OUTDOOR UNIT
No. OBH498
HFC
utilized
SERVICE MANUAL
R410A
Wireless type
Models
MUZ-FD09NA
U1
MUZ-FD09NA-
MUZ-FD12NA
MUZ-FD12NA-
U1
Indoor unit service manual
MSZ-FD•NA Series (OBH497)
CONTENTS
1. TECHNICAL CHANGES ··································· 3
2. PART NAMES AND FUNCTIONS····················· 3
3. SPECIFICATION················································ 4
4. OUTLINES AND DIMENSIONS ························ 6
5. WIRING DIAGRAM············································ 7
6. REFRIGERANT SYSTEM DIAGRAM··············· 8
7. DATA·································································· 9
8. ACTUATOR CONTROL··································· 15
9. SERVICE FUNCTIONS ··································· 16
10. TROUBLESHOOTING····································· 16
11. DISASSEMBLY INSTRUCTIONS···················· 32
PARTS CATALOG (OBB498)
TM
NOTE:
RoHS compliant products have <G> mark on the spec name plate.
1
TECHNICAL CHANGES
MUZ-FD09NA
MUZ-FD12NA
MUZ-FD09NA -
MUZ-FD12NA -
U1
U1
1. New model
2
PART NAMES AND FUNCTIONS
MUZ-FD09NA
MUZ-FD12NA
Air inlet
Piping
Drain hose
Air outlet
Drain outlet
3
3
SPECIFICATION
Outdoor unit model
MUZ-FD09NA
MUZ-FD12NA
Cooling
1
Btu/h
Btu/h
Btu/h
W
W
W
9,000 (2,800~9,000)
10,900 (3,000~18,000)
12,500
12,000 (2,800~12,000)
13,600 (3,000~21,000)
13,600
Capacity
Rated (Minimum~Maximum)
Heating 47
Heating 17
1
2
Capacity Rated
Cooling
1
650 (160~650)
750 (150~2,400)
1,730
960 (160~960)
980 (150~2,400)
1,780
Power consumption
Rated (Minimum~Maximum)
Heating 47
Heating 17
Cooling
1
2
Power consumption Rated
1
EER
[SEER]
3
13.8 [23.0]
12.5 [22.0]
HSPF IV(V)
COP
4
Heating
Heating
10.55 (7.4)
10.55 (7.4)
1
4.30
4.10
External nish
Power supply
Munsell 3Y 7.8/1.1
208/230 , 1 , 60
V , phase , Hz
Max. fuse size (time delay)
Min. circuit ampacity
Fan motor
A
A
F.L.A
15
12
0.56
Model
SNB130FQAH
8.6
Compressor
R.L.A
L.R.A
10.8
Refrigerant control
Liner expansion valve
Cooling
Heating
dB(A)
dB(A)
48
49
48
49
Sound level
1
Defrost method
Dimensions
Reverse cycle
31-1/2
W
D
H
in.
in.
in.
Ib.
11-1/4
21-5/8
80
Weight
Remote controller
Control voltage (by built-in transformer) VDC
Refrigerant piping
Wireless type
12 - 24
Not supplied
1/4 (0.0315)
3/8 (0.0315)
Flared
Liquid
Gas
Indoor
Outdoor
in.
in.
Refrigerant pipe size
(Min. wall thickness)
Connection method
Flared
Height differ-
ence
Piping length ft.
ft.
40
Between the indoor &
outdoor units
65
Refrigerant charge (R410A)
Refrigeration oil (Model)
2 lb. 9 oz.
NE022
NOTE : Test conditions are based on ARI 210/240.
1 : Rating conditions (Cooling) — Indoor : 80 FDB, 67 FWB, Outdoor : 95 FDB, (75 FWB)Rated frequency
(Heating) — Indoor : 70 FDB, 60 FWB, Outdoor : 47 FDB, 43 FWB Rated frequency
2 :
(Heating) — Indoor : 70 FDB, 60 FWB, Outdoor : 17 FDB, 15 FWBMaximum frequency
4
Test condition
3, 4
Indoor air condition
Dry bulb (°F) Wet bulb (°F)
Outdoor air condition
Dry bulb (°F) Wet bulb (°F)
Mode
ARI
Test
"A" Cooling Steady State
at rated compressor Speed
80
67
95
(75)
"B-2" Cooling Steady State
at rated compressor Speed
80
80
80
80
70
70
70
70
70
70
67
67
67
67
60
60
60
60
60
60
82
82
67
87
47
17
62
47
35
35
(65)
(65)
(53.5)
(69)
43
SEER "B-1" Cooling Steady State
(Cooling) at minimum compressor Speed
Low ambient Cooling Steady State
at minimum compressor Speed
Intermediate Cooling Steady State
at Intermediate compressor Speed
5
Standard Rating-Heating
at rated compressor Speed
Low temperature Heating
at rated compressor Speed
15
Max temperature Heating
at minimum compressor Speed
56.5
43
HSPF
(Heating)
High temperature Heating
at minimum compressor Speed
Frost Accumulation
at rated compressor Speed
33
Frost Accumulation
at Intermediate compressor Speed
33
5
5 : At Intermediate compressor Speed
=("Cooling rated compressor speed" - "minimum compressor speed") / 3 + "minimum compressor speed".
OPERATING RANGE
(1) POWER SUPPLY
Rated voltage
Guaranteed Voltage
208/230 V
1 phase
60 Hz
Min.187 V 208 V 230 V Max.253 V
Outdoor unit
(2) OPERATION
Intake air temperature (°F)
Mode
Condition
Standard temperature
Maximum temperature
Minimum temperature
Maximum humidity
lndoor
78 %
Outdoor
DB
80
90
67
WB
67
73
DB
95
115
14
WB
—
—
—
Cooling
57
—
Standard temperature
Heating Maximum temperature
Minimum temperature
70
80
70
60
67
60
47
75
14
43
65
13
5
4
OUTLINES AND DIMENSIONS
Unit: inch
MUZ-FD09NA
MUZ-FD12NA
REQUIRED SPACE
Basically open 4 inch or more
without any obstruction in front
and on both sides of the unit.
