Refrigerant
Composition (Ratio)
Refrigerant handling
Chlorine
Safety group (ASHRAE)
Molecular weight
Boiling point (:)
Steam pressure [25:](Mpa)
Saturated steam density [25:](Kg/K)
Combustibility
ODP w1
GWP w2
Refrigerant charge method
Additional charge on leakage
Kind
Color
Smell
w1:Ozone Destruction Parameter : based on CFC-11
w2 :Global Warmth Parameter : based on CO
2
INFORMATION FOR THE AIR CONDITIONER WITH R410A REFRIGERANT
New SpecificationCurrent Specification
The incompatible refrigerating oil easily separates from
refrigerant and is in the upper layer inside the suction muffler.
Raising position of the oil back hole enables to back the
refrigerating oil of the upper layer to flow back to the
compressor.
Since refrigerant and refrigerating oil are compatible each,
refrigerating oil backs to the compressor through the lower
position oil back hole.
Compressor
Suction muffler
Oil back hole
Refrigerating oil
Refrigerant
Compressor
Suction muffler
Oil back hole
Refrigerating oil /Refrigerant
Compressor
• This room air conditioner adopts an HFC refrigerant (R410A) which never destroys the ozone layer.
• Pay particular attention to the following points, though the basic installation procedure is same as that for R22 conditioners.
1 As R410A has working pressure approximate 1.6 times as high as that of R22, some special tools and piping parts/
materials are required. Refer to the table below.
2 Take sufficient care not to allow water and other contaminations to enter the R410A refrigerant during storage and
installation, since it is more susceptible to contaminations than R22.
3 For refrigerant piping, use clean, pressure-proof parts/materials specifically designed for R410A. (Refer to 2. Refrigerant
piping.)
4 Composition change may occur in R410A since it is a mixed refrigerant. When charging, charge liquid refrigerant to prevent
composition change.
NOTE : The unit of pressure has been changed to MPa on the international system of units(SI unit system).
The conversion factor is: 1(MPa [Gauge]) =10.2(kgf/ff[Gauge])
3
-30 -20 -1001020
30
405060
-0.5
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
(MPa [Gauge])
R410A
R22
Conversion chart of refrigerant temperature and pressure
Saturated liquid pressure
(:)
NOTE : The unit of pressure has been changed to MPa on the
R410A toolsCan R22 tools be used?
Gas leak detector
R410A has high pressures beyond the measurement range of existing
gauges. Port diameters have been changed to prevent any other refrigerant
from being charged into the unit.
Hose material and cap size have been changed to improve the pressure
resistance.
Dedicated for HFC refrigerant.
6.35 mm and 9.52 mm
Description
Clamp bar hole has been enlarged to reinforce the spring strength in the tool.
Provided for flaring work (to be used with R22 flare tool).
Provided to prevent the back flow of oil. This adapter enables you to use
vacuum pumps.
It is difficult to measure R410A with a charging cylinder because the
refrigerant bubbles due to high pressure and high-speed vaporization
No
No
No
Yes
Yes
New
New
New
Gauge manifold
Charge hose
Torque wrench
Flare tool
Flare gauge
Vacuum pump
adapter
Electronic scale for
refrigerant charging
No : Not Substitutable for R410A Yes : Substitutable for R410A
No12.7 mm
Wall
thickness
Outside diameter
Pipe
mm
For liquid
For gas
6.35
9.52
12.7
0.8 mm
0.8 mm
0.8 mm
Heat resisting foam plastic
Specific gravity 0.045 Thickness 8 mm
Insulation material
international system of units(SI unit system).
The conversion factor is: 1(MPa [Gauge]) =10.2(kgf/ff[Gauge])
1.Tools dedicated for the air conditioner with R410A refrigerant
The following tools are required for R410A refrigerant. Some R22 tools can be substituted for R410A tools.
The diameter of the service port on the stop valve in outdoor unit has been changed to prevent any other refrigerant being
charged into the unit. Cap size has been changed from 7/16 UNF with 20 threads to 1/2 UNF with 20 threads.
2.Refrigerant piping
1 Specifications
Use the refrigerant pipes that meet the following specifications.
• Use a copper pipe or a copper-alloy seamless pipe with a thickness of 0.8 mm. Never use any pipe with a thickness less
than 0.8mm, as the pressure resistance is insufficient.
4
2 Flaring work and flare nut
Flaring work for R410A pipe differs from that for R22 pipe.
For details of flaring work, refer to Installation manual “FLARING WORK”.
Pipe diameter
mm
6.35
9.52
12.7
Dimension of flare nut
R410A
17
22
26
R22
17
22
24
3.Refrigerant oil
Apply the special refrigeration oil (accessories: packed with indoor unit) to the flare and the union seat surfaces.
4.Air purge
• Do not discharge the refrigerant into the atmosphere.
Take care not to discharge refrigerant into the atmosphere during installation, reinstallation, or repairs to the refrigerant
circuit.
• Use the vacuum pump for air purging for the purpose of environmental protection.
5.Additional charge
For additional charging, charge the refrigerant from liquid phase of the gas cylinder.
If the refrigerant is charged from the gas phase, composition change may occur in the refrigerant inside the cylinder and the
outdoor unit. In this case, ability of the refrigerating cycle decreases or normal operation can be impossible. However,
charging the liquid refrigerant all at once may cause the compressor to be locked. Thus, charge the refrigerant slowly.
Installation plate
Installation plate fixing screw 4 o 25 mm
Remote controller holder
Fixing screw for 3 3.5 o 16 mm
Battery (AAA) for remote controller
Wireless remote controller
Felt tape (Used for left or left-rear piping)
Deodorizing filter
Air cleaning filter
Refrigerant oil
Air flow(High/Med. /Low )
Power outlet
Running current
Power input
Power factor
Starting current
Fan motor current
Model
Winding
resistance(at 20:)
Dimensions WOHOD
Weight
Air direction
Sound level(High/Med. /Low )
Fan speed (High/Med. /Low )
Fan speed regulator
Thermistor RT11(at 25:)
Thermistor RT12(at 25:)
Outdoor model
Capacity
Dehumidification
Outdoor air flow
Power outlet
Running current
Power input
Auxiliary heater
Power factor
Starting current
Compressor motor current
Fan motor current
Model
Output
Winding
resistance(at 20:)
Model
Winding
resistance(at 20:)
Dimensions WOHOD
Weight
Sound level
Fan speed
Fan speed regulator
Refrigerant filling
capacity (R410A)
Refrigerating oil (Model)
Air flow(High/Med. /Low )
Power outlet
Running current
Power input
Power factor
Starting current
Fan motor current
Model
Winding
resistance(at 20:)
Dimensions WOHOD
Weight
Air direction
Sound level(High/Med. /Low )
Fan speed(High/Med. /Low )
Fan speed regulator
Thermistor RT11(at 25:)
Thermistor RT12(at 25:)
Outdoor model
Capacity
Dehumidification
Outdoor air flow
Power outlet
Running current
Power input
Auxiliary heater
Power factor
Starting current
Compressor motor current
Fan motor current
Model
Output
Winding
resistance (at 20:)
Model
Winding
resistance (at 20:)
Dimensions WOHOD
Weight
Sound level
Fan speed
Fan speed regulator
Refrigerant filling
capacity (R410A)
Refrigerating oil (Model)
Thermistor RT61 (at 0:)
Capacity
Dehumidification
Outdoor air flow
Power outlet
Running current
Power input
Auxiliary heater
Power factor
Starting current
Compressor motor current
Fan motor current
Model
Output
Winding
resistance (at 20:)
Model
Winding
resistance (at 20:)
Dimensions WOHOD
Weight
Sound level
Fan speed
Fan speed regulator
Refrigerant filling
capacity (R410A)
Refrigerating oil (Model)
kW
R/h
K /h
A
A
W
A(kW)
%
A
A
A
W
"
"
mm
kg
dB
rpm
kg
cc
Single phase
230V,50Hz
Double
A+B or A+C
2.6+2.8
0.9+1.1
2,460
20
8.18
1,850
—
98.3
47
7.61
0.57
2.81
MC1 : RN099VHSHT, MC2 : RN125VHSHT
MC1 : 650, MC2 : 800
RA6V60-GA
WHT-BLK 90
BLK-RED 146
840O640O330
65
52
730
1
0.80 (Room A)
1.00 (Room B+C)
MC1 : 350 (NEO22), MC2 : 350 (NEO22)
MUX-A20WV -
E1
Cooling
Compressor
Electrical
data
Fan
motor
Special
remarks
Capacity
Coefficient of performance (C.O.P)
Outdoor unit power supply
Indoor unit No.
Single
A
2.6
0.9
3.64
815
97.3
3.07
3.06
Single
B or C
2.9
1.2
4.86
1,075
96.2
4.29
2.61
Double
B+C
1.75O2
0.3O2
4.86
1,090
97.5
4.29
3.02
Triple
A+B+C
2.5+1.75O2
0.8+0.3O2
8.41
1,885
97.5
7.84
3.02
C-R 3.40
C-S 4.56
MC1 : , MC2 :
C-R 2.86
C-S 5.72
NOTE: As for specification of indoor unit, refer to page 9 (MSC-A07/A09/A12WV) or OB329 (MSC-A07/A09/A12YV).
Capacity
Dehumidification
Outdoor air flow
Power outlet
Running current
Power input
Auxiliary heater
Power factor
Starting current
Compressor motor current
Fan motor current
Model
Output
Winding
resistance (at 20:)
Model
Winding
resistance (at 20:)
Dimensions WOHOD
Weight
Sound level
Fan speed
Fan speed regulator
Refrigerant filling
capacity (R410A)
Refrigerating oil (Model)
kW
R/h
K /h
A
A
W
A(kW)
%
A
A
A
W
"
"
mm
kg
dB
rpm
kg
cc
Compressor
Electrical
data
Fan
motor
Special
remarks
Capacity
Coefficient of performance (C.O.P)
Outdoor unit power supply
Indoor unit No.
