Mitsubishi Electronics Mitsubishi Digital Electronics Air Conditioner Muz D36na User Manual

OUTDOOR UNIT  
No. OBH502  
HFC  
utilized  
SERVICE MANUAL  
R410A  
Wireless type  
Models  
MUZ-D30NA  
U1  
MUZ-D30NA-  
MUZ-D36NA  
U1  
MUZ-D36NA-  
MUY-D30NA  
MUY-D36NA  
Indoor unit service manual  
MSZ-D•NA Series (OBH501)  
MSY-D•NA Series (OBH501)  
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··············· 9  
7. DATA·································································11  
8. ACTUATOR CONTROL··································· 18  
9. SERVICE FUNCTIONS ··································· 19  
10. TROUBLESHOOTING····································· 20  
11. DISASSEMBLY INSTRUCTIONS···················· 39  
PARTS CATALOG (OBB502)  
TM  
NOTE:  
RoHS compliant products have <G> mark on the spec name plate.  
1
TECHNICAL CHANGES  
MUZ-D30NA  
MUZ-D30NA -  
MUZ-D36NA  
MUZ-D36NA -  
MUY-D30NA  
MUY-D36NA  
U1  
U1  
1. New model  
2
PART NAMES AND FUNCTIONS  
MUZ-D30NA MUZ-D36NA  
MUY-D30NA MUY-D36NA  
Air inlet  
(back and side)  
Piping  
Drain hose  
Air outlet  
Drain outlet  
3
3
SPECIFICATION  
Item  
Model  
MSZ-D30NA  
MSY-D30NA  
MSZ-D36NA  
MSY-D36NA  
32,000/33,200  
33,200/34,600  
30,700  
(9,800 ~ 30,700)  
30,700  
(9,800 ~ 30,700)  
Cooling  
1
Btu/h  
(9,800 ~ 32,000) / (9,800 ~ 33,200) /  
Capacity  
(9,800 ~ 33,200)  
(9,800 ~ 34,600)  
Rated(Minimum~Maximum)  
32,600  
35,200  
Heating 47 1 Btu/h  
Heating 17 2 Btu/h  
(8,700 ~ 34,000)  
(8,700 ~ 36,000)  
Capacity Rated  
20,800  
22,800  
4,140/4,360  
(620 ~ 4,140) /  
(620 ~ 4,360)  
3,840  
(520 ~ 4,100)  
4,210/4,240  
(620 ~ 4,210) /  
(620 ~ 4,240)  
3,850  
3,380  
Cooling  
1
W
Power consumption  
(620 ~ 3,850)  
(620 ~ 3,380)  
Rated(Minimum~Maximum)  
(TOTAL)  
3,360  
(520 ~ 3,600)  
Heating 47 1 W  
Heating 17 2 W  
Cooling  
7.9/8.2  
[15.1]  
Power consumption Rated  
2,620  
3,000  
7.7/7.6  
[14.5]  
1
EER  
[SEER]  
3
8.0 [14.5]  
9.1 [16.0]  
HSPF IV(V)  
COP  
4
Heating  
Heating  
(8.2)  
2.84  
(8.2)  
2.69  
1
Outdoor unit model  
External nish  
MUZ-D30NA  
MUY-D30NA  
MUZ-D36NA  
MUY-D36NA  
Munsell 3Y 7.8/1.1  
Power supply  
V , phase , Hz  
208/230 , 1 , 60  
Max. fuse size (time delay)  
Min. circuit ampacity  
Fan motor  
A
A
25  
21  
F.L.A  
Model  
R.L.A  
L.R.A  
0.93  
TNB220FMCHT  
Compressor  
16  
20  
Refrigerant control  
Liner expansion valve  
Cooling  
Heating  
dB(A)  
dB(A)  
55  
57  
55  
56  
57  
56  
Sound level  
1
Defrost method  
Dimensions  
Reverse cycle  
Reverse cycle  
W
D
H
in.  
in.  
in.  
Ib.  
33-1/16  
13  
33-7/16  
Weight  
141  
126  
141  
126  
Remote controller  
Control voltage (by built-in transformer)  
Refrigerant piping  
Wireless type  
12 - 24 VDC  
Not supplied  
3/8 (0.0315)  
5/8 (0.0394)  
Flared  
Liquid  
Gas  
Indoor  
Outdoor  
in.  
in.  
Refrigerant pipe size  
(Min. wall thickness)  
Connection method  
Flared  
Height  
ft.  
50  
Between the indoor &  
outdoor units  
difference  
Piping length ft.  
100  
Refrigerant charge (R410A)  
4 lb. 10 oz.  
4 lb.  
4 lb. 10 oz.  
4 lb.  
Refrigeration oil (Model)  
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  
(Heating) — Indoor : 70 ˚FDB, 60 ˚FWB, Outdoor : 17 ˚FDB, 15 ˚FWBMaximum frequency  
2 :  
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  
Indoor  
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-D30NA  
MUZ-D36NA  
MUY-D30NA  
MUY-D36NA  
Open as a rule  
20 inch or more if  
the front and both  
sides are open  
REQUIRED SPACE  
4 inch or more /  
8 inch or more if  
there are obstacles  
to both sides  
Open as a rule  
20 inch or more if the back,  
both sides and top are open  
6
5
WIRING DIAGRAM  
MUZ-D30NA MUZ-D36NA  
7
MUY-D30NA MUY-D36NA  
8
6
REFRIGERANT SYSTEM DIAGRAM  
Unit:inch  
MUZ-D30NA  
MUZ-D36NA  
Oil  
separator  
Capillary tube  
Strainer  
#100  
O.D. 0.071 x I.D. 0.024  
x 39-3/8  
Refrigerant pipe 5/8  
(with heat insulator)  
( 1.8 x 0.6 x 1,000)  
4-way valve  
Service  
port  
Stop valve  
(with service port)  
Outdoor  
heat  
Defrost  
High-pressure thermistor  
RT61  
Flared connection  
Ambient  
temperature  
thermistor  
RT65  
exchanger  
Switch  
Discharge  
temperature  
thermistor  
RT62  
Service  
port  
Compressor  
Outdoor heat  
exchanger  
temperature  
thermistor  
RT68  
Flared connection  
LEV  
Strainer  
#100  
Strainer  
#100  
R.V. coil  
heating ON  
cooling OFF  
Receiver  
Stop valve  
Capillary tube  
O.D. 0.142 I.D. 0.094  
1-31/32  
Refrigerant pipe 3/8  
(with heat insulator)  
Refrigerant flow in cooling  
Refrigerant flow in heating  
(
3.6  
2.4 50)  
Unit:inch  
MUY-D30NA  
MUY-D36NA  
Oil separator  
Capillary tube  
Outdoor  
heat  
exchanger  
O.D. 0.071 x I.D. 0.024  
Ambient  
x 39-3/8  
Refrigerant pipe 5/8  
(with heat insulator)  
temperature  
( 1.8 x 0.6 x 1,000)  
thermistor  
RT65  
Strainer  
#100  
Service  
Stop valve  
(with service port)  
port  
High-pressure  
Switch  
Flared connection  
Outdoor heat  
exchanger  
temperature  
thermistor  
RT68  
Discharge  
temperature  
thermistor  
RT62  
Service  
port  
Compressor  
Flared connection  
LEV  
Strainer  
#100  
Capillary tube  
Stop valve  
O.D. 0.142 x I.D. 0.094  
x 1-31/32  
( 3.6 x 2.4 x 50)  
Refrigerant pipe 3/8  
(with heat insulator)  
Refrigerant flow in cooling  
9
MAX. REFRIGERANT PIPING LENGTH and MAX. HEIGHT DIFFERENCE  
Refrigerant piping : ft.  
