12. PARTS LIST······················································48
E1E1E1
E1E1
Page 2
1
Refrigerating
oil
Refrigerant
New refrigerant
R410A
HFC-32: HFC-125 (50%:50%)
Pseudo-azeotropic refrigerant
Not included
A1/A1
72.6
-51.4
1.557
64
Non combustible
0
1730
From liquid phase in cylinder
Possible
Incompatible oil
Non
Non
Previous refrigerant
R22
R22 (100%)
Single refrigerant
Included
A1
86.5
-40.8
0.94
44.4
Non combustible
0.055
1700
Gas phase
Possible
Compatible oil
Light yellow
Non
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
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
TECHNICAL CHANGES
INFORMATION FOR THE AIR CONDITIONER WITH R410A REFRIGERANT
• 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 air
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 R410Arefrigerant 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])
2
Page 3
Conversion chart of refrigerant temperature and pressure
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 and 15.88mm
Wall
thickness
Outside diameter
Pipe
mm
For liquid
For gas
6.35
9.52
12.7
15.88
0.8 mm
0.8 mm
0.8 mm
1.0 mm
Heat resisting foam plastic
Specific gravity 0.045 Thickness 8 mm
Insulation material
(MPa [Gauge])
4.0
3.5
3.0
2.5
2.0
1.5
R410A
R22
NOTE : The unit of pressure has been changed to MPa on the
international system of units(SI unit system).
1.0
0.5
Saturated liquid pressure
0.0
-0.5
-30 -20 -10010 20
30
40 5060
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 (6.35, 9.52, 12.7), 1.0 mm (15.88).
Never use any pipe with a thickness less than 0.8 mm (6.35, 9.52, 12.7), 1.0 mm (15.88), as the pressure resistance is
insufficient.
3
Page 4
Electronic scale for refrigerant charging
Outdoor unit
Refrigerant gas
cylinder
operating valve
Refrigerant gas cylinder
for R410A with siphon
Refrigerant (liquid)
Service port
Gauge manifold
valve (for R410A)
Union
Liquid pipe
Gas pipe
Stop valve
Indoor unit
Charge hose (for R410A)
R410A
Pipe diameter
mm
6.35
9.52
12.7
15.88
17
22
26
29
Dimension of flare nut
R22
17
22
24
27
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”.
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.
4
Page 5
2
PART NAMES AND FUNCTIONS
MUZ-A18YV MUZ-A24YV MUZ-A26YV -
E1
E1
E1
OUTDOOR UNIT
Air inlet
(back and side)
Piping
Drain hose
Air outlet
Drain outlet
3
Electrical
Coefficient of performance(C.O.P) ✽1
Fan
Special
NOTE : Test conditions are based on ISO 5151.
SPECIFICATION
Outdoor model
Function
Power supply
Capacity Rated frequency(Min.~Max.)
Dehumidification
Air flow(High/LowW)
Capacity
Power outlet
Running current
Power input
Power factor
Starting current ✽1
data
Compressor motor current ✽1
Fan motor current
Model
Output
Winding
resistance(at 20:)
Compressor
Model
Winding
motor
resistance(at 20:)
Dimensions WOHOD
Weight
Sound level(High/LowW)
Fan speed(High/LowW)
Fan speed regulator
Refrigerant filling
capacity(R410A)
Refrigerating oil(Model)
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.
(1) GUARANTEED VOLTAGE
207 ~ 253V, 50Hz
(2) AIR FLOW
Air flow should be set at MAX.
(3) MAIN READINGS
(1) Indoor intake air wet-bulb temperature :°C WB
(2) Indoor outlet air wet-bulb temperature :°C WB
(3) Outdoor intake air dry-bulb temperature :°C DB
(4) Total input :W
}
Cooling
(5) Indoor intake air dry-bulb temperature :°C DB
(6) Outdoor intake air wet-bulb temperature :°C WB
(7) Total input :W
}
Heating
Indoor air wet/dry-bulb temperature difference on the left side of the chart on this page and next page 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.
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) 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.
11.4
10.5
9.5
8.6
7.7
difference (degree)
6.8
Indoor air Wet-bulb temperature
INDOOR UNIT
Wet and dry-bulb
thermometers
11.3
10.3
9.3
8.4
7.5
6.7
12.9
11.7
10.6
11.1
10.2
9.2
8.3
7.5
6.6
9.6
8.6
7.6
13.9
12.7
11.4
10.3
9.2
8.1
Indoor intake air Wet-bulb temperature (
:)
Outdoor intake air Dry-bulb temperature (:)
OUTDOOR UNIT
Wet and dry-bulb
thermometers
:)
Indoor intake air Wet-bulb temperature (
Outdoor intake air Dry-bulb temperature (:)
MCFZ-A18WV -E1
MUZ-A18YV -E1
Rated frequency 84Hz
MSZ-A24YV -E1
MUZ-A24YV -E1
MSZ-A18YV -E1
MUZ-A18YV -E1
Rated frequency 73Hz
Rated frequency 88Hz
MCFZ-A24WV -E1
MUZ-A24YV -E1
Rated frequency 102Hz
MSZ-A26YV -E1
MUZ-A26YV -E1
Rated frequency 63Hz
14
Page 15
28.0
Capacity correction factors
Input correction factors
Input correction factors
Capacity correction factors
Correction of Cooling capacity
The operational frequency of compressor
Correction of Cooling total input
The operational frequency of compressor
Correction of Heating total input
The operational frequency of compressor
Correction of Heating capacity
The operational frequency of compressor
Capacity correction factors
Input correction factors
Correction of Cooling capacity
The operational frequency of compressor
Correction of Cooling total input
The operational frequency of compressor
