Mitsubishi | MSZ-GA35VA | Service manual | Mitsubishi MSZ-GA35VA Service manual

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Revision A:
● MSZ-GA80VA has been added.
● MUZ-GA•VA - A has been added.
● MXZ-A•VA - A has been added.
SPLIT-TYPE, HEAT PUMP AIR CONDITIONERS
FLOOR TYPE, HEAT PUMP AIR CONDITIONERS
Please void OBT14.
No. OBT14
REVISED EDITION-A
SERVICE TECHNICAL GUIDE
Wireless type
Models
MSZ-FA•VA - · MUZ-FA•VA MSZ-GA•VA - · MUZ-GA•VA MFZ-KA•VA A
A
A
A
A
Inverter-controlled multi system type Models
· MXZ-A•VA -
A
CONTENTS
1.
2.
3.
4.
MSZ-FA MICROPROCESSOR CONTROL ··········4
MSZ-GA MICROPROCESSOR CONTROL ·······22
MFZ MICROPROCESSOR CONTROL ··············50
MXZ MICROPROCESSOR CONTROL ··············62
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Page 2
Revision A:
• MSZ-GA80VA has been added.
• MUZ-GA•VA - A has been added.
• MXZ-A•VA - A has been added.
1. MSZ-FA MICROPROCESSOR CONTROL ···················································4
MSZ-FA·VA
Indoor unit models Outdoor unit models
MSZ-FA25VA MUZ-FA25VA
MSZ-FA35VA MUZ-FA35VA
(
As for outdoor unit MXZ-8A140VA,
refer to service manual OC316.
1-1. COOL OPERATION ··············································································5
1-2. DRY OPERATION ·················································································6
1-3. HEAT OPERATION ···············································································6
1-4. AUTO CHANGE OVER ··· AUTO MODE OPERATION························8
1-5. INDOOR FAN MOTOR CONTROL ·······················································8
1-6. OUTDOOR FAN MOTOR CONTROL ···················································8
1-7. AUTO VANE OPERATION ····································································9
1-8. i-see CONTROL OPERATION ····························································11
1-9. AREA SETTING ··················································································12
1-10. PLASMA DUO OPERATION ······························································14
1-11. AUTO FRONT PANEL ········································································15
1-12. TIMER OPERATION ···········································································15
1-13. EMERGENCY / TEST OPERATION ···················································16
1-14. INVERTER SYSTEM CONTROL ·······················································17
1-15. OPERATIONAL FREQUENCY CONTROL OF OUTDOOR UNIT ····19
1-16. EXPANSION VALVE CONTROL (LEV CONTROL)···························20
2. MSZ-GA MICROPROCESSOR CONTROL·················································22
MSZ-GA·VA
Indoor unit models
Outdoor unit models
MSZ-GA22VA
MSZ-GA25VA MUZ-GA25VA MXZ-A·VA (Refer to 4.)
MSZ-GA35VA MUZ-GA35VA MXZ-8A140A1 (Refer to OC316)
2-1. COOL OPERATION·············································································23
2-2. DRY OPERATION ···············································································24
2-3. HEAT OPERATION ·············································································24
2-4. AUTO CHANGE OVER ··· AUTO MODE OPERATION······················26
2-5. INDOOR FAN MOTOR CONTROL ·····················································27
2-6. OUTDOOR FAN MOTOR CONTROL ·················································27
2-7. AUTO VANE OPERATION ··································································27
2-8. TIMER OPERATION············································································29
2-9. EMERGENCY / TEST OPERATION ···················································30
2-10. INVERTER SYSTEM CONTROL ·······················································31
2-11. OPERATIONAL FREQUENCY CONTROL OF OUTDOOR UNIT·····33
2-12. EXPANSION VALVE CONTROL (LEV CONTROL)···························34
MSZ-GA·VA
Indoor unit models
Outdoor unit models
MSZ-GA50VA
MSZ-GA60VA
MSZ-GA71VA
MSZ-GA80VA
MUZ-GA50VA MXZ-A·VA (Refer to 4.)
MUZ-GA60VA MXZ-8A140VA1 (Refer to OC316)
MUZ-GA71VA
MUZ-GA80VA
2-13. COOL OPERATION ············································································36
2-14. DRY OPERATION ···············································································37
2-15. HEAT OPERATION ·············································································38
2-16. AUTO CHANGE OVER ··· AUTO MODE OPERATION ·····················40
2-17. INDOOR FAN MOTOR CONTROL·····················································40
2-18. OUTDOOR FAN MOTOR CONTROL·················································41
2-19. AUTO VANE OPERATION··································································41
2-20. TIMER OPERATION ···········································································44
2-21. EMERGENCY/TEST OPERATION ·····················································45
2-22. INVERTER SYSTEM CONTROL ·······················································45
2-23. OPERATIONAL FREQUENCY CONTROL OF OUTDOOR UNIT ·····47
2-24. EXPANSION VALVE CONTROL (LEV CONTROL)···························48
2
)
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3. MFZ MICROPROCESSOR CONTROL ·······················································50
MFZ-KA·VA
Indoor unit models
As for outdoor units SUZ-KA25VA.TH,
SUZ-KA35VA.TH and SUZ-KA50VA.TH,
refer to service manual OC323.
3-1. COOL OPERATION·············································································51
3-2. DRY OPERATION ···············································································52
3-3. HEAT OPERATION ·············································································52
3-4. AUTO CHANGE OVER ··· AUTO MODE OPERATION······················54
3-5. INDOOR FAN MOTOR CONTROL ·····················································55
3-6. OUTDOOR FAN MOTOR CONTROL ·················································55
3-7. AUTO VANE OPERATION ··································································55
3-8. i-save OPERATION·············································································59
3-9. TIMER OPERATION············································································60
3-10. EMERGENCY / TEST OPERATION ···················································61
MFZ-KA25VA
MFZ-KA35VA
MFZ-KA50VA
)
(
4. MXZ MICROPROCESSOR CONTROL ·······················································62
MXZ-A·VA
Outdoor unit models
MXZ-2A52VA
MXZ-3A54VA
MXZ-4A71VA
MXZ-4A80VA
4-1. INVERTER SYSTEM CONTROL ·························································62
4-2. EXPANSION VALVE CONTROL (LEV CONTROL) ····························66
4-3. OPERATIONAL FREQUENCY RANGE···············································71
4-4. HEAT DEFROSTING CONTROL ·························································72
4-5. DISCHARGE TEMPERATURE PROTECTION CONTROL·················72
4-6. REFRIGERANT RECOVERY CONTROL ON HEATING·····················72
4-7. OUTDOOR FAN CONTROL·································································73
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MSZ-FA MICROPROCESSOR CONTROL
MSZ-FA25VA MUZ-FA25VA
MSZ-FA35VA MUZ-FA35VA
WIRELESS REMOTE CONTROLLER
Signal transmitting section
Operation display section
OPERATE/STOP
(ON/OFF) button
Temperature buttons
Indication of
remote controller
model
(This diagram shows an overall view.)
(This diagram shows an overall view.)
WIDE VANE button
(Vertical vane button)
FAN SPEED CONTROL button
OFF-TIMER button
OPERATION SELECT button
ON-TIMER button
ECONO COOL button
TIME SET buttons
FORWARD button
BACKWARD button
PLASMA button
AREA button
CLOCK SET button
i-see button
VANE CONTROL button
(Horizontal vane button)
RESET button
Once the operation mode is set, the same operation mode can be repeated by simply turning 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.
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1-1. COOL (
Page 5
) OPERATION
(1) Press OPERATE/STOP(ON/OFF) button.
POWER lamp of the indoor unit turns on with a beep tone.
(2) Select COOL mode with 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
Difference between room
temperature and set temper1. Thermostat control
ature during operation.
Thermostat is ON or OFF by difference between room temperature and set temperature
Set temperature
Initial temperature difference
Thermostat
Room temperature minus set temperature : -1.0 : or more··············································ON
Room temperature minus set temperature : less than -1.0 :············································OFF
-1.0 : -0.7 :
2. Indoor fan speed control
Indoor fan operates continuously at the set speed by FAN SPEED CONTROL button
Difference between room
regardless of the thermostat’s OFF-ON.
temperature and set temperaIn AUTO the fan speed is as follows.
Initial temperature difference
Fan speed ture during operation ( T)
Room temperature minus set temperature : 1.7 : or more ········································High
Room temperature minus set temperature : Between 1 and 1.7 : ··································Med.
Room temperature minus set temperature : less than 1 : ········································Low
3:
1 : 1.7 :
3. Coil frost prevention
Temperature control
When indoor coil thermistor detects following temperature for 90 seconds, operational frequency
of compressor is controlled according to the following table.
Temperature of indoor coil thermistor
Operation frequency
10°C or more
Normal (variable)
8°C to 10°C
Raise 6 Hz
6°C to 8°C
Fixed
3°C to 6°C
Lower 3Hz
Lower 6Hz
Compressor is turned OFF for 5 minutes
when temperature of indoor coil thermistor continues 3°C or less
for 5 minutes or more.
3°C or less
The indoor fan maintains the actual speed of the moment.
4. Low outside temperature operation
If the outside temperature falls to 18°C or less during operation in COOL mode, the unit enters the low outside temperature
operation mode.
<Operation>
(1) If the unit enters the low outside temperature operation mode, the outside fan rotation speed gets slow down.
(2) Even when the unit is in the "thermostat-off" status under the low outside temperature operation mode, the outside fan
rotation does not stop.
(3) In this mode to detect the exact outside temperature the compressor turns OFF with the outdoor fan ON for 3 minutes
once 1 hour; if the outside temperature rises over 18°C, the unit goes back to the normal COOL mode, and if the outside
temperature is still 18°C or less, the unit stays in the low outside temperature operation mode.
(4) Dew drop prevention
When the ambient temperature thermistor RT65 reads -12: or less, as coil frost or dew drop from indoor unit may
occur, the compressor turns OFF with the outdoor fan ON for prevention of them.
WOther protections work as well as in the normal COOL mode.
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1-2. DRY (
Page 6
Set temperature and
: initial room temperature in dry mode
35
) OPERATION
(1) Press OPERATE/STOP(ON/OFF) button.
POWER lamp of the indoor unit turns on with a beep tone.
(2) Select DRY mode with OPERATION SELECT button.
(3) The microprocessor reads the room temperature and determines
the set temperature. Set temperature is as shown on the right
chart.
30
Set temperature
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25
20
15
10
10
15
20
25
30
Initial room temperature
35 :
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.
By such controls, indoor flow amounts will be reduced in order to lower humidity without much room temperature decrease.
Difference between room
temperature and set tem1. Thermostat control
perature during operation
Thermostat is ON or OFF by difference between room temperature and set temperature.
Set temperature
Initial temperature difference
Thermostat
Room temperature minus set temperature : -1.0 : or more················································ON
Room temperature minus set temperature : less than -1.0 :··············································OFF
-1.0 : -0.7 :
2. Indoor fan speed control
Indoor fan operates at the set speed by FAN SPEED CONTROL button.
When thermostat OFF (compressor OFF) fan speed becomes Very Low.
