+) and JP30(-) (MUZ-HE24NA) on the inverter P.C. board
4. Voltage between outdoor terminal block S1-S2
Does the compressor run for 10 seconds or
more after it starts?
Yes
Check the refrigerant circuit.
Check the stop valve.
No
After the compressor is heated with a drier,
does the compressor start? 1
No
Replace the compressor.
1
Heat the compressor with
a drier for about 20 minutes.
Do not recover refrigerant
gas while heating.
Yes
Compressor start failure. Activate pre-heat control.
(Refer to 9-2. "PRE-HEAT CONTROL SETTING")
Heating part
OBH686
40
G Check of outdoor thermistors
Disconnect the connector of thermistor in the inverter P.C. board (see
below table), and measure the resistance of thermistor.
Is the resistance of thermistor normal? (Refer to 10-6.1.)
Yes
No
Replace the thermistor except RT64. When RT64 is
abnormal, replace the inverter P.C. board.
Reconnect the connector of thermistor.
Turn ON the power supply and press EMERGENCY OPERATION switch.
Does the unit operate for 10 minutes or more
without showing thermistor abnormality?
Yes
No
Replace the inverter P.C. board.
OK. (Cause is poor contact.)
MUZ-HE09/12/15/18NA
Thermistor
Symbol
Connector, Pin No.
Defrost
RT61 Between CN641 pin1 and pin2
Discharge temperature
RT62 Between CN641 pin3 and pin4
Fin temperature
RT64 Between CN642 pin1 and pin2
Ambient temperature
RT65 Between CN643 pin1 and pin2
Outdoor heat exchanger temperature RT68 Between CN644 pin1 and pin3
Board
Inverter P.C. board
MUZ-HE24NA
Thermistor
Symbol
Connector, Pin No.
Defrost
RT61 Between CN671 pin1 and pin2
Discharge temperature
RT62 Between CN671 pin3 and pin4
Fin temperature
RT64 Between CN673 pin1 and pin2
Ambient temperature
RT65 Between CN672 pin1 and pin2
Outdoor heat exchanger temperature RT68 Between CN671 pin5 and pin6
Board
Inverter P.C. board
H Check of R.V. coil
First of all, measure the resistance of R.V. coil to check if the coil is defective. Refer to 10-4.
In case CN721 (MUZ-HE09/12/15/18)/CN602 (MUZ-HE24) is disconnected or R.V. coil is open, voltage is generated
between the terminal pins of the connector although no signal is being transmitted to R.V. coil. Check if CN721 (MUZHE09/12/15/18)/CN602 (MUZ-HE24) is connected.
Unit operates COOL mode even if it is set to HEAT mode.
Disconnect connector between the
compressor and intelligent power module/
power module 1.
Turn ON the power supply and press
EMERGENCY OPERATION switch twice
(HEAT mode).
Is there 208/230 VAC between CN721 (MUZHE09/12/15/18)/CN602 (MUZ-HE24) and
on the inverter P.C. board 3 minutes after the
power supply is turned ON?
Yes
Replace the 4-way valve.
1
Intelligent power module: MUZ-HE24NA
Power module: Other models
OBH686
41
No
Replace the inverter
P.C. board.
Unit operates HEAT mode even if it is set to COOL mode.
Disconnect connector between the
compressor and intelligent power
module/ power module 1.
Turn ON the power supply and press
EMERGENCY OPERATION switch
once (COOL mode).
Is there 208/230 VAC between CN721 (MUZHE09/12/15/18)/CN602 (MUZ-HE24) and
on the inverter P.C. board 3 minutes after the
power supply is turned ON?
No
Replace the inverter
Yes P.C. board.
Replace the 4-way valve.
1
Intelligent power module: MUZ-HE24NA
Power module: Other models
I Check of outdoor fan motor
Disconnect the connectors CN931 and CN932
from the inverter P.C. board. Check the connection between the connector CN931 and CN932.
Is the resistance between each terminal of outdoor fan motor normal?
(Refer to 10-4.)
No
Yes
Disconnect CN932 from the inverter P.C. board, and turn on the
power supply.
Rotate the outdoor fan motor manually and measure the voltage
of CN931.
Between 1(+) and 5(-)
Between 2(+) and 5(-)
Between 3(+) and 5(-)
(Fixed to either 5 or 0 VDC)
No
No
Does the voltage between each terminal become 5 and 0
VDC repeatedly?
Yes
Does the outdoor fan motor rotate smoothly?
Yes
Replace the inverter P.C. board.
