Download Mitsubishi MUZ-FD12NA- U1 Service manual

Revision B:
• 7. DATA has been corrected.
Please void OBH498 REVISED EDITION-A.
SPLIT-TYPE AIR CONDITIONERS
OUTDOOR UNIT
No. OBH498
HFC
SERVICE MANUAL
REVISED EDITION-B
utilized
R410A
Models
MUZ-FD09NA
MUZ-FD09NAMUZ-FD12NA
MUZ-FD12NA-
U1
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.
Revision A:
• 3. SPECIFICATION has been corrected.
Revision B:
• 7. DATA has been corrected.
2
1
TECHNICAL CHANGES
MUZ-FD09NA
MUZ-FD09NA MUZ-FD12NA
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
Capacity
Rated (Minimum~Maximum)
Capacity Rated
Power consumption
Rated (Minimum~Maximum)
Power consumption Rated
MUZ-FD09NA
Cooling 1
Heating 47
Heating 17
Cooling 1
Heating 47
Heating 17
EER 1 [SEER] 3
Cooling
Heating
HSPF IV (V) 4
COP
Heating 1
Power supply
Max. fuse size (time delay)
Min. circuit ampacity
Fan motor
Model
Compressor
Btu/h
Btu/h
Btu/h
W
W
W
1
2
1
2
V , phase , Hz
A
A
F.L.A
R.L.A
L.R.A
Refrigeration oil cc. (Model)
Refrigerant control
Sound level 1
Cooling
Heating
dB(A)
dB(A)
W
D
H
in.
in.
in.
Ib.
Defrost method
Dimensions
Weight
External finish
Remote controller
Control voltage (by built-in transformer)
Refrigerant piping
Liquid
Refrigerant pipe size
(Min. wall thickness)
Gas
Indoor
Connection method
Outdoor
Between the indoor & Height difference
outdoor units
Piping length
Refrigerant charge (R410A)
VDC
in.
in.
ft.
ft.
MUZ-FD12NA
9,000 (2,800~9,000)
12,000 (2,800~12,000)
10,900 (3,000~18,000)
13,600 (3,000~21,000)
12,500
13,600
650 (160~650)
960 (160~960)
750 (150~2,400)
980 (150~2,400)
1,730
1,780
13.8 [23.0]
12.5 [22.0]
10.55 (7.4)
10.55 (7.4)
4.26
4.07
208/230 , 1 , 60
15
12
0.56
SNB130FQAH
8.6
10.8
450 (NEO22)
Liner expansion valve
48
48
49
49
Reverse cycle
31-1/2
11-1/4
21-5/8
80
Munsell 3Y 7.8/1.1
Wireless type
12 - 24
Not supplied
1/4 (0.0315)
3/8 (0.0315)
Flared
Flared
40
65
2 lb. 9 oz.
NOTE: Test conditions are based on ARI 210/240.
1: Rating conditions (Cooling) — Indoor: 80˚FDB, 67˚FWB, Outdoor: 95˚FDB, (75˚FWB)
(Heating) — Indoor: 70˚FDB, 60˚FWB, Outdoor: 47˚FDB, 43˚FWB
2:
(Heating) — Indoor: 70˚FDB, 60˚FWB, Outdoor: 17˚FDB, 15˚FWB
4
Rated frequency
Rated frequency
Maximum frequency
Test condition
3, 4
ARI
Mode
Indoor air condition (°F)
Dry bulb
Wet bulb
Test
Outdoor air condition (°F)
Dry bulb
Wet bulb
"A" Cooling Steady State
at rated compressor Speed
80
67
95
(75)
"B-2" Cooling Steady State
at rated compressor Speed
80
67
82
(65)
80
67
82
(65)
Low ambient Cooling Steady State
at minimum compressor Speed
80
67
67
(53.5)
Intermediate Cooling Steady State
at Intermediate compressor Speed 5
80
67
87
(69)
Standard Rating-Heating
at rated compressor Speed
70
60
47
43
Low temperature Heating
at rated compressor Speed
70
60
17
15
70
60
62
56.5
70
60
47
43
Frost Accumulation
at rated compressor Speed
70
60
35
33
Frost Accumulation
at Intermediate compressor Speed 5
70
60
35
33
SEER "B-1" Cooling Steady State
(Cooling) at minimum compressor Speed
Max temperature Heating
at minimum compressor Speed
HSPF
(Heating) High temperature Heating
at minimum compressor Speed
5: At Intermediate compressor Speed
= ("Cooling rated compressor speed" - "minimum compressor speed") / 3 + "minimum compressor speed".