MUX-A26WV -
E1
Cooling
Single phase 230V,50Hz
2,760
20
—
52
0.53
MC1 : RN145VHSHT, MC2 : RN125VHSHT
MC1 : 1,000, MC2 : 800
RA6V60-FA
WHT-BLK 79
BLK-RED 80
840O850O330
76
52
730
1
1.05 (Room A+B)
1.05 (Room C+D)
MC1 : 620 (NEO22), MC2 : 350 (NEO22)
Single
A or B
3.4
1.2
5.28
1,180
97.2
4.75
2.79
Single
C or D
2.75
1.1
4.54
1,015
97.2
4.01
2.62
Double
A+B
1.95O2
0.2O2
5.46
1,210
96.4
4.93
3.02
Double
A+C or A+D
or
B+C or B+D
Triple
A+B+C
or
A+B+D
Triple
A+C+D
or
B+C+D
3.4+2.7
1.2+1.1
9.57
2,095
95.2
9.04
2.81
Double
C+D
1.7O2
0.3O2
4.78
1,060
96.4
4.25
3.01
1.95O2+2.8
0.2O2+1.1
9.61
2,105
95.2
9.08
3.02
3.4+1.7O2
1.2+0.3O2
9.66
2,140
96.3
9.13
3.02
Four
A+B+C+D
1.95O2+1.7O2
0.2O2+0.3O2
9.75
2,210
98.6
9.22
3.09
C-R 2.43
C-S 3.80
MC1 : , MC2 :
C-R 2.86
C-S 5.72
NOTE: As for specification of indoor unit, refer to page 9 (MSC-A07/A09/A12WV) or OB329 (MSC-A07/A09/A12YV).
The standard data contained in these specifications apply only to the operation of the air conditioner under normal conditions,
since operating conditions vary according to the areas where these units are installed. The following information has been provided to clarify the operating characteristics of the air conditioner under the conditions indicated by the performance curve.
E1E1E1E1E1
E1E1E1E1E1
E1E1E1E1E1
E1
E1
(1) GUARANTEED VOLTAGE
198~264V
(2) AIR FLOW
Air flow should be set at MAX.
(3) MAIN READINGS
(1) Indoor intake air wet-bulb temperature :°CWB
(2) Indoor outlet air wet-bulb temperature :°CWB
(3) Outdoor intake air dry-bulb temperature :°CDB
(4) Total input:W
(5) Indoor intake air dry-bulb temperature :°CDB
(6) Outdoor intake air wet-bulb temperature :°CWB
(7) Total input :W
Indoor air wet/dry-bulb temperature difference on the left side of the chart on page 40,41 and 44 shows the difference
between the indoor intake air wet/dry-bulb temperature and the indoor outlet air wet/dry-bulb temperature for your reference at service.
Cooling
}
Heating
}
<MUH-A07/A09/A12WV>
How to measure the indoor air wet-bulb/dry-bulb temperature difference
1. Attach at least 2 sets of wet-and dry-bulb thermometers to the indoor air intake as shown in the figure, and at least 2 sets
of wet-and dry-bulb thermometers to the indoor air outlet. The thermometers must be attached to the position where air
speed is high.
2. Attach at least 2 sets of wet-and dry-bulb thermometers to the outdoor air intake.
Cover the thermometers to prevent direct rays of the sun.
3. Check that the air filter is cleaned.
4. Open windows and doors of room.
5. Press the EMERGENCY OPERATION switch once(twice) to start the EMERGENCY COOL
(HEAT
<MUH-A07/A09/A12WV>) MODE.
6. When system stabilizes after more than 15 minutes, measure temperature and take an average temperature.
7. 10 minutes later, measure temperature again and check that the temperature does not change.
INDOOR UNIT
9-1.CAPACITY AND THE INPUT CURVES
OUTDOOR UNIT
40
10
12
9
8
7
1520
50
25
60
30
70(%)
35(:)
0.7
0.8
0.9
1.0
1.2
11
1.1
230V
1520
50
25
603070(%)
35(:)
2.0
2.5
3.0
3.5
4.0
230V
MSC-A07WV - E1
(MUH-A07WV - E1 )
(MUH-A12WV - E1 )
MSC-A12WV - E1
(MUH-A09WV - E1 )
MSC-A09WV - E1
8.5
7.8
7.1
6.4
5.8
5.1
9.6
8.8
8.0
7.2
6.5
5.1
10.6
9.7
8.8
7.9
7.1
6.3
20.4
18.8
17.2
15.7
14.1
12.5
11.0
9.4
19.2
17.8
16.3
14.8
13.3
11.8
10.4
8.9
MSC-A07WV - E1
(MUH-A07WV - E1 )
(MUH-A09WV - E1 )
MSC-A09WV -
E1
(MUH-A12WV - E1 )
MSC-A12WV - E1
25.2
23.3
21.4
19.4
17.5
15.5
13.6
11.7
NOTE:The above curves are for the heating operation without any frost.
9-2.OUTDOOR LOW PRESSURE AND OUTDOOR UNIT CURRENT
COOL operation
① Both indoor and outdoor unit are under the same temperature/humidity condition.
Dry-bulb temperature
20
25
Relative humidity(%)
50
60
3070
➁ Air flow should be set at MAX.
③ The unit of pressure has been changed to MPa on the international system of units(SI unit system).
The conversion factor is : 1(MPa[Gauge]) =10.2(kgf/ff[Gauge] )
E1
MU-A07WV -
Outdoor unit current (A)
Ambient temperature(˚C)
Ambient humidity(%)
41
(kgf/F[Gauge])(MPa[Gauge])
Outdoor low pressure
MU-A07WV -
Ambient temperature(˚C)
Ambient humidity(%)
E1
1520
50
25
60
30
70(%)
35(:)
3.0
4.0
5.0
6.0
7.0
230V
1520
50
25
6030 70(%)
35(:)
0.7
0.8
0.9
1.0
1.1
1.2
230V
7
8
9
10
11
12
15 20
50
25
60
30
70(%)
35(:)
2.0
2.5
3.0
3.5
4.0
230V
10
11
12
9
8
7
1520
50
25
60
30
70(%)
35(:)
0.7
0.8
0.9
1.0
1.2
1.1
230V
1520
50
25
60
30
70(%)
35(:)
0.7
0.8
0.9
1.0
1.2
10
11
12
1.1
9
8
7
230V
1520
50
25
60
30
70(%)
35(:)
2.0
2.5
3.0
3.5
4.0
230V
1520
50
25
60
30
70(%)
35(:)
0.7
0.8
0.9
1.0
1.2
10
11
12
1.1
9
8
7
230V
1520
50
25
60
30
70(%)
35(:)
2.0
2.5
3.0
3.5
4.0
230V
(kgf/F[Gauge])(MPa[Gauge])
MU-A09WV -
E1
MU-A09WV -
E1
Outdoor low pressure
Ambient temperature(˚C)
Ambient humidity(%)
(kgf/F[Gauge])(MPa[Gauge])
Outdoor low pressure
Ambient temperature(˚C)
Ambient humidity(%)
(kgf/F[Gauge])(MPa[Gauge])
MU-A12WV -
MUH-A07WV -
Outdoor unit current (A)
Ambient temperature(˚C)
Ambient humidity(%)
E1
MU-A12WV -
E1
Outdoor unit current (A)
Ambient temperature(˚C)
Ambient humidity(%)
E1
MUH-A07WV -
E1
(kgf/F[Gauge])(MPa[Gauge])
Outdoor low pressure
Ambient temperature(˚C)
Ambient humidity(%)
MUH-A09WV -
Outdoor low pressure
Ambient temperature(˚C)
Ambient humidity(%)
Outdoor unit current (A)
Ambient temperature(˚C)
Ambient humidity(%)
E1
MUH-A09WV -
E1
Outdoor unit current (A)
Ambient temperature(˚C)
Ambient humidity(%)
42
5 10152025(:)
4.0
4.5
5.0
5.5
6.0
230V
7
5 10152025(:)
2.0
2.5
3.0
3.5
4.0
7
230V
5 10152025(:)
3.0
3.5
4.0
4.5
5.0
7
230V
1520
50
25
60
30
70(%)
35(:)
2.0
3.0
4.0
5.0
6.0
230V
(kgf/F[Gauge])(MPa[Gauge])
1.3
13
1.2
12
1.1
11
1.0
10
0.9
9
Outdoor low pressure
0.8
8
0.7
7
1520
MUH-A12WV -
50
25
60
E1
30
70(%)
230V
35(:)
MUH-A12WV -
Outdoor unit current (A)
E1
HEAT operation
Condition indoor:Dry bulb temperature 20.0°C
Ambient temperature(˚C)
Ambient humidity(%)
Wet bulb temperature 14.5°C
MUH-A07WV -
E1
Ambient temperature(˚C)
Ambient humidity(%)
Outdoor:Dry bulb temperature 7,15,20°C
Wet bulb temperature 6,12,14.5°C
MUH-A09WV -
Outdoor unit current (A)
E1
Outdoor unit current (A)Outdoor unit current (A)
Ambient temperature(˚C)
MUH-A12WV -
Ambient temperature(˚C)
Ambient temperature(˚C)
E1
43
1.3
1.1
1.0
0.9
0.8
0.7
(kgf/F[Gauge])(MPa[Gauge])
Outdoor low pressure (kgf/F[Gauge])
11
10
9
8
7
13
1.2
12
Outdoor unit current (A)
Single operation (Unit A or B)
1.2
1.0
0.9
0.8
0.7
0.6
Outdoor low pressure (kgf/F[Gauge])
10
9
8
7
6
12
1.1
11
Single operation (Unit A)Single operation (Unit B)
2.0
2.5
3.0
3.5
4.0
Outdoor unit current (A)
3.0
4.0
5.0
6.0
7.0
Outdoor unit current (A)
2.0
2.5
3.0
3.5
4.0
230V
230V
230V
230V
230V
230V
(kgf/F[Gauge])(MPa[Gauge])
1.3
1.1
1.0
0.9
0.8
0.7
Outdoor low pressure (kgf/F[Gauge])
11
10
9
8
7
13
1.2
12
(kgf/F[Gauge])(MPa[Gauge])
Ambient temperature(˚C)
Ambient humidity(%)
20
50
25603070 (˚C)
(%)
Ambient temperature(˚C)
Ambient humidity(%)
20
50
2560 30
70
(˚C)
(%)
Ambient temperature(˚C)
Ambient humidity(%)
20
50
2560 30
70
(˚C)
(%)
Ambient temperature(˚C)
Ambient humidity(%)
20
50
2560 30
70
(˚C)
(%)
Ambient temperature(˚C)
Ambient humidity(%)
20
50
2560 30
70
(˚C)
(%)
Ambient temperature(˚C)
Ambient humidity(%)
20
50
2560 30
70
(˚C)
(%)
˚C)
(%)
9-3.CAPACITY AND THE INPUT CURVES
(ONE INDOOR UNIT WITH ONE OUTDOOR UNIT)
10.3
10.2
10.2
10.8
9.4
8.6
7.8
7.1
6.3
5.6
9.5
8.7
7.9
7.1
6.4
5.7
9.9
9.0
8.1
7.3
6.4
9.4
8.5
7.7
6.9
6.1
9.4
8.5
7.7
6.9
6.1
9.4
8.6
7.7
6.9
6.2
10.2
9.4
9.4
8.6
8.5
7.8
7.7
7.1
6.9
6.3
6.1
5.6
Indoor air WB temperature
difference (deg.)