15-3/4
Air in
Drain hole 1-5/8
Air in
1-9/16
2- 3/8 13/16 Oval hole
Air out
29/32
11-1/4
17/32
7/8
Open two sides of left,
right, or rear side.
handle
Liquid pipe :1/4 (flared)
Gas pipe :3/8 (flared)
11-29/32
6-23/32
5-15/16
19-11/16
31-1/2
2-23/32
6
5
WIRING DIAGRAM
MUZ-FD09NA MUZ-FD12NA
7
6
REFRIGERANT SYSTEM DIAGRAM
Unit:inch
MUZ-FD09NA
MUZ-FD12NA
4-way valve
Refrigerant pipe ø3/8
(with heat insulator)
Muffler
Outdoor heat
exchanger
temperature
thermistor
RT68
Stop valve
(with service port)
Outdoor
heat
Muffler
Discharge
temperature
thermistor
RT62
Flared connection
exchanger
Service
port
Ambient
temperature
thermistor
RT65
Compressor
Service
port
Defrost
thermistor
RT61
Capillary tube
O.D. 0.118 × I.D. 0.071
× 23-5/8
(ø3.0 × ø1.8
×
600)
Strainer
#100
Expansion
valve
Flared connection
Stop valve
R.V. coil
heating ON
cooling OFF
(with strainer)
Capillary tube
O.D. 0.118 × I.D. 0.079
× 9-7/16
(ø3.0 × ø2.0 × 240)
Refrigerant pipe 1/4
(with heat insulator)
Refrigerant flow in cooling
Refrigerant flow in heating
MAX. REFRIGERANT PIPING LENGTH and MAX. HEIGHT DIFFERENCE
Refrigerant piping : ft
Piping size O.D : in
Model
Max. Length
Max. Height difference
B
Gas
3/8
Liquid
1/4
A
MUZ-FD09NA
MUZ-FD12NA
65
40
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.
Refrigerant piping length (one way) : ft
Model
Outdoor unit precharged
2 lb. 9 oz.
25
0
30
40
50
60
65
MUZ-FD09NA
MUZ-FD12NA
1.62
4.86
8.10
11.34
12.96
Calculation : X oz. = 1.62/ 5 oz./ ft x (Refrigerant piping length (ft) - 25)
NOTE : Refrigerant piping exceeding 25 ft. requires additional refrigerant charge according to the calculation.
8
7 DATA
MUZ-FD09NA MUZ-FD12NA
7-1. PERFORMANCE DATA
1) COOLING CAPACITY
Indoor air
Outdoor intake air DB temperature (˚F)
85 95 105
TC SHC TPC TC SHC TPC TC SHC TPC TC SHC TPC TC SHC TPC
Model
IWB
(˚F)
71
67
63
75
115
11.0 6.9 0.58 10.3 6.5 0.63 9.7
6.1 0.68 9.0
6.8 0.65 8.4
7.6 0.62 7.7
5.6 0.72 8.3
6.4 0.69 7.7
6.9 0.66 7.0
5.2 0.75
5.8 0.72
6.3 0.69
MUZ-FD09NA
10.4 7.9 0.55 9.7
9.8 8.8 0.52 9.1
7.4 0.60 9.0
8.1 0.58 8.5
71
67
14.7 8.8 0.85 13.7 8.2 0.94 12.9 7.7 1.01 12.0 7.2 1.06 11.0 6.6 1.10
13.9 10.2 0.81 13.0 9.5 0.89 12.0 8.8 0.96 11.2 8.1 1.02 10.3 7.5 1.07
MUZ-FD12NA
63
13.1 11.3 0.77 12.1 10.5 0.85 11.3 9.7 0.92 10.3 8.9 0.98 9.4
8.1 1.02
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.
2) COOLING CAPACITY CORRECTIONS
Refrigerant piping length (one way : ft.)
25 (std.)
40
65
MUZ-FD09NA
MUY-FD12NA
1.0
0.954
0.878
3) HEATING CAPACITY
Indoor air
Outdoor intake air WB temperature (˚F)
35 43
Model
IDB
(˚F)
75
70
65
75
70
65
15
25
45
55
TC
6.3
6.7
6.9
7.9
8.4
8.6
TPC
0.56
0.54
0.52
0.73
0.71
0.68
TC
7.9
8.2
8.6
9.9
TPC
TC
9.4
TPC
0.73
0.71
0.69
0.96
0.93
0.91
TC
TPC
0.77
0.75
0.73
1.00
0.98
0.96
TC
TPC
0.78
0.77
0.74
1.02
1.00
0.97
TC
TPC
0.66
0.64
0.62
0.86
0.84
0.81
10.6
10.9
11.2
13.3
13.6
14.0
11.0
11.2
11.6
13.7
14.0
14.4
12.4
12.7
13.0
15.5
15.8
16.2
0.81
0.80
0.78
1.06
1.04
1.02
MUZ-FD09NA
MUZ-FD12NA
9.6
10.0
11.8
12.0
12.4
10.2
10.7
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.
9
7-2. PERFORMANCE CURVE
Cooling
MUZ-FD12NA
MUZ-FD09NA
SHF at rating condition = 0.76
SHF at rating condition = 0.73
= 307 CFM
= 350 CFM
Airflow
Airflow
Indoor
15
14
13
13
12
11
10
9
intak
Indoor intak
e air WB temperat
e air WB te
mperature (°F
ure
(°F)
12
11
10
9
)
71
67
63
71
67
63
8
7
1.2
1.1
1.0
0.9
0.8
0.7
71
67
63
rature (°F)
mpe
71
67
63
ure (°F)
0.7
0.6
0.5
mperat
WB te
WB te
e air
oor intak
Ind
oor intake air
Ind
65
75
85
95
105
115
65
75
85
95
105
115
Outdoor intake air DB temperature (°F)
Outdoor intake air DB temperature (°F)
Heating
MUZ-FD12NA
MUZ-FD09NA
= 381 CFM
65 70
75
Airflow
= 420 CFM
Airflow
20
18
12
10
65
70
75
16
14
12
8
6
10
8
6
75
70
65
1.1
1.0
0.9
0.8
0.6
0.4
75
70
65
0.8
0.7
0.6
15
25
35
45
55
15
25
35
45
55
Outdoor intake air WB temperature (°F)
Outdoor intake air WB temperature (°F)
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.
10
7-3. CONDENSING PRESSURE
Cooling
Data is based on the condition of indoor humidity 50 %.
Air flow should be set to High speed.