Difference between room
temperature and set temperaIn AUTO the fan speed is as follows.
Initial temperature difference
Fan speed ture during operation ( T)
Room temperature minus set temperature : 1.7 : or more ········································High
Room temperature minus set temperature : Between 1 and 1.7 : ··································Med.
Room temperature minus set temperature : less than 1 : ········································Low
3. Coil frost prevention
Coil frost prevention is as same as COOL mode. (1-1.3.)
The indoor fan maintains the actual speed of the moment.
4. Low outside temperature operation
Low outside temperature operation is as same as COOL mode. (1-1.4.)
1-3. HEAT (
2.5 :
1 : 1.7 :
) OPERATION
(1) Press OPERATE/STOP(ON/OFF) button.
POWER lamp of the indoor unit turns on with a beep tone.
(2) Select HEAT mode with 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.
Difference between room
temperature and set temperature during operation
1. Thermostat control
Thermostat is ON or OFF by difference between room temperature and set temperature.
Initial temperature difference
Thermostat Set temperature
Room temperature minus set temperature : less than 2.0 :···············································ON
Room temperature minus set temperature : 2.0 : or more·················································OFF
2.0 :
1.7 :
2. Indoor fan speed control
(1) Indoor fan operates at the set speed by FAN SPEED CONTROL button.
Difference between room
In Auto the fan speed is as follows.
temperature and set temFan speed
perature during operation
Initial temperature difference
Set temperature minus room temperature: 2 : or more ·················································· High
Set temperature minus room temperature: Between 0.2 and 2 : ································· Med.
2: 4:
Set temperature minus room temperature: less than 0.2 :·············································· Low
0.2 : 1.7 :
(2) Cold air prevention control
1 When the compressor is not operating,
(1) if the temperature of room temperature thermistor RT11 is less than 19°C, the fan stops.
(2) if the temperature of room temperature thermistor RT11 is 19°C or more and
(1) if the temperature of RT12 is less than 0°C, the fan stops.
(2) if the temperature of RT12 is 0°C or more, the fan operates at Very Low.
2 When the compressor is operating,
(1) if the temperature of RT12 is 40°C or more, the fan operates at set speed.
(2) if the temperature of RT12 is less than 40°C and
(1) if heating operation starts after defrosting, the fan stops.
(2) if the temperature of room temperature thermistor RT11 is 19°C or less, the fan stops.
(3) if the temperature of room temperature thermistor RT11 is more than 19°C, the fan operates at Very Low.
NOTE : When 3 minutes have passed since the compressor started operation, this control is released regardless of the
temperature of RT11 and RT12.
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3. High pressure protection
In HEAT operation the indoor coil thermistor detects the temperature of the indoor heat exchanger. The compressor operational frequency is controlled to prevent the condensing pressure from increasing excessively.
4. Overload starting
When the room temperature thermistor RT11 reads 18°C or more, the compressor runs with its maximum frequency regulated for 10 minutes after the start-up.
5. Defrosting
(1) Starting conditions of defrosting
When the following conditions a) ~ c) are satisfied, the defrosting starts.
a) The defrost thermistor reads -3°C or less.
b) The cumulative operation time of the compressor has reached any of the set valuesw (30, 35, 40, 45, 55, 65, 75, 85,
95, 105, 115, 125, 150 minutes).
c) More than 5 minutes have passed since the start-up of the compressor.
w Set value of compressor operation time(hereinafter referred to as defrost interval)
This is decided by the temperature of defrost thermistor and ambient temperature thermistor, the previous defrosting
time. For example, the first defrost interval is 40 minutes long, and the second is 45 minutes long. The third and subsequent intervals are set to be longer, and less frequent, depending on defrosting time.
The third and subsequent defrost intervals follow any of the three patterns …5 or 10 to 20 minutes longer, the same,
or 5 or 10 to 20 minutes shorter compared with the previous defrost interval … with the longest 150 minutes and the
shortest 30 minutes.
(2) Releasing conditions of defrosting
Defrosting is released when any of the following conditions is satisfied:
a) The defrost thermistor continues to read 5°C or more (MUZ-FA25VA) / 10°C or more (MUZ-FA35VA) for 30 seconds.
b) Defrosting time has exceeded 10 minutes.
c) Any other mode than HEAT mode is set during defrosting.
Time chart of defrosting in HEAT mode (reverse type)
<indoor unit>
horizontal
Horizontal vane
set position
Indoor fan
set speed
set position
Very Low (temperature of indoor coil thermistor > 18:)
OFF
set speed
30
seconds
<outdoor unit>
Maximum frequency
Compressor normal
OFF
40
30
seconds seconds
OFF
40
seconds
5 seconds
ON
30
seconds
5 seconds
ON
Outdoor fan
OFF
R.V. coil
(21S4)
ON (HEAT)
ON (HEAT)
OFF (COOL)
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1-4. AUTO CHANGE OVER ··· AUTO MODE OPERATION
Once desired temperature is set, unit operation is switched automatically between COOL and HEAT operation.
1. Mode selection
(1) Initial mode
At first indoor unit operates only indoor fan with outdoor unit OFF for 3 minutes to detect present room temperature.
Following the conditions below, operation mode is selected.
1 If the room temperature thermistor RT11 reads more than set temperature, COOL mode is selected.
2 If the room temperature thermistor RT11 reads set temperature or less, HEAT mode is selected.
(2) Mode change
In case of the following conditions the operation mode is changed.
1 COOL mode changes to HEAT mode when 15 minutes have passed with the room temperature 2 degrees below the
set temperature.
2 HEAT mode changes to COOL mode when 15 minutes have passed with the room temperature 2 degrees above the
set temperature.
In the other cases than the above conditions, the present operation mode is continued.
NOTE1: Mode selection is performed when multi standby (refer to NOTE2) is released and the unit starts operation with
ON-timer.
NOTE2: If two or more indoor units are operating in multi system, there might be a case that the indoor unit, which is
operating in AUTO (
), cannot change over the other operating mode (COOL
HEAT) and becomes a
state of standby.
(3) Indoor fan control/ Vane control
As the indoor fan speed and the horizontal vane position depend on the selected operation mode, when the operation
mode changes over, they change to the exclusive ones.
1-5. INDOOR 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 (Super High, High,
Med., Low), the microprocessor 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.
Rotational frequency
Super High
Super High
High
Med.
Low
time
(2) Fan motor lock-up protection
When the rotational frequency feedback signal has not output for 12 seconds, (or when the microprocessor cannot
detect the signal for 12 seconds) energizing to the fan motor is stopped. Then the microprocessor retries detection 3
times every 30 seconds. If the microprocessor still cannot detect the signal, the fan motor is regarded locked-up. When
the fan motor lock-up, POWER lamp flashes on and off to show the fan motor abnormality.
1-6. OUTDOOR FAN MOTOR CONTROL
Fan speed is switched according to the compressor frequency.
Fan speed
Down
High
Up
Low
Min.
Compressor frequency
Max.
<Relation between compressor frequency and fan speed.>
Mode
COOL
HEAT
Fan speed
Compressor frequency
MUZ-FA25
MUZ-FA35
Up
54Hz
43Hz
Down
41Hz
33Hz
Up
54Hz
43Hz
Down
41Hz
33Hz
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1-7. AUTO VANE OPERATION
1. Horizontal vane
(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 (approximate 12V) transmitted from indoor microprocessor.
(2) The horizontal vane angle and mode change as follows by pressing VANE CONTROL button.
(3) Positioning
The vane presses the vane stopper once to confirm the standard position and then moves to the set angle.
Confirming of standard position is performed in case of follows.
(a) When the operation starts or finishes (including timer operation).
(b) When the test run starts.
(c) When multi-standby starts or finishes.
(4) VANE AUTO (
) mode
In VANE AUTO mode, the microprocessor automatically determines the vane angle and operation to make the optimum
room-temperature distribution.
(1) In COOL and DRY operation
Vane angle is fixed to Horizontal position.
Horizontal
position
Vane angle is fixed to Angle 4.
(2) In HEAT operation
(5) STOP (operation OFF) and ON-TIMER standby
When the following cases occur, the horizontal vane returns to the closed position.
(a) When OPERATE/STOP (ON/OFF) button is pressed (POWER OFF).
(b) When the operation is stopped by the emergency operation.
(c) When ON-TIMER is ON standby.
(6) Dew prevention
During COOL or DRY operation with the vane angle at Angle 2 ~ 4 when the compressor cumulative operation time
exceeds 1 hour, the vane angle automatically changes to Angle 1 for dew prevention.
(7) SWING MODE ( )
By selecting SWING mode with VANE CONTROL button, the horizontal vane swings vertically. The remote controller
displays “ ”. SWING mode is cancelled when VANE CONTROL button is pressed once again.
(8) Cold air prevention in HEAT operation.
When any of the following conditions occurs in HEAT operation, the vane angle changes to Horizontal position 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 39:.
⑤ For about 3 minutes after compressor starts.
NOTE : When 2 or more indoor units are operated with multi outdoor unit, even if any indoor unit turns thermostat off,
this control doesn’t work in the indoor unit.
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Page 10
(9) To change the air flow direction not to blow directly onto your body.
To change the air
flow direction
Pressing and holding
VANE CONTROL
button for 2 seconds
or more causes
the horizontal vane
to reverse and
move to horizontal
position.
When to use this function?
COOL/DRY
HEAT
Use this function if you don’t
want the air from the indoor
unit to blow directly onto your
body.
• Depending on the shape of
the room,the air may blow
directly onto your body.
The air conditioner starts the
cooling or drying operation
approx. 3 minutes after the
vane has moved to the horizontal position.
• When VANE CONTROL
button is pressed again,
the vane returns to the
previously-set position
and the air conditioner
starts the cooling or
drying operation in
approx. 3minutes.
The air conditioner starts heating operation approx. 3 minutes
after the vane has moved to the
horizontal position.
• Sometimes the area
around your feet may not
warm. To warn the area
around the feet, set the
horizontal vane to
(AUTO) or the downwardblowing position.
• Press VANE CONTROL
button again to return the
vane to the previously-set
position.
Horizontal
position
• When VANE CONTROL
button is pressed again,
the vane returns to the
previously-set position
and the air conditioner
starts the heating operation
in approx. 3minutes.
NOTE:
• If you make the air flow not to blow directly onto your body by pressing VANE CONTROL button,
the compressor stops for 3 minutes even during the operation of the air conditioner.
• The air conditioner operates with decreased air flow until the compressor turns on again.
(10) ECONO COOL (
) operation (ECONOmical operation)
When 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 ECONO COOL button is pressed once again or VANE CONTROL
button is pressed or change to other operation mode.
<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 horizontal blow time is decided.
For initial 10 minutes the swing operation is performed in table G~H for quick cooling.
Also, after 10 minutes when the difference of set temperature and room temperature is more than 2:, the swing operation is performed in table D~H for more cooling.
The air conditioner repeats the swing operation in various cycle as follows.