A or B)
MUX-A10WV- E1
(Indoor unit
)
(Indoor unit A
MUX-A19WV- E1
)
(Indoor unit B
MUX-A20WV- E1
MUX-A19WV- E1
)
B or C)
(Indoor unit A
MUX-A20WV- E1
(Indoor unit
A or B)
MUX-A25WV- E1
(Indoor unit
A or B)
MUX-A26WV- E1
(Indoor unit
C or D)
MUX-A26WV- E1
(Indoor unit
9-4.OUTDOOR LOW PRESSURE AND OUTDOOR UNIT CURRENT
COOL operation
① Both indoor and outdoor unit are under same temperature/humidity condition.
Dry-bulb temperatureRelative humidity (%)
20
25
30
➁ Air flow should be set at MAX.
③ The unit of pressure has been changed to MPa on the international system of units(SI unit system).
The conversion factor is : 1(MPa[Gauge]) =10.2(kgf/ff[Gauge] )
Once the operation mode are set, the same operation mode can be repeated by simply turning the OPERATE/STOP
(ON/OFF) button ON. Indoor unit receives the signal with a beep tone.
When the system turns off, 3-minute time delay will operate to protect system from overload and compressor will not restart for
3 minutes.
WIRELESS REMOTE CONTROLLER
INDOOR UNIT DISPLAY SECTION
Operation Indicator lamp
The operation indicator at the right side of the indoor
unit indicates the operation state.
• The following indication does not
depend on the shape of lamp.
Operation Indicator
lighted
not lighted
Difference
between target
Operation stateIndication
This shows that the
air conditioner is
operating to reach
the target temperature.
Please wait until the
target temperature is
obtained.
temperature
and room
temperature
Approx. 2 :
or more
10-1. COOL () OPERATION
(1) Press OPERATE/STOP(ON/OFF) button. OPERATION INDICATOR lamp of the indoor unit turns on with a beep tone.
(2) Select COOL mode with the OPERATION SELECT button.
(3) Press TEMPERATURE buttons (TOO WARM or TOO COOL button)to select the desired temperature.
The setting range is 16 ~ 31°C
1. Thermostat control
Thermostat is ON or OFF by difference between room temperature and set temperature
Room temperature minus set temperature : 0.3 : or more················································ON
Room temperature minus set temperature : less than -0.3 :············································OFF
2. Indoor fan speed control
Indoor fan operates continuously at the set speed by FAN SPEED CONTROL button regardless
of thermostat’s OFF-ON.
In Auto the fan speed is as follows.
Room temperature minus set temperature : 1.7 degrees or more·······························High
Room temperature minus set temperature : Between 1 and 1.7 degrees···················Med.
Room temperature minus set temperature : less than 1 degree··································Low
This shows that the
room temperature is
approaching the
Approx. 2 :
or less
target temperature.
Initial temperature difference Thermostat
Difference between room
temperature and set temperature during operation
Set temperature
-0.3 :
0.3 :
Difference between room
Initial temperature difference
75
Fan speed
temperature and set temperature during operation
3 deg.
1.7 deg.
1 deg.
35
30
25
20
15
10
:
10 15 20 25 30 35
Set temperature
Initial room temperature
Set temperature and
initial room temperature in dry mode
:
3. Coil frost prevention
① Temperature control
When the indoor coil thermistor RT12 reads 4°C or below(MSC-A07/A09WV) / 0°C or below(MSC-A12WV) for 5 minutes,
the coil frost prevention mode starts.
The indoor fan operates at the set speed and the compressor stops for 5 minutes.
After that, if RT12 still reads below 4°C (MSC-A07/A09WV) / 0°C (MSC-A12WV), this mode is prolonged until the RT12
reads over 4°C (MSC-A07/A09WV) / 0°C (MSC-A12WV).
② Time control
When the three conditions as follows have been satisfied for 1 hour and 45 minutes, the compressor stops for 3 minutes.
The indoor fan operates at the set speed.
a. Compressor has been continuously operating.
b. Indoor fan speed is Low or Med.
c. Room temperature is below 26°C.
When compressor stops, the accumulated time is cancelled. When compressor restarts, time counting starts
from the beginning.
Time counting also stops temporarily when the indoor fan speed becomes High or the room temperature exceeds
26°C. However, when two of the above conditions (b.and c.) are satisfied again, time accumulation is resumed.
Operation chart
Example
ON
ON
Compressor
OFF
OFF
Outdoor fan
ON
Indoor fan
( continuously at set speed)
10-2. DRY () OPERATION
(1) Press OPERATE/STOP(ON/OFF) button.
OPERATION INDICATOR lamp of the indoor unit turns on with a beep tone.
(2) Select DRY mode with the OPERATION SELECT button.
(3) The microprocessor reads the room temperature and determines the set tem-
perature. Set temperature is as shown on the right chart.
DRY operation will not function when the room temperature is 13°C or below.
(4) When DRY operation functions the fan speed is lower than COOL operation
except at (fan speed) Low.
The system for dry operation uses the same refrigerant circuit as the cooling
circuit.
The compressor and the indoor fan are controlled by the room temperature.
Difference between room
1. Thermostat control
Thermostat is ON or OFF by difference between room temperature and set temperature.
Initial temperature difference Thermostat
Room temperature minus set temperature : 0.3 : or more················································ON
Room temperature minus set temperature : less than -0.3 :············································OFF
2. Indoor fan speed control
Indoor fan operates at the set speed by FAN SPEED CONTROL button.
In Auto fan speed becomes Low.
3. The operation of the compressor and indoor / outdoor fan <MU-A07/A09/A12WV, MUH-A07/A09/A12WV,
Compressor operates by room temperature control and time control.
MUX-A10/A19/A20/A22/A25/A26WV>
Indoor fan and outdoor fan operate in the same cycle as the compressor.
● When the room temperature is 23°C or over:
When the thermostat is ON, the compressor repeats 8 minutes ON and 3 minutes OFF.
When the thermostat is OFF, the compressor repeats 4 minutes OFF and 1 minute ON.
● When the room temperature is under 23°C.
When the thermostat is ON, the compressor repeats 2 minutes ON and 3 minutes OFF.
When the thermostat is OFF, the compressor repeats 4 minutes OFF and 1 minute ON.
76
temperature and set temperature during operation
Set temperature
-0.3 :
0.3 :
Operation time chart
Released
Cold Air Prevention
18: 22:
Fan speed
Set speed
Very Low or stop
Example
Thermostat
OFF
ON
ON
OFF
Indoor fan
Outdoor fan
Compressor
ON
ON
OFF
8 min.1 min.
OFFOFF
OFF
ON
ON
3 min.
ON
OFF
ON
OFF
4 min.
4. Coil frost prevention
The operation is as same as coil frost prevention during COOL operation.(Refer to 10-1.3.)
However when coil frost prevention works while the indoor fan is OFF, its speed becomes set speed.
10-3. FAN () OPERATION <MU-A07/A09/A12WV, MUX-A10/A19/A20/A22/A25/A26WV>
(1) Press OPERATE/STOP(ON/OFF) button. OPERATION INDICATOR lamp of the indoor unit turns on with a beep tone.
(2) Select FAN mode with the OPERATION SELECT button.
(3) Select the desired fan speed. When AUTO, it becomes Low.
Only indoor fan operates.
Outdoor unit does not operate.
OPERATION INDICATOR lamp of the indoor unit turns on with a beep tone.
(2) Select HEAT mode with the OPERATION SELECT button.
(3) Press TEMPERATURE buttons (TOO WARM or TOO COOL button) to select the desired temperature.
The setting range is 16 ~ 31°C.
1. Thermostat control
Thermostat is ON or OFF by difference between room temperature and set temperature.
Initial temperature difference Thermostat
Room temperature minus set temperature : less than -0.3 :··············································ON
Room temperature minus set temperature : 0.3 : or more·················································OFF
Difference between room
temperature and set temperature during operation
Set temperature
-0.3 deg.
0.3 deg.
2. Indoor fan speed control
(1) Indoor fan operates at the set speed by FAN SPEED CONTROL button.
In Auto the fan speed is as follows.
Initial temperature difference
Fan speed
Difference between room
temperature and set temperature during operation
Set temperature minus room temperature: 1.7 degrees or more·············································· High
Set temperature minus room temperature: Between 1 and 1.7 degrees·································· Med.
Set temperature minus room temperature: less than 1 degree················································· Low
1 deg.
1.7 deg.
(2) Cold air prevention control
1 When the compressor is not operating,
(1) if the temperature of indoor coil thermistor RT12 is 0°C or less, the fan stops.
(2) if the temperature of indoor coil thermistor RT12 is more than 0°C, the fan operates at Very Low.
2 When the compressor is operating,
(1) if the temperature of RT12 is 22°C or more, the fan operates at set speed.
(2) if the temperature of RT12 is less than 22°C and
(1) if the temperature of room temperature thermistor RT11 is 15°C or less, the fan stops.
(2) if the temperature of room temperature thermistor RT11 is more than 15°C, the fan operates at Very Low.
NOTE : If the temperature of RT12 reads from 18°C to 22°C at the air conditioner stating and also after defrosting,
this control works.
77
3 deg.
(3) Warm air control.
<Time condition>
<Indoor fan speed>
less than 2 minutes Low
2 minutes to 4 minutes Med.
more than 4 minutes High
High pressure protection
Released
48: 52:
Outdoor fan
OFF
ON
When the following any condition of 1 (a. ~ c.) and the condition of 2 are satisfied at the same time, warm air control
works.
1 a.) When outdoor unit starts operating in HEAT mode.
b.) When cold air prevention has been released.
c.) When defrosting has been finished
2 When the temperature of indoor coil thermistor RT12 is less than 37°C.
When warm air control works, the fan speed changes as follows to blow out warm air gradually.
Gradation of fan speed in initial
The upper limit of the fan speed in MANUAL is the set speed.