Capacity correction factors
Input correction factors
Input correction factors
Capacity correction factors
Correction of Cooling capacity
The operational frequency of compressor
Correction of Cooling total input
The operational frequency of compressor
Correction of Heating total input
The operational frequency of compressor
Correction of Heating capacity
The operational frequency of compressor
( )
MUZ-A18YV -
E1
Indoor unit :
MSZ-A18 YV -
E1
E1
( )
MUZ-A18YV -
E1
Indoor unit :
MSZ-A18YV -
E1
E1
( )
MUZ-A18YV -
E1
Indoor unit :
MSZ-A18YV -
E1
E1
( )
MUZ-A18YV -
E1
Indoor unit :
MSZ-A18YV -
E1
E1
( )
MUZ-A18YV -
E1
Indoor unit :
MCFZ-A18WV -
E1
E1
( )
MUZ-A18YV -
E1
Indoor unit :
MCFZ-A18WV -
E1
E1
( )
MUZ-A18YV -
E1
Indoor unit :
MCFZ-A18WV -
E1
E1
( )
MUZ-A18YV -
E1
Indoor unit :
MCFZ-A18WV -
E1
E1
( )
MUZ-A24YV -
E1
Indoor unit :
MSZ-A24YV -
E1
E1
( )
MUZ-A24YV -
E1
Indoor unit :
MSZ-A24YV -
E1
E1
( )
MUZ-A24YV -
E1
Indoor unit :
MSZ-A24YV -
E1
E1
( )
MUZ-A24YV -
E1
Indoor unit :
MSZ-A24YV -
E1
E1
Input correction factors
Capacity correction factors
Correction of Heating total input
The operational frequency of compressor
Correction of Heating capacity
The operational frequency of compressor
050100150
0.5
1.0
1.5
(Hz)
050100150
0.5
1.0
1.5
(Hz)
050100150
0.5
1.0
1.5
(Hz)
050100150
0.5
1.0
1.5
(Hz)
050100150
0.5
1.0
1.5
(Hz)
050100150
0.5
1.0
1.5
(Hz)
050100150
0.5
1.0
1.5
(Hz)
050100150
0.5
1.0
1.5
(Hz)
050100150
0.5
1.0
1.5
(Hz)
050100150
0.5
1.0
1.5
050100150
0.5
1.0
1.5
050100150
0.5
1.0
1.5
25.9
23.7
21.6
19.4
17.2
15.1
12.9
26.2
24.1
22.1
20.1
18.1
16.1
14.1
12.1
25.7
23.7
21.8
19.8
17.8
15.8
difference (degree)
13.8
11.9
Indoor air Dry-bulb temperature
29.9
27.6
25.3
23.0
20.7
18.4
16.1
13.8
31.2
28.8
26.4
24.0
21.6
19.2
16.8
14.4
:)
Indoor intake air Dry-bulb temperature (:)
Indoor intake air Dry-bulb temperature (
MCFZ-A18WV -E1
MSZ-A18YV -E1
MUZ-A18YV -E1
Rated frequency 82Hz
MUZ-A18YV -E1
Rated frequency 86Hz
MCFZ-A24WV -E1
MUZ-A24YV -E1
MSZ-A24YV -E1
MUZ-A24YV -E1
Rated frequency 95Hz
Rated frequency 96Hz
MSZ-A26YV -E1
MUZ-A26YV -E1
Rated frequency 65Hz
Outdoor intake air Wet-bulb temperature (:)
Outdoor intake air Wet-bulb temperature (:)
NOTE:The above curves are for the heating operation without any frost.
15
Page 16
OUTDOOR LOW PRESSURE AND OUTDOOR UNIT CURRENT
MUZ-A26YV -
E1
MUZ-A26YV -
E1
MUZ-A26YV -
E1
MUZ-A26YV -
E1
Capacity correction factors
Input correction factors
Input correction factors
Capacity correction factors
Correction of Cooling capacity
The operational frequency of compressor
Correction of Cooling total input
The operational frequency of compressor
Correction of Heating total input
The operational frequency of compressor
Correction of Heating capacity
The operational frequency of compressor
050100150
0.5
1.0
1.5
(Hz)
050100150
0.5
1.0
1.5
(Hz)
050100150
0.5
1.0
1.5
(Hz)
050100150
0.5
1.0
1.5
(Hz)
Capacity correction factors
Input correction factors
Input correction factors
Capacity correction factors
Correction of Cooling capacity
The operational frequency of compressor
Correction of Cooling total input
The operational frequency of compressor
Correction of Heating total input
The operational frequency of compressor
Correction of Heating capacity
The operational frequency of compressor
( )
MUZ-A24YV -
E1
Indoor unit :
MCFZ-A24WV -
E1
E1
( )
MUZ-A24YV -
E1
Indoor unit :
MCFZ-A24WV -
E1
E1
( )
MUZ-A24YV -
E1
Indoor unit :
MCFZ-A24WV -
E1
E1
( )
MUZ-A24YV -
E1
Indoor unit :
MCFZ-A24WV -
E1
E1
050100150
0.5
1.0
1.5
(Hz)
050100150
0.5
1.0
1.5
(Hz)
050100150
0.5
1.0
1.5
(Hz)
050100150
0.5
1.0
1.5
(Hz)
(MPa [Gauge])
(kgf/F [Gauge])
1832
152050256030
70 (%)
35(˚C)
0.4
0.6
0.8
1.0
1.2
1.4
25Hz
4
6
8
10
12
14
16
1.6
Ambient temperature(˚C) Ambient humidity(%)
Outdoor low pressure
152050256030
70 (%)
35(˚C)
1
1.5
2
2.5
3
25Hz
32
18
Outdoor unit current(A)
Ambient temperature(˚C) Ambient humidity(%)
(MPa [Gauge])
(kgf/F [Gauge])
1832
152050256030
70 (%)
35(˚C)
0.4
0.6
0.8
1.0
1.2
1.4
25Hz
4
6
8
10
12
14
16
1.6
Ambient temperature(˚C) Ambient humidity(%)
Outdoor low pressure
152050256030
70 (%)
35(˚C)
1
1.5
2
2.5
3
25Hz
32
18
Outdoor unit current(A)
Ambient temperature(˚C) Ambient humidity(%)
( )
MUZ-A18YV -
E1
Indoor unit :
MCFZ-A18WV -
E1
E1
( )
MUZ-A18YV -
E1
Indoor unit :
MCFZ-A18WV -
E1
E1
( )
MUZ-A18YV -
E1
Indoor unit :
MSZ-A18YV -
E1
E1
( )
MUZ-A18YV -
E1
Indoor unit :
MSZ-A18YV -
E1
E1
<How to operate fixed-frequency operation (Test run operation)>
1. Press the EMERGENCY OPERATION switch to COOL or HEAT mode (COOL : Press once, HEAT : Press twice).
2. Test run operation starts and continue to operate for 30 minutes.
3. Compressor starts at fixed-frequency.
4. Indoor fan operates at High speed.
5. After 30 minutes, test run operation finishes and EMERGENCY OPERATION starts.
6. To cancel test run operation (EMERGENCY OPERATION), press the EMERGENCY OPERATION switch or any button on
remote controller.