Piping size O.D : in.  
Model  
Max. Length  
Max. Height difference  
B
Gas  
5/8  
Liquid  
3/8  
A
MUZ-D30NA  
MUZ-D36NA  
MUY-D30NA  
MUY-D36NA  
100  
50  
Indoor  
unit  
Max. Height  
difference  
B
Max. length  
A
Outdoor unit  
ADDITIONAL REFRIGERANT CHARGE (R410A:oz.)  
Refrigerant piping exceeding 25 ft. requires additional refrigerant charge according to the calculation.  
Refrigerant piping length (one way) : ft.  
Outdoor unit  
precharged  
Model  
25  
0
30  
40  
50  
60  
70  
80  
90  
100  
MUZ-D30NA  
MUZ-D36NA  
4 lb. 10 oz.  
2.96  
8.88  
14.80  
20.72  
26.64  
32.56  
38.48  
44.40  
Calculation : X oz. = 2.96/5 oz. / ft. x (Refrigerant piping length (ft.) - 25)  
Refrigerant piping length (one way) : ft.  
Outdoor unit  
precharged  
Model  
25  
0
30  
40  
50  
60  
70  
80  
90  
100  
MUY-D30NA  
MUY-D36NA  
4 lb.  
1.08  
3.24  
5.40  
7.56  
9.72  
11.88  
14.04  
16.20  
Calculation : X oz. = 1.08/5 oz. / ft. x (Refrigerant piping length (ft.) - 25)  
NOTE : Refrigerant piping exceeding 25 ft. requires additional refrigerant charge according to the calculation.  
10  
7 DATA  
MUZ-D30NA MUZ-D36NA MUY-D30NA MUY-D36NA  
7-1. PERFORMANCE DATA  
1) COOLING CAPACITY  
Indoor air  
IWB  
(˚F)  
71  
Outdoor intake air DB temperature (˚F)  
Model  
75  
85  
95  
105  
115  
TC  
SHC TPC  
TC  
SHC TPC  
TC  
SHC TPC  
TC  
SHC TPC  
TC  
SHC TPC  
37.6 19.1 3.43 35.2 17.8 3.75 33.0 16.7 4.04 30.7 15.6 4.25 28.2 14.3 4.43  
35.6 22.8 3.23 33.2 21.2 3.56 30.7 19.6 3.85 28.6 18.3 4.08 26.2 16.8 4.27  
33.5 25.9 3.08 31.0 24.0 3.41 28.9 22.3 3.68 26.2 20.3 3.93 23.9 18.5 4.08  
40.7 19.8 3.88 38.0 18.5 4.25 35.7 17.4 4.58 33.2 16.2 4.82 30.5 14.9 5.01  
38.5 23.9 3.66 35.9 22.2 4.03 33.2 20.6 4.36 30.9 19.1 4.62 28.4 17.6 4.84  
36.2 27.3 3.49 33.5 25.3 3.86 31.2 23.5 4.16 28.4 21.4 4.45 25.9 19.5 4.62  
37.6 19.1 3.01 35.2 17.8 3.30 33.0 16.7 3.55 30.7 15.6 3.73 28.2 14.3 3.89  
35.6 22.8 2.84 33.2 21.2 3.13 30.7 19.6 3.38 28.6 18.3 3.58 26.2 16.8 3.75  
33.5 25.9 2.70 31.0 24.0 2.99 28.9 22.3 3.23 26.2 20.3 3.45 23.9 18.5 3.58  
40.7 19.8 3.75 38.0 18.5 4.10 35.7 17.4 4.42 33.2 16.2 4.65 30.5 14.9 4.84  
38.5 23.9 3.54 35.9 22.2 3.89 33.2 20.6 4.21 30.9 19.1 4.46 28.4 17.6 4.67  
36.2 27.3 3.37 33.5 25.3 3.73 31.2 23.5 4.02 28.4 21.4 4.29 25.9 19.5 4.46  
42.4 20.6 3.77 39.6 19.3 4.13 37.2 18.1 4.45 34.6 16.8 4.69 31.8 15.5 4.88  
40.1 24.9 3.56 37.4 23.2 3.92 34.6 21.5 4.24 32.2 20.0 4.49 29.6 18.3 4.71  
37.7 28.4 3.39 34.9 26.3 3.75 32.5 24.5 4.05 29.6 22.3 4.32 27.0 20.3 4.49  
MUZ-D30NA  
MUZ-D36NA  
MUY-D30NA  
67  
63  
71  
67  
63  
71  
67  
63  
71  
MUY-D36NA  
(208 V)  
67  
63  
71  
MUY-D36NA  
(230 V)  
67  
63  
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.)  
1.0  
40  
65  
100  
MUZ-D30NA  
MUZ-D36NA  
MUY-D30NA  
MUY-D36NA  
0.95  
0.878  
0.713  
3) HEATING CAPACITY  
Indoor air  
Outdoor intake air WB temperature (˚F)  
Model  
IDB  
(˚F)  
75  
15  
25  
35  
43  
45  
55  
TC  
TPC  
TC  
TPC  
TC  
TPC  
3.28  
3.19  
3.11  
3.74  
3.65  
3.55  
TC  
TPC  
3.44  
3.36  
3.28  
3.94  
3.84  
3.74  
TC  
TPC  
3.49  
3.43  
3.33  
3.99  
3.92  
3.80  
TC  
TPC  
3.63  
3.56  
3.49  
4.15  
4.07  
3.99  
18.9  
20.0  
20.5  
20.4  
21.6  
22.2  
2.50  
2.42  
2.32  
2.86  
2.76  
2.65  
23.6  
24.5  
25.6  
25.5  
26.4  
27.6  
2.94  
2.87  
2.77  
3.36  
3.28  
3.17  
28.2  
28.9  
29.8  
30.4  
31.2  
32.2  
31.8  
32.6  
33.6  
34.3  
35.2  
36.3  
32.8  
33.6  
34.6  
35.4  
36.3  
37.3  
37.2  
38.0  
38.8  
40.1  
41.0  
41.9  
MUZ-D30NA  
MUZ-D36NA  
70  
65  
75  
70  
65  
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.  
11  
7-2. PERFORMANCE CURVE  
Cooling  
MUZ-D36NA  
MUY-D30NA  
MUZ-D30NA  
SHF at rating condition = 0.64  
SHF at rating condition = 0.62  
SHF at rating condition = 0.64  
= 763 CFM  
= 763 CFM  
= 763 CFM  
Airflow  
Airflow  
Airflow  
40  
38  
36  
34  
32  
30  
28  
26  
24  
43  
41  
39  
37  
35  
33  
31  
29  
27  
40  
38  
36  
34  
32  
30  
28  
26  
24  
Indoor intake air  
Indoor intake air  
Indoor intake air  
WB temperature (°F)  
WB temperature (°F)  
WB temperature (°F)  
71  
67  
63  
71  
67  
63  
71  
67  
63  
)
)
4.5  
4.3  
4.1  
3.9  
3.7  
3.5  
3.3  
3.1  
5.2  
4.8  
4.4  
4.0  
3.6  
4.0  
3.8  
3.6  
3.4  
3.2  
3.0  
2.8  
2.6  
71  
67  
63  
71  
67  
63  
71  
67  
63  
ure (°F  
ure (°F  
mperature (°F)  
Indoor intake air WB temperat  
Indoor intake air WB temperat  
Indoor intake air WB te  
65  
75  
85  
95  
105  
115  
65  
75  
85  
95  
105  
115  
65  
75  
85  
95  
105  
115  
Outdoor intake air DB temperature (°F)  
Outdoor intake air DB temperature (°F)  
Outdoor intake air DB temperature (°F)  
MUY-D36NA  
SHF at rating condition = 0.62  
= 763 CFM  
Airflow  
46  
42  
38  
34  
30  
26  
Ind  
oor intak  
e air WB temperature (°F)  
71  
67  
63  
5.0  
4.6  
4.2  
3.8  
3.4  
71  
67  
63  
rature (°F)  
mpe  
oor intake air WB te  
Ind  
65  
75  
85  
95  
105  
115  
Outdoor intake air DB temperature (°F)  
Heating  
MUZ-D36NA  
MUZ-D30NA  
45  
= 848 CFM  
Airflow  
= 848 CFM  
Airflow  
48  
43  
38  
33  
28  
23  
18  
65  
70  
75  
65  
70  
75  
40  
35  
30  
25  
20  
15  
4.0  
3.6  
3.2  
2.8  
2.4  
4.5  
4.1  
3.7  
3.3  
2.9  
75  
70  
65  
75  
70  
65  
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.  