The upper limit of the fan speed in AUTO is the speed decided by indoor fan speed control.(Refer to 10-4.2.(1).)
When the temperature of RT12 has been 37°C or more, or when the set speed has been changed, this control is
released and the fan speed is the set speed.
3. High pressure protection <MUH-A07/A09/A12WV>
During heating operation, the outdoor fan motor is controlled by the temperature of indoor coil thermistor RT12 for excess
rise protection of compressor discharge pressure.
Outdoor fan OFF: 52:
Outdoor fan ON: 48:
Operation chart
Example
Indoor coil thermistor
RT12 temperature
52˚C
48˚C
Outdoor fan motor
turn OFF
Outdoor fan motor
turn ON
Outdoor fan motor
ON
OFF
ON
OFF
NOTE : During high pressure protection and for 4 min. and 15 sec. after high pressure protection, defrosting of outdoor heat
exchanger is not detected by the defrost thermistor RT61.(Refer to 10-4.4. Defrosting.)
78
4. Defrosting <MUH-A07/A09/A12WV>
Defrosting of outdoor heat exchanger is controlled by DEICER P.C. board, with detection by the defrost thermistor RT61.
(1) Starting conditions of defrost
When all conditions of a) ~ c) are satisfied, the defrosting operation starts.
a) The compressor cumulative operation time exceeds 40 minutes without the defrosting operation working.
b) RT61 reads - 3°C or less.
c) After releasing the high pressure protection 4 minutes and 15 seconds have elapsed.
(2) Releasing conditions of defrost
When the condition d) or e) is satisfied, the defrosting operation stops.
d) RT61 reads 3.1°C or more.
e) The defrosting time exceeds 10 minutes.
Operation time chart
Example
Defrost thermistor RT61
3.1: or more
-3: or less
Outdoor 52C
contactor
(Compressor)
ON
OFF
X62
(R.V. coil)
ON
OFF
30 sec.
15 sec.
30 sec.
5 sec.
SR61
Outdoor fan
Defrost
counter
Indoor fan
ON
OFF
ON
OFF
ON
Very Low
❈
NOTE
Max 10 min.
OFF
Indoor
Horizontal
Horizontal vane
Set position
NOTE ● When the indoor coil thermistor RT12 reads above 0°C, indoor fan operates at Very Low for 30 seconds.
● When the indoor coil thermistor RT12 reads 0°C or less, the indoor fan stops.
79
5. R.V. coil control <MUH-A07/A09/A12WV>
Mode
COOL mode of
"I FEEL CONTROL"
DRY mode of
"I FEEL CONTROL"
HEAT mode of
"I FEEL CONTROL"
Initial room temperature
MUH & MXZ type
25: or more
23:or more,
less than 25:
less than 23:
MU&MUX type
25: or more
more than13:,
less than 25:
Heating · · · · · ON
Cooling · · · · · OFF
Dry · · · · · · · · OFF
When operation starts, the 4-way valve reverses for 5 seconds right before start-up of the compressor.
Operation time chart
(COOL/DRY)
5 sec.
(HEAT)
5 sec.
Compressor
R.V. coil
Outdoor fan
ON
OFF
ON
OFF
ON
OFF
ON
OFF
ON
OFF
ON
OFF
10-5. “I FEEL CONTROL” () OPERATION
(1) Press OPERATE/STOP(ON/OFF) button.
OPERATION INDICATOR lamp of the indoor unit turns on
with a beep tone.
(2) Select “I FEEL CONTROL”() mode with the OPERA-
TION SELECT button.
(3) The operation mode is determined by the initial room tem-
perature at start-up of the operation, as shown on the
right table.
● Once the mode is fixed, the mode does not change by room temperature afterwards.
● Under the ON-TIMER () operation, mode is determined according to the room temperature at set time the opera-
tion starts.
● When the system is stopped on the remote controller and restarted within 2 hours in “I FEEL CONTROL” () mode,
the system operates in previous mode automatically regardless of the room temperature.
Operation time chart
Example
When the system is restarted after 2 hours and more, the operation mode is determined by the room temperature at
start-up of the operation.
Operation time chart
Previous operation
COOL mode of
“I FEEL CONTROL”
or COOL mode
Example
Previous operation
COOL mode of
“I FEEL CONTROL”
or COOL mode
Restart
COOL mode of
“I FEEL CONTROL”
Restart
COOL or DRY or
HEAT mode of “I FEEL
CONTROL” that determined by room temperature at start-up of
the operation.
80
(4) The initial set temperature is decided by the initial room temperature.
TOO
COOL
TOO
WARM
Mode
COOL mode of
"I FEEL CONTROL"
DRY mode of
"I FEEL CONTROL"
HEAT mode of
"I FEEL CONTROL"
MU & MUX type
less than 26:
more than 13:,
Initial room temperature
26: or more
25: or more,
less than 25:
MUH & MXZ type
26: or more
25: or more,
less than 26:
23: or more,
less than25:
less than 23:
Initial set temperature
24:
❈1
Initial room temperature
minus 2:
Initial room temperature
minus 2:
26:
❈1 When the system is restarted with the remote controller, the system operates with the previous set temperature regard-
less of the room temperature at restart.
(5) TEMPERATURES buttons
In “I FEEL CONTROL” () mode, set temperature is decided by the microprocessor based on the room temperature.
In addition, set temperature can be controlled by TOO WARM or TOO COOL buttons when you feel too cool or too
warm. Each time the TOO WARM or TOO COOLbutton is pressed, the indoor unit receives the signal and emits a beep
tone.
● Fuzzy control
When the TOO COOL or TOO WARM button is pressed, the microprocessor changes the set temperature, considering
the room temperature, the frequency of pressing TOO COOL or TOO WARM button and the user’s preference to heat or
cool. So this is called “Fuzzy control”, and works only in “I FEEL CONTROL” mode.
In DRY mode of “I FEEL CONTROL”, the set temperature doesn’t change.
…
To raise the set temperature 1~2 degrees(°C)
…
To lower the set temperature 1~2 degrees(°C)
10-5-1. COOL mode of “I FEEL CONTROL”
1. Thermostat control
Thermostat control is as same as COOL OPERATION.(10-1.1.)
2. Indoor fan speed control
Indoor fan speed control is as same as COOL OPERATION.(10-1.2.)
3. Coil frost prevention
Coil frost prevention is as same as COOL OPERATION.(10-1.3.)
10-5-2. DRY mode of “I FEEL CONTROL”
1. Thermostat control
Thermostat control is as same as DRY OPERATION.(10-2.1.)
2. Indoor fan speed control
Indoor fan speed control is as same as DRY OPERATION.(10-2.2.)
3. The operation of the compressor and indoor / outdoor fan
The operation of the compressor and indoor/outdoor fan is as same as DRY OPERATION.(10-2.3.)
4. Coil frost prevention
Coil frost prevention is as same as DRY OPERATION.(10-2.4.)
10-5-3. HEAT mode of “I FEEL CONTROL” <MUH-A07/A09/A12WV, MXZ-A18/A26/A32WV>
1. Thermostat control
Thermostat control is as same as HEAT OPERATION.(10-4.1.)
2. Indoor fan speed control
Indoor fan speed control is as same as HEAT OPERATION.(10-4.2.)
3. High pressure protection <MUH-A07/A09/A12WV>
High pressure protection is as same as HEAT OPERATION.(10-4.3.)
4. Defrosting <MUH-A07/A09/A12WV>
Defrosting is as same as HEAT OPERATION.(10-4.4.)
5. R.V. coil control <MUH-A07/A09/A12WV>
R.V. coil control is as same as HEAT OPERATION.(10-4.5.)
81
HighHigh
Med.
Low
10-6. FAN MOTOR CONTROL
(1) Rotational frequency feedback control
The indoor fan motor is equipped with a rotational frequency sensor, and outputs signal to the microprocessor to
feedback the rotational frequency. Comparing the current rotational frequency with the target rotational
frequency (High,Med.,Low), the microprocessor controls SR141 and adjusts fan motor electric current to make the
current rotational frequency close to the target rotational frequency. With this control, when the fan speed is switched,
the rotational frequency changes smoothly.
(2) Fan motor lock-up protection
When the rotational frequency feedback signal is not output for 12 seconds, (or when the microprocessor cannot detect
the signal for 12 seconds) the fan motor is regarded locked-up. Then the electric current to the fan motor is shut off. 3 minutes later, the electric current is applied to the fan motor again. During the fan motor lock-up, the OPERATION INDICATOR lamp flashes on and off to show the fan motor abnormality. (Refer to page 91.)
10-7. AUTO VANE OPERATION
(1) Vane motor drive
These models are equipped with a stepping motor for the horizontal vane. The rotating direction, speed, and angle of
the motor are controlled by pulse signals (approx. 12V) transmitted from indoor microprocessor.
(2) The horizontal vane angle and mode changes as follows by pressing the VANE CONTROL button.
(3) Positioning
The vane is once pressed to the vane stopper below to confirm the standard position and then set to the desired angle.
Confirming of standard position is performed in case of follows.
(a) When the OPERATE/STOP(ON/OFF) button is pressed.
(b) When the vane control is changed from AUTO to MANUAL.
(c) When the SWING is finished.
(d) When the test run starts.
(e) When the power supply turns ON.
(4) VANE AUTO () mode
In VANE AUTO mode, the microprocessor automatically determines the vane angle to make the optimum room-temperature distribution.
1 In COOL and DRY operation
Vane angle is fixed to Angle 1.
2 In FAN operation <MU-A07/A09/A12WV
MUX-A10/A19/A20/A22/
A25/A26WV>
2 In HEAT operation
(5) Dew prevention
During COOL or DRY operation at Vane Angle 4 or 5 when the cumulative operation time of compressor exceeds 1
hour, the vane angle automatically changes to Angle 1 for dew prevention.
(6) SWING MODE ()
By selecting SWING mode with the VANE CONTROLbutton, the horizontal vane swings vertically. The remote controller
displays “”.
<MUH-A07/A09/A12WV
MXZ-A18/A26/A32WV>
82
Vane angle is fixed to Angle 4.
(7) Cold air prevention in HEAT operation <MUH-A07/A09/A12WV, MXZ-A18/A26/A32WV>
Set position
Angle 1
Released
Cold air prevention
24:
28:
When any of the following conditions occurs in HEAT operation, the horizontal vane angle changes to Angle 1 automatically to prevent cold air blowing on users.