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
Indoor
Outdoor
DB
80
90
67
WB
67
73
57
DB
95
115
14
70
80
60
67
70
60
47
75
5
15 (- U model)
78 %
WB
—
—
—
—
5
43
65
4
14 (- U model)
4
OUTLINES AND DIMENSIONS
MUZ-FD09NA MUZ-FD12NA
Unit: inch
REQUIRED SPACE
1-3/4
15-3/4
Drain hole
1-5/8
. or
13-9/16
11/16
Air out
12 ~ 12-3/4
Air in
Air in
4 in
. or
re
14
mo
. or
8 in
13/16 Oval hole
29/32
11-1/4
17/32
Open two sides of left,
right, or rear side.
Liquid pipe
Gas pipe
5-7/8
2
11-1/32
handle
11-29/32
5-15/16
6-23/32
19-11/16
31-1/2
e
mor
mo
re
7/8
13/32
4 in
1-9/16
2- 3/8
21-5/8
Basically open 4 inch or more
without any obstruction in front
and on both sides of the unit.
2-23/32
6
:1/4 (flared)
:3/8 (flared)
in.
or m
ore
5
WIRING DIAGRAM
MUZ-FD09NA MUZ-FD12NA
7
6
REFRIGERANT SYSTEM DIAGRAM
MUZ-FD09NA MUZ-FD12NA
Unit: inch
4-way valve
Refrigerant pipe ø3/8
(with heat insulator)
Muffler
Stop valve
(with service port)
Discharge
temperature
thermistor
RT62
Service
port
Flared connection
Outdoor
heat
exchanger
Muffler
Service
port
Outdoor heat
exchanger
temperature
thermistor
RT68
Ambient
temperature
thermistor
RT65
Compressor
Defrost
thermistor
RT61
Capillary tube
O.D. 0.118 × I.D. 0.071
× 23-5/8
(ø3.0 × ø1.8 × 600)
Expansion
valve
Flared connection
Stop valve
(with strainer)
Refrigerant pipe ø1/4
(with heat insulator)
Strainer
#100
R.V. coil
heating ON
cooling OFF
Capillary tube
O.D. 0.118 × I.D. 0.079
× 9-7/16
(ø3.0 × ø2.0 × 240)
Refrigerant flow in cooling
Refrigerant flow in heating
MAX. REFRIGERANT PIPING LENGTH and MAX. HEIGHT DIFFERENCE
Model
MUZ-FD09NA
MUZ-FD12NA
Refrigerant piping: ft.
Max. Length
Max. Height difference
A
B
65
Piping size O.D: in.
Gas
Liquid
3/8
1/4
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.
Model
Outdoor unit precharged
MUZ-FD09NA
MUZ-FD12NA
2 lb. 9 oz.
Refrigerant piping length (one way): ft.
30
40
50
60
25
0
1.62
4.86
8.10
11.34
65
12.96
Calculation: X oz. = 1.62 / 5 oz. / ft. × (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
Model
MUZ-FD09NA
MUZ-FD12NA
71
67
63
71
67
TC
11.0
10.4
9.8
14.7
13.9
75
SHC
6.9
7.9
8.8
8.8
10.2
Outdoor intake air DB temperature (˚F)
85
95
105
TPC TC SHC TPC TC SHC TPC TC SHC
0.58 10.3 6.5 0.63 9.7
6.1 0.68 9.0
5.6
0.55 9.7
7.4 0.60 9.0
6.8 0.65 8.4
6.4
0.52 9.1
8.1 0.58 8.5
7.6 0.62 7.7
6.9
0.85 13.7 8.2 0.94 12.9 7.7 1.01 12.0 7.2
0.81 13.0 9.5 0.89 12.0 8.8 0.96 11.2 8.1
115
TPC TC SHC TPC
0.72 8.3
5.2 0.75
0.69 7.7
5.8 0.72
0.66 7.0
6.3 0.69
1.06 11.0 6.6 1.10
1.02 10.3 7.5 1.07
63
13.1
11.3
0.77 12.1 10.5 0.85
0.98
IWB (˚F)
11.3
9.7
0.92 10.3
8.9
9.4
8.1
TPC
0.78
0.77
0.74
1.02
1.00
0.97
TC
12.4
12.7
13.0
15.5
15.8
16.2
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
1.0
0.954
0.878
MUY-FD12NA
3) HEATING CAPACITY
Indoor air
Model
MUZ-FD09NA
MUZ-FD12NA
IDB (˚F)
75
70
65
75
70
65
5
TC
4.8
5.2
5.5
6.0
6.5
6.8
15
TPC
0.44
0.42
0.41
0.58
0.55
0.53
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
Outdoor intake air WB temperature (˚F)
25
35
43
TC TPC TC TPC TC TPC
7.9 0.66 9.4 0.73 10.6 0.77
8.2 0.64 9.6 0.71 10.9 0.75
8.6 0.62 10.0 0.69 11.2 0.73
9.9 0.86 11.8 0.96 13.3 1.00
10.2 0.84 12.0 0.93 13.6 0.98
10.7 0.81 12.4 0.91 14.0 0.96
45
TC
11.0
11.2
11.6
13.7
14.0
14.4
55
TPC
0.81
0.80
0.78
1.06
1.04
1.02
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-FD09NA
MUZ-FD12NA
SHF at rating condition = 0.76
Airflow = 307 CFM
11
10
WB te
mpera
ture (°
F
)
9
71
67
63