Replace the outdoor fan motor.
OBH686
42
J Check of power supply
MUZ-HE09/12/15/18NA
1
Intelligent power module: MUZ-HE24NA
Power module: Other models
Disconnect the connector (CN61) between
compressor and intelligent power module/
power module 1.
Turn ON power supply and press
EMERGENCY OPERATION switch.
Does the upper lamp of
OPERATION INDICATOR lamp on
the indoor unit light up?
Yes
Rectify indoor/outdoor
connecting wire.
No
Is there bus-bar voltage 260-325
VDC between DB61 (+) and DB61 (–)
Yes
on the inverter P.C. board?
(Refer to 10-6.1.)
No
Yes
Is there voltage 208/230 VAC
between the indoor terminal
block S1 and S2?
Does LED on the inverter P.C.
board light up or flash? (Refer
to 10-6.1.)
Yes
No
No
Replace the indoor
electronic control P.C.
board.
Replace the inverter
P.C. board.
If LED lights up, it is OK.
If LED flashes, refer to 10-3.
Check the electric parts in main circuit.
260-325 VDC
DB61
Inverter P.C. board
(Solder side)
MUZ-HE24NA
Disconnect the connector between
compressor and intelligent power module/
power module 1.
Turn ON power supply and press
EMERGENCY OPERATION switch.
Does the upper lamp of
OPERATION INDICATOR on the
indoor unit light up?
Yes
Rectify indoor/outdoor
connecting wire.
No
Is there bus-bar voltage 294 - 370
VDC between JP715 (+) and JP30 (–)
Yes
on the inverter P.C. board?
(Refer to 10-6.1.)
No
Check the electric parts in main circuit.
Yes
Is there voltage 208/230 VAC
between the indoor terminal
block S1 and S2?
Does LED on the inverter P.C.
board light up or flash? (Refer
to 10-6.1.)
Yes
No
No
Replace the indoor
electronic control P.C.
board.
Replace the inverter
P.C. board.
If LED lights up, it is OK.
If LED flashes, refer to 10-3.
JP30 JP715
294 -370 VDC
OBH686
43
K Check of LEV (Expansion valve)
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 buttons.
Press OPERATE/STOP (ON/OFF) button of the remote
controller (the set temperature is displayed) with the
remote controller headed towards the indoor unit. 1
1. Regardless of normal or abnormal condition, a short beep
is emitted once the signal is received.
Expansion valve operates in full-opening direction.
Do you hear the expansion valve "click,
click·······"?
Do you feel the expansion valve vibrate
on touching it ?
No
Is LEV coil properly fixed to
the expansion valve?
No
Yes
Does the resistance of LEV
coil have the characteristics? Yes
(Refer to 10-4.)
No
Replace the LEV coil.
Yes
OK.
Properly fix the LEV coil to the expansion valve.
Measure each voltage between connector
pins of CN724 on the inverter P.C. board.
1. Pin (-) — Pin (+)
2. Pin (-) — Pin (+)
3. Pin (-) — Pin (+)
4. Pin (-) — Pin (+)
Is there about 3 ~ 5 VAC between each?
NOTE: Measure the voltage by an analog
tester.
Yes
Replace the expansion valve.
NOTE: After check of LEV, do the undermentioned operations.
1. Turn OFF the power supply and turn ON it again.
2. Press RESET button on the remote controller.
OBH686
44
No
Replace the inverter P.C.
board.
L Check of inverter P.C. board
Check the outdoor fan motor.
(Refer to 10-5. .)
Is the fuse (F901) blown on the inverter P.C. board?
Yes
No
Check the connection of the connectors
(CN931 , CN932) of the outdoor fan motor.
If the connection is poor, make it correct.
Only for MUZ-HE24NA
Operate the outdoor unit by starting
EMERGENCY OPERATION.
Check the LED indication on the inverter P.C. board.
Does the LED flash 10 times?
Yes
(10-time flash)
No
Check the remedy following LED
indication.
(Refer to 10-3.)
Replace the inverter P.C. board.
OBH686
45
M How to check miswiring and serial signal error
MUZ-HE09/12/15/18NA
Turn OFF the power supply.
Is there rated voltage in the power supply?
Yes
Check the power supply.
No
Turn ON the power supply.
Yes
No
Is there rated voltage between outdoor terminal block S1 and S2?
Check the wiring.
Press EMERGENCY OPERATION switch once.
Does the OPERATION INDICATOR lamp light
up? <Confirmation of the power to the indoor
unit>
Yes
Is serial signal error indicated 6 minutes later?