12  
7-3. CONDENSING PRESSURE  
Cooling  
Data is based on the condition of indoor humidity 50 %.  
Air flow should be set to High speed.  
MUZ-D30NA  
(PSIG)  
580  
86  
80  
75  
70  
540  
500  
460  
420  
380  
340  
300  
260  
(PSIG)  
150  
140  
130  
120  
110  
100  
90  
86  
80  
75  
70  
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-D36NA  
(PSIG)  
580  
86  
80  
75  
70  
540  
500  
460  
420  
380  
340  
300  
260  
(PSIG)  
150  
140  
130  
120  
110  
100  
90  
86  
80  
75  
70  
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  
MUY-D30NA  
(PSIG)  
580  
540  
500  
460  
420  
380  
340  
300  
260  
86  
80  
75  
70  
(PSIG)  
150  
140  
130  
120  
110  
100  
90  
86  
80  
75  
70  
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  
13  
MUY-D36NA  
(PSIG)  
580  
86  
80  
75  
70  
540  
500  
460  
420  
380  
340  
300  
260  
(PSIG)  
150  
140  
130  
120  
110  
100  
90  
86  
80  
75  
70  
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  
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-D30NA  
(PSIG)  
(PSIG)  
500  
480  
460  
440  
420  
400  
380  
360  
340  
320  
300  
280  
260  
240  
220  
200  
150  
140  
130  
120  
110  
100  
90  
75  
70  
65  
75  
70  
65  
58Hz  
80  
58Hz  
70  
60  
50  
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-D36NA  
(PSIG)  
500  
(PSIG)  
150  
75  
70  
65  
480  
460  
440  
420  
400  
380  
360  
340  
320  
300  
280  
260  
240  
220  
200  
140  
130  
120  
110  
100  
90  
75  
70  
65  
58Hz  
80  
58Hz  
70  
60  
50  
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  
14  
7-4. STANDARD OPERATION DATA  
Model  
MSZ-D30NA  
MSZ-D36NA  
MSY-D30NA MSY-D36NA  
Item  
Unit  
Btu / h  
Cooling  
Heating  
32,600  
Cooling  
Heating  
35,200  
Cooling  
30,700  
0.64  
Cooling  
33,200/34,000  
0.62  
Capacity  
SHF  
30,700  
0.64  
3.85  
84  
32,000/33,200  
0.62  
Input  
kW  
3.36  
84  
4.14/4.36  
91  
3.84  
91  
3.38  
4.21/4.24  
92  
Rated frequency  
Indoor unit  
Hz  
79  
MSZ-D30NA  
MSZ-D36NA  
MSY-D30NA MSY-D36NA  
V,  
phase,  
Hz  
Power supply  
Input  
208/230 , 1 , 60  
0.058  
kW  
A
Fan motor current  
Outdoor unit  
0.45/0.42  
MUZ-D30NA  
MUZ-D36NA  
MUY-D30NA MUY-D36NA  
V,  
phase,  
Hz  
Power supply  
208/230 , 1 , 60  
Input  
kW  
A
3.792  
3.302  
4.082/4.302  
3.782  
3.322  
4.152/4.182  
18.95/17.26  
Comp. current  
17.25/15.56  
14.95/13.46  
18.65/17.86  
17.25/15.56  
15.05/13.56  
Fan motor current  
A
0.80/0.72  
Condensing pressure  
Suction pressure  
PSIG  
PSIG  
˚F  
468  
126  
404  
96  
480  
122  
420  
94  
453  
125  
475  
119  
Discharge temperature  
Condensing temperature  
Suction temperature  
Comp. shell bottom temperature  
Ref. pipe length  
186.8  
126.5  
45.5  
169.7  
114.3  
29.8  
156.4  
198.7  
128.5  
48.0  
168.8  
117.0  
29.1  
155.7  
191.3  
123.8  
54.7  
197.1  
127.4  
48.6  
˚F  
˚F  
˚F  
175.6  
187.0  
177.4  
182.7  
ft.  
25  
Refrigerant charge (R410A)  
4 lb. 10 oz.  
4 lb.  
DB  
Intake air temperature  
WB  
˚F  
80  
67  
70  
60  
80  
67  
70  
60  
80  
67  
80  
67  
˚F  
DB  
Discharge air temperature  
WB  
˚F  
53.9  
53  
112.2  
73.9  
53  
114.9  
74.6  
53.7  
52.8  
51.7  
50.8  
˚F  
52.1  
Fan speed (High)  
rpm  
CFM  
˚F  
1,100  
Airow (High)  
741 (Wet)  
795  
47  
738 (Wet)  
794  
47  
718 (Wet)  
710 (Wet)  
DB  
Intake air temperature  
WB  
95  
95  
95  
95  
˚F  
43  
43  
Fan speed  
rpm  
CFM  
800  
Airow  
1,941  
15  
7-5. CAPACITY AND INPUT CORRECTION BY INVERTER OUTPUT FREQUENCY  
MUZ-D30NA  
Correction of Cooling capacity  
Correction of Cooling total input  
Correction of Heating total input  
Correction of Heating capacity  
1.5  
1.0  
0.5  
1.5  
1.0  
0.5  
1.5  
1.0  
0.5  
1.5  
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-D36NA  
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  
1.5  
1.0  
0.5  
1.0  
0.5  
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  
MUY-D30NA  
Correction of Cooling capacity  
Correction of Cooling total input  
1.5  
1.5  
1.0  
0.5  
1.0  
0.5  
(Hz)  
0
50  
100  
150  
0
50  
100  
150  
The operational frequency of compressor  
The operational frequency of compressor  
MUY-D36NA  
Correction of Cooling capacity  
1.5  
Correction of Cooling total input  
1.5  
1.0  
0.5  
1.0  
0.5  
(Hz)  
0
50  
100  
150  
0
50  
100  
150  
The operational frequency of compressor  
The operational frequency of compressor  
16  
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.  
17  
8
ACTUATOR CONTROL  
MUZ-D30NA  
MUZ-D36NA  
MUY-D30NA  
MUY-D36NA  
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  
<MUZ>  
. . . . . . . . . . . . . . . . .  
. . . . . . . . . . . . . . . . .  
Heating  
ON  
OFF  
OFF  
Cooling  
. . . . . . . . . . . . . . . . . . . .  
Dry  
NOTE: The 4-way valve reverses for 5 seconds right before start-up of the compressor.  