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])
OUTDOOR LOW PRESSURE AND OUTDOOR UNIT CURRENT
COOL operation
1 Both indoor and outdoor unit are under the
same temperature/humidity condition.
2 Air flow : High speed
3 Operational frequency : 25Hz(MUZ-A18YV)
25Hz(MUZ-A24YV)
24Hz(MUZ-A26YV)
Dry-bulb temperature
20
25
3070
Relative humidity(%)
50
60
16
Page 17
HEAT operation
Outdoor unit current (A)
Outdoor unit current (A)
Ambient temperature(˚C)
Ambient temperature(˚C)
Outdoor unit current (A)
Ambient temperature(˚C)
MUZ-A26YV -
E1
( )
MUZ-A18YV -
E1
Indoor unit :
MSZ-A18YV -
E1
E1
( )
MUZ-A24YV -
E1
Indoor unit :
MSZ-A24YV -
E1
E1
Outdoor unit current (A)
Outdoor unit current (A)
Ambient temperature(˚C)
Ambient temperature(˚C)
4.0
3.5
3.0
2.5
2.0
1.5
1.0
2 510 15 20 25(:)
32Hz
32Hz
4.0
3.5
3.0
2.5
2.0
1.5
1.0
2 510 15 20 25(:)
( )
MUZ-A18YV -
E1
Indoor unit :
MCFZ-A18WV -
E1
E1
( )
MUZ-A24YV -
E1
Indoor unit :
MCFZ-A24WV -
E1
E1
4.0
3.5
3.0
2.5
2.0
1.5
1.0
2 510 15 20 25(:)
32Hz
32Hz
4.0
3.5
3.0
2.5
2.0
1.5
1.0
2 510 15 20 25(:)
6
5.5
5
4.5
4.0
3.5
3.0
2 510 15 20 25(:)
32Hz
0.4
0.6
0.8
1.0
1.2
1.4
4
6
8
10
12
14
16
1.6
MUZ-A26YV -
E1
15205025
60
30
70 (%)
35(˚C)
2.5
3
3.5
4
4.5
24Hz
32
18
Outdoor unit current(A)
Ambient temperature(˚C) Ambient humidity(%)
MUZ-A26YV -
E1
(MPa [Gauge])
(kgf/F [Gauge])
1832
152050256030
70 (%)
35(˚C)
24Hz
Ambient temperature(˚C) Ambient humidity(%)
Outdoor low pressure
0.4
0.6
0.8
1.0
1.2
1.4
4
6
8
10
12
14
16
1.6
(MPa [Gauge])
(kgf/F [Gauge])
1832
152050256030
70 (%)
35(˚C)
25Hz
15205025
60
30
70 (%)
35(˚C)
1
2
3
4
5
25Hz
32
18
Ambient temperature(˚C) Ambient humidity(%)
Outdoor low pressure
Outdoor unit current(A)
Ambient temperature(˚C) Ambient humidity(%)
0.4
0.6
0.8
1.0
1.2
1.4
4
6
8
10
12
14
16
1.6
(MPa [Gauge])
(kgf/F [Gauge])
1832
152050256030
70 (%)
35(˚C)
25Hz
15205025
60
30
70 (%)
35(˚C)
1
2
3
4
5
25Hz
32
18
Ambient temperature(˚C) Ambient humidity(%)
Outdoor low pressure
Outdoor unit current(A)
Ambient temperature(˚C) Ambient humidity(%)
( )
MUZ-A24YV -
E1
Indoor unit :
MCFZ-A24YV -
E1
E1
( )
MUZ-A24YV -
E1
Indoor unit :
MCFZ-A24YV -
E1
E1
( )
MUZ-A24YV -
E1
Indoor unit :
MSZ-A24YV -
E1
E1
( )
MUZ-A24YV -
E1
Indoor unit :
MSZ-A24YV -
E1
E1
Condition indoor: Dry bulb temperature 20.0°C
Wet bulb temperature 14.5°C
Condition outdoor: Dry bulb temperature 2,7,15,20.0°C
Wet bulb temperature 1,6,12,14.5°C
17
Operational frequency : 32Hz(MUZ-A18YV)
32Hz(MUZ-A24YV)
32Hz(MUZ-A26YV)
Page 18
PERFORMANCE DATA COOL operation Rated frequency 73Hz
NOTE Q : Total capacity (kW) INPUT : Total power input (W) DB : Dry-bulb temperature WB : Wet-bulb temperature
INPUT:2440(W)
OUTDOOR WB(:)
E1E1
2828
Page 29
9
ON
OFF
ON
OFF
Outdoor fan
Compressor
5 seconds15 seconds
ON
OFF
Compressor
Outdoor fan
R.V.coil
ON
OFF
ON
OFF
<COOL>
5 seconds
<HEAT>
5 seconds
Discharge temperature thermistor
Indoor pipe temperature thermistor
Defrost thermistor
Fin temperature thermistor
Outdoor heat exchanger temperature
Purpose
Protection
Defrosting Protection
Defrosting
Protection
Protection
CompressorLEV
Outdoor
fan motor
4-way
valve
Sensor
Actuator
ACTUATOR CONTROL
MUZ-A18YV MUZ-A24YV MUZ-A26YV -
E1
E1
E1
9-1. 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.
9-2. R.V. coil control
Heating
Cooling . . . . . . . . . . . . . . . . . OFF
Dry
NOTE: The 4-way valve reverses for 5 seconds right before start-up of the compressor.
. . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . .
ON
OFF
9-3. Relation between main sensor and actuator
Relation between main sensor and actuator.
2929
Page 30
10
Housing point
TROUBLESHOOTING
MUZ-A18YV MUZ-A24YV MUZ-A26YV -
E1
E1
E1
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 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 main 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 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
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) 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.
4) When troubleshooting, refer to the flow chart on page 31 and the check table on page 32 and 33.
3030
Page 31
Start
Indoor unit
operates.
Outdoor unit
doesn't
operate.
Indoor unit
doesn't receive
the signal from
remote controller.
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".
Refer to E
"Check of
inverter/
compressor"
on page 38.
Refer to
"Check of
remote controller
and receiver
P.C. board".
1. Check indoor/ outdoor
connecting wire.
(Check if the power
is supplied to the
indoor unit.)
2. Refer to
"Check of indoor
electronic control
P.C. board".
Unit doesn't
operate
normal
operation in
COOL or
HEAT mode.
Refer to C
"Check of
R.V. coil"
on page 37.