8
Total power consumption
(kW)
7
0.7
e air
r intak
Indoo
0.6
ture
mpera
WB te
(°F)
75
85
95
71
67
63
105
14
ir W
B te
13
mpe
12
ratu
re (°
F)
11
10
71
67
63
9
0.5
65
Indo
or in
take
a
15
Total capacity
( 103 Btu/h)
Indoo
r inta
ke air
12
Total power consumption
(kW)
Total capacity
( 103 Btu/h)
13
SHF at rating condition = 0.73
Airflow = 350 CFM
115
1.2
1.1
1.0
0.9
r
Indoo
e air
intak
ture
mpera
WB te
(°F)
71
67
63
0.8
0.7
65
Outdoor intake air DB temperature (°F)
75
85
95
105
115
Outdoor intake air DB temperature (°F)
Heating
MUZ-FD12NA
MUZ-FD09NA
Airflow = 381 CFM
8
e
tak
r in
oo
d
n
I
6
°F)
F)
re (°
16
14
B
air D
take
or in
Indo
12
10
tu
pera
tem
65
70
75
8
6
4
Total power consumption
(kW)
Airflow = 420 CFM
18
Total capacity
( 103 Btu/h)
10
(
ure
rat
pe
em
t
DB
air
65 70 75
0.8
D
ke air
r inta
Indoo
)
re (°F
peratu
B tem
0.6
75
70
65
Total power consumption
(kW)
Total capacity
( 103 Btu/h)
12
75
70
65
1.0
0.9
F)
re (°
tu
0.8
air
take
or in
Indo
0.7
0.6
DB te
ra
mpe
0.5
5
15
25
35
45
55
Outdoor intake air WB temperature (°F)
0.4
5
15
25
35
45
55
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
500
460
420
86
80
75
70
°F)
re (
atu
per
380
oor
Ind
340
m
B te
D
300
260
68 70
75
80
85
90
95
100
105(°F)
(PSIG)
180
175
170
165
160
155
150
145
140
135
130
125
120
68 70
rature (°F)
Indoor DB tempe
86
Suction pressure
Condensing pressure
540
Outdoor ambient temperature
80
75
70
75
80
85
90
95
Outdoor ambient temperature
100
105(°F)
MUZ-FD12NA
(PSIG)
580
500
460
86
80
75
70
)
°F
re (
420
atu
per
m
B te
D
oor
Ind
380
340
300
260
68 70
75
80
85
90
95
100
105(°F)
(PSIG)
180
175
170
165
160
155
150
145
140
135
130
125
120
68 70
Suction pressure
Condensing pressure
540
Outdoor ambient temperature
11
rature (°F)
Indoor DB tempe
86
80
75
70
75
80
85
90
95
Outdoor ambient temperature
100
105(°F)
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)
170
360
B
rD
doo
Condensing pressure
340
75
70
65
In
320
300
280
260
240
75
70
65
160
°F)
re(
atu
per
m
e
t
150
140
Suction pressure
380
58Hz
130
120
110
Ind
100
B
rD
oo
(
re
atu
er
p
tem
°F
)
58Hz
90
220
80
200
180
70
160
60
50
140
5
10 15 20 25 30 35 40 45 50 55 60 65 70(°F)
5
10
15
20
25
30
35
40
45
50
55
60
65 70(°F)
Outdoor ambient temperature
Outdoor ambient temperature
MUZ-FD12NA
(PSIG)
400
(PSIG)
170
380
°F)
per
em
Bt
rD
doo
340
320
150
70
65
In
140
130
300
280
260
240
58Hz
220
Suction pressure
Condensing pressure
75
a
360
75
70
65
160
(
ture
120
B
rD
oo
Ind
110
100
e(
tur
ra
e
p
tem
°F
)
58Hz
90
80
200
180
70
160
60
50
140
5
10 15 20 25 30 35 40 45 50 55 60 65 70(°F)
5
10
15
20
25
30
35
40
45
50
55
Outdoor ambient temperature
Outdoor ambient temperature
12
60
65 70(°F)
7-4. STANDARD OPERATION DATA
Model
Item
Unit
Total
Capacity
Btu/h
10,900
—
0.76
—
0.73
—
0.650
0.750
0.960
0.980
Rated frequency
Hz
35
43
51
54
MSZ-FD09NA
V,
phase,
Hz
kW
Input
Fan motor current
Outdoor unit
A
MSZ-FD12NA
208/230 , 1 , 60
0.018
0.024
0.024
0.19/0.17
0.25/0.23
MUZ-FD09NA
0.030
0.25/0.23
0.32/0.29
MUZ-FD12NA
V,
phase,
Hz
kW
0.632
0.726
0.936
0.950
Comp. current
A
2.96/2.68
3.39/3.06
4.40/3.97
4.43/4.01
Fan motor current
A
Power supply
208/230 , 1 , 60
0.35/0.32
Condensing pressure
PSIG
376
355
402
392
Suction pressure
PSIG
154
108
148
104
Discharge temperature
˚F
143
144
161
159
Condensing temperature
˚F
112
108
117
115
Suction temperature
˚F
51
46
51
45
Comp. shell bottom temperature
˚F
144
128
146
129
Ref. pipe length
ft.