Temperature of indoor
coil thermistor RT12
Downward blow time
(second)
Horizontal blow time
(second)
A
15°C or less
2
23
B
15°C to 17°C
5
20
C
17°C to 18°C
8
17
D
18°C to 20°C
11
14
E
20°C to 21°C
14
11
F
21°C to 22°C
17
8
G
22°C to 24°C
20
5
H
more than 24°C
23
2
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Page 11
2. Vertical vane
(1) Vane motor drive
These models are equipped with a stepping motor for the vertical vane. The rotating direction, speed, and angle of the
motor are controlled by pulse signals (approximate 12V) transmitted from microprocessor.
(2) The vertical vane angle and mode change as follows by pressing WIDE VANE button.
1
2
4
3
5
(SWING)
(3) Positioning
The vane is once pressed to the vane stopper to confirm the standard position and then set to the desired angle.
Confirming of standard position is performed in case of follows.
(a) When OPERATE/STOP(ON/OFF) button is pressed (POWER ON).
(b) When SWING is started.
(4) SWING MODE ( )
By selecting SWING mode with WIDE VANE button, the vertical vane swings horizontally. The remote controller displays
“
”. Swing mode is cancelled when WIDE MODE button is pressed once again.
1-8. i-see CONTROL OPERATION
The sensors constantly measure the room and floor/wall temperatures to automatically adjust to the set temperature
by estimating the temperature actually perceived by a person inside the room (“sensory temperature”).
Advantages
· The air inside the room is conditioned quickly to a comfortable condition.
· The room will not become too cold or hot even when the air conditioner is kept on for a long period.
· The air conditioner will not overcool or overheat, which means you can save on electricity.
i-see control operation is activated when i-see button is pressed with a thin stick in manual COOL or manual HEAT mode.
NOTE :
i-see control operation is activated when the remote controller is first used following replacement of the batteries or
resetting of the remote controller.
i-see control operation is cancelled when i-see button is pressed with a thin stick once again.
NOTE :
If the conditioner is turned OFF without cancelling i-see control operation, i-see control operation is activated the next
time the air conditioner is turned ON.
i-see Sensor
i-see Sensor, which is installed on the right side of the air outlet of the indoor unit, is moved with the stepping motor and it
detects the floor/ wall temperature.
Enlarged view of i-see Sensor
i-see Sensor is installed here.
i-see Sensor
·
When AREA setting is not activated, the sensing range of i-see Sensor differs depending on the installation
location of the air conditioner.
Installation
position
Installed at left
Installed at center
Installed at right
Right
Center
Left
Image of sensing
range
Direction of sensor
Refer to the description on service manual OB371 (8-4. Remote controller) for slide switch settinng.
·
Install the front panel correctly after being removed for maintenance or service so that the
floor/wall temperatures can be measured correctly.
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1-9. AREA (
Page 12
) SETTING
(1) Press OPERATE / STOP (ON/ OFF)button to start the air conditioner.
(2) Press i-see button. (NOTE 1)
(3) Press AREA button.
Each time the button is pressed, the area is changed in sequence:
(AUTO)
(LEFT)
(RIGHT)
Cancel
i-see Sensor moves intermittenly, measuring the floor and wall temperature.
NOTE1: AREA setting is only available during i-see control operation.
NOTE2: If AREA setting is canceled, the vertical vane returns to the previously set position before AREA setting.
NOTE3: The horizontal air flow direction (WIDE VANE button), including horizontal SWING, can not be set during AREA setting.
Moving of horizontal air flow direction
·
·
If AREA setting is set to AUTO in heating operation, the indoor unit automatically delivers warm air to the area
where the floor/wall temperature is the lowest in the room.
If AREA setting is set to AUTO in cooling operation, the indoor unit automatically delivers cool air to the area
where the floor/wall temperature is the highest in the room.
Ex.) In heating operation
Day
Night
Warm area
Cold area
NOTE
Indoor unit
display
The indoor unit delivers warm air detecting the cold area in the room.
Indication of AREA setting
Lighted
Not lighted
·
·
The horizontal air flow direction changes if i-see Sensor detects approx. 3; temperature difference.
In AUTO of AREA setting, both right and left lamps are lighted when the room is evenly air-conditioned.
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Page 13
(4) AREA setting is cancelled when the "cancel" is sellected by pressing AREA button, or when WIDE VANE
button is pressed.
Indoor unit installation location and air-conditioning area
Installed at left
LEFT
·
Installed at center
RIGHT
LEFT
Installed at right
RIGHT
LEFT
RIGHT
Be sure to set the slide switch inside the remote controller to an appropriate position in accordance with the installed
position of the indoor unit. If the switch is not set correctly, the air conditioner may not function properly.
(Refer to Service manual OB371 8-4.)
To air-condition mainly
the left area of the room
Remote controller button
Press AREA button
to select LEFT.
To air-condition the entire room
The horizontal air flow direction and indoor unit display are switched according to the room temperature (floor/wall).
Press AREA button to select AUTO.
To air-condition mainly
the right area of the room
Press AREA button
to select RIGHT.
Remote controller display
i-see Sensor operation
Control range
of horizontal air
flow direction.
The vertical air
flow direction
conforms to the
setting on the
remote controller.
(The horizontal
air flow direction
is controlled in
this range.)
Indoor unit
display
Installed
at center
Installed
at left
Installed
at right
AREA
or
or
NOTE: If the AREA setting is activated (AUTO), i-see Sensor moves in a range of 150 degrees detecting
floor/wall temperature of 3 area (left, right, center). Therefore, the detected temperatures
may be different from the temperatures measured on commercial thermometers
depending on the condition or temperature distribution on the floor and/or wall.
Approx. 150 degrees
Operation and operating range
i-see sensor moves 30 degrees from the center in both right and left side.
i-see Sensor turning to the left
i-see Sensor turning to the center
i-see Sensor turning to the right
i-see Sensor operates as follows in accordance with AREA setting made with the remote controller.
“AUTO” in AREA setting; first turning to the LEFT for adjusting the position then.....
CENTER
RIGHT
CENTER
LEFT
CENTER......
(The sensor turns to the right, left and center.)
“RIGHT” in AREA setting; first turning to the LEFT for adjusting the position then....
CENTER
RIGHT
CENTER
RIGHT
CENTER......
(The sensor turns to the right and center.)
“LEFT” in AREA setting; first turning to the LEFT for adjusting the position then....
CENTER
LEFT
CENTER
LEFT
CENTER......
(The sensor turns to the left and center.)
The sensor finishes turning to one area to another for 3 seconds and it operates one area for 5 seconds.
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1-10. PLASMA DUO (
Page 14
) OPERATION
(1) Press OPERATE/STOP (ON/OFF) button to start the air conditioner.
(2) Press PLASMA button to set PLASMA DUO operation.
Each time this button is pressed, the operation mode of PLASMA is changed in
sequence:
Cancel (The sign of PLASMA operation disappears .)
PLASMA/WASH lamp
Lighted
Not lighted
PLASMA/WASH lamp turns on in the display section of the indoor unit and
PLASMA DEODORIZING and/or PLASMA AIR PURIFYING unit is energyzed.
Adjust the air flow to your desired speed.
(3) PLASMA operation is cancelled when the "cancel" is selected by pressing PLASMA button.
Once PLASMA operation is selected, PLASMA operation will be performed every time
the air conditioner is turned on until the "Cancel" is selected with PLASMA button.
● Never touch the PLASMA DEODORIZING/AIR PURIFYING filter units during the operation of the air
conditioner. Although the filter units are safety-conscious design, touching the units could be the cause
of trouble as they discharge high voltage electricity.
Description of PLASMA DUO operation:
<
function>
Both PLASMA DEODORIZING and PLASMA AIR PURIFYING operation work.
function>
<
PLASMA DEODORIZING operation cleans the air inside the room by adsorbing and decomposing
the particles of odor-releasing substances and gases such as formaldehyde.
function>
<
PLASMA AIR PURIFYING operation cleans the air inside the room by absorbing the particles of cigarette
smoke or allergens such as pollens and house dust.
NOTE1: Carbon monoxide released from cigarettes cannot be removed by PLASMA operation.
Open the windows to let the outside air in from time to time.
NOTE2: During PLASMA operation, you may smell ozone that is generated in small quantities
from PLASMA DEODORIZING/AIR PURIFYING filter units. This is not a malfunction.
NOTE3: You may hear a small "hissing" sound during PLASMA operation. This is the sound of plasma
discharge, and not a malfunction.
<Cleaning>
When PLASMA/WASH lamp is blinking, please clean PLASMA DEODORIZING/AIR PURIFYING filter units.
After cleaning of PLASMA DEODORIZING/AIR PURIFYING filter units, press WASH reset switch.
A short “beep” is heard and the blinks of PLASMA/WASH lamp will be cancelled.
PLASMA/WASH lamp
E.O.
SW
Lighted
Blinking
Not lighted
WASH reset switch
14
WASH
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1-11. AUTO FRONT PANEL
When the unit starts operating, the front panel opens automatically to draw in air.
When the unit stops operating, the front panel closes automatically.
Open
Closed
Operation and operating range of the auto front panel
The front panel fully opens 10 mm or more upper than the level line of the top end of the nozzle assembly.
It takes about 13 seconds to open the front panel completely.
10 mm or more
Z-Z Side view
1-12. 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.
ON timer setting
START
(1) Press ON-TIMER button(
) to set ON timer.
Each time the button is pressed, ON timer mode alternates between ON and OFF.
(2) Set the time of the timer using TIME SET buttons (
and
).
Each time FORWARD button(
) is pressed, the set time increases by 10 minutes; each time BACKWARD
button (
) is pressed, the set time decreases by 10 minutes.
OFF timer setting
STOP
(1) Press OFF-TIMER button (
) to set OFF timer.
Each time the button is pressed, OFF timer mode alternates between ON and OFF.
(2) Set the time of the timer using TIME SET buttons (
and
).
Each time FORWARD button (
) is pressed, the set time increases by 10 minutes; each time BACKWARD (
button is pressed, the set time decreases by 10 minutes.
2. Cancel
TIMER setting can be cancelled with ON/OFF TIMER
buttons.
START
To cancel ON timer, press ON-TIMER button (
).
STOP
To cancel OFF timer, press OFF-TIMER button(
).
TIMER is cancelled and the display of set time disappears.
15
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PROGRAM TIMER
• The OFF timer and ON timer can be used in combination. The timer of the set time that is reached first will operate first.
• “ ” and “ ” display shows the order of the OFF timer and the ON timer operation.
(Example 1) The current time is 8:00 PM.
(Example 2) The current time is 11:00 AM.
The unit turns off at 11:00 PM, and on at 6:00 AM.
The unit turns on at 5:00 PM, and off at 9:00 PM.
NOTE : If the main power is turned off or a power failure occurs while AUTO START/STOP timer is active, the timer setting is
cancelled. As these models are equipped with an auto restart function, the air conditioner starts operating with timer
cancelled when power is restored.
1-13. EMERGENCY / TEST OPERATION
In case of test run operation or emergency operation, use 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 the remote
controller run down. The unit will start and AREA 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 in ON).
After 30 minutes of test run operation the system shifts to EMERGENCY COOL / HEAT MODE with a set temperature of
24°C. The fan speed shifts to Med..