Flash on and
off at
0.5-second
intervals
Cause:
Indoor/
Outdoor unit
• Mis-wiring
or trouble of
serial signal
2-time flash
Cause:
Indoor unit
• Trouble of
room temp erature/
indoor coil
thermistor
MSZ type
3-time flash
Cause:
Indoor unit
• Trouble of
indoor fan
motor
5-time flash
Cause:
Outdoor unit
• Outdoor
power
system
abnormality
6-time flash
Cause:
Outdoor unit
• Trouble of
thermistor
in outdoor
unit
7-time flash
Cause:
Outdoor unit
• Trouble of
outdoor
control
system
Refer to B
"How to
check
mis-wiring
and serial
signal error
(When
outdoor unit
doesn't
work)".
Check room
temperature
thermistor
and indoor
coil thermistor.
Refer to
"Test point
diagram and
voltage".
Refer to
"Check of
indoor fan
motor".
Refer to E
"Check of
inverter/
compressor"
on page 38.
Refer to F
"Check of
outdoor
thermistors"
on page 39.
Replace the
outdoor
electronic
control P.C.
board.
4-time flash
Cause:
Indoor unit
• Trouble of
indoor unit
control
system
Replace the
indoor
electronic
control
P.C. board.
As for indoor unit MSZ type, refer to service manual OB345.
As for indoor unit MCFZ type, refer to service manual OB344 REVISED EDITION - A.
Indoor unit operates.
Outdoor unit doesn't
operate normally.
10-2. Instruction of troubleshooting
31
Page 32
Indication
Abnormal pointDetecting method
Symptom: Outdoor unit does not operate.
Check points
LED 1
(Red)
Lighting Twice Outdoor power system
When the compressor operation has been interrupted by over current
protection continuously three times within 1 minute after start-up, or
when power factor control module protection or DC control protection is
activated three times within 3 minutes after the compressor get started.
• Check the inverter/compressor.
• Replace the outdoor electronic control
P.C. board.
Lighting 7 times Outdoor control system
When the nonvolatile memory data cannot be read properly on the
outdoor electronic control P.C. board.
LED 2
(Yellow)
Indication
Abnormal pointDetecting method
Symptom: It is repeated that outdoor unit stops and restarts 3 minutes later.
Check points
LED 1
(Red)
Lighting
Outdoor heat exchanger
temperature thermistor
When the outdoor heat exchanger temperature thermistor is short or
open while compressor is operating.
• Replace the outdoor electronic control
P.C. board.
• Check the amount of gas and the
refrigerant cycle.
• Check the outdoor unit air passage.
• Check the characteristic of the discharge
temperature thermistor.
• Check the connector. (CN661)
Lighting 3 times
Discharge temperature
thermistor
When a short or open circuit occurs in the discharge temperature
thermistor during compressor operating.
Twice Goes out
Overcurrent protection When overcurrent is applied to the power module.
3 times Goes out
Discharge temperature
overheat protection
When the discharge temperature thermistor detects 116: or above.
(Protection will be released at 100: or below.)
4 times Goes out
Fin temperature
overheat protection
When the fin temperature thermistor detects 87: or above.
• Check the characteristic of the high
pressure protect thermistor.
• Check the connector. (CN661)
5 times
LightingCurrent sensor
When the output from compressor current sensor becomes 25A or
more while the compressor is operating.
• Check if the connection lead wires of com-
pressor are correctly connected.
6 times
• Check if the connection wires between
outdoor electronic control P.C. board and
power board are correctly connected.
Lighting 11 times
Communication error
between P.C. boards
When the communication failure between the outdoor electronic control
P.C. board and power board occurs twice consecutively.
• Check if the connection wires between
noise filter P.C. board and power board are
correctly connected.
Lighting
12 times
Zero cross signal error
When the zero cross signal cannot be detected while the compressor is
operating.
• Check the outdoor unit air passage.
• Check the outdoor fan motor.
• Check the power module.
• Check the inverter/ compressor.
• Check the amount of gas.
• Check the indoor/ outdoor air flow for
short cycle.
• Check the indoor unit air filter for clogging.
• Check the characteristic of the fin
temperature thermistor.
• Check the connector. (CN3)
Lighting 4 times
Fin temperature
thermistor
When a short or open circuit occurs in the fin temperature thermistor
during compressor operating.
P.C. board temperature
thermistor
When a short or open circuit occurs in the P.C. board temperature
thermistor during compressor operating.
LED 2
(Yellow)
Indication
Abnormal pointDetecting method
Symptom: It is repeated that outdoor unit stops and restarts 3 minutes later
Check points
LED 1
(Red)
5 times Goes out
High-pressure protection
When the outdoor heat exchanger temperature thermistor detects 69:
or more.
When high-pressure switch detects 4MPa or more. (MUZ-A26YV)
4 times Goes out
P.C. board temperature
overheat protection
When the P.C. board temperature thermistor detects 70: or above.
• Check the outdoor unit air passage.
• Check the outdoor fan motor.
• Replace the outdoor electronic control
P.C. board.
• Check the outdoor unit air passage.
• Check the outdoor fan motor.
8 times Goes out
Power factor control
module protection
When the overcurrent to power factor controller occurs or the output
voltage from power factor controller becomes 400V or more.
• Check the input voltage.
• Check the inverter.
9 times Goes out
DC voltage protection
When it's detected that DC voltage becomes 200V or less, or reaches
400V or more.
• Check the voltage of power supply.
• Check the inverter.
13 times Goes out
Fan motor protection
When the fan motor current is 2A or more, or when the abnormality is
detected in the feedback signal from fan motor.
• Check the outdoor fan motor.
• Check the fan motor connector.
LED 2
(Yellow)
11 times Goes out
Connectivity of indoor
and outdoor unit
When the unusual signal is transmitted from the indoor unit.
• Check if the indoor unit can be connected
with the outdoor unit.
1. Troubleshooting check table
LED 1 (Red)
Lighting
LED 2 (Yellow)
Lighting
Error mode
Normal
Refer to page 35.
32
Page 33
Indication
LED 1
LED 2
(Red)
(Yellow)
Once Lighting Current protection
Twice Lighting
Twice Lighting Defrosting in cooling
3 times Lighting
4 times Lighting
5 times Lighting
Indication
LED 1
LED 2
(Red)
(Yellow)
5 times
Lighting
Lighting
11 times
Lighting
9 times
Abnormal pointDetecting method
High-pressure protection
Discharge temperature
protection
Low discharge
temperature protection
High-pressure protection
Abnormal pointDetecting method
Defrost thermistor
Initial-setting
Service mode
Symptom: Outdoor unit operates (The compressor operates at reduced frequency)
When the outdoor unit input current exceeds 14.5A.