<COOL>  
<HEAT>  
5 seconds  
5 seconds  
ON  
ON or OFF  
R.V.coil  
ON or OFF  
OFF  
ON  
Outdoor fan  
motor  
OFF  
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 Protection  
○ ○  
Cooling : Coil frost prevention  
Heating : High pressure protection  
Defrosting  
Indoor coil temperature thermistor  
○ ○ ○  
Defrost thermistor  
○ ○ ○ ○ ○  
Fin temperature thermistor  
Protection  
Outdoor heat exchanger temperature Protection  
Ambient temperature thermistor Cooling : Low ambient temperature operation  
○ ○ ○  
○ ○ ○  
18  
9
SERVICE FUNCTIONS  
MUZ-D30NA MUZ-D36NA MUY-D30NA MUY-D36NA  
9-1. PRE-HEAT CONTROL  
If moisture gets into the refrigerant cycle, or when refrigerant is liqueed and col-  
lected in the compressor, it may interfere the start-up of the compressor.  
To improve start-up condition, the compressor is energized even while it is not  
operating.  
ON  
This is to generate heat at the winding.  
1
2
3
4
The compressor uses about 50 W when pre-heat control is turned ON.  
Pre-heat control is ON at initial setting.  
[How to activate pre-heat control]  
1. Turn OFF the power supply for the air conditioner before making the setting.  
2. Set the 2nd Dip Switch of SW1 on the outdoor electronic control P.C. board to  
ON to activate pre-heat control function.  
The compressor is energized even while it is not operating.  
This is to generate heat at the winding to improve the compressor's start-up condition.  
ON  
Power  
OFF  
ON  
Compressor  
OFF  
Outside temperature  
68 °F (20 °C)  
30min.  
30min.  
30min.  
30min.  
30min.  
30min. 15min. 30min. 15min. 30min.  
ON  
Pre-heat  
OFF  
Breaker ON  
Start  
Stop  
When outside  
temperature is  
above 68 °F  
(20 °C)  
operation operation  
1. Pre-heat control is turned ON for 15 or 30 min. after the breaker is turned ON.  
2. 30 min. after the unit is stopped, pre-heat control is turned ON for 15 or 30 min. and turned OFF for 30 min.  
This is repeated as shown in the graph until the breaker is turned OFF.  
When outside temperature is 68 °F (20 °C) or below , pre-heat control is ON for 30 min.  
When outside temperature is 70 °F (21 °C) or above, pre-heat control is ON for 15 min.  
NOTE: When the unit is started with the remote controller, pre-heat control is turned OFF.  
Compressor uses 50 W when pre-heat control is turned ON.  
9-2. CHANGE IN DEFROST SETTING  
Changing defrost finish temperature  
1. Turn OFF the power supply for the air conditioner before making the setting.  
2. Set the 4th Dip Switch of SW1 on the outdoor electronic control P.C. board to  
ON to change the defrost finish temperature. (Refer to 10-6-1.)  
ON  
1
2
3
4
4th Dip Switch of SW1  
Defrost nish temperature  
49.5 °F (9.7 °C)  
OFF  
(Initial setting)  
ON  
64.9 °F (18.3 °C)  
19  
10  
TROUBLESHOOTING  
MUZ-D30NA MUZ-D36NA MUY-D30NA MUY-D36NA  
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.  
20  
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.  
This figures show about MSZ type.  
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.  
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.  
Does the left lamp of OPERATION INDICATOR lamp on the  
indoor unit blink at the interval of 0.5 seconds?  
Blinks: Either indoor or outdoor unit is abnormal. Beep is emit-  
ted at the same timing as the blinking of the left lamp  
Indoor unit is normal.  
But the outdoor unit might be abnormal because there are some abnor-  
malities that can't be recalled with this way.  
Conrm if outdoor unit is abnormal according to the detailed outdoor  
unit failure mode recall function. (Refer to 10-2.2)  
No  
(OFF)  
of OPERATION INDICATOR lamp.  
2
Yes  
(Blinks)  
Judgment of indoor/outdoor abnormality  
Before blinking, does the left lamp of OPERATION INDICA-  
TOR lamp stay ON for 3 seconds?  
Yes  
Stays ON for 3 seconds (without beep):  
The outdoor unit is abnormal.  
No  
The indoor unit is abnormal.  
The outdoor unit is abnormal.  
Check the blinking pattern, and conrm the abnormal point with the indoor unit  
failure mode table. (Refer to indoor unit service manual.)  
Check the blinking pattern, and conrm 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-  
Blinking at 0.5-  
second interval  
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  
21  
2. Flow chart of the detailed outdoor unit failure mode recall function  
Operational procedure  
The outdoor unit might be abnormal.  
Conrm if outdoor unit is abnormal according to the following procedures.  
Conrm 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 left lamp of OPERATION INDICATOR lamp on  
the indoor unit blink at the interval of 0.5 seconds?  
Blinks: The outdoor unit is abnormal. Beep is emitted  
No  
at the same timing as the blinking of the left  
(OFF)  
lamp of OPERATION INDICATOR lamp.  
Yes  
2
)
(Blinks  
The outdoor unit is abnormal.  
Check the blinking pattern, and conrm 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"  
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 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  
Beeps  
No beep  
Beeps  
Repeated cycle  
Repeated cycle  
Repeated cycle  
22  
3. Outdoor unit failure mode table  
MUZ-D30NA MUZ-D36NA MUY-D30NA MUY-D36NA  
LED indication  
(Outdoor P.C.  
board)  
The left lamp of OPERA-  
TION INDICATOR lamp  
(Indoor unit)  
Indoor/outdoor  
unit failure mode  
recall function  
Abnormal point  
Condition  
Correspondence  
(Failure mode / protection)  
LED 1  
LED 2  
OFF  
Non (Normal)  
Check the connection of the  
compressor connecting wire.  
Refer to 10-5. "How to check  
inverter / compressor".  
IPM protection stop or lock protection stop is continuously  
performed 3 times within 1 minute after the compres-  
2-time ash  
Outdoor power system  
Lighting Lighting sor gets started, or converter protection stop or bus-bar  
voltage protection stop is continuously performed 3 times Refer to 10-5. "Check of  
within 3 minutes after start-up.  
compressor start failure".  
Check the stop valve.  
Discharge temperature thermistor Lighting  
Once  
Once  
Twice  
Defrost thermistor (MUZ)  
Lighting  
Lighting  
Refer to 10-5. "Check of  
outdoor thermistors".  
Ambient temperature thermistor  
Fin temperature thermistor  
3-time ash  
Thermistor shorts or opens during compressor running.  
Lighting 3 times  
Replace the outdoor electronic  
control P.C. board.  
P.C. board temperature thermistor Lighting 4 times  
Outdoor heat exchanger tempera-  
Lighting 9 times  
Refer to 10-5. "Check of  
outdoor thermistors".  
ture thermistor  
Reconnect compressor con-  
nector.  
Refer to 10-5. "How to check  
inverter/ compressor."  
Refer to 10-5. "Check of  
compressor start failure".  
Check the stop valve.  
Goes  
out  
4-time ash  
Overcurrent  
Once  
28 A current ow into intelligent power module.  
Temperature of discharge temperature thermistor exceeds Check refrigerant circuit and  
241 °F (116 °C), compressor stops. Compressor can  
restart if discharge temperature thermistor reads 212 °F  
(100 °C) or less 3 minutes later.  
refrigerant amount.  
Refer to 10-5. "Check of  
LEV".  
5-time ash  
Discharge temperature  
High pressure  
Lighting Lighting  
The outdoor heat exchanger temperature exceeds 158 °F Check refrigerant circuit and  
Lighting Lighting (70 °C) during cooling or the indoor gas pipe temperature  
exceeds 158 °F (70 °C) during heating (MUZ).  