No
No
Yes
A
Turn OFF the power supply.
Check once more if the indoor/outdoor
B connecting wire is not miswiring.
Bridge the outdoor terminal block S2 and
S3. 1
Is there any miswiring, poor
contact, or wire disconnection of the indoor/outdoor
connecting wire?
No
Yes
Correct them.
1. Miswiring may damage indoor electronic control P.C.
board during the operation.
Be sure to confirm the wiring is correct before the operation starts.
3. Be sure to check this within 3 minutes after turning ON.
After 3 minutes, LED blinks 6 times. Even when the
inverter P.C. board is normal, LED blinks 6 times after 3
minutes.
Turn ON the power supply.
Is the bus-bar voltage of the inverter P.C. board normal? (Refer to "TEST POINT DIAGRAM AND
VOLTAGE" in the outdoor service manual.)
No
Check of power supply.
(Refer to 10-5. .)
Yes
Does the LED on the inverter P.C. board repeat "3.6-second-OFF and 0.8-second-ON quick blinking"? 3
Yes
Turn OFF the power supply.
Remove the bidge between the outdoor terminal block S2 and S3.
Turn ON the power supply.
Is there rated voltage between the indoor terminal block S1 and S2?
<Confirmation of power voltage>
No
Yes
Is there amplitude of 10 to 20 VDC between the indoor terminal block
S2 and S3? <Confirmation of serial signal>
No
(Lighted
or not
lighted)
Replace the inverter P.C. board. 2
2. Be careful of the residual voltage of smoothing
capacitor.
Check the wiring
If there are any error of the indoor/outdoor connecting wire:
such as the damage of the wire, intermediate connection,
and/or poor contact to the terminal block, replace the indoor/
outdoor connecting wire.
No
Yes
A
• Turn OFF inverter-controlled lighting
equipment.
• Turn OFF the power supply and then
turn ON again.
• Press EMERGENCY OPERATION
switch.
Is serial signal
error indicated 6
minutes later?
Yes
B
• Reinstall
either the unit
or the light
away from
each other.
• Attach a filter
No on remote
control receiving section
of the indoor
unit.
OBH686
Is there 2 VDC or less between CN10A (+)
and JPG (GND)(-) on the indoor electronic
control P.C. board?
No
Yes
Is there 2 VDC or less between
CN10A (+) and JPG (GND)(-) on
the indoor electronic control P.C.
board?
No
Yes
Replace the indoor power
P.C. board and the indoor
terminal P.C. board
46
Is there 2 VDC or less between
CN10A (+) and JPG (GND)(-) on
the indoor electronic control P.C.
board?
No
Replace the indoor electronic control P.C. board.
Yes
MUZ-HE24NA
Turn OFF the power supply.
Is there rated voltage in the power supply?
Yes
Check the power supply.
No
Turn ON the power supply.
No
Is there rated voltage between outdoor terminal block S1 and S2?
Yes
Check the wiring.
Press EMERGENCY OPERATION switch once.
Does the OPERATION INDICATOR lamp light
up? <Confirmation of the power to the indoor
unit>
Yes
Is serial signal error indicated 6 minutes later?
Yes
A
Turn OFF the power supply.
Check once more if the indoor/outdoor
B connecting wire is not miswiring.
Bridge the outdoor terminal block S2 and
S3. 1
No
No
Is there any miswiring,
poor contact, or wire
disconnection of the
indoor/outdoor connecting wire?
No
Yes
Correct them.
1. Miswiring may damage indoor electronic control P.C.
board during the operation.
Be sure to confirm the wiring is correct before the operation starts.
3. Be sure to check this within 3 minutes after turning ON.
After 3 minutes, LED blinks 6 times. Even when the
inverter P.C. board is normal, LED blinks 6 times after 3
minutes.
Turn ON the power supply.
Is the bus-bar voltage of the inverter P.C. board normal? (Refer to "TEST POINT DIAGRAM AND
VOLTAGE" in this manual.)
No
Check of power supply.
(Refer to 10-5. .)
Yes
Does the LED on the inverter P.C. board repeat "3.6-second-OFF and 0.8-second-ON quick blinking"? 3
Yes
Turn OFF the power supply.
Remove the bridge between the outdoor terminal block S2 and S3.
Replace the indoor electronic control P.C. board.
A
• Turn OFF inverter-controlled lighting
equipment.
• Turn OFF the power supply and then
turn ON again.
• Press EMERGENCY OPERATION
switch.