MUZ-FD09NA
(PSIG)
580
540
500
(PSIG)
180
175
170
165
160
155
150
145
140
135
130
125
120
86
80
460
86
80
75
420
70
380
75
70
340
300
260
68 70
75
80
85
90
95
100 105(°F)
68 70
75
80
85
90
95
100 105(°F)
Outdoor ambient temperature
Outdoor ambient temperature
MUZ-FD12NA
(PSIG)
580
540
500
460
420
380
340
300
(PSIG)
180
175
170
165
160
155
150
145
140
135
130
125
120
86
80
75
70
86
80
75
70
260
68 70
75
80
85
90
95
100 105(°F)
68 70
75
80
85
90
95
100 105(°F)
Outdoor ambient temperature
Outdoor ambient temperature
11
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-FD09NA
(PSIG)
400
(PSIG)
380
360
340
320
300
280
260
240
220
200
180
160
140
170
160
150
140
130
120
110
100
90
75
70
65
75
70
65
58Hz
58Hz
80
70
60
14
20 25 30 35 40 45 50 55 60 65 70(°F)
Outdoor ambient temperature
14 20 25 30 35 40 45 50 55 60 6570(°F)
Outdoor ambient temperature
MUZ-FD12NA
(PSIG)
400
(PSIG)
380
360
340
320
300
280
260
240
220
200
180
160
140
170
160
150
140
130
120
110
100
90
75
70
65
75
70
65
58Hz
58Hz
80
70
60
14
20 25 30 35 40 45 50 55 60 65 70(°F)
Outdoor ambient temperature
14 20 25 30 35 40 45 50 55 60 6570(°F)
Outdoor ambient temperature
12
7-4. STANDARD OPERATION DATA
Model
MSZ-FD09NA
MSZ-FD12NA
Item
Unit
Cooling
Heating
10,900
—
Cooling
Heating
13,600
—
Capacity
SHF
Btu/h
—
9,000
0.76
0.650
35
12,000
0.73
Input
kW
Hz
0.750
43
0.960
51
0.980
54
Rated frequency
Indoor unit
MSZ-FD09NA
MSZ-FD12NA
V,
phase,
Hz
Power supply
208/230 , 1 , 60
Input
kW
A
0.018
0.024
0.024
0.030
Fan motor current
Outdoor unit
0.19/0.17
0.25/0.23
0.25/0.23
0.32/0.29
MUZ-FD09NA
MUZ-FD12NA
V,
phase,
Hz
Power supply
208/230 , 1 , 60
Input
kW
A
0.632
0.726
0.936
0.950
Comp. current
2.96/2.68
3.39/3.06
4.40/3.97
4.43/4.01
Fan motor current
A
0.35/0.32
Condensing pressure
Suction pressure
PSIG
PSIG
˚F
376
154
143
112
51
355
108
144
108
46
402
148
161
117
51
392
104
159
115
45
Discharge temperature
Condensing temperature
Suction temperature
Comp. shell bottom temperature
Ref. pipe length
˚F
˚F
˚F
144
128
146
129
ft.
25
2 lb. 9 oz.
Refrigerant charge (R410A)
DB
Intake air temperature
WB
˚F
˚F
80
67
70
60
80
67
70
60
DB
Discharge air temperature
WB
˚F
59
100
—
56
105
—
˚F
56
54
Fan speed (High)
rpm
CFM
˚F
1,020
307 (Wet)
95
1,120
381
47
1,120
350 (Wet)
95
1,220
420
47
Airflow (High)
DB
Intake air temperature
WB
˚F
—
43
—
43
Fan speed
rpm
CFM
810
870
1,187
810
870
1,187
Airflow
1,102
1,102
13
7-5. CAPACITY AND INPUT CORRECTION BY INVERTER OUTPUT FREQUENCY
MUZ-FD09NA
Correction of Cooling capacity
Correction of Cooling total input
Correction of Heating total input
Correction of Heating capacity
2.0
1.5
1.5
1.0
0.5
1.5
1.0
0.5
3.0
2.0
1.0
1.0
0.5
(Hz)
(Hz)
150
(Hz)
(Hz)
150
0
50
100
150
0
50
100
0
50
100
150
0
50
100
The operational frequency of compressor
The operational frequency of compressor The operational frequency of compressor
The operational frequency of compressor
MUZ-FD12NA
Correction of Cooling capacity
1.5
Correction of Cooling total input
Correction of Heating capacity
Correction of Heating total input
1.5
1.0
0.5
1.5
1.0
0.5
2.0
1.0
0.5
1.0
(Hz)
(Hz)
150
(Hz)
(Hz)
150
0
50
100
150
0
50
100
0
50
100
150
0
50
100
The operational frequency of compressor
The operational frequency of compressor The operational frequency of compressor
The operational frequency of compressor
7-6. TEST RUN OPERATION (How to operate fixed-frequency operation)
1. Press EMERGENCY OPERATION switch to 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.
14
8
ACTUATOR CONTROL
MUZ-FD09NA
MUZ-FD12NA
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
Cooling
ON
OFF
OFF
. . . . . . . . . . . . . . . . . . . .
Dry
NOTE: The 4-way valve reverses for 5 seconds right before start-up of the compressor.
<COOL>
<HEAT>
5 seconds
5 seconds
ON
OFF
Compressor
R.V.coil
ON
OFF
ON
OFF
Outdoor fan
motor
8-3. RELATION BETWEEN MAIN SENSOR AND ACTUATOR
Actuator
Sensor
Purpose
Outdoor
fan motor
Indoor fan
motor
Compressor
LEV
R.V. coil
Discharge temperature thermistor
Indoor coil temperature thermistor
Protection
○ ○
Cooling : Coil frost prevention
Heating : High pressure protection
Cooling : High pressure protection
Heating : Defrosting
○
○ ○
○ ○
○ ○ ○ ○ ○
Defrost thermistor
Fin temperature thermistor
Protection
○
○
Outdoor heat exchanger temperature thermistor
Ambient temperature thermistor
High pressure protection
Low ambient temperature operation
○ ○ ○
○ ○ ○
15
9
SERVICE FUNCTIONS
MUZ-FD09VA
MUZ-FD12VA
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
Defrost finish temperature
41 °F (5 °C)
Soldered
(Initial setting)
JS
None
(Cut)
50 °F (10 °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 tempera-
ture. The pre-heat control prevents this interference. The pre-heat control turns ON when outside temperature is 68 °F (20
°C) or below. When pre-heat control is turned ON, compressor is energized. (about 50 W)
<JK> To activate the pre-heat control, cut the 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-FD09NA MUZ-FD12NA
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 con-
firming 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 to 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.
Lead wiring
Housing point
3. Troubleshooting procedure
1) First, check if the OPERATION INDICATOR lamp on the indoor unit is flashing on and off to indicate an abnormality.
To make sure, check how many times the abnormality indication is flashing on and off before starting service work.
2) Before servicing check that the connector and terminal are connected properly.
3) When the electronic control P.C. board seems to be defective, check the copper foil pattern for disconnection and the
components for bursting and discoloration.