6-time ash  
refrigerant amount.  
Check the stop valve.  
Goes  
out  
The n temperature exceeds 189 °F (87 °C) during opera-  
Check around outdoor unit.  
Check outdoor unit air pas-  
sage.  
Refer to 10-5. "Check of  
outdoor fan motor".  
Fin temperature  
3 times  
4 times  
tion.  
7-time ash  
Goes  
out  
The P.C. board temperature exceeds 158 °F (70 °C) during  
operation.  
P.C. board temperature  
Failure occurs continuously 3 times within 30 seconds  
after the fan gets started.  
Refer to 10-5. "Check of  
outdoor fan motor".  
8-time ash  
Outdoor fan motor  
Lighting Lighting  
Replace the outdoor electronic  
control P.C. board.  
9-time ash  
Nonvolatile memory data  
Lighting 5 times Nonvolatile memory data cannot be read properly.  
Check refrigerant circuit and  
refrigerant amount.  
Refer to 10-5. "Check of  
LEV".  
The frequency of the compressor is kept 80 Hz or more  
Lighting Lighting and the discharge temperature is kept under 102 °F (39 °C)  
for more than 20 minutes.  
10-time ash  
Discharge temperature  
Check the connecting wire  
between outdoor electronic  
control P.C. board and power  
board.  
Communication error occurs between the electronic control  
P.C. board and power board for more than 10 seconds.  
Lighting 6 times  
Communication error between  
P.C. boards  
The communication between boards protection stop is  
continuously performed twice.  
Replace the power board.  
A short or open circuit is detected in the current sensor  
during compressor operating.  
Current sensor  
Lighting 7 times  
11-time ash  
Current sensor protection stop is continuously performed  
twice.  
Check the connecting wire  
among electronic control P.C.  
board, noise lter P.C. board  
and power board.  
Zero cross signal cannot be detected while the compres-  
sor is operating.  
Zero cross detecting circuit  
5 times Goes out  
The protection stop of the zero cross detecting circuit is  
continuously performed 10 times.  
NOTE : Blinking patterns of this mode differ from the ones of Troubleshooting check table (10-3.).  
23  
LED indication (Out-  
door P.C. board)  
The left lamp of OPERA-  
TION INDICATOR lamp  
(Indoor unit)  
Indoor/outdoor  
unit failure mode  
recall function  
Abnormal point  
(Failure mode / protection)  
Condition  
Correspondence  
LED 1  
LED 2  
Replace the power board.  
A failure is detected in the operation of the converter dur-  
ing operation.  
Converter  
5 times Goes out  
5 times Goes out  
Bus-bar voltage  
(1)  
The bus-bar voltage exceeds 400 V or falls to 200 V or  
below during compressor operating.  
11-time ash  
Bus-bar voltage  
(2)  
Even if this protection stop  
The bus-bar voltage exceeds 400 V or falls to 50 V or  
below during compressor operating.  
is performed continuously 3 6 times Goes out  
times, it does not mean the  
abnormality in outdoor power  
system.  
24  
10-3. TROUBLESHOOTING CHECK TABLE  
MUZ-D30NA MUZ-D36NA MUY-D30NA MUY-D36NA  
Indication  
No. Symptom  
Abnormal point / Condition  
Condition  
Correspondence  
LED1  
(Red)  
LED2  
(Yellow)  
Check the connection of the compressor connect-  
ing wire.  
Refer to 10-5. "How to check inverter/compres-  
sor".  
Refer to 10-5. "Check of compressor start failure".  
Check the stop valve.  
IPM protection stop or lock protection stop is continuously  
performed three times within 1 minute after the compressor  
gets started, or converter protection stop or bus-bar voltage  
protection stop is continuously performed 3 times within 3  
minutes after start-up.  
1
Lightning Twice  
Outdoor power system  
A short circuit is detected in the thermistor during opera-  
tion, or an open circuit is detected in the thermistor after 10  
minutes of compressor start-up.  
Discharge temperature therm-  
istor  
2
3
Lightning 3 times  
Lightning 4 times  
Refer to 10-5. "Check of outdoor thermistor".  
Fin temperature thermistor  
Refer to 10-5. "Check of outdoor thermistor".  
Replace the outdoor electronic control P.C. board.  
A short or open circuit is detected in the thermistor during  
operation.  
P.C. board temperature therm-  
istor  
Ambient temperature thermis- A short or open circuit is detected in the thermistor during  
tor  
operation.  
Outdoor  
A short circuit is detected in the thermistor during operation,  
or an open circuit is detected in the thermistor after 5 minutes  
(in cooling) and 10 minutes (in heating (MUZ)) of compressor Refer to 10-5. "Check of outdoor thermistor".  
start-up.  
unit does  
not oper-  
ate.  
Outdoor heat exchanger  
temperature thermistor  
4
Lightning 5 times  
A short circuit is detected in the thermistor during operation,  
or an open circuit is detected in the thermistor after 5 minutes  
of compressor start-up.  
Defrost thermistor (MUZ)  
The communication fails between the indoor and outdoor unit Refer to 10-5. "How to check miswiring and serial  
5
6
7
Lightning 6 times  
Lightning 7 times  
Lightning 8 times  
Serial signal  
for 3 minutes.  
signal error.  
Nonvolatile memory data  
Current sensor  
The nonvolatile memory data cannot be read properly.  
Replace the outdoor electronic control P.C. board.  
Current sensor protection stop is continuously performed  
twice.  
Replace the power board.  
Communication error between The communication protection stop between boards is con-  
Check the connecting wire between outdoor elec-  
tronic control P.C. board and power board.  
8
9
Lightning 11 times  
P.C. boards  
tinuously performed twice.  
Check the connecting wire among outdoor elec-  
tronic control P.C. board, noise lter P.C. board and  
power board.  
The protection stop of the zero cross detecting circuit is  
continuously performed 10 times.  
Lightning 12 times Zero cross detecting circuit  
IPM protection  
Overcurrent is detected after 30 minutes of compressor start- Reconnect compressor connector.  
up.  
Refer to 10-5. "How to check inverter/compres-  
sor".  
10  
11  
Twice  
Goes out  
Refer to 10-5. "Check of compressor start failure".  
Check the stop valve.  
Check the power module (PAM module).  
Overcurrent is detected within 30 minutes of compressor  
start-up  
Lock protection  
Temperature of discharge temperature thermistor exceeds  
Discharge temperature protec- 241 °F (116 °C), compressor stops. Compressor can restart  
Check the amount of gas and refrigerant circuit.  
if discharge temperature thermistor reads 212 °F (100 °C) or Refer to 10-5. "Check of LEV".  
3 times  
4 times  
Goes out  
Goes out  
tion  
less 3 minutes later.  
Fin temperature protection  
The n temperature exceeds 189 °F (87 °C) during operation.  
Check refrigerant circuit and refrigerant amount.  
Refer to 10-5. "Check of LEV".  
12  
P.C. board temperature pro-  
tection  
The P.C. board temperature exceeds 158 °F (70 °C) during  
operation.  
The outdoor heat exchanger temperature exceeds 158 °F (70  
°C) during cooling or indoor gas pipe temperature exceeds  
158 °F (70 °C) during heating (MUZ).  
'Outdoor  
unit stops  
and restarts  
3 minutes  
later' is  
repeated.  
Check around of gas and the refrigerant circuit.  
Check of stop valve.  
13  
5 times  
8 times  
Goes out High-pressure protection  
Goes out Converter protection  
A failure is detected in the operation of the converter during  
operation.  
14  
Replace the power board.  
Replace the power board.  