Is serial signal
error indicated 6
minutes later?
Yes
B
OBH686
• Reinstall
either the unit
or the light
away from
each other.
• Attach a filter
No on remote
control receiving section
of the indoor
unit.
47
No
(Lighted
or not
lighted)
Replace the inverter P.C. board . 2
2. Be careful of the residual voltage of smoothing
capacitor.
N Electromagnetic noise enters into TV sets or radios
Is the unit grounded?
Yes
Ground the unit.
No
Is the distance between the antennas
and the indoor unit within 9.91 ft. (3 m),
or is the distance between the antennas
Yes
and the outdoor unit within 9.91 ft. (3 m)?
Extend the distance between the antennas and
the indoor unit, and/or the antennas and the
outdoor unit.
No
Is the distance between the TV sets or
radios and the indoor unit within 3.28
ft. (1 m), or is the distance between the
TV sets or radios and the outdoor unit
within 9.91 ft. (3 m)?
No
Are the antennas damaged?
Is the coaxial cable damaged?
Is there any poor contact in the antenna wiring?
Yes
Extend the distance between the TV sets and/or
radios and the indoor unit, or the TV sets or
radios and the outdoor unit.
Yes
Replace or repair the antenna.
Replace or repair the coaxial cable.
Yes
Extend the distance between the indoor/outdoor
connecting wire of the air conditioner and the wiring of the antennas.
No
Is the indoor/outdoor connecting wire
of the air conditioner and the wiring of
the antennas close?
No
Even if all of the above conditions are fulfilled, the electromagnetic noise may enter, depending on the electric field strength
or the installation condition (combination of specific conditions such as antennas or wiring).
Check the followings before asking for service.
1. Devices affected by the electromagnetic noise
TV sets, radios (FM/AM broadcast, shortwave)
2. Channel, frequency, broadcast station affected by the electromagnetic noise
3. Channel, frequency, broadcast station unaffected by the electromagnetic noise
4. Layout of:
indoor/outdoor unit of the air conditioner, indoor/outdoor wiring, grounding wire, antennas, wiring from antennas, receiver
5. Electric field intensity of the broadcast station affected by the electromagnetic noise
6. Presence or absence of amplifier such as booster
7. Operation condition of air conditioner when the electromagnetic noise enters in
1) Turn OFF the power supply once, and then turn ON the power supply. In this situation, check for the electromagnetic
noise.
2) Within 3 minutes after turning ON the power supply, press OPERATE/STOP (ON/OFF) button on the remote controller
for power ON, and check for the electromagnetic noise.
3) After a short time (3 minutes later after turning ON), the outdoor unit starts running. During operation, check for the electromagnetic noise.
4) Press OPERATE/STOP (ON/OFF) button on the remote controller for power OFF, when the outdoor unit stops but the
indoor/outdoor communication still runs on. In this situation, check for the electromagnetic noise.
OBH686
48
10-6. TEST POINT DIAGRAM AND VOLTAGE
1. Inverter P.C. board
MUZ-HE09NA
MUZ-HE12NA
Back side of unit
208/230 VAC
MUZ-HE15NA
Bus-bar voltage
DB61
260-325 VDC
(+)
(-)
Smoothing
capacitor
(C63)
Smoothing
capacitor
(C62)
Smoothing
capacitor
(C61)
Fuse (F701)
T3.15AL250V
Fuse (F801)
T3.15AL250V
R.V.coil
(CN721)
208/230
VAC
Fuse (F901)
T3.15AL250V
Signal of
outdoor
fan motor
(CN931)
Output to
drive
compressor
(LDU,
LDV,
LDW)
208/230
VAC
Front side of unit
Jumper wire for
LED LEV
Discharge temperature connector changing defrost
thermistor/RT62
(CN724) setting (JS)
(CN641)
Defrost thermistor
/RT61(CN641)
Ambient temperature
thermistor/RT65 (CN643)
Output to drive outdoor
fan motor (CN932)
Fin temperature
thermistor/RT64 (CN642)