① Compressor is not operating.
➁ Defrosting is performed.
➂ Indoor coil thermistor RT12 reads 24: or below.
➃ Indoor coil thermistor RT12 temperature is raising from 24°C or below, but it does not exceed 28:.
Indoor coil thermistor
RT12 temperature
NOTE : If the temperature of RT12 reads from 24°C to 28°C at the air conditioner stating , this control works.
When the ECONO COOL button is pressed in COOL mode, set temperature is automatically set 2°C higher than that in
COOL mode.
Also the horizontal vane swings in various cycle according to the temperature of indoor heat exchanger(RT12).
SWING operation makes you feel cooler than set temperature. So, even though the set temperature is higher than that
in COOL mode, the air conditioner can keep comfort. As a result, energy can be saved.
ECONO COOL operation is cancelled when the ECONO COOL button is pressed once again or VANE CONTROL button is pressed or operation mode is changed.
NOTE : ECONO COOL operation does not work in COOL mode of “I FEEL CONTROL”.
SWING operation
In swing operation of ECONO COOL operation mode, the initial air flow direction is adjusted to “Horizontal”.
According to the temperature of indoor coil thermistor RT12 at starting of this operation, next downward blow time is
decided. Then when the downward blow has been finished, next upward blow time is decided.
For initial 10 min. the swing operation is performed in table G~H for quick cooling.
Also, after 10 min. when the difference of set temperature and room temperature is more than 2 degrees, the swing
operation is performed in table D~H for more cooling.
The air conditioner repeats the swing operation in various cycle as follows.
Horizontal vane
Temperature of indoor
coil thermistor RT12
A
B
C
D
E
F
G
H
15°C or less
15°C to 17°C
17°C to 18°C
18°C to 20°C
20°C to 21°C
21°C to 22°C
22°C to 24°C
more than 24°C
Downward blow time
(sec.)
2
5
8
11
14
17
20
23
Horizontal blow time
(sec.)
23
20
17
14
11
8
5
2
10-8. TIMER OPERATION
1. How to set the timer
(1) Press OPERATE/STOP(ON/OFF) button to start the air conditioner.
(2) Check that the current time is set correctly.
NOTE : Timer operation will not work without setting the current time. Initially “AM0:00” blinks at the current time display
of TIME MONITOR, so set the current time correctly with CLOCK SET button.
(3) Press ON or OFF TIMER buttons to select the operation.
“” button... AUTO START operation (ON timer)
“” button... AUTO STOP operation (OFF timer)
83
EMERGENCY OPERATION switch
PM
AM
PM
PM
(4) Press HR. and MIN. button to set the timer. Time setting is 10-minute units.
HR. and MIN. button will work when “” or “” mark is flashing.
These marks disappear in 1 minute.
After setting the ON timer, check that OPERATION INDICATOR lamp of the indoor unit lights.
NOTE1 : Be sure to place the remote controller at the position where its signal can reach the air conditioner even during
TIMER operation, or the set time may deviate within the range of about 10 minutes.
NOTE2 : Reset the timer in the following cases, or the set time may deviate and other malfunctions may occur.
● A power failure occurs.
● The circuit breaker functions.
2. Cancel
TIMER setting can be cancelled with the ON or OFF TIMER buttons. (“” or “”)
To cancel the ON timer, press the “” button.
To cancel the OFF timer, press the “” button.
TIMER is cancelled and the display of set time disappears.
PROGRAM TIMER
● The OFF timer and ON timer can be used in combination.
● “” and “ ” display shows the order of the OFF timer and ON timer operation.
(Example 1) The current time is 8:00 PM.
The unit turns off at 11:00 PM, and on at 6:00 AM.
(Example 2) The current time is 11:00 AM.
The unit turns on at 5:00 PM, and off at 9:00 PM.
NOTE : TIMER setting will be cancelled by power failure or breaker functioning.
10-9. EMERGENCY-TEST OPERATION
In case of test run operation or emergency operation, use the EMERGENCY OPERATION switch on the front of the
indoor unit. Emergency operation is available when the remote controller is missing, has failed or the batteries of remote
controller run down. The unit will start and the OPERATION INDICATOR lamp will light.
The first 30 minutes of operation is the test run operation. This operation is for servicing. The indoor fan speed runs at
High speed and the system is in continuous operation. (The thermostat is ON.)
After 30 minutes of test run operation the system shifts to EMERGENCY COOL [/HEAT <MUH-A07/A09/A12WV,
MXZ-A18/A26/A32WV>] MODE with a set temperature of 24°C. The fan speed shifts to Med. speed.
The coil frost prevention works even in emergency operation [, and defrosting <MUH-A07/A09/A12WV,
MXZ-A18/A26/A32WV> too].
In the test run or emergency operation, the horizontal vane operates in VANE AUTO () mode.
Emergency operation continues until the EMERGENCY OPERATION switch is pressed once again (MU-A07/A09/A12WV,
MUX-A10/A19/A20/A22/A25/A26WV)/once or twice (MUH-A07/A09/A12WV, MXZ-A18/A26/A32WV) or the unit receives
any signal from the remote controller. In case of latter normal operation will start.
NOTE : Do not press the EMERGENCY OPERATION switch during normal operation.
84
• The following indication does not depend on the
shape of lamp.
OPERATION INDICATOR lamp
Press once <Cool>
Press again <Heat>
Press once again <Stop>
w Heat is available only in MUH-A07/A09/A12WV and
MXZ-A18/A26/A32WV.
10-10. OUTDOOR UNIT ACTUATOR CONTROL
ACTUATOR
ON
OFF
ON
OFF
ON
OFF
ON (OPEN)
OFF (CLOSE)
ON (OPEN)
OFF (CLOSE)
ON (OPEN)
OFF (CLOSE)
ON (OPEN)
OFF (CLOSE)
ON (CLOSE)
OFF (OPEN)
ON (CLOSE)
OFF (OPEN)
SOLENOID
VALVE
MUX-A26WV -
E1
INDOOR UNIT
MC1
MC2
MF61
21R1
21R2
21R3
21R4
21RA
(BALANCE)
21RB
(BALANCE)
COMPRESSOR
OUTDOOR
FAN MOTOR
A
ON
ON
OFF
OFF
–
–
–
–
OFF
ON
OFF
–
–
–
–
–
–
ON
ON
OFF
OFF
–
–
–
–
B
ON
OFF
ON
OFF
–
–
–
–
ANY UNIT ON
OFF
–
–
ON
OFF
–
–
–
–
ON
OFF
ON
OFF
–
–
–
–
C
–
–
–
–
ON
ON
OFF
OFF
OFF
–
–
–
–
ON
OFF
–
–
–
–
–
–
ON
ON
OFF
OFF
D
–
–
–
–
ON
OFF
ON
OFF
OFF
–
–
–
–
–
–
ON
OFF
–
–
–
–
ON
OFF
ON
OFF
ACTUATOR
ON
OFF
ON
OFF
ON
OFF
ON (OPEN)
OFF (CLOSE)
ON (OPEN)
OFF (CLOSE)
ON (CLOSE)
OFF (OPEN)
SOLENOID
VALVE
MUX-A20WV -
E1
INDOOR UNIT
MC1
MC2
MF61
21R3
21R4
21RB
COMPRESSOR
OUTDOOR
FAN MOTOR
A
ON
OFF
–
–
–
–
OFF
–
–
–
–
–
–
–
–
B
–
–
ON
ON
OFF
OFF
ANY UNIT ON
OFF
ON
OFF
–
–
ON
ON
OFF
OFF
C
–
–
ON
OFF
ON
OFF
OFF
–
–
ON
OFF
ON
OFF
ON
OFF
ACTUATOR
ON
OFF
ON
OFF
ON (CLOSE)
OFF (OPEN)
ON (OPEN)
OFF (CLOSE)
ON (OPEN)
OFF (CLOSE)
SOLENOID
VALVE
MUX-A10WV - E1
INDOOR UNIT
MC
MF
21R
(BALANCE)
21R1
21R2
COMPRESSOR
OUTDOOR
FAN MOTOR
A
ON
ON
OFF
OFF
ANY UNIT ON
OFF
ON
ON
OFF
OFF
ON
OFF
–
–
B
ON
OFF
ON
OFF
OFF
ON
OFF
ON
OFF
–
–
ON
OFF
ACTUATOR
ON
OFF
ON
OFF
ON
OFF
MUX-A19WV -
E1 MUX-A25WV - E1
INDOOR UNIT
MC1
MC2
MF61
COMPRESSOR
OUTDOOR
FAN MOTOR
A
ON
OFF
–
–
ANY UNIT ON
OFF
B
–
–
ON
OFF
OFF
“–” means that the indoor unit is not related to the control of actuator.
85
11
MUH-A07WV MUH-A09WV MUH-A12WV -
Jumper wire
JRF
JRG
MODELChange point
Defrost interval time changes from 40 minutes to 15 minutes
Deforst start temperature changes from -3: to 0:
Deforst finish temperature changes from 3.1: to 10.1:.
11-1. COMPULSORY DEFROSTING MODE FOR SERVICE <MUH-A07/A09/A12WV>
By short circuit of the connector JPDS and JPSG on the outdoor deicer P.C. board, defrosting mode can be accomplished regardless of the defrost interval restriction. (Refer to page 103.)
Defrost thermistor RT61 must read below -3°C.
11-2. CHANGE IN DEFROST SETTING <MUH-A07/A09/A12WV>
<JRF> When the JRF wire of the deicer P.C. board is cut, the defrost interval time will be changed. (Refer to page 103.)
<JRG> When the JRG wire of the deicer P.C. board is cut, the defrost temperature will be changed. (Refer to page 103.)
11-3. TIMER SHORT MODE
For service, set time can be shortened by short circuit of JPG and JPS the electronic control P.C. board.
The time will be shortened as follows. (Refer to page 102.)
Set time : 1 minute ➔ 1-second
Set time : 3 minutes ➔ 3-second (It takes 3 minutes for the compressor to start operation. However, the starting time is
shortened by short circuit of JPG and JPS.)
E1E1E1E1
E1E1E1E1E1
E1E1E1E1E1
11-4. P.C. BOARD MODIFICATION FOR INDIVIDUAL OPERATION
A maximum of 4 indoor units with wireless remote controllers can be used in a room.
In this case, to operate each indoor unit individually by each remote controller, P.C. boards of remote controller must be
modified according to the number of the indoor unit.