80
70
25
Refrigerant charge (R410A)
Intake air temperature
Indoor unit
13,600
kW
Input
Discharge air temperature
2 lb. 9 oz.
DB
80
70
˚F
67
60
67
60
DB
˚F
59
100
56
105
WB
Fan speed (High)
Intake air temperature
˚F
WB
Airflow (High)
Outdoor unit
12,000
Input
Power supply
Electrical circuit
9,000
MSZ-FD12NA
Cooling
Heating
SHF
Indoor unit
Refrigerant circuit
MSZ-FD09NA
Cooling
Heating
˚F
56
—
54
—
rpm
1,020
1,120
1,120
1,220
CFM
307 (Wet)
381
350 (Wet)
420
DB
˚F
95
47
95
47
WB
˚F
—
43
—
43
Fan speed
rpm
810
870
810
870
Airflow
CFM
1,102
1,187
1,102
1,187
13
7-5. CAPACITY AND INPUT CORRECTION BY INVERTER OUTPUT FREQUENCY
MUZ-FD09NA
Correction of Cooling total input
0.5
0
50
100
Capacity correction factors
Input correction factors
Capacity correction factors
1.0
1.0
0.5
150 (Hz)
Correction of Heating total input
Correction of Heating capacity
2.0
1.5
0
50
100
Input correction factors
Correction of Cooling capacity
1.5
1.5
1.0
0.5
0
150 (Hz)
50
100
3.0
2.0
1.0
150 (Hz)
The operational frequency of compressor The operational frequency of compressor The operational frequency of compressor
0
50
100
150 (Hz)
The operational frequency of compressor
MUZ-FD12NA
Correction of Cooling total input
0.5
0
50
100
150 (Hz)
Capacity correction factors
Input correction factors
Capacity correction factors
1.0
1.0
0.5
0
Correction of Heating total input
Correction of Heating capacity
1.5
1.5
50
100
150 (Hz)
Input correction factors
Correction of Cooling capacity
1.5
1.0
0.5
0
50
100
150 (Hz)
The operational frequency of compressor The operational frequency of compressor The operational frequency of compressor
2.0
1.0
0
50
100
150 (Hz)
The operational frequency of compressor
7-6. TEST RUN OPERATION (How to operate fixed-frequency 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.
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 . . . . . . . . . . . . . . . . . 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
Purpose
Protection
Cooling: Coil frost prevention
Heating: High pressure protection
Cooling: High pressure protection
Heating: Defrosting
Fin temperature thermistor
Protection
Outdoor heat exchanger temperature thermistor
High pressure protection
Ambient temperature thermistor
Low ambient temperature operation
Compressor
LEV
○
○
○
○
○
○
○
○
○
○
○
○
○
○
15
Actuator
Outdoor
fan motor
○
○
○
○
R.V. coil
Indoor fan
motor
○
○
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
JS
Defrost finish temperature
Soldered
(Initial setting)
41°F (5°C)
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 temperature. 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 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.
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.
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.
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 abnormal 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
0.5 seconds?
Blinks: Either indoor or outdoor unit is abnormal. Beep is emitted at the same timing as the blinking of POWER lamp.
2
Judgment of indoor/outdoor abnormality
No
(OFF)
Indoor unit is normal.
But the outdoor unit might be abnormal because there are some abnormalities that can not 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)
Yes
(Blinks)
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.
Check the blinking pattern, and confirm the abnormal point with the indoor unit
failure mode table. (Refer to indoor unit service manual.)
Make sure to check at least two consecutive blinking cycles. 2
The outdoor unit is abnormal.
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. 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 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
3.Blinking pattern when the outdoor unit is abnormal:
Blinking at 0.52.5-second OFF
3-second ON
second interval
Beeps
Repeated cycle
2.5-second OFF
3-second ON
Blinking at 0.5second interval
ON
OFF
No beep
Repeated cycle
Beeps
No beep
Repeated cycle
17
Beeps
Repeated cycle
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
Does POWER 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 POWER
lamp. 2
1. Regardless of normal or abnormal condition, 2 short
beeps are emitted as the signal is received.
No
(OFF)
Yes
(Blinks)
The outdoor unit is abnormal.
Check the blinking pattern, and confirm the abnormal point with the 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 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" mentioned above.