The coil frost prevention works even in emergency operation, and defrosting too.
In the test run or emergency operation, the horizontal vane operates in VANE AUTO (
) mode.
Emergency operation continues until EMERGENCY OPERATION switch is pressed once or twice or the unit receives any
signal from the remote controller. In case of latter normal operation will start.
NOTE1 : Do not press EMERGENCY OPERATION switch during normal operation.
NOTE2 : 3 seconds after EMERGENCY OPERATION switch is pressed, the front panel starts moving forward
automatically.
Operation mode
Set temperature
Fan speed
E.O.
SW
WASH
reset
EMERGENCY OPERATION switch
Horizontal vane
Vertical vane
COOL
HEAT
24:
24:
Medium
Medium
Auto
Auto
Straight
Straight
The operation mode is indicated by the Operation Indicator lamp on the indoor unit as following figure.
Operation Indicator lamp
Press once <Cool>
Lighted
Not lighted
Press again <Heat>
Press once again <Stop>
NOTE:
This is the indication of EMERGENCY OPERATION
mode. AREA setting is not available during EMERGENCY OPERATION.
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1-14. INVERTER SYSTEM CONTROL
1-14-1. Inverter main power supply circuit
POWER P.C. BOARD
L62
INVERTER P.C. BOARD
L61
L63
Power
supply
DB61
U
P
+ C63A
C63B
V
C63C
N
W
R64A R64B
X64
CT
CT761
IPM CT781
U
W
MC
V
TR821
DB65
Booster chopper circucuit
Function of main parts
NAME
SYMBOL
IPM
INTELLIGENT POWER MODULE
FUNCTION
It supplies three-phase AC power to compressor.
C63A/C63B/C63C SMOOTHING CAPACITOR
It stabilizes the DC voltage.
CT761/CT781 CURRENT TRANSFORMER
It measures the current of the compressor motor.
CT
CURRENT TRANSFORMER
DB61
DIODE MODULE
R64A, R64B CURRENT-LIMITING RESISTOR
It measures the value of current which is supplied to the main power
supply circuit.
It converts the AC voltage to DC voltage.
It absorbs the rush current not to run into the main power supply circuit
when the electricity turns ON.
It short-circuits the resistance which restricts rush current during the
X64
RELAY
DB65
DIODE MODULE
Booster
TR821
SWITCHING POWER TRANSISTOR
chopper
L61
REACTOR
circuit
normal operation after the compressor startup.
It improves power factor.
It rectifies AC and controls its voltage.
1-14-2. Outline of main power supply circuit
1. At the start of operation
Main power supply circuit is formed when X64 (Relay) is turned ON at compressor startup.
To prevent rush current from running into the circuit when power supply is turned ON,
R64A and R64B (Current-limitting resistor) are placed in sub circuit.
2. At normal operation
1 When AC runs into POWER P.C. board, its external noise is eliminated in the noise filter circuit.
2 After noise is eliminated from AC, it is rectified to DC by DB61 (Diode module).
3 DC voltage, to which AC has been rectified by process 2, is stabilized by C63A, C63B and C63C (Smoothing capacitor)
and supplied to IPM (Intelligent power module).
4 DC voltage, which has been stabilized in process 3, is converted to three-phase AC by IPM and supplied to
compressor.
5 CT761 and CT781 (Current Transformer), which are placed in the power supply circuit to compressor, are used to
measure the value of phase current and locate the polar direction of rotor with algorithm. PWM (Pulse width modulation)
controls impressed voltage and frequency with those information.
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3. Purpose of PAM adoption
PAM : Pulse Amplitude Modulation
PAM has been adopted for the efficiency improvement and the adaptation to IEC harmonic current emission standard.
Outline of simple partial switching method
In conventional inverter models, diode module rectifies AC voltage to DC voltage, smoothing capacitor makes its DC waveform
smooth, and IPM converts its DC voltage to imitated AC voltage again in order to drive the compressor motor.
However, it has been difficult to meet IEC harmonic current emission standard by above circuit because harmonic gets
generated in the input current waveform and power factor gets down. The simple partial switching method with PAM, which has
been adopted this time, places and utilizes the booster chopper circuit (L61, DB65 and TR821) before rectifying AC voltage in
the general passive-method converter circuit. As harmonic gets suppressed and the peak of waveform gets lower by adding
booster chopper circuit as mentioned above and by synchronizing the timing of one-time switching with the zero-cross point of
waveform, the input current waveform can be improved and the requirement of IEC harmonic current emission standard can be
satisfied. Since the switching times is just once by synchronizing with the zero cross point, this simple partial switching method
has the feature of lower energy loss compared to active filter method. In addition, output and efficiency is enhanced by
combining with vector-controlled inverter in order to boost the voltage of power supplied to IPM.
Input current waveform without PAM
Due to the time of no electricity;
· Power factor gets worse.
· Harmonic gets increased.
Input voltage
Input current
Energized time is short in
case L inductance is small.
No electricity runs into
diode module because the
voltage at both sides of smoothing
capacitor is higher than input voltage.
Input current waveform with PAM
Owing to the increase of energized time;
· Power factor gets better.
· Harmonic gets suppressed.
Release of energy stored in L
Peak gets down.
Energized time is
extended by optimization
of L inductance.
Compulsory energizing
by switching.
4. Intelligent power module
IPM consists of the following components
· IGBT (x6)
: Converts DC waveform to three-phase AC waveform and outputs it.
· Drive Circuit
: Drives transistors.
· Protection circuit
: Protects transistors from overcurrent.
Since the above components are all integrated in IPM, IPM has a merit to make the control circuit simplify and miniaturize.
5. Smoothing capacitor
C63A, C63B and C63C stabilize the DC voltage and supply it to IPM.
6. Elimination of electrical noice
Noise filter circuit, which is formed by *CMC COILS capacitors placed on the POWER P.C. board, eliminates electrical
noise of AC power that is supplied to main power supply circuit. And this circuit prevents the electrical noise generated in
the inverter circuit from leaking out.
*CMC COILS; Common mode choke coils
Sine wave control
In these air conditioners, compressor equips brushless DC motor which doesn't have Hall element.
In short, the motor is sensorless. However, it's necessary to locate the polar direction of rotor in order to drive brushless DC
motor efficiently. The general detection method of the polar direction for such a DC motor is to locate it from the voltage induced
by unenergized stator.
Therefore, It is necessary to have a certain period of time in which the stator is being unenergized for the rotor position
detection when the voltage of supplied power is impressed.
So the motor has been driven by square wave control (the conventional motor drive system) which energizes the motor only
when the range of electrical angle is within 120_ because it is forced to be unenergized within 30_ at start & end of one heap
in one waveform cycle (180_) when the voltage is impressed.
However, torque pulsation occurs at rotation in this method when the current-carrying phases are switched over to other
phases in sequence. Therefore, sine wave control system is adopted for these air conditioners because it can make the
phase-to-phase current waveform smoother (sine wave) in order to drive the motor more efficiently and smoothly.
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1-14-3. Characteristics of sine wave control in case of brushless DC motor
● Although ordinary three-phase induction motor requires energy to excite the magnetic field of rotor, brushless DC motor
doesn't need it. So, higher efficiency and torque are provided.
● This control provides the most efficient waveform corresponding to the rotation times of compressor motor.
● The rotation can be set to higher compared to the conventional motor drive system. So, the time in which air conditioner
can be operated with energy saved is longer than conventional models. This can save annual electric consumption.
● Compared to square wave control, the torque pulsation is reduced at rotation so that the motor operates more quietly.
● Since response and efficiency of motor are enhanced in sine wave control, finer adjustment can be provided.
Rotor
DC Motor
Permanent magnet is embedded.
AC Motor
Excited by magnetic field of stator
Rotor Position Signal
Necessary
Unnecessary
w In brushless DC motor, permanent magnet is embedded in the rotor. Therefore, it doesn't require energy to excite the rotor
like AC motor does. However, it's necessary to control the frequency of three-phase AC current supplied to the stator
according to the polar direction of magnet embedded in the rotor so as to drive the motor efficiently. Controlling three-phase
AC current frequency also means controlling the timing to switch the polarity of stator. Therefore, the polar direction of rotor
needs to be detected.
1-14-4. Control Method of Rotation Times
Sine wave control makes the current transformers conduct real time detection of the value of the current running into the motor,
locates the rotor position from the detected value, and decides if voltage should be impressed and if frequency should be changed.
Compared to the conventional control and rotor position detection method, sine wave control can provide finer adjustment of the
voltage of supplied power. The value of the current running into the motor is determined by each motor characteristic.
1-15. OPERATIONAL FREQUENCY CONTROL OF OUTDOOR UNIT
1. Outline
The operational frequency is as following:
First, the target operational frequency is set based on the difference between the room temperature and the set temperature.
Second, the target operational frequency is regulated by discharge temperature protection, high pressure protection,
electric current protection and overload protection and also by the maximum/minimum frequency.
2. Maximum/minimum frequency in each operation mode.
COOL
Applied
model
DRY
HEAT
Minimum
frequency
Rated
frequency
Maximum
frequency
Minimum
frequency
Rated
frequency
Maximum
frequency
Minimum
frequency
Maximum
frequency
MUZ-FA25VA
28
57
98
45
77
105
28
58
MUZ-FA35VA
28
70
86
35
73
98
28
57
w The operation frequency in COOL mode is restricted the upper limit frequency after 1 hour as shown below for
dew prevention.
It is rated frequency or less.
Maximum
frequency
Upper limit
Rated frequency or less
frequency
1 hour
Time
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1-16. EXPANSION VALVE CONTROL (LEV CONTROL)
standard
specification
(1) Outline of LEV control
The LEV basic control is comprised of setting LEV opening degree to the standard opening degrees set for each operational frequency of the compressor. However, when any change in indoor/outdoor temperatures or other factors cause
air conditioning load fluctuation, the LEV control also works to correct LEV opening degree based on discharge temperature (Shell temperature) of the compressor, developing the unit’s performance.
Control range
from minimum 33 pulse to maximum 500 pulse.
Actuating speed
LEV opens 40 pulse/second and close 90 pulse/second
Opening degree adjustment
LEV opening degree is always adjusted in opening direction.
(When reducing the opening degree, LEV is once overclosed, and then adjusted to the proper degree by opening.
Unit OFF
LEV remains at maximum opening degree (reaches maximum opening degree approximate in 15 minutes after compressor stops)
Remote controller ON
LEV is positioned. (first full-closed at zero pulse and then
positioned.)
COOL · DRY MODE
During 1 to 5 minutes after compressor starts
LEV is fixed to standard opening degree according to operational frequency of compressor.
general operation
HEAT MODE
During 1 to 15 minutes after compressor starts
More than COOL, DRY: 5/ HEAT: 15 minutes have
passed since compressor start-up
LEV opening degree is corrected to get target discharge
temperature of compressor.
(For discharge temperature lower than target temperature,
LEV is corrected in closing direction.)
(For discharge temperature higher than target temperature,
LEV is corrected in opening direction.)
wIt may take more than 30 minutes to reach target temperature, depending on operating conditions.