How to modify the remote controller P.C. board
Remove batteries before modification. The board has a print as shown below :
NOTE : For remodelling, take out the bat-
teries and press the
OPERATE/STOP(ON/OFF) button
twice or 3 times at first.
After finish remodelling, put back
the batteries then press the
RESET button.
The P.C. board has the print “J1” and “J2”.
Solder “J1” and “J2” according to the number of indoor unit as shown in Table 1.
After modification, press the RESET button.
Table 1
86
SW2-1 sets the AUTO RESTART FUNCTION ON / OFF.
SW2-2 switches over the MU & MUX type / MUH & MXZ type.
When the units are shipped from the factory, SW2 is as follows.
SW2-1: AUTO RESTART FUNCTION OFF
SW2-2: MUH & MXZ type
}
12
12
SW2
FRONT
IC101
SW2
CN151
SW1
CN112
CN121
L101
CN201
F11
TAB12
CN202
C11
CN211
1 2
1 2
1 2
SW2SW2
1 2
Outdoor unit
MUH & MXZ type
Set 2 switch downside.
Outdoor unit
MU & MUX type
Set 2 switch upside.
1 2
SW2SW2
1 2
1 2
1 2
AUTO RESTART
FUNCTION OFF
Set 1 switch upside.
AUTO RESTART
FUNCTION ON
Set 1 switch downside.
Slide switch
Type
The position
of the slide
switch
COOL ONLYCOOL & HEAT
How to set the remote controller exclusively for particular indoor unit
After you turn the breaker ON, the first remote controller that sends the signal to the indoor unit will be regarded as the
remote controller for the indoor unit.
The indoor unit will only accepts the signal from the remote controller that has been assigned to the indoor unit once they
are set.
The setting will be cancelled if the breaker has turned off, or the power supply has shut down.
Please conduct the above setting once again after the power has restored.
11-5. REMOTE CONTROLLER (How to set the type)
This remote controller setting needs to be switched according to the type of air conditioner (COOL & HEAT or COOL
ONLY).
If the setting is incorrect, the air conditioner does not operate normally. Therefore, check if the setting corresponds to the
type of air conditioner. If it does not, correct the setting as shown below.
11-6. MU & MUX TYPE / MUH & MXZ TYPE SWITCH OVER AND AUTO RESTART FUNCTION
1. MU & MUX TYPE / MUH & MXZ TYPE SWITCH OVER
The indoor units for MU & MUX type and MUH & MXZ type
are common specifications. Set switch according to the
type of outdoor unit. The units are set for
MUH & MXZ type when they are shipped from the factory.
How to switch over MU & MUX TYPE / MUH & MXZ TYPE
! Turn off the main power for the unit.
@ Pull out the electronic control P.C. board, and change
switch(SW2-2) on the indoor electronic control P.C. board
according to the type of outdoor unit as following figures.
2. AUTO RESTART FUNCTION
When the indoor unit is controlled with the remote controller, the operation mode, set temperature, and the fan speed
are memorized by the indoor electronic control P.C.board. The “AUTO RESTART FUNCTION” sets to work the moment
power has restored after power failure.Then, the unit will restart automatically. However if the unit is operated in “I
FEEL CONTROL” mode before power failure, the operation is not memorized. In “I FEEL CONTROL” mode, the operation is decided by the initial room temperature. “AUTO RESTART FUNCTION” is OFF when the units are shipped from
the factory.
How to set “AUTO RESTART FUNCTION”
! Turn off the main power for the unit.
@ Pull out the electronic control P.C. board, and change switch(SW2-1) on the indoor electronic control P.C. board as
following figures.
NOTE:•If the indoor-outdoor connecting wire is incorrectly
connected on the terminal block, the unit does not
operate normally.
•If a ground is incorrect, it may cause an electric shock.
Operation
! If the main power (230V AC) has been cut, the operation settings remain.
@ After the power is restored, the unit restarts automatically according to the memory. (However, it takes at least 3
minutes for the compressor to start running.)
87
Lead wiring
Housing point
Insert the negative pole
of the batteries first.
Check if the polarity of
the batteries are correct.
HEAT
/FAN
/
RESET button
HEAT
/FAN
/
NOTE
•The operation settings are memorized when 10 seconds have passed after the remote controller was operated.
•If main power is cut while AUTO START/STOP timer is active, the timer setting is cancelled.
•If the unit has been off with the remote controller before power failure, the auto restart function does not work as the
power button of the remote controller is off.
•To prevent breaker off due to the rush of starting current, systematize other home appliance not to turn on at the same
time.
•When some air conditioners are connected to the same supply system, if they are operated before power failure, the
starting current of all the compressors may flow simultaneously at restart.
Therefore, the special counter-measures are required to prevent the main voltage-drop or the rush of the starting current
by adding to the system that allows the units to start one by one.
2) Check the indoor/outdoor connecting wire for mis-wiring.
2. Take care the following during servicing.
1) Before servicing the air conditioner, be sure to first turn off the remote controller to stop the unit, and 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 electronic control P.C. board, hold the edge of the board with care NOT to apply stress on the
components.
4) When connecting or disconnecting the connectors, hold the housing of the connector. DO NOT pull the lead wires.
E1E1E1E1
E1E1E1E1E1
E1E1E1E1E1
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) If the electronic control P.C. board is supposed to be defective, check the copper foil pattern for disconnection and the
components for bursting and discoloration.
3) When troubleshooting, refer to the flow chart on page 90 and the check table on page 91.
4. How to replace batteries
Weak batteries may cause the remote controller malfunction.
In this case, replace the batteries to operate the remote controller normally.
1 Remove the front lid and insert batteries.
2 Press the RESET button.
Then reattach the front lid.
NOTE : If the RESET button is not pressed, the remote controller may not operate correctly.
88
INFORMATION FOR MULTI SYSTEM AIR CONDITIONER
OUTDOOR UNIT : MXZ-A18WV-MXZ-A26WV-MXZ-A32WV-
Multi system air conditioner can connect two or more indoor units with one outdoor unit.
•Unit won’t operate in case the total capacity of indoor units exceeds the capacity of outdoor units. Do not connect
indoor units beyond the outdoor unit capacity.
•When you try to operate two or more indoor units with one outdoor unit simultaneously, one for the cooling and the
other for heating, the operation mode of the indoor unit that operates earlier is selected. The other indoor units that
will start the operation later cannot operate, indicating as shown in the figure below. In this case, please set all the
indoor units to the same operation mode.
Operation Indicator
•When indoor units starts the operation while the defrosting of outdoor unit is being done, it takes a few minutes
(max. 10 minutes) to blow out the warm air.
•In the heating operation, though indoor unit that does not operate may get warm or the sound of refrigerant flowing
may be heard, they are not malfunction. The reason is that the refrigerant continuously flows into it.
E1E1E1
Lighted
Blinking
89
12-2. Instruction of troubleshooting
Start
Indoor unit
operates.
Outdoor unit
doesn't
operate.
Indoor unit
doesn't receive
the signal from
remote controller.
Indoor unit
operates.
But indoor
unit doesn't
blow out
cool air.
Indoor unit
operates.
Outdoor unit
doesn't operate
normally.
OPERATION
INDICATOR
lamp on the
indoor unit is
flashing on
and off.
Outdoor unit
operates in
only Test Run
operation.
Outdoor unit
doesn't
operate
even in
Test Run
operation.
Indoor unit
operates,
when the
EMERGENCY
OPERATION
switch is
pressed.
Indoor unit
doesn't operate,
when the
EMERGENCY
OPERATION
switch is
pressed.
Check room
temperature
thermistor.
Refer to
"Test point
diagram and
voltage" on
page 102.
MUH-A07/A09/A12WV
MUX-A19/A20/A22/
A25/A26WV
Refer to D
"Check of
outdoor unit"
on page 96
or 97.
Refer to B
"Check of
remote
controller
and receiver
P.C. board"
on page 95.
MUH-A07/A09/A12WV
MXZ-A18/A26/A32WV
Flash on and
off at 0.5second
intervals
Cause:
Indoor/
Outdoor unit
• Mis-wiring
2-time flash
Cause:
Indoor unit
• Trouble of
room temp erature/
indoor coil
thermistor
3-time flash
Cause:
Indoor unit
• Trouble of
indoor fan
motor
MUH-A07/A09/A12WV
MXZ-A18/A26/A32WV
6-time flash
Cause:
Outdoor unit
• Trouble of
thermistor
in outdoor
unit
MUH-A07/A09/A12WV
MXZ-A18/A26/A32WV
7-time flash
Cause:
Outdoor unit
• Trouble of
outdoor
control
system
Check room
temperature
thermistor
and indoor
coil thermistor.
Refer to
"Test point
diagram and
voltage"
on page 102.
Refer to A
"Check of
indoor fan
motor"
on page 95.
Refer to H
"Check of
outdoor
thermistor"
on page 101
and others.
Replace the
deicer
P.C. board or
the outdoor
electronic
control P.C.
board.
MUH-A07/A09/A12WV
MXZ-A18/A26/A32WV
1-time flash
Cause:
Outdoor /
Indoor unit
• Trouble of
serial signal
Refer to G "How to check
mis-wiring and serial signal
error (When outdoor unit
doesn't work)" on page 100.
W1
1. Check indoor /
outdoor
connecting wire.
2. Refer to C
"Check of indoor
electronic control
P.C. board"
on page 96.
Outdoor unit
doesn't
stop even
if indoor unit
stops.
Unit doesn't
operate
normal
operation in
COOL or
HEAT mode.
MU/H-A07/A09/A12WV
Refer to E
"Check of
outdoor unit"
on page 98.
MUH-A07/A09/A12WV
MXZ-A18/A26/A32WV
Refer to F
"Check of
R.V. coil"
on page 99
and others.
MUX-A10/A19/A20/
A22/A25/A26WV
Refer to I
"Check of
indoor/outdoor
units' connection
and outdoor unit"
on page 101.
W1.<The case of the trouble of the serial signal>
When the power is turned off and then turned on again, the indication shows “the trouble of mis-wiring”.
MXZ-A18/A26/A32WV
5-time flash
Cause:
Outdoor unit
• Outdoor
power
system
abnormality
Refer to
"Check of
inverter/
compressor"
and "Check
of power
supply".
NOTE:
As for outdoor unit
MXZ type, refer to
service manual
OB319.
As for outdoor unit
MUX-A22WV,
refer to
service manual
OB318 REVISED
EDITION-A.