NOTE: 1. Make sure to release the failure mode recall function once 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
3-second ON
Blinking at 0.5second interval
2.5-second OFF
3-second ON
Blinking at 0.5second interval
ON
OFF
No beep
Repeated cycle
No beep
Repeated cycle
Beeps
18
Beeps
Repeated cycle
3. Outdoor unit failure mode table
POWER lamp
(Indoor unit)
Abnormal point
(Failure mode / protection)
Condition
Correspondence
—
—
—
—
—
Overcurrent protection stop is
continuously performed 3 times within
1 minute after the compressor gets
started.
• Reconnect connectors.
• Refer to 10-5. "How
to check inverter/
compressor".
• Check stop valve.
○
○
Thermistor shorts or opens during
compressor running.
• Refer to 10-5. "Check
of outdoor thermistors".
Defective outdoor
thermistors can be
identified by checking
the blinking pattern of
LED.
○
○
• Reconnect compressor
connector.
• Refer to 10-5. "How
to check inverter/
compressor".
• Check stop valve.
—
○
• Reconnect compressor
connector.
• Refer to 10-5. "How
to check inverter/
compressor".
—
○
—
○
—
○
—
○
—
○
○
○
—
○
OFF
None (Normal)
2-time flash
2.5 seconds
OFF
Outdoor power system
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
P.C. board temperature
thermistor
4-time flash
2.5 seconds OFF
Ambient temperature
thermistor
2-time flash
2.5 seconds OFF
Overcurrent
11-time flash
2.5 seconds OFF
4-time flash
2.5 seconds
OFF
5-time flash
2.5 seconds
OFF
—
Large current flows into intelligent
power module.
Compressor synchronous
12-time flash
abnormality (Compressor start- 2.5 seconds OFF
up failure protection)
Waveform of compressor current is
distorted.
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.
• Check refrigerant circuit
and refrigerant amount.
• Refer to 10-5. "Check
of LEV".
Temperature of indoor coil thermistor
exceeds 158°F (70°C) in HEAT mode.
Temperature of defrost thermistor
exceeds 158°F (70°C) in COOL mode.
• Check refrigerant circuit
and refrigerant amount.
• Check stop valve.
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).
• Check around outdoor
unit.
• Check outdoor unit air
passage.
• Refer to 10-5. "Check
of outdoor fan motor".
—
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
—
7-time flash
2.5 seconds OFF
—
9-time flash Nonvolatile memory data
2.5 seconds
OFF
10-time flash Discharge temperature
2.5 seconds
OFF
5-time flash
2.5 seconds OFF
11-time flash DC voltage
2.5 seconds
OFF
Each phase current of
compressor
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
read properly.
• Replace the inverter
P.C. board.
Temperature of discharge temperature
thermistor has been 122°F (50°C) or
less for 20 minutes.
• Refer to 10-5. "Check
of LEV".
• Check refrigerant circuit
and refrigerant amount.
8-time flash
2.5 seconds OFF
DC voltage of inverter cannot be
detected normally.
9-time flash
2.5 seconds OFF
Each phase current of compressor
cannot be detected normally.
• Refer to 10-5. "How
to check inverter/
compressor".
—
○
• Reconnect compressor
connector.
• Refer to 10-5. "How
to check inverter/
compressor".
—
○
○
○
—
12-time flash Overcurrent Compressor open- 10-time flash
2.5 seconds phase
2.5 seconds OFF
OFF
14-time flash Stop valve (Closed valve)
2.5 seconds
OFF
Indoor/
unit
outdoor unit Outdoor
failure mode
failure mode recall
function
recall function
LED indication
(Outdoor P.C. board)
14-time flash
2.5 seconds OFF
Large current flows into intelligent
power module (IPM).
The open-phase operation of
compressor is detected.
The interphase short out occurs in the
output of the intelligent power module
(IPM).
The compressor winding shorts out.
Closed valve is detected by compressor • Check stop valve
current.
NOTE: Blinking patterns of this mode differ from the ones of Troubleshooting check table (10-3.).
19
10-3. TROUBLESHOOTING CHECK TABLE
No.
1
Symptom
LED indication
Outdoor unit 1-time flash every
does not oper- 2.5 seconds
ate.
2
3
6-time flash
2.5 seconds OFF
11-time flash
2.5 seconds OFF
14-time flash
2.5 seconds OFF
4
5
6
7
8
'Outdoor unit 2-time flash
stops and
2.5 seconds OFF
restarts 3 minutes later' is
repeated.
3-time flash
2.5 seconds OFF
4-time flash
2.5 seconds OFF
9
10
5-time flash
2.5 seconds OFF
11
8-time flash
2.5 seconds OFF
12
10-time flash
2.5 seconds OFF
13
14
unit
15 Outdoor
operates.