4) Refer to 10-2. and 10-3.
16
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.
This mode is very useful when the unit needs to be repaired for the abnormality which doesn't recur.
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 doesn't 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.
And release the other two buttons after all LCD in operation display section of the
remote controller is displayed after 3 seconds.
1. Regardless of normal or ab-
normal condition, a short beep
is emitted once the signal is
received.
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 POWER lamp on the indoor unit blink at the interval of
Indoor unit is normal.
0.5 seconds?
But the outdoor unit might be abnormal because there are some abnor-
malities that can't be recalled with this way.
Confirm if outdoor unit is abnormal according to the detailed outdoor
unit failure mode recall function. (Refer to 10-2.2)
Blinks: Either indoor or outdoor unit is abnormal. Beep is emit-
No
(OFF)
ted at the same timing as the blinking of POWER lamp.
2
Yes
(Blinks)
Judgment of indoor/outdoor abnormality
Before blinking, does POWER lamp stay ON for 3 seconds?
Stays ON for 3 seconds (without beep):
The outdoor unit is abnormal.
Yes
No
The indoor unit is abnormal.
The outdoor unit is abnormal.
Check the blinking pattern, and confirm the abnormal point with the indoor unit
failure mode table. (Refer to indoor unit service manual.)
Check the blinking pattern, and confirm the abnormal point with the
outdoor unit failure mode table. (Refer to 10-2.3)
Make sure to check at least two consecutive blinking cycles.
2
Make sure to check at least two consecutive blinking cycles.
3
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 defective 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 once it's 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 0.5-
second interval
Blinking at 0.5-
second interval
2.5-second OFF
2.5-second OFF
ON
OFF
Beeps
Beeps
Beeps
Repeated cycle
Repeated cycle
Repeated cycle
3.Blinking pattern when the outdoor unit is abnormal:
Blinking at 0.5-
second interval
Blinking at 0.5-
2.5-second OFF
3-second ON
second interval
2.5-second OFF
3-second ON
ON
OFF
No beep
Beeps
No beep
Beeps
Repeated cycle
Repeated cycle
Repeated cycle
17
2. Flow chart of the detailed outdoor unit failure mode recall function
Operational procedure
The outdoor unit might be abnormal.
Confirm if outdoor unit is abnormal according to the following procedures.
Confirm that the remote controller is in 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
1. Regardless of normal or abnormal condition, 2 short
beeps are emitted as the signal is received.
Does POWER lamp on the indoor unit blink at the
interval of 0.5 seconds?
Blinks: The outdoor unit is abnormal. Beep is emitted
No
at the same timing as the blinking of POWER
(OFF)
lamp.
2
Yes
(Blinks
)
The outdoor unit is abnormal.
Check the blinking pattern, and confirm the abnormal point with the out-
door unit failure mode table (10-2.3.).
The outdoor unit is normal.
Make sure to check at least two consecutive blinking cycles.
2
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 accord-
ing to the left mentioned procedure.
Repair the defective 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" men-
tioned above.
NOTE: 1. Make sure to release the failure mode recall function once it's 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:
Blinking at 0.5-
second interval
Blinking at 0.5-
second interval
2.5-second OFF
3-second ON
2.5-second OFF
3-second ON
ON
OFF
No beep
Repeated cycle
Beeps
No beep
Repeated cycle
Beeps
Repeated cycle
18
3. Outdoor unit failure mode table
Indoor/outdoor
unit failure
mode recall
function
Outdoor unit
failure mode
recall function
POWER lamp
(Indoor unit)
Abnormal point
LED indication
Condition
Correspondence
(Failure mode / protection) (Outdoor P.C. board)
OFF
None (Normal)
—
—
—
—
—
2-time flash
2.5 seconds
OFF
Outdoor power system
Overcurrent protection stop is
•Reconnect connectors.
continuously performed 3 times within •Refer to 10-5. "How
1 minute after the compressor gets
started.
to check inverter/
compressor".
•Check stop valve.
—
○
○
3-time flash
Discharge temperature
1-time flash every
Thermistor shorts or opens during
compressor running.
•Refer to 10-5.
2.5 seconds thermistor
OFF
2.5 seconds
"Check of outdoor
thermistors".
Defrost thermistor
Defective outdoor
thermistors can be
identified by checking
the blinking pattern of
LED.
Fin temperature thermistor
3-time flash
2.5 seconds OFF
○
○
P.C. board temperature
thermistor
4-time flash
2.5 seconds OFF
Ambient temperature
thermistor
2-time flash
2.5 seconds OFF
4-time flash
2.5 seconds
OFF
Overcurrent
11-time flash
Large current flows into intelligent
•Reconnect compressor
connector.
2.5 seconds OFF
power module.
•Refer to 10-5. "How
to check inverter/
compressor".
—
—
○
○
•Check stop valve.
Compressor synchronous
abnormality (Compressor
start-up failure protection)
12-time flash
2.5 seconds OFF
Waveform of compressor current is
distorted.
•Reconnect compressor
connector.
•Refer to 10-5. "How
to check inverter/
compressor".
5-time flash
2.5 seconds
OFF
Discharge temperature
Temperature of discharge temperature •Check refrigerant
thermistor exceeds 241 °F (116 °C),
compressor stops.
circuit and refrigerant
amount.
Compressor can restart if discharge
temperature thermistor reads 212 °F
(100 °C) or less 3 minutes later.
•Refer to 10-5. "Check
of LEV".
—
—
—
—
○
6-time flash
2.5 seconds
OFF
High pressure
Temperature of indoor coil thermistor •Check refrigerant
exceeds 158 °F (70 °C) in HEAT mode. circuit and refrigerant
Temperature of defrost thermistor
exceeds 158 °F (70 °C) in COOL
mode.
amount.
•Check stop valve.
○
○
7-time flash
Fin temperature/ P.C. board
7-time flash
2.5 seconds OFF
Temperature of fin temperature
•Check around outdoor
unit.
2.5 seconds temperature
OFF
thermistor on the inverter P.C. board
exceeds 167 ~ 176 °F (75 ~ 80 °C), or •Check outdoor unit air
temperature of P.C. board temperature passage.
thermistor on the inverter P.C. board
exceeds 158 ~ 167 °F (70 ~ 75 °C).
—
—
•Refer to 10-5. "Check
of outdoor fan motor".
8-time flash
2.5 seconds
OFF
Outdoor fan motor
Outdoor fan has stopped 3 times in a •Refer to 10-5. "Check
row within 30 seconds after outdoor
fan start-up.
of outdoor fan motor".
Refer to 10-5. "Check
of inverter P.C. board".