Thermostat OFF
LEV is adjusted to exclusive opening degree for thermostat
OFF.
Thermostat ON
LEV is controlled in the same way as that after the compressor has started up.
Defrosting in HEAT mode
LEV is adjusted to open 500 pulse.
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Page 21
(2) Time chart
Air conditioner OFF
(thermostat off)
Air conditioner ON
LEV opening degree
Positioning
Opening degree is
corrected according
to discharge
temperature.
Standard
opening
degree
about 5 minutes <COOL, DRY>
about 15 minutes <HEAT>
Commanded
to open
Operational frequency
of the compressor
Time
ON
OFF Time
(a) Reference value of target discharge temperature
(COOL/HEAT :)
A
B
C
D
E
F
MUZ-FA25VA
47/41
53/48
58/55
63/60
67/65
67/65
MUZ-FA35VA
50/45
53/52
60/59
66/68
70/76
70/76
Applied model
LEV opening degree
(3) Control data
06
05
04
03
02
01
F
E
D
C
B
A(target discharge temperature)
30
50
70
90
110
130 (Hz)
Operational frequency of the compressor
In COOL operation, the two indoor coil thermistors (one main and one sub) sense temperature ununiformity (super
heat) at the heat exchanger, and when temperature difference have developed, the indoor coil thermistors adjust
LEV opening degree to get approximate 10 degrees lower temperature than the target temperature in the table
above, thus diminishing super heat.
(b) Reference value of LEV standard opening degree
(COOL/ HEAT pulse)
Applied model
01
02
03
04
05
06
MUZ-FA25VA
150/110 190/110 240/150 280/170 310/200 340/230
MUZ-FA35VA
130/100 190/130 240/170 260/210 260/230 260/230
21
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Page 22
MSZ-GA MICROPROCESSOR CONTROL
MSZ-GA22VA
MSZ-GA25VA MUZ-GA25VA
MSZ-GA35VA MUZ-GA35VA
WIRELESS REMOTE CONTROLLER
Signal transmitting section
Operation display section
OPERATE/STOP
(ON/OFF) button
Temperature buttons
Indication of
remote controller
model is on back
(This diagram shows an overall view.)
FAN SPEED CONTROL button
OFF-TIMER button
OPERATION SELECT button
ON-TIMER button
ECONO COOL button
TIME SET buttons
FORWARD button
BACKWARD button
CLOCK SET button
VANE CONTROL button
RESET button
Once the operation mode is set, the same operation mode can be repeated by simply turning 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.
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 applies regardless of shape of the indicator.
Operation Indicator
Lighted
Not lighted
Indication
Operation state
This shows that the
air conditioner is
operating to reach
the target temperature.
Please wait until the
target temperature is
obtained.
This shows that the
room temperature is
approaching the
target temperature.
Difference
between target
temperature
and room
temperature
Approximate
2:
or more
Approximate
2:
or less
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2-1. COOL (
Page 23
) 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 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
Difference between room
temperature and set temper1. Thermostat control
ature during operation.
Thermostat is ON or OFF by difference between room temperature and set temperature
Initial temperature difference
Thermostat
Set temperature
Room temperature minus set temperature : -1.0 : or more··············································ON
Room temperature minus set temperature : less than -1.0 :············································OFF
-1.0 : -0.7 :
2. Indoor fan speed control
Difference between room
Indoor fan operates continuously at the set speed by FAN SPEED CONTROL button
regardless of the thermostat’s OFF-ON.
temperature and set temperaIn AUTO the fan speed is as follows.
Initial temperature difference
Fan speed ture during operation ( T)
Room temperature minus set temperature : 1.7 : or more ········································High
Room temperature minus set temperature : Between 1 and 1.7 : ··································Med.
Room temperature minus set temperature : less than 1 : ········································Low
3. Coil frost prevention
Temperature control
When indoor coil thermistor detects following temperature for 90 seconds, operational frequency
of compressor is controlled according to the following table.
Temperature of indoor coil thermistor
Operation frequency
10°C or more
Normal (variable)
8°C to 10°C
Raise 6Hz
6°C to 8°C
Fixed
3°C to 6°C
Lower 3Hz
3:
1 : 1.7 :
Lower 6Hz
Compressor is turned OFF for 5 minutes when temperature of
3°C or less
indoor coil thermistor continues 3°C or less for 5 minutes or more.
The indoor fan maintains the actual speed of the moment.
4. Low outside temperature operation
MSZ-GA25
When the ambient temperature thermistor RT65 reads 17: or less, the operation mode moves to cool operation in low outside temperature from normal cool operation.
Each outdoor actuators (compressor/ fan/ solenoid valve) are operated in the exclusive control, which is different from one
of normal cool operation.
Especially fan motor doesn’t operates continuously to maintain sufficient cooling capacity.
(1) Outdoor fan control
Outdoor unit (compressor) operates with outdoor fan OFF basically.
But any of following conditions is satisfied, the outdoor fan turns ON for about 5 seconds.
a). the defrost thermistor RT61 reads 50: or more.
b). the fin temperature thermistor RT64 reads 60: or more.
(2) Solenoid valve control
In low outside temperature operation solenoid valve coil is energized and solenoid valve is open.
(3) Dew drop prevention
When the ambient temperature thermistor RT65 reads -12: or less, as coil frost or dew drop from indoor unit may
occur, the compressor turns OFF with the outdoor fan ON for prevention of them.
NOTE: This control can be released by cut of the jumper line JG on the outdoor inverter P.C. board.
Be sure to cut it since user accepts that maker can’t be responsible for coil frost or dew drop from indoor unit.
(4) Outside temperature detecting control
In this mode to detect the exact outside temperature the compressor turns OFF with the outdoor fan ON for 3 minutes
once 1 hour.
MSZ-GA35
If the outside temperature falls to 18°C or less during operation in COOL mode, the unit enters the low outside temperature
operation mode.
<Operation>
(1) If the unit enters the low outside temperature operation mode, the outside fan rotation speed gets slow down.
(2) Even when the unit is in the "thermostat-off" status under the low outside temperature operation mode, the outside fan
rotation does not stop.
(3) In this mode to detect the exact outside temperature the compressor turns OFF with the outdoor fan ON for 3 minutes
once 1 hour; if the outside temperature rises over 18°C, the unit goes back to the normal COOL mode, and if the
outside temperature is still 18°C or less, the unit stays in the low outside temperature operation mode.
(4) Dew drop prevention
When the ambient temperature thermistor RT65 reads -12: or less, as coil frost or dew drop from indoor unit may
occur, the compressor turns OFF with the outdoor fan ON for prevention of them.
WOther protections work as well as in the normal COOL mode.
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06.1.12 1:07 PM
2-2. DRY (
Page 24
Set temperature and
: initial room temperature in dry mode
35
) 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 OPERATION SELECT button.
(3) The microprocessor reads the room temperature and determines
the set temperature. Set temperature is as shown on the right
chart.
30
Set temperature
OBT14A--1qxp
25
20
15
10
10
15
20
25
30
Initial room temperature
35 :
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.
By such controls, indoor flow amounts will be reduced in order to lower humidity without much room temperature decrease.
Difference between room
temperature and set tem1. Thermostat control
perature during operation
Thermostat is ON or OFF by difference between room temperature and set temperature.
Initial temperature difference
Thermostat
Set temperature
Room temperature minus set temperature : -1.0 : or more··············································ON
Room temperature minus set temperature : less than -1.0 :············································OFF
-1.0 : -0.7 :
2. Indoor fan speed control
Indoor fan operates at the set speed by FAN SPEED CONTROL button.
When thermostat OFF (compressor OFF) fan speed becomes Very Low.
Difference between room
temperature and set temperaIn AUTO the fan speed is as follows.
Initial temperature difference
Fan speed ture during operation ( T)
Room temperature minus set temperature : 1.7 : or more ········································High
Room temperature minus set temperature : Between 1 and 1.7 : ··································Med.
2.5 :
Room temperature minus set temperature : less than 1 : ········································Low
1.7 :
1
:
3. Coil frost prevention
Coil frost prevention is as same as COOL mode. (2-1.3.)
The indoor fan maintains the actual speed of the moment.
4. Low outside temperature operation
Low outside temperature operation is as same as COOL mode. (2-1.4.)
2-3. HEAT (
) OPERATION
(1) Press OPERATE/STOP(ON/OFF) button.
OPERATION INDICATOR lamp of the indoor unit turns on with a beep tone.
(2) Select HEAT mode with 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.
Difference between room
temperature and set temperature during operation
1. Thermostat control
Thermostat is ON or OFF by difference between room temperature and set temperature.
Initial temperature difference
Thermostat Set temperature
Room temperature minus set temperature : less than 2.0 :··············································ON
Room temperature minus set temperature : 2.0 : or more················································OFF
1.7 : 2.0 :
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.
Fan speed
Initial temperature difference
Set temperature minus room temperature: 2 : or more·················································· High
Set temperature minus room temperature: Between 0.2 and 2 : ································· Med.
Set temperature minus room temperature: less than 0.2 :·············································· Low
Difference between room
temperature and set temperature during operation
2:
0.2 : 1.7 :
4:
(2) Cold air prevention control
1 When the compressor is not operating,
(1) if the temperature of room temperature thermistor RT11 is less than 19°C, the fan stops.
(2) if the temperature of room temperature thermistor RT11 is 19°C or more and
(1) if the temperature of RT12 is less than 0°C, the fan stops.
(2) if the temperature of RT12 is 0°C or more, the fan operates at Very Low.
2 When the compressor is operating,
(1) if the temperature of RT12 is 40°C or more, the fan operates at set speed.
(2) if the temperature of RT12 is less than 40°C and
(1) if heating operation starts after defrosting, the fan stops.
(2) if the temperature of room temperature thermistor RT11 is 19°C or less, the fan stops.
(3) if the temperature of room temperature thermistor RT11 is more than 19°C, the fan operates at Very Low.
NOTE : When 3 minutes have passed since the compressor started operation, this control is released regardless of the
temperature of RT11 and RT12.
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Page 25
3. High pressure protection
In HEAT operation the indoor coil thermistor detects the temperature of the indoor heat exchanger. The compressor operational frequency is controlled to prevent the condensing pressure from increasing excessively.
4. Overload starting
When the room temperature thermistor RT11 reads 18°C or more, the compressor runs with its maximum frequency regulated for 10 minutes after the start-up.
5. Defrosting
(1) Starting conditions of defrosting
When the following conditions a) ~ c) are satisfied, the defrosting starts.
a) The defrost thermistor reads -3°C or less.
b) The cumulative operation time of the compressor has reached any of the set valuesw (40, 45, 55, 65, 75, 85, 95, 105,
115, 125, 150 minutes).
c) More than 5 minutes have passed since the start-up of the compressor.
w Set value of compressor operation time(hereinafter referred to as defrost interval)
This is decided by the temperature of defrost thermistor and ambient temperature thermistor, the previous defrosting
time. For example, the first defrost interval is 40 minutes long, and the second is 45 minutes long. The third and subsequent intervals are set to be longer, and less frequent, depending on defrosting time.