· Flashing of the OPERATION INDICATOR lamp (left-hand side)
indicates possible abnormalities.
· The OPERATION INDICATOR lamp (left-hand side lamp) is
lighting during normal operation.
Lighted
Not lighted
• The following indication applies regardless of shape of the indicator.
No.
1
2
4
6
7
SymptomOperation indicator lampDetection method
Checkpoint
0.5-second ON
0.5-second OFF
MUH or
MXZ type
Mis-wiring
MUH or
MXZ type
Outdoor
thermistor
MUH or
MXZ type
Outdoor
control
system
error
When serial signal stops for 4 to 5 seconds after 1st on of 52C relay by POWER turning on.
When the defrost thermistor shorts or opens
after the compressor start-up.
When it cannot properly read data in the
nonvolatile memory of outdoor deicer P.C.
board or outdoor electronic control P.C. board.
When the operation mode of each indoor unit
is differently set to COOL(includes DRY) and
HEAT at same time, the operation mode of
indoor unit that has operated at first has the
priority.
● Check outdoor deicer P.C.
board or outdoor electronic
control P.C. board.
● Check resistance of
thermistor.
● Reconnect connector.
● Check outdoor deicer P.C.
board or outdoor electronic
control P.C. board.
● Unify the operation mode.
● Check switch SW2-2.(MU &
MUX type or MUH & MXZ
type)
● Check wiring (visual check
and conductivity check).
● Check indoor electronic
control P.C.board.
● Check outdoor DEICER P.C.
board and others.
● Check electrical parts.
● Check resistance of
thermistor.
● Reconnect connector.
● Check indoor electronic
control P.C.board.
3
Indoor coil
thermistor
Room
temperature
thermistor
Abnormal
point
Outdoor unit
does not run.
Outdoor unit
does not run.
Outdoor unit
does not run.
Outdoor unit
does not run.
Outdoor unit
does not run.
MUH or
MXZ type
Serial
signal
1-time flash
2.5-second OFF
2-time flash
2.5-second OFF
When serial signal from outdoor unit stops for
4 to 5 seconds.
Detect Indoor coil/room temperature thermistor short or open circuit every 8 seconds during operation.
3-time flash
2.5-second OFF
Indoor fan motor
repeats 12 seconds ON and 3
minutes OFF.
When the indoor
fan motor
breaks, the fan
keeps stopping.
When rotational frequency feedback pulse
signal is not emit during 12-second indoor fan
operation.
When the compressor operation is
continuously three times interrupted by over
current protection within 1 minute after startup , it stops operation.
● Disconnect connector
CN211 and then check
connector CN121 2-3 to
make sure rotational
frequency feedback signal of
1.5V or over exists.
● Check indoor electronic
control P.C. board.
● Check indoor fan motor.
● Reconnect connector.
● Check the inverter output.
● Check the compressor.
Indoor fan
motor
6-time flash
2.5-second OFF
5
5-time flash
2.5-second OFF
MXZ type
Operation
mode
setting
Outdoor unit
operates but
indoor unit
does not run.
Operation Indicator
Lighted
Blinking
NOTE: As for outdoor unit MXZ type, refer to service manual OB319.
7-time flash
2.5-second OFF
MXZ type
Outdoor
power
system
2.5-second OFF
Right lamp flashes
12-3. Troubleshooting check table
❈ Before taking measures, make sure that the symptom reappears, for accurate troubleshooting.
Self check table
91
12-4. Trouble criterion of main parts
RED
BLK
YLW
FUSE
GRY
BRN
WHT
RED
YLW
BRN
ORN
GRN
ROTOR
MSC-A07WV MSC-A09WV MSC-A12WV -
Part name
Room
temperature
thermistor (RT11)
Indoor coil
thermistor (RT12)
Indoor fan
motor (MF)
INNER FUSE
136i3°C
CUT OFF
E1
E1
E1
Measure the resistance with a tester.
(Part temperature 10°C ~ 30°C)
Measure the resistance between the terminals with a tester.
(Coil wiring temperature10°C ~ 30°C)
Color of
lead wire
Motor partSensor part
BLK-RED
Measure the voltage Power ON.
Color of
lead wire
BRN-YLW
YLW-GRY
Check method and criterion
Normal
MSC-A07/A09/A12WV
8kΩ ~ 20kΩ
Normal
MSC-A07/A09WV
396 ~ 430ΩWHT-BLK
320 ~ 348Ω
Normal
MSC-A07/A09/A12WV
4.5 ~ 5.5V
(When fan revolved one time)
0V➔5V➔0V
(Approx.)
MSC-A12WV
303 ~ 329Ω
287 ~ 311Ω
Remain 0V or 5V
Figure
Abnormal
Open or
short-circuit
Abnormal
Open or
short-circuit
Abnormal
Vane motor
(MV)
Measure the resistance between the terminals with a tester.
(Part temperature10°C ~ 30°C)
Compressor
(MC, MC1,
MC2)
INNER
PROTECTOR
150°C OPEN
90°C CLOSE
Outdoor fan
motor
(MF, MF61)
INNER FUSE
MUX-A10WV
145°C OPEN
INNER
PROTECTOR
MUX-A19/A20/A25/
A26WV
145i8°C OPEN
Check method and criterion
Measure the resistance between the terminals with a tester.
(Coil wiring temperature-10°C ~ 40°C)
Normal
MUX-A10WV
RN092VHSHT
3.41 ~ 4.18
C-R
5.41 ~ 6.63
C-S
C-R
C-S
Ω
Ω
MUX-A25WV
RN145VHSHT
2.14 ~ 2.63
3.35 ~ 4.11
MUX-A19WV
RN145VHSHT RN092VHSHT
2.14 ~ 2.63Ω3.41 ~ 4.18
3.35 ~ 4.11Ω5.41 ~ 6.63
Normal
Ω
Ω
RN145VHSHT
2.14 ~ 2.63
3.35 ~ 4.11
Ω
Ω
RN145VHSHT
2.14 ~ 2.63
3.35 ~ 4.11
Ω
Ω
MUX-A20WV
RN099VHSHT
2.99 ~ 3.67
4.02 ~ 4.39
MUX-A26WV
Ω
Ω
Measure the resistance between the terminals with a tester.
(Coil wiring temperature -10°C ~ 40°C)
Color of
lead wire
WHT-BLK
BLK-RED
MUX-A10WV
196 ~ 241
208 ~ 246
Ω
Ω
Normal
MUX-A19WV
79 ~ 98
129 ~ 158
Ω
Ω
MUX-A20WV
79 ~ 98
129 ~ 158
Measure the resistance between the terminals with a tester.
(Coil wiring temperature -10°C ~ 40°C)
Color of
lead wire
WHT-BLK
BLK-RED
MUX-A25WV
79 ~ 98
129 ~ 158
Normal
MUX-A26WV
Ω
Ω
69 ~ 85
70 ~ 86
RN125VHSHT
Ω
2.52 ~ 3.09
5.04 ~ 6.18
Ω
RN125VHSHT
2.52 ~ 3.09
5.04 ~ 6.18
Ω
Ω
Ω
Ω
Abnormal
Open
Ω
short-circuit
Ω
Abnormal
Open
Ω
short-circuit
Ω
Abnormal
Open or
short-circuit
Abnormal
Open or
short-circuit
or
or
Figure
P
MUX-A10WV
MUX-A19/A20/A25/
A26WV
Solenoid coil
21R, 21RA,
21RB, 21R1,
21R2, 21R3,
21R4
Measure the resistance with a tester. (Part temperature -10°C ~ 40°C)
Normal
1410 ~ 1730Ω
Abnormal
Open or short-circuit
P INNER PROTECTOR
94
When OPERATION INDICATOR lamp flashes 3-time.
Indoor fan motor doesn’t operate.
AA
Check of indoor fan motor
Turn OFF the power supply.
Check connector CN211 visually.
Yes
No
Resolder it.
Reconnect the lead wires.
Disconnect lead wires from connector CN211 on indoor electronic control P.C. board.
Measure resistance between lead wires No.1 and No.5 and then No.3 and No.5.
No
Is resistance 0 (short circuit) or ∞ (open circuit)?
Are lead wires connected?
Yes
Yes ( 0 or ∞ )
Repair or replace the indoor fan motor.
Yes
Is soldered point of the
connector correctly soldered?
Turn ON the power supply. Stop it if the unit operates.
Insert screwdriver into air outlet to rotate indoor fan
motor slowly for 1 revolution or over, and measure volt-
No
(others)
age No.2(+) and No.3(-) on CN121.
No
Does voltage repeat 0V DC and 5V DC?
Replace the indoor electronic control P.C. board.
Indoor unit operates by pressing the EMERGENCY OPERATION switch, but doesn’t operate with the remote controller.
BB
Check of remote controller and receiver P.C. board
wCheck the remote controller is exclusive for this air conditioner.
Switch on the remote controller.
Is LCD display on the remote controller displayed?
Yes
Remove batteries, then set them back and press the RESET
button. Check if the unit operates with the remote controller.
Does the unit operate with the
remote controller?
Yes
OK
No
(not clear)
No
Measure the voltage between receiver P.C. board connector CN302
(–)
No.3
and No.5
Replace the batteries. (Refer to page 88.)
Turn on a radio to AM and press switch
on the remote controller.
(+)
Is noise heard from radio?
Yes
Are there any fluorescent lights of
inverter or rapid-start type within
the range of 1m?
No
when the remote controller button is pressed.
Is the voltage approx. 4V DC?
No(5V or 0V DC)
Replace the receiver P.C. board.
No
Yes
Yes
Replace the remote controller.
• Reinstall the unit away from lights.
• Attach a filter on receiving part.
Replace the indoor electronic control
P.C. board.
95
Check the both “parts side” and “pattern
side” of indoor electronic control P.C.
board visually.
Replace the fuse.
Is fuse (F11) blown?
Be sure to check both fuse
and varistor in any case.
Replace the fan motor.
Replace the indoor
electronic control
P.C. board.
Is winding
resistance of
fan motor 0 "?
Is winding
resistance of
vane motor 0 "?
No
Yes
Replace the vane
motor.
No
Yes
Yes
Is varistor (NR11) burnt?
Replace the varistor.
Yes
Turn OFF the power supply.
Remove indoor fan motor connector CN211 and
vane motor connector CN151 from the indoor electronic
control P.C. board and turn ON the power supply.
No
No
Does the unit operate with the remote controller?