—
○
○
9-time flash
2.5 seconds
OFF
Nonvolatile memory data
5-time flash
2.5 seconds OFF
Nonvolatile memory data cannot be
read properly.
•Replace the inverter
P.C. board.
○
10-time flash Discharge temperature
2.5 seconds
OFF
Temperature of discharge temperature •Refer to 10-5. "Check
thermistor has been 122 °F (50 °C) or of LEV".
—
less for 20 minutes.
•Check refrigerant
circuit and refrigerant
amount.
—
○
○
11-time flash DC voltage
8-time flash
DC voltage of inverter cannot be
detected normally.
•Refer to 10-5. "How
to check inverter/
compressor".
2.5 seconds
2.5 seconds OFF
OFF
—
Each phase current of
9-time flash
2.5 seconds OFF
Each phase current of compressor
cannot be detected normally.
compressor
12-time flash Overcurrent Compressor
2.5 seconds open-phase
OFF
10-time flash
2.5 seconds OFF
Large current flows into intelligent
power module (IPM).
The open-phase operation of
compressor is detected.
•Reconnect compressor
connector.
•Refer to 10-5. "How
to check inverter/
—
The interphase short out occurs in the compressor".
output of the intelligent power module
(IPM).
○
○
The compressor winding shorts out.
14-time flash Stop valve (Closed valve)
2.5 seconds
OFF
14-time flash
2.5 seconds OFF
Closed valve is detected by
compressor current.
•Check stop valve
○
NOTE: Blinking patterns of this mode differ from the ones of Troubleshooting check table (10-3.).
19
10-3. TROUBLESHOOTING CHECK TABLE
Abnormal point/
Condition
No.
Symptom
LED indication
Condition
Correspondence
Outdoor unit 1-time flash every Outdoor power sys- Overcurrent protection stop is continuously performed 3 times •Reconnect connector of compres-
does not oper- 2.5 seconds
ate.
tem
within 1 minute after the compressor gets started, or failure of sor.
restart of compressor has repeated 24 times.
1
•Refer to 10-5. "How to check in-
verter/ compressor".
•Check stop valve.
Outdoor thermistors Discharge temperature thermistor, fin temperature thermistor, •Refer to 10-5. "Check of outdoor
defrost thermistor, P.C. board temperature thermistor or ambi- thermistors".
ent temperature thermistor shorts or opens during compressor
running.
2
3
Outdoor control sys- Nonvolatile memory data cannot be read properly.
tem
•Replace inverter P.C. board.
(POWER lamp of the indoor unit lights up or flashes 7-time.)
6-time flash
Serial signal
Stop valve/
The communication fails between the indoor and outdoor unit •Refer to 10-5. "How to check
4
5
2.5 seconds OFF
for 3 minutes.
miswiring and serial signal error.
11-time flash
Closed valve is detected by compressor current.
•Check stop valve.
2.5 seconds OFF Closed valve
14-time flash Outdoor unit
2.5 seconds OFF (Other abnormality)
Outdoor unit is defective.
•Refer to 10-2.2. "Flow chart of the
detailed outdoor unit failure mode
recall function".
6
7
'Outdoor unit 2-time flash
Overcurrent protec- Large current flows into intelligent power module.
•Reconnect connector of compres-
stops and
2.5 seconds OFF tion
When overcurrent protection occurs within 10 seconds after sor.
restarts 3 min-
utes later' is
repeated.
compressor starts, compressor restarts after 15 seconds. •Refer to 10-5. "How to check in-
verter/compressor".
•Check stop valve.
3-time flash
Discharge tempera- Temperature of discharge temperature thermistor exceeds 241 •Check refrigerant circuit and refrig-
2.5 seconds OFF ture overheat protec- °F (116 °C), compressor stops. Compressor can restart if dis- erant amount.
8
9
tion
charge temperature thermistor reads 212 °F (100 °C) or less 3 •Refer to 10-5. "Check of LEV".
minutes later.
4-time flash
Fin temperature /P.C. Temperature of fin temperature thermistor on the heat sink ex- •Check around outdoor unit.
ceeds 167 ~ 176 °F (75 ~ 80 °C) or temperature of P.C. board •Check outdoor unit air passage.
2.5 seconds OFF board temperature
thermistor overheat temperature thermistor on the inverter P.C. board exceeds 158 •Refer to 10-5. "Check of outdoor
protection
~ 167 °F (70 ~ 75 °C).
fan motor".
5-time flash
High pressure pro-
Indoor coil thermistor exceeds 158 °F (70 °C) in HEAT mode. •Check refrigerant circuit and refrig-
10
11
2.5 seconds OFF tection
Defrost thermistor exceeds 158 °F (70 °C) in COOL mode.
erant amount.
•Check stop valve.
8-time flash
2.5 seconds OFF chronous abnormal-
ity
Compressor syn-
The waveform of compressor current is distorted.
•Reconnect connector of compres-
sor.
•Refer to 10-5. "How to check in-
verter/compressor".
10-time flash
2.5 seconds OFF
Outdoor fan motor
Outdoor fan has stopped 3 times in a row within 30 seconds
after outdoor fan start-up.
•Refer to 10-5. "Check of outdoor
fan motor.
•Refer to 10-5. "Check of inverter
P.C. board.
12
12-time flash
Each phase current Each phase current of compressor cannot be detected nor-
•Refer to 10-5. "How to check in-
verter/compressor".
13
14
15
2.5 seconds OFF of compressor
mally
13-time flash
2.5 seconds OFF
DC voltage
DC voltage of inverter cannot be detected normally.
•Refer to 10-5. "How to check in-
verter/compressor".
Outdoor unit 1-time flash
operates. 2.5 seconds OFF current protection
Frequency drop by Current from power outlet reaches the protection current, and The unit is normal, but check the
compressor frequency lowers.
following.
•Check if indoor filters are clogged.
•Check if refrigerant is short.
•Check if indoor/outdoor unit air cir-
culation is short cycled.
3-time flash
Frequency drop by Temperature of indoor coil thermistor exceeds 131 °F (55 °C)
2.5 seconds OFF high pressure pro-
tection
in HEAT mode, compressor frequency lowers.
16
17
Frequency drop by Indoor coil thermistor reads 46 °F (8 °C) or less in COOL
defrosting in COOL mode, compressor frequency lowers.
mode
4-time flash
Frequency drop by Temperature of discharge temperature thermistor exceeds 232 •Check refrigerant circuit and refrig-
2.5 seconds OFF discharge tempera- °F (111 °C), compressor frequency lowers.
ture protection
erant 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.