When the indoor gas pipe temperature exceeds 55˚C during heating.
When the indoor gas pipe temperature falls to 6˚C or below during cooling.
When the discharge temperature exceeds 104˚C.
When the state with low discharge temperature of which 37˚C or below
in COOL and 35
When outdoor heat exchanger temperature thermistor detects 58: or
more.
When a short or open circuit occurs in the defrost thermistor during
heating.
When the initial-setting information from an indoor unit is now being read.
When the unit operates EMERGENCY OPERATION.
˚C
or below in HEAT lasts for 20 minutes.
Symptom: Outdoor unit operates.
These symptoms do not mean any
abnormality of the product, but check
the following points.
• Air filter clogging
• Amount of gas
• Short cycle of indoor/outdoor air flow
• Check the characteristic of the defrost
• Check the connector. (CN661)
Check points
Check points
temperature thermistor.
33
Page 34
W
U
V
WHT
RED
BLK
LEV
WHT
RED
YLW
BRN
ORN
BLU
U
RED
WHT
BLK
V
W
(W)
(V)
(U)
2. Trouble criterion of main parts
MUZ-A18YV MUZ-A24YV MUZ-A26YV -
E1
E1
E1
Part nameCheck method and criterion
Measure the resistance using a tester.
Defrost thermistor/
(Part temperature : -10°C ~ 40°C)
Outdoor heat exchanger
temperature thermistor
Measure the resistance using a tester, after warming up the thermistor by holding by hand.
Discharge temperature
(Part temperature : 20°C ~ 40°C)
thermistor
Measure the resistance using a tester.
(Part temperature : 10°C ~ 40°C)
Fin temperature thermistor
Normalabnormal
5kΩ ~ 55kΩ
Open or short-circuit
Normalabnormal
100kΩ ~ 250kΩ
Opened or short-circuit
Normalabnormal
25kΩ ~ 100kΩ
Open or short-circuit
Compressor
Outdoor fan motor
R. V. coil
Linear expansion valve
Measure the resistance between terminals using a tester.
(Winding temperature : -10°C ~ 40°C)
MUZ-A18/A24YV
0.40Ω ~ 0.49Ω
Normal
MUZ-A26YV
1.29Ω ~ 1.49Ω
abnormal
Open or short-circuit
Measure the resistance between lead wires using a tester.
(Part temperature : -10°C ~ 40°C)
Color of
lead wire
Normal
RED - BLK
BLK - WHT
13.4Ω ~ 16.4Ω
WHT - RED
Measure the resistance using a tester. (Part temperature : -10°C ~ 40°C)
Normalabnormal
2.6kΩ ~ 3.3kΩ
Open or short-circuit
Measure the resistance using a tester.(Part temperature : -10°C ~ 40°C)
Color of lead wire
Normal
WHT - RED
RED - ORN
YLW - BRN
37.4Ω ~ 53.9Ω
BRN - BLU
abnormal
Open or
short-circuit
(Not including
WHT - ORN)
Abnormal
Open or
short-circuit
MUZ-A26YV
High pressure switch
(HPS)
MUZ-A26YV
HPS1
PressureNormal abnormal
Operation OFF
3.7 ± 0.15MPa
0.05
+
4.8 MPa
0.1
-
Short
Open
Other than
those list-
ed at left
34
Page 35
Outdoor unit does not operate. (LED display: display OFF)
Turn on power supply.
No
Yes
Yes
No
No
Yes
No
Yes
Yes
No
Replace the power board.
Start
Check the connecting of parts of main power supply circuit.
Is there voltage of 230V AC in the
power supply terminal block?
Is the output voltage from the noise
filter P.C. board 230V AC?
Is the input voltage to the outdoor
electronic control P.C. board 325V DC?
Check the power supply cable.
Replace the outdoor electronic control
P.C. board.
Replace the noise
filter P.C. board.
Is fuse (F912) blown?
Is the input voltage to the power board
230V AC?
Replace the fuse.
Replace the reactor.
AA
Check of power supply
35
Page 36
When OPERATION INDICATOR lamp flashes ON and OFF in every 0.5-second.
Reconnect the
power supply
cable.
Is there 325V DC between CN801 1 and 3 on the
outdoor electronic control P.C. board?
Replace the outdoor
electronic control P.C.
board.
Does the right side of OPERATION INDICATOR
lamp blink quickly?
w2 Mis-wiring may damage indoor electronic
control P.C. board during the operation.
Be sure to confirm the wiring is correct
before the operation starts.
Replace the indoor
electronic control
P.C. board.
No
Release the failure mode. w3
Yes
Yes
A
B
Turn OFF the power supply (Indoor/ outdoor unit).
Disconnect the indoor/ outdoor connecting wire.
Short-circuit indoor terminal block N and 3.
Turn ON the power supply (Indoor/ outdoor unit).
During pressing the OPERATION SELECT button on
the remote controller, press the RESET button.
At first, release the RESET button.
And release the OPERATION SELECT button since all
LCD in operation display section of the remote controller
is displayed after 3 seconds.
Transmit the signal of remote controller, pressing
OPERATE/STOP (ON/OFF) button on the remote
controller.
(The above procedure allows OPERATION INDICATOR
lamp to indicate the failure-mode.)
Remove the short-circuit between indoor terminal block N
and 3.
Reconnect the indoor/ outdoor connecting wire.
Turn ON the power supply (Indoor/ outdoor unit).
Press the EMERGENCY OPERATION switch.
Is there amplitude of 5 to 10V DC between outdoor
terminal block N and 3 after 3 minutes (for confirmation of
serial signal)?
Yes
(light up or OFF)
Yes
No
· Turn OFF inverter-controlled lighting
equipment.
· Turn OFF the power supply and then
turn ON again (Indoor/ outdoor unit).
· Press the EMERGENCY
OPERATION switch.
B
· Reinstall
either the
unit or the
light each
other away.
· Attach a filter
on receiving
section of
the indoor
unit.
w3 Be sure to release the failure-mode
recall function after checking.
Procedure of release of failure-mode.
1 Press the EMERGENCY
OPERATION switch.
2 Turn OFF the power supply
(Indoor/ outdoor unit).
3 Press the RESET button on the
remote controller.
Start
No
• Turn ON the power supply (Indoor/ outdoor unit).