Does the OPERATION INDICATOR lamp light up
by pressing the EMERGENCY OPERATION switch?
Yes
No
Be sure to check both resistances.
Turn OFF the
power supply.
Turn OFF the
power supply.
The unit doesn’t operate with the remote controller.
Yes
Compressor
doesn't operate.
Yes
Yes
Is there 230V AC between 3 on the
compressor contactor (52C) and N
on the outdoor terminal block (TB1)?
Operate the unit in COOL or HEAT mode by pressing the EMERGENCY OPERATION switch.
3-minute time delay works.
Test run operation operates for 30 minutes.
Outdoor fan motor
doesn't operate.
No
Rectify the indoor and
outdoor connecting wire.
Rectify the connecting wire.
Check the compressor and compressor
capacitor, and rectify the connecting wire.
Start
Yes
Is there 230V AC between 4 on the
compressor contactor (52C) and
TAB20 on the deicer P.C. board?
Is there 230V AC between L–N
on the outdoor terminal block (TB1)?
Replace the
deicer P.C. board.
Replace the
deicer P.C.
board.
No
No
Yes
Yes
No
Check the outdoor fan motor
and rectify the connecting
wire.
Is there 230V AC between 4 on the
compressor contactor (52C) and
TAB 20 on the deicer P.C. board?
Replace the
deicer P.C. board.
No
Yes
Rectify the indoor and
outdoor connecting wire.
Rectify the connecting wire.
Is there 230V AC between L–N on
the outdoor terminal block (TB1)?
No
No
Is the switch SW2-2 on the
indoor electronic control
P.C. board set to MUH type?
No
Change the switch SW-2-2
on the indoor electronic control
P.C. board to MUH type.
Yes
+
–
Is there 5V DC between J205 –J101 on
the deicer P.C. board?
+
–
Is there 5V DC between J205 –J101 on
the deicer P.C. board?
Also, the OPERATION INDICATOR lamp doesn’t light up by pressing the EMERGENCY OPERATION switch.
CC
Check of indoor electronic control P.C. board
Compressor and/or outdoor fan motor doesn’t operate.
DD
Check of outdoor unit
<MUH-A07/A09/A12WV>
96
No
Start
Press the EMERGENCY
OPEERATION switch of all
indoor units.
Yes
Is there 230V AC
between L
- N
on the TB1
of outdoor unit?
No
Is fuse(F61) on the outdoor
control P.C. board blown?
Check and rectify the
connecting wire of
indoor and outdoor unit.
3 minutes later, is there
12V DC between
1 - 2 on the all terminal
blocks of outdoor unit?
Is there 10~15V DC between
JP20 DC12V and JP19 GND
on outdoor control P.C.
board?
Fan motor doesn't operate.
Compressor doesn't operate.
Yes
Yes
Turn OFF the power supply
to outdoor unit.
Does outdoor control P.C.
board connect with outdoor
fan capacitor C61?
Yes
Connect the outdoor control
P.C. board with outdoor fan
capacitor C61.
Disconnect connector of
outdoor fan motor CN91
and outdoor fan capacitor
C61.
Replace the outdoor
fan motor.
Replace the outdoor
control P.C. board.
No
Yes
Turn OFF the power supply.
Replace the outdoor
control P.C. board.
No
Disconnect connector of outdoor fan motor
CN91 and outdoor fan capacitor C61.
Is the resistance 0" or ∞ between the lead wire
WHT and BLK of outdoor fan motor, or between
the lead wire RED and BLK of outdoor fan motor?
(Refer to page 94.)
Yes
Replace the outdoor
fan motor and fuse(F61).
No
Check the power supply
and connecting wire.
No
Is there 12V DC between
1
- 2
on the terminal
block of each indoor unit?
No
Short both terminal
of fuse(F61).
Yes
Is the resistance 0" between
the fuse(F61) and the terminal
of CN903?
Replace the outdoor
control P.C. board.
Yes
Replace
the fuse(F61).
No
No
Check the indoor unit.
Yes
Turn OFF the power supply to outdoor unit.
Disconnect connecting wire of X521 and X522 from outdoor control P.C. board.
Insulate terminal of connecting wires to prevent contact of other parts.
Turn ON the power supply to outdoor unit.
Press the EMERGENCY OPERATION switch of all indoor unit.
Is the resistance 0" or ∞
between the terminal C and
R of MC1, and between the
terminal C and S of MC1?
(Refer to page 94.)
3 minutes later, is the resistance 0" between the
terminal 3 and 4 of X521 on outdoor control P.C. board,
and between the terminal 3 and 4 of X522 on outdoor
control P.C. board?
Turn OFF the power supply
to outdoor unit.
Yes
Replace the
compressor MC1.
No
Replace the
compressor MC2.
No
Check and
rectify the
connecting wire
of terminal and
compressor.
Turn OFF the power supply
to outdoor unit.
No
Replace the outdoor
control P.C. board.
Is the resistance 0" or ∞
between the terminal C and
R of MC2, and between the
terminal C and S of MC2?
(Refer to page 94.)
Yes
Yes
Is the resistance 0" or ∞
between the lead wire
WHT and BLK of outdoor
fan motor, or between the
lead wire RED and BLK
of outdoor fan motor?
(Refer to page 94.)
Measure resistance all
the solenoid coil.
Is resistance 0"?
MUX-A20/A26WV
MUX-A19/A25WV
Replace the solenoid coil.
Yes
No
Compressor and/or outdoor fan doesn’t operate.
DD
Check of outdoor unit
<MUX-A19/A20/A25/A26WV>
97
Compressor and/or outdoor fan motor doesn’t stop.
EE
Check of outdoor unit
Start
Turn OFF the power supply.
After 1 minute, turn ON
power supply again.
Does compressor or
outdoor fan motor stop?
Yes
OK
No
<MU-A07/A09/A12WV>
Is there 12V DC between
1–2 on the outdoor
terminal block (TB2)?
Yes
Replace the indoor
electoronic control
P.C. board.
Compressor and/or outdoor fan motor doesn’t stop.
EE
Check of outdoor unit
Start
Turn OFF the power supply.
After 1 minute, turn ON
power supply again.
<MUH-A07/A09/A12WV>
Is there 230V AC between COM on the
No
compressor contactor (52C) and N on the
outdoor terminal block (TB1)?
Rectify the connecting wire.
No
Yes
Replace the compressor
contactor(52C).
Does compressor stop?
Yes
OK
Does outdoor fan motor stop?
Yes
OK
Is there 230V AC between 3 on the
No
compressor contactor (52C) and N on the
outdoor terminal block (TB1)?
Yes
Replace the
deicer P.C. board.
No
Replace the
deicer P.C. board.
No
Rectify the connecting wire.
98
Unit operates COOL mode even if it is set to HEAT mode.
After 3 minutes, does the unit
operate in HEAT mode?
Ok
No
Is there 230V AC between
CN7211 – 2 on the deicer
P.C. board?
Replace the
deicer P.C. board.
Yes
Yes
Yes
No
Replace the R.V. coil.
Turn ON the power supply and operate
the indoor unit in COOL mode by pressing
the EMERGENCY OPERATION switch.
After 3 minutes, does the unit
operate in COOL mode?
OK
Yes
Yes
No
Replace the
deicer P.C. board
No
Replace the R.V. coil.
Turn ON the power supply and operate
the indoor unit in HEAT mode by pressing
the EMERGENCY OPERATION switch.
Is there 230V AC between
CN7211 – 2 on the deicer P.C.
board?
w First, measure the resistance of R.V. coil to confirm it is disconnected or is not short-circuit.
FF
Check of R.V. coil
<MUH-A07/A09/A12WV>
Unit operates HEAT mode even if it is set to COOL mode.
w First, measure the resistance of R.V. coil to confirm it is disconnected or is not short-circuit.
FF
Check of R.V. coil
<MUH-A07/A09/A12WV>
99
When OPERATION INDICATOR lamp flashes 0.5-second intervals or 1-time.
Outdoor unit does not operate.
GG
How to check mis-wiring and serial signal error
<MUH-A07/A09/A12WV>
w1 Set the switch(SW2-2) on indoor electronic control P.C. board to
MU or MUX type, when the outdoor unit is MU or MUX type.
If the setting is MUH or MXZ type, the unit does not work.
Start
Turn OFF the power supply(indoor/outdoor unit).
Is the outdoor unit "MUH" or "MXZ" type?
Yes
•Turn ON the power supply(indoor/outdoor unit).
•Press once EMERGENCY OPERATION switch.
3 min. later, what self-check result is
displayed on OPERATION INDICATOR
lamp on indoor unit?
w2
Mis-wiring is indicated.
w2 Short circuit of JPG and JPS on the indoor electronic control
P.C. board enables self-check to be displayed in 3 seconds.
No
Serial signal error is indicated.
(0.5-sec. ON, 2.5-sec. OFF)
Set the switch(SW2-2) on the indoor electronic
control P.C. board to MU or MUX type.
Does the unit operate?
Refer to the
"Instruction of
troubleshooting."
(0.5-sec. ON, 0.5-sec. OFF)
Make them sure.
Yes
Is this mis-wiring, poor contact,
or disconnection of wire?
No
1. Turn OFF the power supply(indoor/outdoor unit) and disconnect indoor and outdoor connecting wire on indoor side.
2. Short-circuit between indoor terminal block N and 3.
3. Turn ON the power supply(indoor unit) and press once EMERGENCY OPERATION switch.
No
Yes
w1
OK
Is there 20V DC between both ends of
R132 on indoor electronic control P.C.
board ?
( By tester, the stylus is between 0 ~ 20V. )
Yes
•Turn OFF the power supply(indoor unit).
•Connect ON indoor and outdoor connecting wire.
Turn ON the power supply(outdoor unit).
Is there 230V AC between outdoor terminal
block L-N (TB1)?
Yes
Is there 5V DC between J205 + –J101 - on the deicer P.C. board?
Yes
Turn ON the power supply(indoor unit).
During EMERGENCY OPERATION,
is there 10V DC between both ends
of R601?
(By tester, the stylus is between 5 ~10V)
Yes
Replace the deicer P.C. board.
No
No
No
Replace the indoor electronic
control P.C. board.
Check the outdoor power supply,
power supply cord and
connection.
No
Replace the deicer P.C. board.
Make the wiring between CN730
on the deicer P.C. board and
outdoor terminal block correct.
NOTE: As for outdoor units MXZ-A18/A26/A32WV, refer to service manual OB319.
100
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