Inverter P.C. board(Parts side)
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”.
LED
Flashing →
0.5-second ON
0.5-second ON
2.5-second OFF
ON
2.5-second OFF
OFF
20
Abnormal point/
Condition
No.
18
Symptom
LED indication
Condition
Correspondence
Outdoor unit 7-time flash
Low discharge tem- Temperature of discharge temperature thermistor has been
operates. 2.5 seconds OFF perature protection 122 °F (50 °C) or less for 20 minutes.
•Refer to 10-5. "Check of LEV".
•Check refrigerant circuit and refrig-
erant amount.
8-time flash
PAM protection PAM: The overcurrent flows into IGBT (Insulated Gate Bipolar tran- This is not malfunction. PAM protec-
2.5 seconds OFF Pulse Amplitude
Modulation
sistor : TR821) or when the bus-bar voltage reaches 320 V or tion will be activated in the following
more, PAM stops and restarts.
cases;
19
20
1 Instantaneous power voltage drop
(Short time power failure)
2 When the power supply voltage is
high.
9-time flash
2.5 seconds OFF
Inverter check mode The connector of compressor is disconnected, inverter check •Check if the connector of the com-
mode starts.
pressor is correctly connected.
Refer to 10-5. "How to check
inverter/ compressor".
21
10-4. TROUBLE CRITERION OF MAIN PARTS
MUZ-FD09NA MUZ-FD12NA
Part name
Check method and criterion
Figure
Defrost thermistor
(RT61)
Measure the resistance with a tester.
Ambient temperature
thermistor (RT65)
Refer to 10-6. “Test point diagram and voltage”,1. “Inverter P.C.
board”, the chart of thermistor.
Outdoor heat ex-
changer temperature
thermistor (RT68)
Discharge tem-
perature 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”, the chart of thermistor.
Fin temperature
thermistor (RT64)
Measure the resistance between terminals using a tester.
(Winding temperature : -4 ~ 104 °F (-20 ~ 40 °C))
WHT
2
RED BLK
3
1
W
Normal
U-V
U-W
V-W
Compressor
1.52 ~ 2.17 Ω
V
U
Measure the resistance between lead wires using a tester.
(Part temperature : 14 ~ 104 °F (-10 ~ 40 °C))
WHT
RED BLK
2
3
1
Color of lead wire
Normal
Outdoor fan motor
R. V. coil (21S4)
W
RED – BLK
BLK – WHT
WHT – RED
11 ~ 16 Ω
V
U
Measure the resistance using a tester.
(Part temperature : 14 ~ 104 °F (-10 ~ 40 °C))
Normal
970 ~ 1380 Ω
Measure the resistance using a tester.
(Part temperature : 14 ~ 104 °F (-10 ~ 40 °C))
WHT
RED
ORN
LEV
Color of lead wire
WHT – RED
RED – ORN
YLW – BRN
BRN – BLU
Normal
Expansion valve coil
(LEV)
37 ~ 54 Ω
22
10-5. TROUBLESHOOTING FLOW
POWER lamp flashes 5-times.
Outdoor unit does not operate.
A How to check inverter/ compressor
Disconnect the connector (CN61) between
compressor and the intelligent power module
(IPM).
See 10-5. “Check of open phase”.
Replace the inverter P.C. board.
See 10-5. “Check of compressor”.
Check the voltage between terminals.
Are the voltages balanced?
Yes
No
Check the compressor.
B Check of open phase
●With the connector between the compressor and the intelligent power module disconnected,
activate the inverter and check if the inverter is normal by measuring the balance of voltage
between the terminals.
Output voltage 115 V
<< 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)
BLK (U)-RED (W)
WHT(V)-RED (W)
9-time flash
Measure AC voltage between the
lead wires at 3 points.
2.5-second OFF
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?
Replace the compressor.
No
No
Yes
Refer to 10-5. “Check of compressor
operation time”.
Does the compressor operate continuously?
Refer to 10-5. “Check of compressor start failure”.
Yes
OK.
23
D Check of compressor winding
●Disconnect the connector (CN61) between the compressor and intelligent power module, 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
<<Judgement>>
Refer to 10-4.
0[Ω] ················Abnormal [short]
Infinite[Ω] ·······Abnormal [open]
NOTE: Be sure to zero the ohmmeter before measurement.
E Check of compressor operation time
<<Judgement>>
0 second
●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.
Compressor starts
1 second
Abnormal
(IPM failure)
(Compressor winding short)
2 seconds
(TEST RUN OPERATION : Refer to 7-6.)
<<Measurement>>
Measure the time from the start of compressor to the stop of
compressor due to overcurrent.
Abnormal
(Compressor lock out)
(Starting defect)
Abnormal
(Poor contact,)
(Outdoor P.C. board defect)
(Disconnected connector)
10 seconds
10 minutes
Abnormal
(Refrigerant circuit defect)
(Closed valve)
Normal
F Check of compressor start failure
Confirm that 1~4 is normal.
• Electrical circuit check
1.Contact of the compressor connector (including CN61)
2.Output voltage of inverter P.C. board and balance of them (See 10-5. )
3.Direct current voltage between DB61(+) and (-) on the inverter P.C. board
4.Voltage between outdoor terminal block S1-S2
Check the refrigerant circuit.
Check the stop valve.
Does the compressor run for 10 seconds or
more after it starts?
Yes
No
No
After the compressor is heated with a drier,
Replace the compressor.
does the compressor start?
1
Yes
1
Heat the compressor with
a drier for about 20 minutes.
Do not recover refrigerant
gas while heating.
Compressor start failure. Activate pre-heat control.
(Refer to 9-2. "PRE-HEAT CONTROL SETTING")
Heating part
24
POWER lamp flashes 6-time.
The thermistors in the outdoor unit are abnormal.
G Check of outdoor thermistors
Disconnect the connector of thermistor in the outdoor P.C. board (see
below table), and measure the resistance of thermistor.
Replace the thermistor except RT64. When RT64 is
abnormal, replace the inverter P.C. board.
Is the thermistor normal? (Refer to 10-6.1.)
No
Yes
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?
Replace the inverter P.C. board.
No
Yes
OK.
(Cause is poor contact.)
Thermistor
Symbol
Connector, Pin No.
Board
Defrost
Discharge temperature
Fin temperature
RT61 Between CN641 pin1 and pin2
RT62 Between CN641 pin3 and pin4
RT64 Between CN642 pin1 and pin2
RT65 Between CN643 pin1 and pin2
Inverter P.C. board
Ambient temperature
Outdoor heat exchanger temperature RT68 Between CN644 pin1 and pin3
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 is not connected or R.V. coil is open, voltage is generated between the terminal pins of the connector
although any signal is not being transmitted to R.V. coil.