Outdoor heat exchanger
temperature thermistor
/RT68 (CN644)
100
Defrost thermistor (RT61)
Ambient temperature thermistor (RT65)
Outdoor heat exchanger temperature thermistor (RT68)
200
90
60
600
50
40
30
20
10
14
32 50 68 86
Temperature(°F)
104
140
Resistance(kΩ)
700
Resistance(kΩ)
Resistance(kΩ)
160
Discharge temperature thermistor (RT62)
70
OBH686
Fin temperature thermistor (RT64)
180
80
0
-4
Jumper wire
for pre-heat
control setting
(JK)
500
400
300
120
100
80
60
200
40
100
20
0
32
50
68
86 104 122 140 158 176 194 212 230 248
Temperature(°F)
49
0
32 50 68 86 104 122 140 158 176
Temperature(°F)
MUZ-HE18NA
Back side of unit
208/230 VAC
Bus-bar voltage Smoothing
DB61
capacitor
260-325 VDC
(C63)
(+)
(-)
Smoothing
capacitor
(C62)
Smoothing
Fuse (F701)
capacitor
T3.15AL250V
(C61)
Fuse (F801)
T3.15AL250V
R.V.coil
(CN721)
208/230 VAC
Fuse (F901)
T3.15AL250V
Output to
drive
compressor
(LDU,
LDV,
LDW)
100
Defrost thermistor (RT61)
Ambient temperature thermistor (RT65)
Outdoor heat exchanger temperature thermistor (RT68)
200
90
Jumper wire for pre-heat
control setting (JK)
Jumper wire for changing
defrost setting (JS)
LED
160
Discharge temperature thermistor (RT62)
60
600
50
40
30
20
10
14
32 50 68 86
Temperature(°F)
OBH686
104
140
Resistance(kΩ)
70
700
Resistance(kΩ)
Resistance(kΩ)
Fin temperature thermistor (RT64)
180
80
0
-4
LEV connector (CN724)
Signal of outdoor fan
motor (CN931)
Output to drive outdoor
fan motor (CN932)
Discharge temperature
thermistor /RT62
(CN641)
Defrost thermistor
/RT61(CN641)
Ambient temperature
thermistor /RT65
(CN643)
Outdoor heat exchanger
temperature thermistor
/RT68(CN644)
Front side of unit
Fin temperature
thermistor /RT64
(CN642)
208/230
VAC
500
400
300
120
100
80
60
200
40
100
20
0
32
50
68
86 104 122 140 158 176 194 212 230 248
Temperature(°F)
50
0
32 50 68 86 104 122 140 158 176
Temperature(°F)
MUZ-HE24NA
Fuse (F62)
T2.0AL250V
Fuse (F601)
T3.15AL250V
R.V. coil (CN602)
208/230 VAC
Jumper wire for
changing defrost
setting (JS)
Jumper wire for
pre-heat control
setting (JK)
Signal of outdoor fan motor
(CN931)
Defrost thermistor
/RT61 (CN671)
Discharge temperature
thermistor/RT62
(CN671)
Outdoor heat exchanger
temperature thermistor
/RT68 (CN671)
Ambient temperature
thermistor/RT65
(CN672)
Fin temperature
thermistor/RT64
(CN673)
LED
Output to
drive outdoor
fan motor
(CN932)
Fuse (F901)
T3.15AL250V
Fuse (F880)
T3.15AL250V
LEV connector (CN724)
100
JP715 (+)
Bus-bar voltage
294 - 370 VDC
Fin temperature thermistor (RT64)
JP30 (-)
200
Defrost thermistor (RT61)
Ambient temperature thermistor (RT65)
Outdoor heat exchanger temperature thermistor (RT68)
90
180
60
600
50
40
30
20
10
14
OBH686
32 50 68 86
Temperature(°F)
104
140
Resistance(kΩ)
70
0
-4
160
Discharge temperature thermistor (RT62)
700
Resistance(kΩ)
Resistance(kΩ)
80
500
400
300
120
100
80
60
200
40
100
20
0
32
50
68
86 104 122 140 158 176 194 212 230 248
Temperature(°F)
51
0
32 50 68 86 104 122 140 158 176
Temperature(°F)
11
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.
(2) The terminal with this connector has the
locking mechanism.
Sleeve
Locking lever
Slide the sleeve.
Pull the terminal while
pushing the locking
lever.
Hold the sleeve, and
pull out the terminal
slowly.
Connector
11-1. MUZ-HE09NA MUZ-HE12NA MUZ-HE15NA
NOTE: Turn OFF power supply before disassembly.
OPERATING PROCEDURE
PHOTOS
1. Removing the cabinet
Photo 1
(1)
(2)
(3)
(4)
(5)
Remove the screw fixing the service panel.
Pull down the service panel and remove it.
Remove the screws fixing the conduit cover.
Remove the conduit cover.
Disconnect the power supply wire and indoor/outdoor
connecting wire.
(6) Remove the screws fixing the top panel.
(7) Remove the top panel.