•
Press once EMERGENCY OPERATION switch.
Is there any mis-wiring, poor contact,
or wire disconnection? w2
Make them sure.
Yes
After 3 minutes, mis-wiring is indicated
(0.5-second ON, 0.5-second OFF)
on OPERATION INDICATOR
lamp on the indoor unit.w
w Short circuit of JPG and JPS on the indoor
electronic control P.C. board enables
self-check to be displayed in 3 seconds.
Yes
Is there 230V AC between outdoor terminal
block L and N?
No
Replace the
indoor/ outdoor
connecting wire.
A
No
Check of power
supply.
No
After 3 minutes,
is mis-wiring
indicated on
OPERATION
INDICATOR
lamp on the
indoor unit?
•The following indication
applies regardless of shape
of the indicator.
As for indoor unit MSZ type, refer to service manual OB345.
As for indoor unit MCFZ type, refer to service manual
OB344 REVISED EDITION - A.
Blinking
Operation Indicator
AMPM
CLOCK
˚C
AMPM
Outdoor unit does’t operate. (LED display: Both LED1 and LED2 lighting)
B
How to check mis-wiring and serial signal error (when outdoor unit does not work)
36
Page 37
The cooling operation or heating operation does not operate. (LED display: Both LED1 and LED2 lighting)
CC
Check of R.V. coil
• When heating operation does not work.
Start
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 230V AC between pin1 and
pin 2 at connector CN912?
Yes
Turn off power supply of indoor and outdoor unit.
Disconnect the connector
CN912 in noise filter P. C.
board. Is there normal
resistance to R.V. coil?
Yes
Replace the 4-way valve.
• When cooling operation does not work.
Start
1. Disconnect the lead wire leading to the compressor.
2. 3 minutes after turning on the power supply, start EMERGENCY
OPERATION in COOL mode.
Is there voltage of 230V AC between pin1 and
pin 2 at connector CN912?
Yes
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
EMERGENCY OPERATION in COOL mode.
No
Replace the R.V. coil.
No
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
EMERGENCY OPERATION in HEAT mode.
Is there voltage 12V DC
between the connector CN781
pin 5 (+) and pin 3 (-)?
Replace the noise filter P.C. board.
Replace the 4-way valve.
Yes
No
Replace the electronic
control P.C. board.
Is there voltage 12V DC
between the connector CN781
pin 5 (+) and pin 3 (-)? W
Yes
Replace the outdoor electronic control P.C. board.
No
Replace the noise filter P.C. board.
W If the connector CN912 is not connected or R.V. coil is open, voltage
occurs between terminals even when the control is OFF.
37
Page 38
• When cooling, heat exchanger of non-operating indoor unit frosts.
No
No
Yes
Yes
Yes
No
Yes
No
Start
Disconnect the terminal of the compressor.
3 minutes after turning on the power supply, start
EMERGENCY OPERATION.
Is output balanced?
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 5minutes: refrigerant circuit defective
5 minutes or more: normal
Measure the voltage between each
lead wire leading to the compressor.
U (BLK) - V (WHT)
V (WHT) - W (RED)
W (RED) - U (BLK)
Output voltage
COOL: 150V(48Hz) HEAT: 170V(64Hz)
Is voltage output? W
Turn off power supply of indoor and outdoor unit,
and measure the compressor winding resistance
between the compressor terminals.
Is the resistance between each terminal normal?
Is the input voltage to the outdoor electronic
control P.C. board 370V or more?
Reconnect the lead wire of compressor, and turn on
power supply to indoor and outdoor unit.
3 minutes later, starts EMERGENCY OPERATION.
Replace the
compressor.
Replace the power board.
W • After the outdoor fan starts running, wait for 1 minutes or more before
measuring the voltage.
•The output voltage values have the tolerance of i20%.
• When heating, non-operating indoor unit get warm.
DD
Check of LEV
LED display:
LED1LED2
LightingLighting
Start
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?
No
Disconnect the connector CN795.
Is there normal resistance to LEV coil?
No
Replace the LEV coil.
6 timeGoes out
Yes
Yes
Replace the outdoor electronic
control P.C. board.
Normal
When OPERATION INDICATOR lamp flashes 5-time.
• When heating, room does not get warm.
• When cooling, room does not get cool.
EE
Check of inverter/ compressor
LED display:
LED1LED2
LightingLighting
Lighting
Twice
Twice
Goes out
38
Page 39
• When OPERATION INDICATOR lamp flashes 6-time.
No
Yes
No
Yes
Reconnect the connector CN661 on the outdoor electronic control P.C. board and CN3 on the power board, and
disconnect the lead wire leading to the compressor.
3 minutes after turning on the power supply, start EMERGENCY OPERATION.
Thermistor
Discharge temperature thermistor
Defrost thermistor
Outdoor heat exchanger temperature thermistor
Fin temperature thermistor
Symbol
RT61
RT62
RT68
RT65
Connector, Pin No.
Between CN661 pin3 and pin4
Between CN661 pin1 and pin2
Between CN661 pin7 and pin8
Between CN3 pin1 and pin2
Start
Disconnect the connector in the electronic control P.C. board (see below table), and
measure the resistance of thermistor. Is the thermistor normal?
Does thermistor operate 10 minutes or more though the
thermistor abnormality is not displayed?
Replace the thermistor.
Normal
Replace the outdoor electronic
control P.C. board.
Yes
Yes
Yes
No
No
(Fixed to either 5V or 0V DC)
Start
Check the connection between the
connector CN931 and CN932.
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(-)
Is the resistance between each terminal
of outdoor fan motor normal?
Does the outdoor fan motor rotates smoothly?
Does the voltage between each terminal become 5V DC and 0V DC
repeatedly?
Replace the outdoor DC fan motor.
Replace the outdoor electronic control P.C. board.
• When thermistor is abnormal. (When the LED display is a table below.)
FF
Check of outdoor thermistors
• Fan motor does not operate or stops operating shortly after starting the operation.
GG
Check of outdoor fan motor
39
Page 40
• When the operation frequency does not go up from lowest frequency.
HH
Check of HPS
MUZ-A26YV
Start
1. Disconnect the connector CN681 in the electronic control P.C. board.
2. Check the resistance of HPS after 1 minutes have passed since the outdoor unit power supply was turned off.
Check the resistance between
each terminal.
0"
Reconnect CN681.
Turn on power supply to the indoor and outdoor unit.
3 minutes later, starts EMERGENCY OPERATION.