Check if CN721 is connected.
Unit operates COOL mode even if it is set to HEAT mode.
Disconnect connector (CN61)
between the compressor and the
intelligent power module.
Turn ON the power supply and
press EMERGENCY OPERATION
switch twice (HEAT mode).
Is there 230 VAC between CN721 and
on the inverter P.C. board 3 minutes
after the power supply is turned ON?
Replace the inverter
P.C. board.
No
Yes
Replace the 4-way valve.
Unit operates HEAT mode even if it is set to COOL mode.
Disconnect connector (CN61)
between the compressor and the
intelligent power module.
Turn ON the power supply and
press EMERGENCY OPERATION
switch once (COOL mode).
Is there 230 VAC between CN721 and
on the inverter P.C. board 3 minutes
after the power supply is turned ON?
Replace the inverter
P.C. board.
Yes
No
Replace the 4-way valve.
25
Outdoor fan motor does not operate.
I Check of outdoor fan motor
Disconnect CN932 from the inverter P.C. board, and
measure the resistance of the outdoor fan motor.
Is the outdoor fan motor normal?
(Refer to 10-4.)
Replace the outdoor fan motor.
No
Yes
Replace the inverter P.C. board.
Inverter does not operate.
J Check of power supply
Disconnect the connector (CN61)
between compressor and intelligent
power module.
Turn ON power supply and press
EMERGENCY OPERATION switch.
Rectify indoor/ outdoor
connecting wire.
Yes
Is there voltage 208 / 230 VAC
between the indoor terminal
block S1 and S2?
Replace the indoor
electronic control P.C.
board.
Does POWER lamp on the indoor
unit light up?
No
No
No
Yes
Is there voltage 280 ~ 370 VDC
between DB61 (+) and DB61 (–) on
the inverter P.C. board?
Dose LED on the inverter P.C.
board light up or flash? (Refer
to 10-6.1.)
Replace the inverter
P.C. board.
Yes
(Refer to 10-6.1.)
Yes
No
280 ~ 370 VDC
If light up, OK.
If flash, refer to 10-3.
Check the electric parts in main circuit.
DB61
Inverter P.C. board
(Solder side)
26
Heating/Cooling does not work sufficiently.
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.
And release the other two buttons after all LCD except
the set temperature in operation display ection of the
remote controller is displayed after 3 seconds.
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·······"?
OK.
Do you feel the expansion valve vibrate
Yes
on touching it ?
No
Is LEV coil properly fixed to
the expansion valve?
Properly fix the LEV coil to the expansion valve.
No
Yes
Measure each voltage between connector
pins of CN724 on the inverter P.C. board.
1.Pin (-) — Pin (+)
2.Pin (-) — Pin (+)
Does the resistance of LEV
coil have the characteristics?
(Refer to 10-4.)
Replace the inverter P.C.
board.
3.Pin (-) — Pin (+)
4.Pin (-) — Pin (+)
Is there about 3 ~ 5 VAC between each?
NOTE: Measure the voltage by an analog
tester.
Yes
No
No
Replace the LEV coil.
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.
27
Outdoor fan motor does not operate, or stops immediately after starting up.
L Check of inverter P.C. board
Check the outdoor fan motor.
(Refer to10-5. .)
Is the fuse (F901) blown on the in-
verter P.C. board?
Yes
No
Inverter P.C. board
(Solder side)
Check the connection of the connectors
(CN932) of the outdoor fan motor.
If the connection is poor, make it correct.
CN932
Operate the outdoor unit by starting
EMERGENCY OPERATION.
Check the corresponding parts
following LED indication.
(Refer to 10-3.)
Check the LED indication on the in-
verter P.C. board.
Does the LED flash 10-time?
No
Yes
(10-time flash)
Replace the inverter P.C. board.
28
• Unit cannot operate neither by the remote controller nor by EMERGENCY OPERATION switch.
Indoor unit does not operate.
• POWER lamp flashes ON and OFF in every 0.5 seconds.
Outdoor unit doesn’t operate.
M How to check miswiring and serial signal error (outdoor unit does not work)
Turn OFF the power supply.
Is there rated voltage in the
Check the power supply.
power supply?
No
No
Yes
Turn ON the power supply.
Is there rated voltage between
outdoor terminal block S1 and
S2?
Yes
Check the wiring.
Press EMERGENCY OPERATION switch once.
Does AREA-L lamp light up? <Confirmation of
the power to the indoor unit>
No
No
Yes
Is there any miswiring,
poor contact, or wire
disconnection of the
indoor/outdoor connect-
ing wire?
Is serial signal error indicated 6 minutes later?
Yes
Correct them.
Yes
No
A
Turn OFF the power supply.
Check once more if the indoor/outdoor
connecting wire is not miswiring.
B
1. Miswiring may damage indoor electronic control P.C.
board during the operation.
Be sure to confirm the wiring is correct before the opera-
tion starts.
Short-circuit outdoor terminal block S2
and S3.
1
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 or the outdoor electronic control P.C.
board is normal, LED blinks 6 times after 3 minutes.
Turn ON the power supply.
Does the LED on the inverter P.C. board or
the outdoor electronic control P.C. board
repeat "3.6-second-OFF and 0.8-second-
Replace the inverter P.C. board or the out-
door electronic control P.C. board.
2
No
(Lighted
or not
ON quick blinking"?
3
2. Be careful to the residual
voltage of smoothing capacitor.
Yes
lighted)
Turn OFF the power supply.
Remove the short-circuit between
outdoor terminal block S2 and S3.
Turn ON the power supply.
Is there amplitude of 10 to 20 VDC
between outdoor terminal block S2 and
S3? <Confirmation of serial signal>
Yes
Is there any error of the in-
Replace the indoor/
outdoor connecting
wire.
door/outdoor connecting wire,
such as the damage of the wire,
intermediate connection, poor
contact to the terminal block?
No
A
No
Yes
• Turn OFF inverter-controlled lighting
equipment.
• Turn OFF the power supply and then
turn ON again.
• Press EMERGENCY OPERATION
switch.
Is there any error of the in-
door/outdoor connecting wire,
such as the damage of the wire,
intermediate connection, poor
contact to the terminal block?
No
Is there rated voltage between
indoor terminal block S1 and S2?
<Confirmation of power voltage>
Replace the indoor/
outdoor connecting
wire.
• Reinstall
No
Yes
either the unit
or the light
each other
Yes
away.