(8) Remove the screws fixing the cabinet.
(9) Remove the cabinet.
(10) Remove the screws fixing the back panel.
(11) Remove the back panel.
Screw of the cabinet
Screws of the top panel
Screw of the cabinet
Screws of the top panel
Back
panel
Service
panel
Screws
of the
back
panel
Screw of
the cabinet
Screws of the cabinet
Hooks
Direction
to remove
Photo 2
Screws of the
conduit cover
Conduit cover
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Conduit plate
OPERATING PROCEDURE
PHOTOS
2. Removing the inverter assembly, inverter P.C. board
(1) Remove the cabinet and panels. (Refer to 1.)
(2) Disconnect the lead wire to the reactor and the following
connectors:
<Inverter P.C. board>
CN641 (Defrost thermistor and discharge temperature thermistor)
CN643 (Ambient temperature thermistor)
CN644 (Outdoor heat exchanger temperature thermistor)
CN721 (R.V. coil)
CN724 (LEV)
CN931, CN932 (Fan motor)
(3) Remove the compressor connector (CN61).
(4) Remove the screws fixing the heat sink support and the
separator.
(5) Remove the fixing screws of the terminal block support and
the back panel.
(6) Remove the inverter assembly.
(7) Remove the screw of the ground wire and screw of the terminal block support.
(8) Remove the heat sink support from the P.C. board support.
(9) Remove the screw of the inverter P.C. board and remove
the inverter P.C. board from the P.C. board support.
Screws of the
terminal block
support and the
back panel
Photo 3
Screw of the heat sink
support and the separator
Photo 4 (Inverter assembly)
Heat sink
Inverter P.C. board
Hook of the
P.C. board
support
Screw of the
terminal block
support
P.C. board
support
Terminal
block support
Screw of the
ground wire
Heat sink support
Hook of the P.C.
board support
Photo 5
3. Removing R.V. coil
Screw of the P.C.
board fixture
R.V. coil
(1) Remove the cabinet and panels. (Refer to 1.)
(2) Disconnect the following connectors:
<Inverter P.C. board>
CN721 (R.V. coil)
(3) Remove the R.V. coil.
Discharge temperature thermistor
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OPERATING PROCEDURE
PHOTOS
4. Removing the discharge temperature thermistor,
defrost thermistor, outdoor heat exchanger temperature thermistor and ambient temperature thermistor
Photo 6
(1) Remove the cabinet and panels. (Refer to 1.)
(2) Disconnect the lead wire to the reactor and the following
connectors:
<Inverter P.C. board>
CN641 (Defrost thermistor and discharge temperature thermistor)
CN643 (Ambient temperature thermistor)
CN644 (Outdoor heat exchanger temperature thermistor)
(3) Pull out the discharge temperature thermistor from its holder.
(Photo 5)
(4) Pull out the defrost thermistor from its holder.
(5) Pull out the outdoor heat exchanger temperature thermistor
from its holder.
(6) Pull out the ambient temperature thermistor from its holder.
5. Removing outdoor fan motor
Outdoor heat
exchanger temperature thermistor
Defrost thermistor
Photo 7
(1) Remove the cabinet and panels. (Refer to 1.)
(2) Disconnect the following connectors:
<Inverter P.C. board>
CN931, CN932 (Fan motor)
(3) Remove the propeller nut.
(4) Remove the propeller.
(5) Remove the screws fixing the fan motor.
(6) Remove the fan motor.
Propeller
6. Removing the compressor and 4-way valve
(1) Remove the cabinet and panels. (Refer to 1.)
(2) Remove the inverter assembly. (Refer to 2.)
(3) Recover gas from the refrigerant circuit.
NOTE: Recover gas from the pipes until the pressure
gauge shows 0 PSIG.
(4) Detach the brazed part of the suction and the discharge
pipes connected with compressor.
(5) Remove the compressor nuts.
(6) Remove the compressor.
(7) Detach the brazed part of the pipes connected with 4-way
valve.
Screws of the outdoor fan motor
Propeller nut
Photo 8
Brazed parts of 4-way valve
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11-2. MUZ-HE18NA
NOTE: Turn OFF power supply before disassembly.
OPERATING PROCEDURE
PHOTOS
1. Removing the cabinet
Photo 1
(1)
(2)
(3)
(4)
(5)
(6)
(7)
Remove the screws of the service panel.
Remove the screws of the top panel.
Remove the screw of the valve cover.
Remove the service panel.
Remove the top panel.
Remove the valve cover.