Is HPS protection displayed
immediately after compressor
starts?
Yes
Normal
Infinity
No
Replace the electronic control P.C. board.
Replace HPS.
40
Page 41
MUZ-A18YV -MUZ-A24YV -MUZ-A26YV -
-20 -10 0 10 20 30 40
100
90
80
70
60
50
40
30
20
10
0
0 1020304050607080
200
180
160
140
120
100
80
60
40
20
0
Resistance (k')
Resistance (k')
Temperature (;)
Temperature (;)
Defrost temperature thermistor (RT62)
Outdoor heat exchanger temperature thermistor (RT68)
Fin temperature thermistor (RT65)
0 102030405060708090100110120
700
600
500
400
300
200
100
0
Resistance (k')
Temperature (;)
Discharge temperature thermistor (RT61)
Outdoor electronic control P.C. board
Discharge temperature thermistor (RT61)
CN661
Outdoor heat exchanger
temperature thermistor (RT68)
Signal reception
(From power board)
5V DC pulse wave
CN701
Signal transmission
(
GND
(+)
(+)
(
CN932
20-90V AC
(
To fan
motor
5V DC
pulse wave
CN931
GND
5V
(
Defrost thermistor (RT62)
(
(To power board)
5V DC pulse wave
(
(
(–)
(
CN702
15V
(–)
E1E1E1
15V
12V
DC
(
Rush current relay
GND (power board)
CN781
LEV
R.V. coil (–)
(
(+)
(+)
(–)
(
CN795
12V DC
pulse wave
(–)
(
LED 1
LED 2
CN601
325V DC
~
370V DC
Input
F801
FUSE
3.15A/250V
MUZ-A26YV
CN681
(
High pressure switch
41
(+)
(–)
CN601
(
Serial signal
5~10V DC
Page 42
MUZ-A18YV MUZ-A24YV MUZ-A26YV -
E1
E1
E1
Noise filter P.C. board
CN901
Electronic
CN912
R.V. coil
230V AC
230V AC
50Hz Output
control
board
{
{
CN902 CN903
Power board
{
230V AC
{
50Hz
Input
F911 FUSE
1A/250V
F912 FUSE
3.15A/250V
NR63 VARISTOR
42
Page 43
MUZ-A18YV MUZ-A24YV MUZ-A26YV Power board
325-370V DC
Output
(+)
(Red)
1
E1
E1
E1
Connect to the compressor
Voltage among phases: 5V to 180V
(–)
3
(White)
CN3
Fin temperature thermistor RT65
CN2
Connect to the controller board
(+)1-5(–): Signal transmission (To electronic control P.C. board)
5V DC pulse wave
(+)2-5(–): Zero cross signal
3-4 : Not used
(+)6-5(–): 15V
(+)7-5(–): 15V
Connect to
the earth
Signal
)
reception
(From
electronic
control P.C.
board)
5V DC
pulse wave
CN5
Primary current detection
(Connect to the noise filter)
43
Page 44
11
(1) Slide the sleeve and check if there is a locking lever or not.(2) The terminal with this connector is a terminal
with lock mechanism
1Slide the sleeve.
2Pull the terminal while
pushing the locking
lever.
1Hold the sleeve, and
pull out the terminal
slowly.
In case of terminal with lock mechanism, detach the terminal as shown below.
There are two types ( Refer to (1) and (2)) of the terminal with lock mechanism.
The terminal with no lock mechanism can be removed by pulling it out.
Check the shape of the terminal and work.
<"Terminal with lock mechanism" Detaching points>
Connector
Sleeve
Locking lever
DISASSEMBLY INSTRUCTIONS
MUZ-A18YV -MUZ-A24YV -MUZ-A26YV OUTDOOR UNIT
OPERATING PROCEDUREPHOTOS
NOTE :
E1E1E1
These photos are MUZ-A26YV.
Other models are almost the same as MUZ-A26YV.
1. Removing the cabinet
(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.
(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.
Photo 3
Screw of the motor support
Screws
of the
back
panel
Set screws of the back panel
44
Photo 1
Screws
of the
cabinet
Photo 2
Screws
of the
cabinet
Screw of the top panel
Screws of the cabinet
Screw of the service panel
Screws
of the
top
panel
Screw
of the
valve
cover
Page 45
OPERATING PROCEDURE
PHOTOS
2. Removing the inverter assembly, inverter P.C. board
and power board
(1) Remove the top panel, cabinet and service panel.
(Refer to 1.)
(2) Remove the back panel.(Refer to 1.)
(3) Disconnect the following connectors;
<Electronic control P.C. board>
CN931 and CN932 (Fan motor)
CN975 (LEV)
CN661 (Discharge temperature thermistor, defrost
thermistor and outdoor heat exchanger
temperature thermistor)
<Noise filter P.C. board>
CN912 (4-way valve)
(4) Remove the compressor connector.
(5) Remove the screws fixing the relay panel.
(6) Remove the inverter assembly.
(7) Disconnect all connectors and lead wires on the electronic
control P.C. board.
(8) Remove the electronic control P.C. board from the inverter
assembly.
(9) Remove the screws fixing the power board assembly.
(10)
Disconnect all connectors and lead wires on the power
board.
(11)
Remove the power board from the inverter assembly.
(12)
Disconnect all connectors and lead wires on the noise filter
P.C. board.
(13)
Remove the noise filter P.C. board from the inverter
assembly.
Photo 4
Screws of the power board assembly
Screws of the relay panel
3. Removing R.V. coil
(1) Remove the top panel, cabinet and service panel.
(2) Remove the back panel. (Refer to 1.)
(3) Remove the inverter assembly. (Refer to 2.)
(4) Remove the R.V. coil. (Photo 9)
45
Page 46
OPERATING PROCEDURE
PHOTOS
4. Removing the defrost thermistor, discharge temperature thermistor and outdoor heat exchanger tem perature thermistor
(1) Remove the top panel, cabinet and service panel.
(Refer to 1.)
(2) Remove the back panel. (Refer to 1.)
(3) Remove the inverter assembly. (Refer to 2.)
(4) Pull out the defrost thermistor from its holder. (Photo 6)
(5) Pull out the discharge temperature thermistor from its
holder. (Photo 5)
(6) Pull out the outdoor heat exchanger temperature thermistor
from its holder. (Photo 6)
Photo 5
Discharge temperature thermistor
Photo 6
Outdoor heat
exchanger
temperature
thermistor
5. Removing outdoor fan motor
(1) Remove the top panel, cabinet and service panel.