The third and subsequent defrost intervals follow any of the three patterns …5 or 10 to 20 minutes longer, the same,
or 5 or 10 to 20 minutes shorter compared with the previous defrost interval … with the longest 125 minutes and the
shortest 40 minutes.
(2) Releasing conditions of defrosting
Defrosting is released when any of the following conditions is satisfied:
a) The defrost thermistor continues to read 5°C or more for 30 seconds.
b) Defrosting time has exceeded 10 minutes.
c) Any other mode than HEAT mode is set during defrosting.
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Time chart of defrosting in HEAT mode (reverse type)
<indoor unit>
horizontal
Horizontal vane
set position
Indoor fan
set speed
set position
Very Low (temperature of indoor coil thermistor > 18:)
OFF
set speed
30
seconds
<outdoor unit>
Maximum frequency
Compressor normal
OFF
40
30
seconds seconds
OFF
40
seconds
5 seconds
30
seconds
ON
5 seconds
ON
Outdoor fan
OFF
R.V. coil
(21S4)
ON (HEAT)
ON (HEAT)
OFF (COOL)
2-4. AUTO CHANGE OVER ··· AUTO MODE OPERATION
Once desired temperature is set, unit operation is switched automatically between COOL and HEAT operation.
1. Mode selection
(1) Initial mode
At first indoor unit operates only indoor fan with outdoor unit OFF for 3 minutes to detect present room temperature.
Following the conditions below, operation mode is selected.
1 If the room temperature thermistor RT11 reads more than set temperature, COOL mode is selected.
2 If the room temperature thermistor RT11 reads set temperature or less, HEAT mode is selected.
(2) Mode change
In case of the following conditions the operation mode is changed.
1 COOL mode changes to HEAT mode when 15 minutes have passed with the room temperature 2 degrees below the
set temperature.
2 HEAT mode changes to COOL mode when 15 minutes have passed with the room temperature 2 degrees above the
set temperature.
In the other cases than the above conditions, the present operation mode is continued.
NOTE1: Mode selection is performed when multi standby (refer to NOTE2) is released and the unit starts operation with
ON-timer.
NOTE2: If two or more indoor units are operating in multi system, there might be a case that the indoor unit, which is
operating in AUTO (
), cannot change over the other operating mode (COOL
HEAT) and becomes a
state of standby.
(3) Indoor fan control/ Vane control
As the indoor fan speed and the horizontal vane position depend on the selected operation mode, when the operation
mode changes over, they change to the exclusive ones.
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2-5. INDOOR 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 (Super High, High,
Med., Low), the microprocessor 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.
Rotational frequency
Super High
Super High
High
Med.
Low
time
(2) Fan motor lock-up protection
When the rotational frequency feedback signal has not output for 12 seconds, (or when the microprocessor cannot
detect the signal for 12 seconds) energizing to the fan motor is stopped. Then the microprocessor retries detection 3
times every 30 seconds. If the microprocessor still cannot detect the signal, the fan motor is regarded locked-up. When
the fan motor lock-up, POWER lamp flashes on and off to show the fan motor abnormality.
2-6. OUTDOOR FAN MOTOR CONTROL MUZ-GA35
Fan speed is switched according to the compressor frequency.
Fan speed
Down
High
Up
Low
Min.
Compressor frequency
Max.
<Relation between compressor frequency and fan speed.>
Mode
COOL
HEAT
Fan speed
Compressor frequency
MUZ-GA35
Up
54Hz
Down
41Hz
Up
54Hz
Down
41Hz
2-7. AUTO VANE OPERATION
1. Horizontal vane
(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 (approximate 12V) transmitted from indoor microprocessor.
(2) The horizontal vane angle and mode changes as follows by pressing VANE CONTROL button.
(3) Positioning
The vane presses the vane stopper once to confirm the standard position and then moves to the set angle.
Confirming of standard position is performed in case of follows.
(a) When the operation starts or finishes (including timer operation).
(b) When the test run starts.
(c) When multi-standby starts or finishes.
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(4) VANE AUTO (
) mode
In VANE AUTO mode, the microprocessor automatically determines the vane angle and operation to make the optimum
room-temperature distribution.
(1) In COOL and DRY operation
Vane angle is fixed to Horizontal position.
Horizontal
position
Vane angle is fixed to Angle 4.
(2) In HEAT operation
(5) STOP (operation OFF) and ON-TIMER standby
When the following cases occur, the horizontal vane returns to the closed position.
(a) When OPERATE/STOP (ON/OFF) button is pressed (POWER OFF).
(b) When the operation is stopped by the emergency operation.
(c) When ON-TIMER is ON standby.
(6) Dew prevention
During COOL or DRY operation with the vane angle at Angle 2 ~ 4 when the compressor cumulative operation time
exceeds 1 hour, the vane angle automatically changes to Angle 1 for dew prevention.
(7) SWING MODE ( )
By selecting SWING mode with VANE CONTROL button, the horizontal vane swings vertically. The remote controller
displays “
”. SWING mode is cancelled when VANE CONTROL button is pressed once again.
(8) Cold air prevention in HEAT operation.
When any of the following conditions occurs in HEAT operation, the vane angle changes to Horizontal position 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 39:.
⑤ For about 3 minutes after compressor starts.
NOTE: When 2 or more indoor units are operated with multi outdoor unit, even if any indoor unit turns thermostat off,
this control doesn’t work in the indoor unit.
(9) To change the air flow direction not to blow directly onto your body.
To change the air
flow direction
Pressing and holding
VANE CONTROL
button for 2 seconds
or more causes
the horizontal vane
to reverse and
move to horizontal
position.
Horizontal
position
When to use this function?
COOL/DRY
HEAT
Use this function if you don’t
want the air from the indoor
unit to blow directly onto your
body.
• Depending on the shape of
the room,the air may blow
directly onto your body.
The air conditioner starts the
cooling or drying operation
approx. 3 minutes after the
vane has moved to the horizontal position.
• When VANE CONTROL
button is pressed again,
the vane returns to the
previously-set position
and the air conditioner
starts the cooling or
drying operation in
approx. 3minutes.
The air conditioner starts heating operation approx. 3 minutes
after the vane has moved to the
horizontal position.
• Sometimes the area
around your feet may not
warm. To warn the area
around the feet, set the
horizontal vane to
(AUTO) or the downwardblowing position.
• Press VANE CONTROL
button again to return the
vane to the previously-set
position.
• When VANE CONTROL
button is pressed again,
the vane returns to the
previously-set position
and the air conditioner
starts the heating operation
in approx. 3minutes.
NOTE:
• If you make the air flow not to blow directly onto your body by pressing VANE CONTROL button,
the compressor stops for 3 minutes even during the operation of the air conditioner.
• The air conditioner operates with decreased air flow until the compressor turns on again.
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(10) ECONO COOL (
) operation (ECONOmical operation)
When 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 ECONO COOL button is pressed once again or VANE CONTROL
button is pressed or change to other operation mode.
<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 horizontal blow time is decided.
For initial 10 minutes the swing operation is performed in table G~H for quick cooling.
Also, after 10 minutes when the difference of set temperature and room temperature is more than 2:, the swing operation is performed in table D~H for more cooling.
The air conditioner repeats the swing operation in various cycle as follows.
Temperature of indoor
coil thermistor RT12
Downward blow time
(second)
Horizontal blow time
(second)
A
15°C or less
2
23
B
15°C to 17°C
5
20
C
17°C to 18°C
8
17
D
18°C to 20°C
11
14
E
20°C to 21°C
14
11
F
21°C to 22°C
17
8
G
22°C to 24°C
20
5
H
more than 24°C
23
2
2-8. 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.
ON timer setting
START
(1) Press ON-TIMER button(
) to set ON timer.
Each time the button is pressed, ON timer mode alternates between ON and OFF.
(2) Set the time of the timer using TIME SET buttons (
and
).
Each time FORWARD button(
) is pressed, the set time increases by 10 minutes; each time BACKWARD
button (
) is pressed, the set time decreases by 10 minutes.
OFF timer setting
STOP
(1) Press OFF-TIMER button (
) to set OFF timer.
Each time the button is pressed, OFF timer mode alternates between ON and OFF.
(2) Set the time of the timer using TIME SET buttons (
and
).
Each time FORWARD button (
) is pressed, the set time increases by 10 minutes; each time BACKWARD (
button is pressed, the set time decreases by 10 minutes.
2. Cancel
TIMER setting can be cancelled with ON/OFF TIMER
buttons.
START
To cancel ON timer, press ON-TIMER button (
).
STOP
To cancel OFF timer, press OFF-TIMER button(
).
TIMER is cancelled and the display of set time disappears.
29
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Page 30
PROGRAM TIMER
• OFF timer and ON timer can be used in combination. The timer of the set time that is reached first will operate first.
• “ ” and “ ” display shows the order of OFF timer and ON timer operation.
(Example 1) The current time is 8:00 PM.
(Example 2) The current time is 11:00 AM.
The unit turns off at 11:00 PM, and on at 6:00 AM.
The unit turns on at 5:00 PM, and off at 9:00 PM.
NOTE : If the main power is turned off or a power failure occurs while AUTO START/STOP timer is active, the timer setting is
cancelled. As these models are equipped with an auto restart function, the air conditioner starts operating with timer
cancelled when power is restored.
2-9. EMERGENCY/TEST OPERATION
In case of test run operation or emergency operation, use 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 the remote
controller run down. The unit will start and 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 in ON).
After 30 minutes of test run operation the system shifts to EMERGENCY COOL / HEAT MODE with a set temperature of
24°C. The fan speed shifts to Med..
The coil frost prevention works even in emergency operation, and defrosting too.
In the test run or emergency operation, the horizontal vane operates in VANE AUTO (
) mode.
Emergency operation continues until EMERGENCY OPERATION switch is pressed once or twice or the unit receives any
signal from the remote controller. In case of latter normal operation will start.
NOTE : Do not press EMERGENCY OPERATION switch during normal operation.
Operation mode
Set temperature
Fan speed
E.O.
SW
Horizontal vane
COOL
HEAT
24:
24:
Medium
Medium
Auto
Auto
The operation mode is indicated by the Operation
Indicator lamp on the indoor unit as following
EMERGENCY OPERATION switch
Operation indicator lamp
Press once <Cool>
Lighted
Not lighted
Press again <Heat>
Press once again <Stop>
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2-10. INVERTER SYSTEM CONTROL
2-10-1. Inverter main power supply circuit
POWER P.C. BOARD
L62
INVERTER P.C. BOARD
L61
L63
Power
supply
DB61
U
P
+ C63A
C63B
V
C63C
N
W
R64A R64B
X64
CT
CT761
IPM CT781
U
W
MC
V
TR821
DB65
Booster chopper circucuit
Function of main parts
NAME
SYMBOL
IPM
INTELLIGENT POWER MODULE
FUNCTION
It supplies three-phase AC power to compressor.
C63A/C63B/C63C SMOOTHING CAPACITOR
It stabilizes the DC voltage.
CT761/CT781 CURRENT TRANSFORMER
It measures the current of the compressor motor.