Disconnect the power supply and indoor/outdoor connecting wire.
(8) Remove the screws of the cabinet.
(9) Remove the cabinet.
(10) Remove the screws of the back panel.
(11) Remove the back panel.
Screw of the top panel
Screws of the cabinet
Screws
of the
back
panel
Screws
of the
cabinet
Photo 2
Screws of the top panel
Screws
of the
cabinet
Screw
of the
service
panel
Screw
of the
valve
cover
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55
Screws of
the back
panel
OPERATING PROCEDURE
PHOTOS
2. Removing the inverter assembly, inverter P.C. board
Photo 3
Screw of the heat sink
(1) Remove the cabinet and panels. (Refer to 1.)
support and the separator
(2) Disconnect the lead wire to the reactor and the following connectors:
Screws of
<Inverter P.C. board>
the terminal
CN641 (Defrost thermistor and discharge temperature therblock support
mistor)
and the back
CN643 (Ambient temperature thermistor)
panel
CN644 (Outdoor heat exchanger temperature thermistor)
CN721 (R.V.coil)
CN724 (LEV)
CN931, CN932 (Fan motor)
(3) Remove the compressor connector (CN61).
(4) Remove the screws fixing the heat sink support and the separator.
(5) Remove the fixing screws of the terminal block support and
Screws of
the back panel.
the reactor
(6) Remove the inverter assembly.
(7) Remove the screw of the ground wire and screw of the terminal
block support.
(8) Remove the heat sink support from the P.C. board support.
(9) Remove the screw of the inverter P.C. board and remove the Photo 4 (Inverter assembly)
inverter P.C. board from the P.C. board support.
Heat sink
Inverter P.C. board
Screw of the
terminal block
P.C. board
support
Hook of the P.C.
support
board support
Heat sink support
Hook of the P.C.
board support
3. Removing R.V. coil
Screw of the
ground wire
Screw of the P.C.
board fixture
Terminal block
support
Photo 5
(1) Remove the cabinet and panels. (Refer to 1.)
(2) Disconnect the following connectors:
<Inverter P.C. board>
CN721 (R.V. coil)
(3) Remove the R.V. coil.
R.V. coil
Brazed parts of 4-way valve
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OPERATING PROCEDURE
PHOTOS
4. Removing the discharge temperature thermistor,
defrost thermistor, outdoor heat exchanger temperature thermistor and ambient temperature thermistor
(1) Remove the cabinet and panels. (Refer to 1.)
(2) Disconnect the lead wire to the reactor and the following
connectors:
<Inverter P.C. board>
CN641 (Defrost thermistor and discharge temperature thermistor)
CN643 (Ambient temperature thermistor)
CN644 (Outdoor heat exchanger temperature thermistor)
(3) Pull out the discharge temperature thermistor from its holder.
(4) Pull out the defrost thermistor from its holder.
(5) Pull out the outdoor heat exchanger temperature thermistor
from its holder.
(6) Pull out the ambient temperature thermistor from its holder.
Photo 6
Outdoor heat
exchanger temperature thermistor
Ambient temperature
thermistor
5. Removing outdoor fan motor
(1) Remove the top panel, cabinet and service panel. (Refer to 1.)
(2) Disconnect the following connectors:
<Inverter P.C. board>
CN931 and CN932 (Fan motor)
Defrost thermistor
Photo 7
(3) Remove the propeller.
(4) Remove the screws fixing the fan motor.
(5) Remove the fan motor.
Screws of
the outdoor
fan motor
6. Removing the compressor and 4-way valve
(1) Remove the top panel, cabinet and service panel. (Refer to 1.)
(2) Remove the back panel. (Refer to 1.)
(3) Remove the inverter assembly. (Refer to 2.)
(4) Recover gas from the refrigerant circuit.
NOTE: Recover gas from the pipes until the pressure gauge
shows 0 PSIG.
(5) Detach the brazed part of the suction and the discharge
pipes connected with compressor.
(6) Remove the compressor nuts.
(7) Remove the compressor.
(8) Detach the brazed parts of 4-way valve and pipes. (Photo 5)
Photo 8
Brazed part of the
discharge pipe
Discharge temperature
thermistor
Brazed part of the
suction pipe
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11-3. MUZ-HE24NA
NOTE: Turn OFF power supply before disassembly.
OPERATING PROCEDURE
PHOTOS
1. Removing the cabinet
Photo 1
(1)
(2)
(3)
(4)
(5)
(6)
(7)
(8)
(9)
Remove the screws of the service panel.