(Refer to 1.)
(2) Remove the back panel. (Refer to 1.)
(3) Remove the inverter assembly. (Refer to 2.)
(4) Remove the propeller.
(5) Remove the screws fixing the fan motor.
(6) Remove the fan motor.
46
Photo 7
Propeller
Defrost
thermistor
Screws of the outdoor fan motor
Page 47
OPERATING PROCEDURE
PHOTOS
6. Removing the compressor and 4-way valve
(1) Remove the top panel, cabinet and service panel.
(Refer to 1.)
(2) Remove the back panel. (Refer to 1.)
(3) Remove the inverter assembly. (Refer to 2.)
(4) Recover gas from the refrigerant circuit.
NOTE: Recover gas from the pipes until the pressure
gauge shows 0 kg/cm
(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)
2
(0 MPa).
Photo 8
Welded parts of 4-way valve
Photo 9
R.V. coil
Welded part
of the discharge pipe
7. Removing the reactor
(1) Remove the top panel. (Refer to 1.)
(2) Disconnect the reactor lead wire.
(3) Remove the screws of the reactor, and remove the reactor.
Welded part
of the suction
pipe
Photo 10
Screws of the reactor
47
Page 48
12
PARTS LIST
MUZ-A18YV -MUZ-A24YV -MUZ-A26YV -
E1E1E1
12-1. OUTDOOR UNIT STRUCTURAL PARTS, ELECTRICAL PARTS AND
FUNCTIONAL PARTS
282930
1
2
3
4
5
27
26
25
24
23
22
21
6
7
8
9
11
18
17
16
15
14
131012
These figures show about MUZ-A26YV.
20
19
48
Page 49
MUZ-A18YV -MUZ-A24YV -MUZ-A26YV -
E1E1E1
12-1. OUTDOOR UNIT STRUCTURAL PARTS, ELECTRICAL PARTS AND
FUNCTIONAL PARTS
Part numbers that are circled are not shown in the illustration.
E1
Q'ty/unit
MUZ-A24
E1
YV -
1
1
1
1
1
1
1
1
3
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
MUZ-A26
YV -
No.
Part No.
E02 819 297
1
E02 851 630
2
E02 853 630
E02 851 301
3
E02 851 501
4
E02 851 290
5
E02 853 290
6
E02 819 232
7
E02 819 009
8
E02 819 521
9
E02 853 646
E02 065 506
10
E02 853 506
E02 851 900
11
E02 853 900
E02 851 661
12
E02 819 661
E02 821 662
13
E02 822 662
E02 851 640
14
E02 853 640
E02 851 493
15
16
E02 853 299
17
E02 851 490
18
E02 679 961
19
E02 819 650
20
E02 819 245
E02 851 450
E02 852 450
21
E02 853 450
E02 836 374
22
E02 823 375
23
E02 851 337
24
E02 851 444
25
E02 851 308
26
E02 851 440
27
E02 819 233
28
E02 817 009
29
E02 851 515
30
E02 127 382
31
E02 737 382
32
E02 735 385
33
E02 851 936
E02 853 936
34
E02 861 936
Part Name
TOP PANEL
OUTDOOR HEAT EXCHANGER
OUTDOOR HEAT EXCHANGER
OUTDOOR FAN MOTOR
PROPELLER
BASE
BASE
CABINET
HANDLE
FAN GUARD
HIGH PRESSURE SWITCH
COMPRESSOR RUBBER SET
COMPRESSOR RUBBER SET
COMPRESSOR
COMPRESSOR
STOP VALVE(GAS)
STOP VALVE(GAS)
STOP VALVE(LIQUID)
STOP VALVE(LIQUID)
EXPANSION VALVE
EXPANSION VALVE
EXPANSION VALVE COIL
OIL SEPARATOR
R.V. COIL
4-WAY VALVE
VALVE COVER
SERVICE PANEL
OUTDOOR ELECTRONIC CONTROL P.C. BOARD
OUTDOOR ELECTRONIC CONTROL P.C. BOARD
OUTDOOR ELECTRONIC CONTROL P.C. BOARD
TERMINAL BLOCK
TERMINAL BLOCK
REACTOR
NOISE FILTER P.C. BOARD
THERMISTOR SET
POWER BOARD
BACK PANEL(OUT)
HANDLE
MOTOR SUPPORT
FUSE
FUSE
FUSE & VARISTOR
CAPILLARY TUBE(TAPER PIPE)
CAPILLARY TUBE(TAPER PIPE)
CAPILLARY TUBE
Symbol
in Wiring
Diagram
MUZ-A18
YV -
MF
HPS
MC
MC
LEV
21S4
TB2
TB1
L
RT61,RT62,RT68
F801
F911
F912,NR63
1
1
1
1
1
1
1
1
3
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
Remarks
E1
1
1
PM8H60-
1
1
1
1
1
1
1
3RUBBERS/SET
3RUBBERS/SET
3
SNB130FLDH
TNB220FMCH
1
{12.7
{15.88
1
{6.35
{9.52
1
1
1
1
1
1
1
1
1
2P
1
3P
1
1
1
DISCHARGE, DEFROST
1
OUTDOOR HEAT EXCHANGER
Including heat sink and RT65
1
1
1
1
250V/3.15A
1
250V/1A
1
250V/3.15A
1
{3.6x{2.4x50
{3.6x{2.4x50
1
{1.8x{0.6x1000
1
49
Page 50
MUZ-A18YV MUZ-A24YV MUZ-A26YV -
E1
E1
E1
12-2. ACCESSORY
1
2
No.
Part No.
1
E02 817 704
2
E02 444 705
Part Name
DRAIN SOCKET
DRAIN CAP
Symbol
in Wiring
Diagram
MUZ-A18
E1
YV -
1
2
Q'ty/unit
MUZ-A24
E1
YV -
1
2
MUZ-A26
E1
YV -
1
2
Remarks
[33
50
Page 51
51
Page 52
HEAD OFFICE: MITSUBISHI DENKI BLDG., 2-2-3, MARUNOUCHI, CHIYODA-KU, TOKYO100-8310, JAPAN
CC
Copyright 2004 MITSUBISHI ELECTRIC ENGINEERING CO.,LTD
Distributed in Jun. 2004. No. OB346 REVISED EDITION - A 6
Distributed in Apr. 2004. No. OB346 6
Made in Japan
New publication, effective Jun. 2004
Specifications subject to change without notice.
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