The bus-bar voltage exceeds 400 V or falls to 200 V or below  
during compressor operating.  
Bus-bar voltage protection (1)  
Goes out  
15  
9 times  
The bus-bar voltage exceeds 400 V or falls to 50 V or below  
during compressor operating.  
Bus-bar voltage protection (2)  
Failure occurs continuously three times within 30 seconds  
after the fan gets started.  
16  
17  
13 times Goes out Outdoor fan motor  
Refer to 10-5. "Check of outdoor fan motor".  
Replace the power board.  
A short or open circuit is detected in the current sensor during  
compressor operating.  
Lighting  
Lighting  
8 times  
Current sensor protection  
Communication error occurs between the outdoor electronic  
control P.C. board and power board for more than 10 sec-  
onds.  
Communication between P.C.  
boards protection  
Check the connecting wire between outdoor elec-  
tronic control P.C. board and power board.  
18  
19  
11 times  
Check the connecting wire among outdoor elec-  
tronic control P.C. board, noise lter P.C. board and  
power board.  
Zero cross detecting circuit  
protection  
Zero cross signal cannot be detected while the compressor is  
operating.  
Lighting  
12 times  
NOTE 1. The location of LED is illustrated at the right figure. Refer to 10-6.1.  
Outdoor electronic control P.C. board(Parts side)  
2. LED is lighted during normal operation.  
LED2 LED1  
Lighting  
0.5-second ON  
0.5-second ON  
ON  
OFF  
2.5-second OFF  
2.5-second OFF  
The flashing frequency shows the number of times the LED blinks after every 2.5-second OFF.  
(Example) When the flashing frequency is “2”.  
25  
Indication  
No. Symptom  
20  
Abnormal point / Condition  
Primary current protection  
Condition  
The input current exceeds 15 A.  
Correspondence  
LED1  
(Red)  
LED2  
(Yellow)  
These symptoms do not mean any abnormality of  
the product, but check the following points.  
Check if indoor lters are clogged.  
Check if refrigerant is short.  
Check if indoor/outdoor unit air circulation is short  
cycled.  
Once  
Lighting  
Lighting  
Secondary current protection The current of the compressor exceeds 15 A.  
High-pressure protection  
(MUZ)  
The indoor gas pipe temperature exceeds 113 °F (45 °C) dur-  
ing heating.  
21  
Twice  
The indoor gas pipe temperature falls 37 °F (3 °C) or below  
during cooling.  
Defrosting in cooling  
Check refrigerant circuit and refrigerant amount.  
Refer to 10-5. "Check of LEV".  
Refer to 10-5. "Check of outdoor thermistors".  
Discharge temperature protec- The discharge temperature exceeds 212 °F (100 °C) during  
22  
23  
3 times  
4 times  
Lighting  
Lighting  
Outdoor  
unit oper-  
ates.  
tion  
operation.  
The frequency of the compressor is kept 80 Hz or more and  
the discharge temperature is kept under 102 °F (39 °C) for  
more than 20 minutes.  
Low discharge temperature  
protection  
Refer to 10-5. "Check of LEV".  
Check refrigerant circuit and refrigerant amount.  
This symptom does not mean any abnormality of  
the product, but check the following points.  
Cooling high-pressure protec- The outdoor heat exchanger temperature exceeds 136 °F (58 Check if indoor lters are clogged.  
24  
5 times  
Lighting  
tion  
°C) during operation.  
Check if refrigerant is short.  
Check if indoor/outdoor unit air circulation is short  
cycled.  
25  
26  
9 times  
Lighting  
Lighting Inverter check mode  
Lighting Normal  
The unit is operated with emergency operation switch.  
Outdoor  
unit oper-  
ates  
26  
10-4. TROUBLE CRITERION OF MAIN PARTS  
MUZ-D30NA MUZ-D36NA MUY-D30NA MUY-D36NA  
Part name  
Check method and criterion  
Figure  
Defrost thermistor  
(RT61) (MUZ)  
Measure the resistance with a tester.  
Ambient temperature  
thermistor (RT65)  
Refer to 10-6. “Test point diagram and voltage”, 1. “Outdoor electron-  
ic control 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. “Outdoor electron-  
ic control P.C. board”, the chart of thermistor.  
Fin temperature  
thermistor (RT64)  
Measure the resistance between terminals using a tester.  
(Winding temperature : 14 ~ 104 °F (-10 ~ 40 °C))  
W
RED  
Compressor  
Normal  
V
WHT  
U
BLK  
1.24 ~ 1.53 Ω  
Measure the resistance between lead wires using a tester.  
(Part temperature : 14 ~ 104 °F (-10 ~ 40 °C))  
RED  
(W)  
U
Color of lead wire  
RED – BLK  
BLK – WHT  
WHT – RED  
Normal  
WHT  
BLK  
Outdoor fan motor  
R. V. coil (MUZ)  
(V)  
(U)  
V
13 ~ 16 Ω  
W
Measure the resistance using a tester.  
(Part temperature : 14 ~ 104 °F (-10 ~ 40 °C))  
Normal  
1.20 ~ 1.55 kΩ  
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  
Linear expansion  
valve  
38 ~ 50 Ω  
YLW BRN BLU  
27  
10-5. TROUBLESHOOTING FLOW  
OPERATION / INDICATOR lamp flashes 5-times.  
Outdoor unit does not operate.  
A How to check inverter/ compressor  
Disconnect the terminal of the compressor. 3 minutes after turn-  
ing on the power supply, start EMERGENCY OPERATION.  
•After the outdoor fan starts running, wait for 1 minute or more  
before measuring the voltage.  
•The output voltage values have the tolerance of ±20 %.  
Measure the voltage between each lead wire leading  
to the compressor.  
U (BLK) - V (WHT)  
V (WHT) - W (RED)  
No  
W (RED) - U (BLK)  
Is voltage output on right table?  
Yes  
Is output balanced?  
Yes  
No  
No  
Is the input voltage to the outdoor electronic control  
P.C. board 370 V or more?  
Replace the power board.  
Replace the compressor.  
Yes  
Turn off power supply of indoor and outdoor unit, and  
measure the compressor winding resistance between  
the compressor terminals.  
No  
Is the resistance between each terminal normal?  
Yes  
Reconnect the lead wire of compressor, and turn on power  
supply to indoor and outdoor unit.  
3 minutes later, starts EMERGENCY OPERATION.  
Clarify the causes by counting time until the inverter stops.  
0 to 10 seconds: compressor rare short  
10 to 60 seconds: compressor lock  
60 seconds to 5 minutes: refrigerant circuit defective  
5 minutes or more: normal  
28  
OPERATION INDICATOR lamp flashes 6-times.  
Thermistor is abnormal.  
B 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  
outdoor power 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 outdoor power board.  
No  
Yes  
OK.  
(Cause is poor contact.)  
Thermistor  
Defrost (MUZ)  
Discharge temperature  
Outdoor heat exchanger temperature RT68  
Ambient temperature  
Fin temperature  
Symbol  
RT61  
RT62  
Connector, Pin No.  
Board  
Between CN661 pin1 and pin2  
Between CN661 pin3 and pin4  
Between CN661 pin7 and pin8  
Between CN663 pin1 and pin2  
Between CN3 pin1 and pin2  
Outdoor electronic control P.C. board  
Outdoor power board  
RT65  
RT64  
29  
The cooling operation or heating operation does not operate.  
C Check of R.V. coil  
MUZ-D30/36  
• Heating operation does not work.  
1. Disconnect the lead wire leading to the compressor.  
2. 3 minutes after turning on the power supply, start EMERGENCY  
OPERATION in HEAT mode.  