12-time flash
2.5 seconds OFF
13-time flash
2.5 seconds OFF
1-time flash
2.5 seconds OFF
3-time flash
2.5 seconds OFF
16
17
4-time flash
2.5 seconds OFF
Abnormal point/
Condition
Correspondence
Condition
Outdoor power sys- Overcurrent protection stop is continuously performed 3 times • Reconnect connector of comprestem
within 1 minute after the compressor gets started, or failure of sor.
restart of compressor has repeated 24 times.
• Refer to 10-5. "How to check inverter/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.
Outdoor control sys- Nonvolatile memory data cannot be read properly.
tem
(POWER lamp of the indoor unit lights up or flashes 7 times.)
Serial signal
The communication fails between the indoor and outdoor unit
for 3 minutes.
Stop valve/
Closed valve is detected by compressor current.
Closed valve
Outdoor unit
Outdoor unit is defective.
(Other abnormality)
High pressure protection
Indoor coil thermistor exceeds 158°F (70°C) in HEAT mode.
Defrost thermistor exceeds 158°F (70°C) in COOL mode.
• Check refrigerant circuit and refrigerant amount.
• Check stop valve.
Compressor synThe waveform of compressor current is distorted.
• Reconnect connector of compreschronous abnormalsor.
ity
• Refer to 10-5. "How to check inverter/compressor".
Outdoor fan motor
Outdoor fan has stopped 3 times in a row within 30 seconds
• Refer to 10-5. "Check of outdoor
after outdoor fan start-up.
fan motor.
• Refer to 10-5. "Check of inverter
P.C. board.
Each phase current Each phase current of compressor cannot be detected nor• Refer to 10-5. "How to check inof compressor
mally.
verter/compressor".
DC voltage
DC voltage of inverter cannot be detected normally.
• Refer to 10-5. "How to check inverter/compressor".
Frequency drop by Current from power outlet is nearing Max. fuse size.
The unit is normal, but check the
current protection
following.
Frequency drop by Temperature of indoor coil thermistor exceeds 131°F (55°C) in • Check if indoor filters are clogged.
•
Check if refrigerant is short.
high pressure proHEAT mode, compressor frequency lowers.
• Check if indoor/outdoor unit air cirtection
culation is short cycled.
Frequency drop by Indoor coil thermistor reads 46°F (8°C) or less in COOL mode,
defrosting in COOL compressor frequency lowers.
mode
Frequency drop by
discharge temperature protection
Temperature of discharge temperature thermistor exceeds 232 • Check refrigerant circuit and refrig°F (111°C), compressor frequency lowers.
erant amount.
• Refer to 10-5. "Check of LEV".
• Refer to 10-5. "Check of outdoor
thermistors".
Inverter P.C. board (Parts side)
0.5-second ON
0.5-second ON
2.5-second OFF
• Refer to 10-2.2. "Flow chart of the
detailed outdoor unit failure mode
recall function".
Large current flows into intelligent power module.
• Reconnect connector of compresWhen overcurrent protection occurs within 10 seconds after sor.
compressor starts, compressor restarts after 15 seconds.
• Refer to 10-5. "How to check inverter/compressor".
• Check stop valve.
Discharge tempera- Temperature of discharge temperature thermistor exceeds 241 • Check refrigerant circuit and refrigture overheat protec- °F (116°C), compressor stops. Compressor can restart if diserant amount.
tion
charge temperature thermistor reads 212°F (100°C) or less 3 • Refer to 10-5. "Check of LEV".
minutes later.
Fin temperature
Temperature of fin temperature thermistor on the heat sink
• Check around outdoor unit.
/P.C. board temexceeds 167 ~ 176°F (75 ~ 80°C) or temperature of P.C. board • Check outdoor unit air passage.
perature thermistor temperature thermistor on the inverter P.C. board exceeds 158 • Refer to 10-5. "Check of outdoor
overheat protection ~ 167°F (70 ~ 75°C).
fan motor".
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
• Refer to 10-5. "How to check
miswiring and serial signal error.
• Check stop valve.
Overcurrent protection
NOTE: 1. The location of LED is illustrated at the right figure. Refer to 10-6.1.
2. LED is lighted during normal operation.
ON
• Replace inverter P.C. board.
2.5-second OFF
20
LED
Flashing →
No.
Symptom
LED indication
Outdoor unit
18 operates.
7-time flash
2.5 seconds OFF
8-time flash
2.5 seconds OFF
PAM protection
PAM: Pulse Amplitude Modulation
9-time flash
2.5 seconds OFF
Inverter check mode The connector of compressor is disconnected, inverter check
mode starts.
19
20
Abnormal point/
Condition
Condition
Low discharge tem- Temperature of discharge temperature thermistor has been
perature protection 122°F (50°C) or less for 20 minutes.
The overcurrent flows into IGBT (Insulated Gate Bipolar transistor: TR821) or the bus-bar voltage reaches 320 V or more,
PAM stops and restarts.
21
Correspondence
• Refer to 10-5. "Check of LEV".