CT
CURRENT TRANSFORMER
DB61
DIODE MODULE
R64A, R64B CURRENT-LIMITING RESISTOR
It measures the value of current which is supplied to the main power
supply circuit.
It converts the AC voltage to DC voltage.
It absorbs the rush current not to run into the main power supply circuit
when the electricity turns ON.
It short-circuits the resistance which restricts rush current during the
X64
RELAY
DB65
DIODE MODULE
Booster
TR821
SWITCHING POWER TRANSISTOR
chopper
L61
REACTOR
circuit
normal operation after the compressor startup.
It improves power factor.
It rectifies AC and controls its voltage.
2-10-2. Outline of main power supply circuit
1. At the start of operation
Main power supply circuit is formed when X64 (Relay) is turned ON at compressor startup.
To prevent rush current from running into the circuit when power supply is turned ON,
R64A and R64B (Current-limitting resistor) are placed in sub circuit.
2. At normal operation
1 When AC runs into POWER P.C. board, its external noise is eliminated in the noise filter circuit.
2 After noise is eliminated from AC, it is rectified to DC by DB61 (Diode module).
3 DC voltage, to which AC has been rectified by process 2, is stabilized by C63A, C63B and C63C (Smoothing capacitor)
and supplied to IPM (Intelligent power module).
4 DC voltage, which has been stabilized in process 3, is converted to three-phase AC by IPM and supplied to
compressor.
5 CT761 and CT781 (Current Transformer), which are placed in the power supply circuit to compressor, are used to
measure the value of phase current and locate the polar direction of rotor with algorithm. PWM (Pulse width modulation)
controls impressed voltage and frequency with those information.
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3. Purpose of PAM adoption
PAM : Pulse Amplitude Modulation
PAM has been adopted for the efficiency improvement and the adaptation to IEC harmonic current emission standard.
Outline of simple partial switching method
In conventional inverter models, diode module rectifies AC voltage to DC voltage, smoothing capacitor makes its DC waveform
smooth, and IPM converts its DC voltage to imitated AC voltage again in order to drive the compressor motor.
However, it has been difficult to meet IEC harmonic current emission standard by above circuit because harmonic gets
generated in the input current waveform and power factor gets down. The simple partial switching method with PAM, which has
been adopted this time, places and utilizes the booster chopper circuit (L61, DB65 and TR821) before rectifying AC voltage in
the general passive-method converter circuit. As harmonic gets suppressed and the peak of waveform gets lower by adding
booster chopper circuit as mentioned above and by synchronizing the timing of one-time switching with the zero-cross point of
waveform, the input current waveform can be improved and the requirement of IEC harmonic current emission standard can be
satisfied. Since the switching times is just once by synchronizing with the zero cross point, this simple partial switching method
has the feature of lower energy loss compared to active filter method. In addition, output and efficiency is enhanced by
combining with vector-controlled inverter in order to boost the voltage of power supplied to IPM.
Input current waveform without PAM
Due to the time of no electricity;
· Power factor gets worse.
· Harmonic gets increased.
Input voltage
Input current
Energized time is short in
case L inductance is small.
No electricity runs into
diode module because the
voltage at both sides of smoothing
capacitor is higher than input voltage.
Input current waveform with PAM
Owing to the increase of energized time;
· Power factor gets better.
· Harmonic gets suppressed.
Release of energy stored in L
Peak gets down.
Energized time is
extended by optimization
of L inductance.
Compulsory energizing
by switching.
4. Intelligent power module
IPM consists of the following components
· IGBT (x6)
: Converts DC waveform to three-phase AC waveform and outputs it.
· Drive Circuit
: Drives transistors.
· Protection circuit
: Protects transistors from overcurrent.
Since the above components are all integrated in IPM, IPM has a merit to make the control circuit simplify and miniaturize.
5. Smoothing capacitor
C63A, C63B and C63C stabilize the DC voltage and supply it to IPM.
6. Elimination of electrical noice
Noise filter circuit, which is formed by *CMC COILS capacitors placed on the POWER P.C. board, eliminates electrical
noise of AC power that is supplied to main power supply circuit. And this circuit prevents the electrical noise generated in
the inverter circuit from leaking out.
*CMC COILS; Common mode choke coils
Sine wave control
In these air conditioners, compressor equips brushless DC motor which doesn't have Hall element.
In short, the motor is sensorless. However, it's necessary to locate the polar direction of rotor in order to drive brushless DC
motor efficiently. The general detection method of the polar direction for such a DC motor is to locate it from the voltage induced
by unenergized stator.
Therefore, It is necessary to have a certain period of time in which the stator is being unenergized for the rotor position
detection when the voltage of supplied power is impressed.
So the motor has been driven by square wave control (the conventional motor drive system) which energizes the motor only
when the range of electrical angle is within 120_ because it is forced to be unenergized within 30_ at start & end of one heap
in one waveform cycle (180_) when the voltage is impressed.
However, torque pulsation occurs at rotation in this method when the current-carrying phases are switched over to other
phases in sequence. Therefore, sine wave control system is adopted for these air conditioners because it can make the
phase-to-phase current waveform smoother (sine wave) in order to drive the motor more efficiently and smoothly.
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2-10-3. Characteristics of sine wave control in case of brushless DC motor
● Although ordinary three-phase induction motor requires energy to excite the magnetic field of rotor, brushless DC motor
doesn't need it. So, higher efficiency and torque are provided.
● This control provides the most efficient waveform corresponding to the rotation times of compressor motor.
● The rotation can be set to higher compared to the conventional motor drive system. So, the time in which air conditioner
can be operated with energy saved is longer than conventional models. This can save annual electric consumption.
● Compared to square wave control, the torque pulsation is reduced at rotation so that the motor operates more quietly.
● Since response and efficiency of motor are enhanced in sine wave control, finer adjustment can be provided.
Rotor
DC Motor
Permanent magnet is embedded.
AC Motor
Excited by magnetic field of stator
Rotor Position Signal
Necessary
Unnecessary
w In brushless DC motor, permanent magnet is embedded in the rotor. Therefore, it doesn't require energy to excite the rotor
like AC motor does. However, it's necessary to control the frequency of three-phase AC current supplied to the stator
according to the polar direction of magnet embedded in the rotor so as to drive the motor efficiently. Controlling three-phase
AC current frequency also means controlling the timing to switch the polarity of stator. Therefore, the polar direction of rotor
needs to be detected.
2-10-4. Control Method of Rotation Times
Sine wave control makes the current transformers conduct real time detection of the value of the current running into the motor,
locates the rotor position from the detected value, and decides if voltage should be impressed and if frequency should be changed.
Compared to the conventional control and rotor position detection method, sine wave control can provide finer adjustment of the
voltage of supplied power. The value of the current running into the motor is determined by each motor characteristic.
2-11. OPERATIONAL FREQUENCY CONTROL OF OUTDOOR UNIT
1. Outline
The operational frequency is as following:
First, the target operational frequency is set based on the difference between the room temperature and the set temperature.
Second, the target operational frequency is regulated by discharge temperature protection, high pressure protection,
electric current protection and overload protection and also by the maximum/minimum frequency.
2. Maximum/minimum frequency in each operation mode.
COOL
Applied
model
DRY
HEAT
Minimum
frequency
Rated
frequency
Maximum
frequency
Minimum
frequency
Rated
frequency
Maximum
frequency
Minimum
frequency
Maximum
frequency
MUZ-GA25VA
28
65
70
48
85
105
28
40
MUZ-GA35VA
28
88
98
45
96
105
28
58
w The operation frequency in COOL mode is restricted the upper limit frequency after 1 hour as shown below for
dew prevention.
It is rated frequency or less.
Maximum
frequency
Upper limit
Rated frequency or less
frequency
1 hour
Time
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2-12. EXPANSION VALVE CONTROL (LEV CONTROL)
MSZ-GA35
standard
specification
(1) Outline of LEV control
The LEV basic control is comprised of setting LEV opening degree to the standard opening degrees set for each operational frequency of the compressor. However, when any change in indoor/outdoor temperatures or other factors cause
air conditioning load fluctuation, the LEV control also works to correct LEV opening degree based on discharge temperature (Shell temperature) of the compressor, developing the unit’s performance.
Control range
from minimum 33 pulse to maximum 500 pulse.
Actuating speed
LEV opens 40 pulse/second and close 90 pulse/second
Opening degree adjustment
LEV opening degree is always adjusted in opening direction.
(When reducing the opening degree, LEV is once overclosed, and then adjusted to the proper degree by opening.
Unit OFF
LEV remains at maximum opening degree (reaches maximum opening degree approximate in 15 minutes after compressor stops)
Remote controller ON
LEV is positioned. (first full-closed at zero pulse and then
positioned.)
COOL · DRY MODE
During 1 to 5 minutes after compressor starts
LEV is fixed to standard opening degree according to operational frequency of compressor.
general operation
HEAT MODE
During 1 to 15 minutes after compressor starts
More than COOL, DRY: 5/ HEAT: 15 minutes have
passed since compressor start-up
LEV opening degree is corrected to get target discharge
temperature of compressor.
(For discharge temperature lower than target temperature,
LEV is corrected in closing direction.)
(For discharge temperature higher than target temperature,
LEV is corrected in opening direction.)
wIt may take more than 30 minutes to reach target temperature, depending on operating conditions.
Thermostat OFF
LEV is adjusted to exclusive opening degree for thermostat
OFF.
Thermostat ON
LEV is controlled in the same way as that after the compressor has started up.
Defrosting in HEAT mode
LEV is adjusted to open 500 pulse.
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(2) Time chart
Air conditioner OFF
(thermostat off)
Air conditioner ON
LEV opening degree
Positioning
Opening degree is
corrected according
to discharge
temperature.
Standard
opening
degree
about 5 minutes <COOL, DRY>
about 15 minutes <HEAT>
Commanded
to open
Operational frequency
of the compressor
Time
ON
OFF Time
(a) Reference value of target discharge temperature
(COOL/HEAT :)
Applied model
MUZ-GA35VA
A
B
C
D
E
F
47/41
53/48
58/55
63/60
67/65
67/65
LEV opening degree
(3) Control data
06
05
04
03
02
01
F
E
D
C
B
A(target discharge temperature)
30
50
70
90
110
130 (Hz)
Operational frequency of the compressor
In COOL operation, the two indoor coil thermistors (one main and one sub) sense temperature ununiformity (super
heat) at the heat exchanger, and when temperature difference have developed, the indoor coil thermistors adjust
LEV opening degree to get approximate 10 degrees lower temperature than the target temperature in the table
above, thus diminishing super heat.
(b) Reference value of LEV standard opening degree
(COOL/ HEAT pulse)
Applied model
MUZ-GA35VA
01
02
03
04
05
06
150/110 190/110 240/150 280/170 310/200 340/230
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MSZ-GA50VA MSZ-GA60VA MUZ-GA50VA MUZ-GA60VA
MSZ-GA71VA MSZ-GA80VA MUZ-GA71VA MUZ-GA80VA
WIRELESS REMOTE CONTROLLER
Signal transmitting section
Operation display section
OPERATE /STOP
(ON /OFF)button
TOO
ON/OFF WARM
TOO
COOL
TEMPERATURE buttons
Indication of remote controller
model is on back.