Is serial signal
error indicated 6
minutes later?
• Attach a filter
on remote
control receiv-
ing section
of the indoor
unit.
No
Yes
Replace the indoor electronic control P.C. board.
Be sure to release the failure-mode recall function
after checking.
B
29
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., or is
the distance between the antennas and
the outdoor unit within 9.91 ft.?
Extend the distance between the antennas and
the indoor unit, and/or the antennas and the
outdoor unit.
Yes
No
Is the distance between the TV sets or
radios and the indoor unit within 3.28
ft., or is the distance between the TV
sets or radios and the outdoor unit
within 9.91 ft.?
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
No
Are the antennas damaged?
Is the coaxial cable damaged?
Is there any poor contact in the anten-
na wiring?
Replace or repair the antenna.
Replace or repair the coaxial cable.
Yes
Yes
No
Is the indoor/outdoor connecting wire
of the air conditioner and the wiring of
the antennas close?
Extend the distance between the indoor/outdoor
connecting wire of the air conditioner and the wir-
ing of the antennas.
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 elec-
tromagnetic 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.
30
10-6. TEST POINT DIAGRAM AND VOLTAGE
1. Inverter P.C. board
MUZ-FD09NA MUZ-FD12NA
Smoothing
capacitor
(C62)
Smoothing
capacitor
(C63)
Smoothing
capacitor
(C61)
Fuse(F701)
250 V 3.15 A
DB61
Back side of unit
DC260 ~300 V
(-)
(+)
Fuse(F801)
AC 208 / 230 V
250 V 3.15 A
R.V.coil
(CN721)
208 / 230 VAC
Fuse(F901)
250 V 3.15 A
Output to
drive com-
pressor
(LDU,
AC208/230 V
LDV,
LDW)
Jumper wire
for pre-heat
control setting
(JK)
LEV
connector
(CN724)
Jumper wire for
changing defrost
setting (JS)
Front side of unit
Defrost thermistor(RT61)
Ambient temperature thermistor(RT65)
Outdoor heat exchanger temperature thermistor(RT68)
Fin temperature thermistor(RT64)
200
100
90
80
70
60
50
40
30
20
10
0
180
160
140
120
100
80
Discharge temperature thermistor(RT62)
700
600
500
400
300
200
100
0
60
40
20
0
32 50 68 86 104 122 140 158 176 194 212 230 248
32 50 68 86 104 122 140 158 176
-4
14 32 50 68 86 104
Temperature(°F)
Temperature(°F)
Temperature(°F)
31
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
Slide the sleeve.
Hold the sleeve, and
Pull the terminal while
pull out the terminal
slowly.
pushing the locking
lever.
Locking lever
Connector
11-1. MUZ-FD09NA MUZ-FD12NA
OPERATING PROCEDURE
NOTE : Turn OFF power supply before disassembling.
PHOTOS
1. Removing the cabinet
Photo 1
(1) Remove the screw fixing the service panel. (See
Photo 1.)
Screws
of the top
panel
(2) Pull down the service panel and remove it. (See Photo
1.)
(3) Remove the screws fixing the conduit cover. (See
Photo 2.)
Screw of the
cabinet
Screws of
the top panel
Back
panel
(4) Remove the conduit cover. (See Photo 2.)
(5) Disconnect the power supply wire and indoor/outdoor
connecting wire.
(6) Remove the screws fixing the top panel. (See Photo 1.)
(7) Remove the top panel. (See Photo 1.)
(8) Remove the screws fixing the cabinet.
(9) Remove the cabinet.
Screw of
the service
panel
(10) Remove the screws fixing the back panel.
(11) Remove the back panel.
Photo 2
Hooks
Screw of the
conduit cover
Screws of
Service
panel
the cabinet
Conduit plate
Conduit cover
32
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;
Photo 3
Screws of the
relay panel
<Inverter P.C. board>
CN721 (R.V.coil)
CN932 (Fan motor)
CN641 (Defrost thermistor and discharge temperature ther-
mistor)
CN643 (Ambient temperature thermistor)
CN644 (Outdoor heat exchanger temperature thermistor)
CN724 (LEV)
(3) Remove the compressor connector (CN61).
(4) Remove the screws fixing the relay panel. (See Photo 3.)
(5) Remove the inverter assembly. (See Photo 4.)
(6) Remove the screw of the ground wire and screw of the
T.B.support. (See Photo 4.)
(7) Remove the inverter P.C. board from the inverter assembly.
Photo 4 (inverter assembly)
Inverter
P.C. board
Screw of the
T.B.support
Heat sink
T.B.support
3. Removing R.V. coil
(1) Remove the cabinet and panels. (Refer to 1.)
(2) Remove the R.V. coil. (See Photo 5.)
Screw of the
ground wire
4. Removing the discharge temperature thermistor,
defrost thermistor and outdoor heat exchanger tem-
perature thermistor.
Photo 5
R.V. coil
(1) Remove the cabinet and panels. (Refer to 1.)
(2) Pull out the discharge temperature thermistor from its hold-
er. (See Photo 5.)
(3) Pull out the defrost thermistor from its holder. (See Photo 6.)
(4) Pull out the outdoor heat exchanger temperature thermistor
from its holder. (See Photo 6.)
Discharge temperature thermistor
33
OPERATING PROCEDURE
PHOTOS
Photo 6
5. Removing outdoor fan motor
(1) Remove the cabinet and panels. (Refer to 1.)
(2) Disconnect the connectors for outdoor fan motor.
(3) Remove the propeller nut. (See Photo 7.)
(4) Remove the propeller. (See Photo 7.)
Outdoor heat
exchanger tempera-
ture thermistor
(5) Remove the screws fixing the fan motor. (See Photo 7.)
(6) Remove the fan motor.
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.
Defrost thermistor
Photo 7
Screws of the outdoor fan motor
(4) Detach the welded part of the suction and the discharge
pipe connected with compressor.
(5) Remove the nuts of compressor legs.
(6) Remove the compressor.
(7) Detach the welded part of pipes connected with 4-way
valve. (See Photo 8.)
Propeller nut
Propeller
Photo 8
Welded parts of 4-way valve
34
35
TM
HEAD OFFICE: TOKYO BLDG., 2-7-3, MARUNOUCHI, CHIYODA-KU, TOKYO 100-8310, JAPAN
Copyright 2008 MITSUBISHI ELECTRIC ENGINEERING CO.,LTD
Distributed in Jan. 2008. No. OBH498 7
Made in Japan
New publication, effective Jan. 2008
Specifications subject to change without notice.
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