• Check refrigerant circuit and refrigerant amount.
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.
• Check if the connector of the compressor is correctly connected.
Refer to 10-5. "How to check inverter/compressor".
10-4. TROUBLE CRITERION OF MAIN PARTS
MUZ-FD09NA MUZ-FD12NA
Part name
Defrost thermistor
(RT61)
Check method and criterion
Figure
Ambient temperature Measure the resistance with a tester.
thermistor (RT65)
Refer to 10-6. “Test point diagram and voltage”, 1. “Inverter P.C.
board”, 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.
Fin temperature
thermistor (RT64)
Refer to 10-6. “Test point diagram and voltage”, 1. “Inverter P.C.
board”, the chart of thermistor.
Measure the resistance between terminals using a tester.
(Winding temperature: -4 ~ 104°F (-20 ~ 40°C))
WHT
2
3
U-V
U-W
V-W
1.52 ~ 2.17 Ω
Measure the resistance between lead wires using a tester.
(Part temperature: 14 ~ 104°F (-10 ~ 40°C))
V
WHT
2
Color of lead wire
RED – BLK
BLK – WHT
WHT – RED
1
W
Normal
Compressor
Outdoor fan motor
RED BLK
U
RED BLK
3
Normal
1
W
11 ~ 16 Ω
V
U
Measure the resistance using a tester.
(Part temperature: 14 ~ 104°F (-10 ~ 40°C))
R. V. coil (21S4)
Normal
970 ~ 1380 Ω
Measure the resistance using a tester.
(Part temperature: 14 ~ 104°F (-10 ~ 40°C))
WHT
LEV
RED
Normal
22
BLU
37 ~ 54 Ω
YLW
Color of lead wire
WHT – RED
RED – ORN
YLW – BRN
BRN – BLU
BRN
Expansion valve coil
(LEV)
ORN
10-5. TROUBLESHOOTING FLOW
A How to check inverter/compressor
Disconnect the connector (CN61) between
compressor and the intelligent power module
(IPM).
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 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 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
Refer to 10-5. “Check of compressor
operation time”.
Does the compressor operate continuously?
Yes
No
No
Replace the compressor.
Refer to 10-5.
OK.
23
“Check of compressor start failure”.
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
Measure the resistance between the lead wires at 3 points.
BLK - RED
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>>
●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.
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,)
(Outdoor P.C. board defect)
(Disconnected connector)
Abnormal
(Refrigerant circuit defect)
(Closed valve)
10 minutes
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
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.
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
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.
Is the 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.)
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
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 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 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?
No
Replace the inverter
P.C. board.
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?
No
Replace the 4-way valve.
25
Replace the inverter
Yes P.C. board.
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.)
Yes
No
Replace the outdoor fan motor.
Replace the inverter P.C. board.
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.
Does POWER lamp on the indoor
unit light up?
Yes
No
Is there voltage 280 ~ 370 VDC
between DB61 (+) and DB61 (–) on
the inverter P.C. board?
(Refer to 10-6.1.)
No
Yes
Check the electric parts in main circuit.
Yes
Is there voltage 208/230 VAC
between the indoor terminal
block S1 and S2?
Dose LED on the inverter P.C.
board light up or flash? (Refer
to 10-6.1.)
Yes
If light up, OK.
If flash, refer to 10-3.
No
No
Replace the indoor
electronic control P.C.
board.
Replace the inverter
P.C. board.
280 ~ 370 VDC
DB61
Inverter P.C. board
(Solder side)
26
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 section 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·······"?
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.
27
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
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 LED indication on the inverter P.C. board.
Does the LED flash 10 times?
Yes
(10-time flash)
No
Check the corresponding parts
following LED indication.
(Refer to 10-3.)
Replace the inverter P.C. board.
28
M How to check miswiring and serial signal error
Turn OFF the power supply.
Is there rated voltage in the
power supply?
Check the power supply.
No
Yes
Turn ON the power supply.
Is there rated voltage between
outdoor terminal block S1 and
S2?
Yes
Check the wiring.
No
Press EMERGENCY OPERATION switch once.
Does AREA-L lamp light up? <Confirmation of
the power to the indoor unit>
No
Yes
Is serial signal error indicated 6 minutes later?
No
Yes
Is there any miswiring,
poor contact, or wire
disconnection of the
indoor/outdoor connecting wire?
No
Yes
Correct them.
A
Turn OFF the power supply.
Check once more if the indoor/outdoor
B connecting wire is not miswiring.
Short-circuit outdoor terminal block S2
and S3. 1
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 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-secondON quick blinking"? 3
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
each other
away.
• Attach a filter
No on remote
control receiving section
of the indoor
unit.
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 rated voltage between
indoor terminal block S1 and S2?
<Confirmation of power voltage>
Yes
No
(Lighted
or not
lighted)
2. Be careful of the residual voltage
of smoothing capacitor.