Remove the screws of the top panel.
Remove the screw of the valve cover.
Remove the service panel.
Remove the screws fixing the conduit cover.
Remove the conduit cover.
Remove the top panel.
Remove the valve cover.
Disconnect the power supply and indoor/outdoor connecting wire.
(10) Remove the screws of the cabinet.
(11) Remove the cabinet.
(12) Remove the screws of the back panel.
(13) Remove the back panel.
Screws of the top panel
Photo 2
Screws of the
back panel
Screws of the
top panel
Screws of the
back panel
Screws of the
cabinet
Screws of
the back
panel
Screws of the
cabinet
Photo 3
Screws of the
conduit cover
Conduit plate
Screws
of the
cabinet
Screws of
the service
panel
Screws of the
back panel
OBH686
Screws of
the back
panel
Screw of
the valve
cover
58
OPERATING PROCEDURE
PHOTOS
2. Removing the inverter assembly, inverter P.C. board
(1) Remove the cabinet and panels. (Refer to 1.)
(2) Disconnect the lead wire to the reactor and the following connectors:
<Inverter P.C. board>
CN602 (R.V. coil)
CN671 (Defrost thermistor, discharge temperature thermistor
and outdoor heat exchanger temperature thermistor)
CN672 (Ambient temperature thermistor)
CN724 (LEV)
CN931, CN932 (Fan motor)
(3) Remove the compressor connector.
(4) Remove the screws fixing the relay panel.
(5) Remove the relay panel.
(6) Remove the ground wires and the lead wires of the inverter
P.C. board.
(7) Remove the screw of the PB support.
(8) Remove the inverter P.C. board from the relay panel.
Photo 4
Inverter P.C.
board
Screw of the
relay panel
Ground wires
Screws of the
PB support
Screws
of the PB
support
Screws of the
relay panel
3. Removing R.V. coil
Photo 5
(1) Remove the cabinet and panels. (Refer to 1.)
(2) Disconnect the following connector:
<Inverter P.C. board>
CN602 (R.V. coil)
(3) Remove the R.V. coil.
Screw of the
R.V. coil
Brazed parts of
4-way valve
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OPERATING PROCEDURE
PHOTOS
4. Removing the discharge temperature thermistor,
defrost thermistor, outdoor heat exchanger temperature thermistor and ambient temperature thermistor
(1) Remove the cabinet and panels. (Refer to 1.)
(2) Disconnect the lead wire to the reactor and the following
connectors:
<Inverter P.C. board>
CN671 (Defrost thermistor, discharge temperature thermistor and outdoor heart exchanger temperature thermistor)
CN672 (Ambient temperature thermistor)
(3) Pull out the discharge temperature thermistor from its holder.
(4) Pull out the defrost thermistor from its holder.
(5) Pull out the outdoor heat exchanger temperature thermistor
from its holder.
(6) Pull out the ambient temperature thermistor from its holder.
Photo 6
Outdoor heat
exchanger temperature thermistor
Ambient temperature
thermistor
5. Removing outdoor fan motor
(1) Remove the top panel, cabinet and service panel. (Refer to 1.)
(2) Disconnect the following connectors:
<Inverter P.C. board>
CN931 and CN932 (Fan motor)
(3) Remove the propeller.
(4) Remove the screws fixing the fan motor.
(5) Remove the fan motor.
Defrost thermistor
Photo 7
Screws of the
outdoor fan motor
6. Removing the compressor and 4-way valve
(1) Remove the top panel, cabinet and service panel. (Refer to 1.)
(2) Remove the back panel. (Refer to 1.)
(3) Remove the inverter assembly. (Refer to 2.)
(4) Recover gas from the refrigerant circuit.
NOTE: Recover gas from the pipes until the pressure gauge
shows 0 PSIG.
(5) Detach the brazed part of the suction and the discharge
pipes connected with compressor.
(6) Remove the compressor nuts.
(7) Remove the compressor.
(8) Detach the brazed parts of 4-way valve and pipes. (Photo 5)
Photo 8
Brazed part of the
discharge pipe
Discharge temperature
thermistor
Brazed part of the suction pipe
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OBH686
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HEAD OFFICE: TOKYO BLDG., 2-7-3, MARUNOUCHI, CHIYODA-KU, TOKYO 100-8310, JAPAN
© Copyright 2014 MITSUBISHI ELECTRIC CORPORATION
Distributed in Feb. 2014. No. OBH686
Made in Japan
New publication, effective Feb. 2014
Specifications are subject to change without notice.