Is there voltage of 208 / 230 VAC between pin1  
and pin 2 at connector CN912?  
1. Turn off power supply of indoor and outdoor unit, and discon-  
nect the connector CN781 in the outdoor electronic control P.C.  
board.  
2. 3 minutes after turning ON the power supply, start EMER-  
GENCY OPERATION in HEAT mode.  
No  
Yes  
Turn OFF power supply of indoor and outdoor unit.  
Disconnect the connec-  
tor CN912 in noise lter  
P.C. board. Is there normal  
resistance to R.V. coil?  
Is there voltage 12 VDC be-  
Replace the electronic  
tween the connector CN781  
Replace the R.V. coil.  
No  
control P.C. board.  
No  
pin 5 (+) and pin 3 (-)?  
Yes  
Yes  
Replace the noise lter P.C. board.  
Replace the 4-way valve.  
• Cooling operation does not work.  
If the connector CN912 is not  
1. Disconnect the lead wire leading to the compressor.  
2. 3 minutes after turning on the power supply, start EMERGENCY  
OPERATION in COOL mode.  
connected or R.V. coil is open,  
voltage occurs between terminals  
even when the control is OFF.  
Is there voltage of 208 / 230 VAC between pin1  
and pin 2 at connector CN912?  
Replace the 4-way valve.  
No  
1. Turn OFF power supply of indoor and outdoor unit, and  
disconnect the connector CN781 in the outdoor electronic  
control P.C. board.  
2. 3 minutes after turning ON the power supply, start EMER-  
GENCY OPERATION in COOL mode.  
Is there voltage 12 VDC between the connector  
CN781 pin 5 (+) and pin 3 (-)?  
Replace the noise lter P.C. board.  
No  
Yes  
Replace the outdoor electronic control P.C. board.  
30  
Fan motor does not operate or stops operating shortly after starting the operation.  
D Check of outdoor fan motor  
Check the connection between the  
connector CN931 and CN932.  
Is the resistance between each ter-  
minal of outdoor fan motor normal?  
(Refer to 10-4.)  
Yes  
No  
Disconnect CN932 from outdoor electronic control P.C. board,  
and turn on the power supply.  
Rotate the outdoor fan motor manually and measure the voltage  
of CN931.  
Between 1(+) and 5(-)  
Between 2(+) and 5(-)  
Between 3(+) and 5(-)  
(Fixed to either 5 or 0 VDC)  
No  
Does the voltage between each terminal become 5 VDC  
and 0 VDC repeatedly?  
Yes  
Does the outdoor fan motor rotate smoothly?  
Yes  
No  
Replace the outdoor DC fan motor.  
Replace the outdoor electronic control P.C. board.  
Outdoor unit does not operate.  
E Check of power supply  
Check the connecting of parts of main power  
supply circuit.  
Turn ON power supply.  
Is there voltage of 208 / 230 VAC in the  
power supply terminal block?  
Check the power supply cable.  
Replace the noise lter P.C. board.  
Replace the reactor.  
No  
No  
No  
No  
Yes  
Is the output voltage from the noise lter P.C.  
board 208 / 230 VAC?  
Yes  
Is the input voltage to the power board 208 /  
230 VAC?  
Yes  
Is the input voltage to the outdoor electronic  
control P.C. board 294 / 325 VDC?  
Replace the power board.  
Yes  
Replace the outdoor electronic control P.C. board.  
31  
F Check of compressor start failure  
Conrm that 1~4 is normal.  
•Electrical circuit check  
1.Contact of lead wire leading to compressor  
2.Output voltage of the outdoor electronic control P.C. board and balance of them  
(See 10-5. )  
3.Direct current voltage to the outdoor electronic control 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
Compressor start failure. Activate pre-heat control.  
(Refer to 9-1. "PRE-HEAT CONTROL")  
Heat the compressor with  
a drier for about 20 minutes.  
Do not recover refrigerant  
gas while heating.  
Heating part  
When cooling, heat exchanger of non-operating indoor unit frosts.  
When heating, non-operating indoor unit gets warm.  
G Check of LEV  
Turn ON power supply to the outdoor unit after checking  
LEV coil is mounted to the LEV body securely.  
Is "click - click" sound heard?  
Or, do you feel vibration of the LEV coil with a hand?  
Normal  
Yes  
Yes  
No  
Disconnect the connector CN795.  
Is there normal resistance to LEV coil?  
Replace the outdoor electronic  
control P.C. board.  
No  
Replace the LEV coil.  
32  
• Unit cannot operate neither by the remote controller nor by EMERGENCY OPERATION switch.  
Indoor unit does not operate.  
• OPERATION INDICATOR lamp flashes ON and OFF in every 0.5 seconds.  
Outdoor unit doesn’t operate.  
H How to check miswiring and serial signal error  
Turn OFF the power supply.  
Is there rated voltage in the  
Check the power supply.  
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 the left lamp of OPERATION INDICA-  
TOR lamp light up? <Conrmation of the  
power to the indoor unit>  
No  
No  
Yes  
Is there any miswiring, poor  
contact, or wire disconnec-  
tion of the indoor/outdoor  
connecting wire?  
Is serial signal error indicated 6 minutes later?  
Yes  
Correct them.  
Yes  
Is fuse (F65) broken?  
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 conrm 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.  
Outdoor electronic control P.C. board  
(Parts side)  
LED2 LED1  
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 outdoor electronic control P.C. board.  
2
No  
(Lighted  
or not  
ON quick blinking"?  
3
Lighted Blinking  
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? <Conrmation 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?  
<Conrmation 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 lter  
on remote  
control  
No  
Yes  
Replace the indoor electronic control P.C. board.  
receiving  
Be sure to release the failure-mode recall function  
after checking.  
section of the  
indoor unit.  
B
33  
The operation frequency does not go up from lowest frequency.  
I Check of HPS  
1. Disconnect the connector CN681 in the electronic control P.C. board.  
2. Check the resistance of HPS 1 minute after the outdoor unit power supply was turned OFF.  
Check the resistance between each terminal.  
Replace HPS.  
Innity  
0 Ω  
Reconnect CN681.  
Turn ON power supply to the indoor and outdoor unit.  
3 minutes later, start EMERGENCY OPERATION.  
Is HPS protection displayed immediately after  
compressor starts?  
Replace the outdoor electronic  
control P.C. board.  
Yes  
No  
Normal  
34  
J 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 fullled, the electromagnetic noise may enter, depending on the electric eld strength  
or the installation condition (combination of specic 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 eld intensity of the broadcast station affected by the electromagnetic noise  
6. Presence or absence of amplier 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.  
35  
10-6. TEST POINT DIAGRAM AND VOLTAGE  
1. Outdoor electronic control P.C. board  
MUZ-D30NA MUZ-D36NA MUY-D30NA MUY-D36NA  
Defrost thermistor (RT61)  
Ambient temperature thermistor (RT65)  
Outdoor heat exchanger temperature thermistor (RT68)  
100  
Fin temperature thermistor (RT64)  
Discharge temperature thermistor (RT62)  
200  
180  
160  
140  
120  
100  
80  
700  
600  
500  
400  
300  
200  
100  
0
90  
80  
70  
60  
50  
40  
30  
20  
10  
0
60  
40  
20  
0
32 50 68 86 104 122 140 158 176  
32  
50  
68  
86 104 122 140 176 194 122 212 230 248  
Temperature (°F)  
Temperature (°F)  
-4  
14  
32  
50  
68  
86 104  
Temperature (°F)  
LED 1  
LED 2  
CN801  
294 ~ 370  
VDC  
Input  
F801  
FUSE  
3.15 A / 250 V  
CN601  
(
(
208/230 VAC  
60 Hz  
for indoor  
5~10 VDC  
Input  
(
CN681  
High pressure switch  
36  
2. Noise filter P.C. board  
MUZ-D30NA MUZ-D36NA MUY-D30NA MUY-D36NA  
CN901  
To electronic  
control P.C.  