No
Is there any error of the indoor/outdoor connecting wire,
such as the damage of the wire,
Yes
intermediate connection, poor
contact to the terminal block?
No
No
Is there any error of the indoor/outdoor connecting wire,
such as the damage of the wire,
Yes
intermediate connection, poor
contact to the terminal block?
No
Replace the indoor electronic control P.C. board.
Be sure to release the failure-mode recall function
after checking.
29
Replace the inverter P.C. board or the outdoor electronic control P.C. board.
2
Replace the indoor/
outdoor connecting
wire.
Replace the indoor/
outdoor connecting
wire.
N Electromagnetic noise enters into TV sets or radios
Is the unit grounded?
Yes
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.?
Ground the unit.
No
Yes
Extend the distance between the antennas and
the indoor unit, and/or the antennas and the
outdoor unit.
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 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.?
No
Are the antennas damaged?
Is the coaxial cable damaged?
Is there any poor contact in the antenna wiring?
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.
30
10-6. TEST POINT DIAGRAM AND VOLTAGE
1. Inverter P.C. board
MUZ-FD09NA MUZ-FD12NA
Smoothing
capacitor
(C63)
DB61
DC260 ~300 V
(-)
(+)
Back side of unit
Smoothing
capacitor
(C62)
Smoothing
capacitor
(C61)
Fuse (F701)
250 V 3.15 A
Fuse (F801)
250 V 3.15 A
AC 208/230 V
R.V. coil
(CN721)
208/230 VAC
Fuse (F901)
250 V 3.15 A
Output to
drive compressor
(LDU,
LDV,
LDW)
100
Discharge temperature
thermistor /RT62
(CN641)
Defrost thermistor
/RT61(CN641)
Ambient temperature
thermistor /RT65
(CN643)
Outdoor heat exchanger
temperature thermistor
/RT68(CN644)
Fin temperature
thermistor /RT64
(CN642)
Front side of unit
Output to drive outdoor
fan motor (CN932)
AC 208/230 V
LEV
connector
(CN724)
Defrost thermistor(RT61)
Ambient temperature thermistor(RT65)
Outdoor heat exchanger temperature thermistor(RT68)
200
80
Fin temperature thermistor(RT64)
160
Discharge temperature thermistor(RT62)
60
600
50
40
30
20
10
14
32 50 68 86
Temperature(°F)
104
140
Resistance(kΩ)
70
700
Resistance(kΩ)
Resistance(kΩ)
Jumper wire
for pre-heat
control setting
(JK)
180
90
0
-4
Jumper wire for
changing defrost
setting (JS)
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)
31
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.
Sleeve
Locking lever
(2) The terminal with this connector has the
locking mechanism.
Slide the sleeve.
Pull the terminal while
pushing the locking
lever.
Hold the sleeve, and
pull out the terminal
slowly.
Connector
11-1. MUZ-FD09NA MUZ-FD12NA
NOTE: Turn OFF power supply before disassembling.
OPERATING PROCEDURE
PHOTOS
1. Removing the cabinet
Photo 1
(1) Remove the screw fixing the service panel. (See
Photo 1.)
(2) Pull down the service panel and remove it. (See Photo
1.)
(3) Remove the screws fixing the conduit cover. (See
Photo 2.)
(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.
(10) Remove the screws fixing the back panel.
(11) Remove the back panel.
Screws
of the top
panel
Screw of the
cabinet
Screws of
the top panel
Back
panel
Screw of
the service
panel
Photo 2
Hooks
Screw of the
conduit cover
Conduit cover
Screws of
the cabinet
Conduit plate
32
Service
panel
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>
CN721 (R.V.coil)
CN932 (Fan motor)
CN641 (Defrost thermistor and discharge temperature thermistor)
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 3
Screws of the
relay panel
Photo 4 (Inverter assembly)
Heat sink
Inverter
P.C. board
Screw of the
T.B.support
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 temperature thermistor.
Photo 5
R.V. coil
(1) Remove the cabinet and panels. (Refer to 1.)
(2) Pull out the discharge temperature thermistor from its holder. (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)
(2)
(3)
(4)
(5)
(6)
Remove the cabinet and panels. (Refer to 1.)
Disconnect the connectors for outdoor fan motor.
Remove the propeller nut. (See Photo 7.)
Remove the propeller. (See Photo 7.)
Remove the screws fixing the fan motor. (See Photo 7.)
Remove the fan motor.
Outdoor heat
exchanger temperature thermistor
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
(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
Screws of the outdoor fan motor
Propeller nut
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 CO.,LTD
Distributed in Nov. 2008. No. OBH498 REVISED EDITION-B 5
Distributed in Mar. 2008. No. OBH498 REVISED EDITION-A 7
Distributed in Jan. 2008. No. OBH498 7
Made in Japan
New publication, effective Nov. 2008
Specifications subject to change without notice.