board  
CN902  
To power  
board  
CN903  
To power  
board  
208 / 230 VAC  
60 Hz  
Input  
MUZ  
CN912  
R.V. coil  
208 / 230 VAC  
60 Hz  
{
Output  
208 / 230 VAC  
60 Hz  
Output  
{
CN61  
F64 FUSE  
2 A / 250 V  
NR64 VARISTOR  
37  
3. Outdoor power board  
MUZ-D30NA MUZ-D36NA MUY-D30NA MUY-D36NA  
Connect to the compressor  
Voltage among phases: 180 V  
Connect to the earth  
294-370 VDC  
CN2  
Output  
(Red)  
Connect to the controller board  
(+)1-5(–): Signal transmission  
(To electronic control P.C. board)  
5 VDC pulse wave  
(+)  
(–)  
1
3
(+)2-5(–): Zero cross signal  
3-4 : Not used  
(White)  
(+)6-5(–): 15 V  
(+)7-5(–): 15 V  
CN3  
Fin temperature thermistor RT64  
Signal reception (From electronic  
control P.C. board)  
)
5 VDC pulse wave  
CN5  
Primary current detection  
(Connect to the noise filter)  
38  
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  
pushing the locking  
pull out the terminal  
slowly.  
Locking lever  
lever.  
Connector  
MUZ-D30NA MUZ-D36NA MUY-D30NA MUY-D36NA  
OPERATING PROCEDURE  
PHOTOS  
1. Removing the cabinet  
Photo 1  
(1) Remove the screws of the service panel.  
(2) Remove the screws of the top panel.  
(3) Remove the screw of the valve cover.  
(4) Remove the service panel.  
Screw of  
the top  
panel  
(5) Remove the top panel.  
(6) Remove the valve cover.  
(7) Remove the screws of the cabinet.  
(8) Remove the cabinet.  
(9) Remove the screws of the back panel.  
(10) Remove the back panel.  
Screws  
of the  
cabinet  
Screws of the cabinet  
Photo 2  
Photo 3  
Screw of the motor support  
Screw of the service panel  
Screws of the  
top panel  
Conduit plate  
Set screws of  
the back panel  
Screws of  
the back  
panel  
Screws  
of the  
cabinet  
Screw of the  
valve cover  
Set screws of the back panel  
39  
OPERATING PROCEDURE  
PHOTOS  
2. Removing the inverter assembly, P.C. board and  
power board  
Photo 4  
(1) Remove the top panel, cabinet, service panel and the back  
panel. (Refer to 1.)  
(2) Disconnect the following connectors;  
<Electronic control P.C. board>  
Screws of the reactor  
CN931 and CN932 (Fan motor)  
CN795 (LEV)  
CN661 (Discharge temperature thermistor, defrost  
thermistor (MUZ) and outdoor heat exchanger  
temperature thermistor)  
HPS  
CN663 (Ambient temperature thermistor)  
CN681 (High pressure switch) (MUZ)  
<Noise filter P.C. board>  
Discharge temperature  
thermistor  
CN912 (4-way valve) (MUZ)  
<Compressor>  
<Reactor>  
(4) Remove the screws fixing the relay panel.  
(5) Remove the inverter assembly.  
(6) Disconnect all connectors and lead wires on the electronic  
control P.C. board.  
(7) Remove the electronic control P.C. board from the inverter  
assembly.  
Photo 5 (Inverter assembly)  
(8) Remove the screws fixing the power board assembly.  
(9) Disconnect all connectors and lead wires on the power  
board.  
Screws of the power board assembly  
(10) Remove the power board from the inverter assembly.  
(11) Disconnect all connectors and lead wires on the noise filter  
P.C. board.  
(12) Remove the noise filter P.C. board from the inverter  
assembly.  
3. Removing R.V. coil (MUZ)  
(1) Remove the top panel, cabinet, service panel and the back  
panel. (Refer to 1.)  
(2) Disconnect the following connectors;  
<Noise filter P.C. board>  
Screws of the relay panel  
CN912 (4-way valve)  
(3) Remove the R.V. coil. (Photo 9)  
Photo 6  
Screws of the  
relay panel  
Propeller  
40  
OPERATING PROCEDURE  
PHOTOS  
4. Removing the defrost thermistor (MUZ), discharge  
temperature thermistor, outdoor heat exchanger  
temperature thermistor and ambient temperature  
thermistor  
Photo 7  
Outdoor heat  
exchanger  
temperature  
thermistor  
(1) Remove the top panel, cabinet, service panel and the back  
panel. (Refer to 1.)  
(2) Disconnect the following connectors;  
<Electronic control P.C. board>  
CN661 (Discharge temperature thermistor, defrost therm-  
istor (MUZ) and outdoor heat exchanger tem-  
perature thermistor)  
Ambient  
temperature  
thermistor  
CN663 (Ambient temperature thermistor)  
(3) Pull out the defrost thermistor from its holder. (Photo 7)  
(MUZ)  
(4) Pull out the discharge temperature thermistor from its hold-  
er. (Photo 4)  
(5) Pull out the outdoor heat exchanger temperature thermistor  
from its holder. (Photo 7)  
(6) Pull out the ambient temperature thermistor from its holder.  
(Photo 7)  
Defrost  
thermistor  
(for MUZ)  
5. Removing outdoor fan motor  
(1) Remove the top panel, cabinet, service panel and the back  
panel. (Refer to 1.)  
Photo 8  
Screws of the outdoor fan motor  
(2) Disconnect the following connectors;  
<Electronic control P.C. board>  
Propeller  
CN931 and CN932 (Fan motor)  
(3) Remove the propeller.  
(4) Remove the screws fixing the outdoor fan motor.  
(5) Remove the outdoor fan motor.  
41  
OPERATING PROCEDURE  
PHOTOS  
6. Removing the compressor and 4-way valve  
(1) Remove the top panel, cabinet, service panel and the back  
panel. (Refer to 1.)  
Photo 9  
(2) Remove the inverter assembly. (Refer to 2.)  
(3) Remove the R.V. coil. (Refer to 3.)  
(4) Recover gas from the refrigerant circuit.  
NOTE: Recover gas from the pipes until the pressure  
gauge shows 0 PSIG.  
(5) Detach the welded part of the suction and the discharge  
pipe connected with compressor. (Photo 9)  
(6) Remove the compressor nuts.  
(7) Remove the compressor.  
(8) Detach the welded part of 4-way valve and pipe. (Photo 8)  
Welded parts of 4-way valve  
R.V. coil  
Photo 10  
Welded part of the  
discharge pipe  
Welded part of the  
suction pipe  
7. Removing the reactor  
(1) Remove the top panel, cabinet, service panel and the back  
panel. (Refer to 1.)  
(2) Disconnect the reactor lead wire.  
(3) Remove the screws of the reactor, and remove the reactor.  
42  
43  
TM  
HEAD OFFICE: TOKYO BLDG., 2-7-3, MARUNOUCHI, CHIYODA-KU, TOKYO 100-8310, JAPAN  
Copyright 2008 MITSUBISHI ELECTRIC ENGINEERING CO.,LTD  
Distributed in Feb. 2008. No. OBH502 7  
Made in Japan  
New publication, effective Feb. 2008  
Specifications subject to change without notice.  

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