WIDE VANE button
(Vertical vane button)
FAN SPEED CONTROL button
OPERATION SELECT button
OFF-TIMER button
ECONO COOL button
ON-TIMER button
TIME SET buttons
FORWARD button
BACKWARD button
LONG
LONG button
CLOCK SET button
VANE CONTROL button
(Horizontal vane button)
RESET button
Once the operation mode is set, the same operation mode can be repeated by simply turning 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.
2-13. 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 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
Difference between room
temperature and set temper1. Thermostat control
ature during operation.
Thermostat is ON or OFF by difference between room temperature and set temperature
Set temperature
Initial temperature difference
Thermostat
Room temperature minus set temperature : -1.0 : or more··············································ON
Room temperature minus set temperature : less than -1.0 :············································OFF
-1.0 : -0.7 :
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2. Indoor fan speed control
Indoor fan operates continuously at the set speed by FAN SPEED CONTROL button
Difference between room
regardless of the thermostat’s OFF-ON.
temperature and set temperaIn AUTO the fan speed is as follows.
Initial temperature difference
Fan speed ture during operation ( T)
Room temperature minus set temperature : 1.7 : or more ········································High
Room temperature minus set temperature : Between 1 and 1.7 : ··································Med.
Room temperature minus set temperature : less than 1 : ········································Low
3:
1 : 1.7 :
3. Coil frost prevention
Temperature control
When indoor coil thermistor detects following temperature for 90 seconds, operational frequency
of compressor is controlled according to the following table.
Operation frequency
Temperature of indoor coil thermistor
10°C or more
Normal (variable)
8°C to 10°C
Raise 6Hz
6°C to 8°C
Fixed
3°C to 6°C
Lower 3Hz
3°C or less
Lower 6Hz
Compressor is turned OFF for 5 minutes when temperature of
indoor coil thermistor continues 3°C or less for 5 minutes or more.
The indoor fan maintains the actual speed of the moment.
4. Low outside temperature operation
If the outside temperature falls to 18°C or less during operation in COOL mode, the unit enters the low outside temperature
operation mode.
<Operation>
(1) If the unit enters the low outside temperature operation mode, the outside fan rotation speed gets slow down.
(2) Even when the unit is in the "thermostat-off" status under the low outside temperature operation mode, the outside fan
rotation does not stop.
(3) Outside temperature detecting control
In this mode to detect the exact outside temperature the compressor turns OFF with the outdoor fan ON for 3 minutes
once 1 hour; if the outside temperature rises over 18°C, the unit goes back to the normal COOL mode, and if the outside
temperature is still 18°C or less, the unit stays in the low outside temperature operation mode.
(4) Dew drop prevention
When the ambient temperature thermistor RT65 reads -12: or less, as coil frost or dew drop from indoor unit may
occur, the compressor turns OFF with the outdoor fan ON for prevention of them.
WOther protections work as well as in the normal COOL mode.
Set temperature and
: initial room temperature in dry mode
35
) 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 OPERATION SELECT button.
(3) The microprocessor reads the room temperature and determines
the set temperature. Set temperature is as shown on the right
chart.
30
Set temperature
2-14. DRY (
25
20
15
10
10
15
20
25
30
Initial room temperature
35 :
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.
By such controls, indoor flow amounts will be reduced in order to lower humidity without much room temperature decrease.
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Difference between room
temperature and set tem1. Thermostat control
perature during operation
Thermostat is ON or OFF by difference between room temperature and set temperature.
Initial temperature difference
Thermostat
Set temperature
Room temperature minus set temperature : -1.0 : or more··············································ON
Room temperature minus set temperature : less than -1.0 :············································OFF
-1.0 : -0.7 :
2. Indoor fan speed control
Indoor fan operates at the set speed by FAN SPEED CONTROL button.
When thermostat OFF (compressor OFF) fan speed becomes Very Low.
3. Coil frost prevention
Coil frost prevention is as same as COOL mode. (2-13.3.)
The indoor fan maintains the actual speed of the moment. However, when coil frost prevention works while the compressor
is not operating it’s speed becomes the set speed.
4. Low outside temperature operation
Low outside temperature operation is as same as COOL mode. (2-13.4.)
2-15. HEAT (
) OPERATION
(1) Press OPERATE/STOP(ON/OFF) button.
OPERATION INDICATOR lamp of the indoor unit turns on with a beep tone.
(2) Select HEAT mode with OPERATION SELECT button.
(3) Press TEMPERATURE buttons (TOO WARM or TOO COOL button) to select the desired temperature.
Difference between room
The setting range is 16 ~ 31°C.
temperature and set tem1. Thermostat control
perature during operation
Thermostat is ON or OFF by difference between room temperature and set temperature.
Initial temperature difference
Thermostat Set temperature
Room temperature minus set temperature : less than 2.0 :··············································ON
Room temperature minus set temperature : 2.0 : or more················································OFF
1.7 : 2.0 :
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.
Fan speed
Initial temperature difference
Set temperature minus room temperature: 2 : or more·················································· High
Set temperature minus room temperature: Between 1 and 2 : ···································· Med.
Set temperature minus room temperature: less than 1 :················································· Low
Difference between room
temperature and set temperature during operation
2: 4:
1 : 1.7 :
(2) Cold air prevention control
1 When the compressor is not operating,
(1) if the temperature of room temperature thermistor RT11 is 15°C or less, or RT12 is less than 18°C,
the fan stops.
(2) if the temperature of room temperature thermistor RT11 is more than 15°C, or RT12 is more than 18°C,
the fan operates at Very Low.
2 When the compressor is operating,
(1) if the temperature of RT12 is 18°C or more, the fan operates at set speed.
(2) if the temperature of RT12 is less than 18°C and
(1) if heating operation starts after defrosting, the fan stops.
(2) if the temperature of room temperature thermistor RT11 is 15°C or less, the fan stops.
(3) if the temperature of room temperature thermistor RT11 is more than 15°C, the fan operates at Very Low.
NOTE : When 3 minutes have passed since the compressor started operation, this control is released regardless of the
temperature of RT11 and RT12.
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3. High pressure protection
In HEAT operation the indoor coil thermistor detects the temperature of the indoor heat exchanger. The compressor operational frequency is controlled to prevent the condensing pressure from increasing excessively.
4. Overload starting
When the room temperature thermistor RT11 reads 18°C or more, the compressor runs with its maximum frequency regulated for 10 minutes after the start-up.
5. Defrosting
(1) Starting conditions of defrosting
When the following conditions a) ~ c) are satisfied, the defrosting starts.
a) The defrost thermistor reads -3°C or less.
b) The cumulative operation time of the compressor has reached any of the set valuesw (31, 35, 45, 55, 65, 75, 85, 95,
105, 115, 150 minutes).
c) More than 5 minutes have passed since the start-up of the compressor.
w Set value of compressor operation time(hereinafter referred to as defrost interval)
This is decided by the temperature of defrost thermistor and ambient temperature thermistor, the previous defrosting
time. For example, the first defrost interval is 40 minutes long, and the second is 45 minutes long. The third and subsequent intervals are set to be longer, and less frequent, depending on defrosting time.
The third and subsequent defrost intervals follow any of the three patterns …5 or 10 to 20 minutes longer, the same,
or 5 or 10 to 20 minutes shorter compared with the previous defrost interval … with the longest 125 minutes and the
shortest 40 minutes.
(2) Releasing conditions of defrosting
Defrosting is released when any of the following conditions is satisfied:
a) The defrost thermistor continues to read 15°C or more for 30 seconds.
b) Defrosting time has exceeded 10 minutes.
c) Any other mode than HEAT mode is set during defrosting.
Time chart of defrosting in HEAT mode (reverse type)
<indoor unit>
horizontal
Horizontal vane
set position
Indoor fan
set speed
set position
Very Low (temperature of indoor coil thermistor > 18:)
OFF
set speed
30
seconds
<outdoor unit>
Maximum frequency
Compressor normal
OFF
40
30
seconds seconds
OFF
40
seconds
5 seconds
ON
30
seconds
5 seconds
ON
Outdoor fan
OFF
R.V. coil
(21S4)
ON (HEAT)
ON (HEAT)
OFF (COOL)
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2-16. AUTO CHANGE OVER ··· AUTO MODE OPERATION
Once desired temperature is set, unit operation is switched automatically between COOL and HEAT operation.
1. Mode selection
(1) Initial mode
At first indoor unit operates only indoor fan with outdoor unit OFF for 3 minutes to detect present room temperature.
Following the conditions below, operation mode is selected.
1 If the room temperature thermistor RT11 reads more than set temperature, COOL mode is selected.
2 If the room temperature thermistor RT11 reads set temperature or less, HEAT mode is selected.
(2) Mode change
In case of the following conditions the operation mode is changed.
1 COOL mode changes to HEAT mode when 15 minutes have passed with the room temperature 2 degrees below the
set temperature.
2 HEAT mode changes to COOL mode when 15 minutes have passed with the room temperature 2 degrees above the
set temperature.
In the other cases than the above conditions, the present operation mode is continued.
NOTE1: Mode selection is performed when multi standby (refer to NOTE2) is released and the unit starts operation with
ON-timer.
NOTE2: If two or more indoor units are operating in multi system, there might be a case that the indoor unit, which is
operating in AUTO (
), cannot change over the other operating mode (COOL
HEAT) and becomes a
state of standby.
(3) Indoor fan control/ Vane control
As the indoor fan speed and the horizontal vane position depend on the selected operation mode, when the operation
mode changes over, they change to the exclusive ones.
2-17. INDOOR 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 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.
Rotational frequency
High
High
Med.
Low
time
(2) Fan motor lock-up protection
When the rotational frequency feedback signal has not output for 12 seconds, (or when the microprocessor cannot
detect the signal for 12 seconds) energizing to the fan motor is stopped. Then the microprocessor retries detection 3
times every 30 seconds. If the microprocessor still cannot detect the signal, the fan motor is regarded locked-up. When
the fan motor lock-up, POWER lamp flashes on and off to show the fan motor abnormality.
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2-18. OUTDOOR FAN MOTOR CONTROL
Fan speed is switched according to the compressor frequency.
Fan speed
Down
Up
High
Low
Min.
Compressor frequency
Max.
<Relation between compressor frequency and fan speed.>
Mode
Fan speed
COOL
HEAT
Indoor unit operation
MUZ-GA50/60 MUZ-GA71/80
Up
44Hz
54Hz
Down
33Hz
39Hz
Up
52Hz
54Hz
Down
42Hz
39Hz
2-19. AUTO VANE OPERATION
1. Horizontal vane
(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 (approximate 12V) transmitted from indoor microprocessor.
(2) The horizontal vane angle and mode changes as follows by pressing VANE CONTROL button.
(3) Positioning
The vane presses to the vane stopper once to confirm the standard position and then moves to the set angle.
Confirming of standard position is performed in case of follows.
(a) When the power supply turns ON.
(b) When the operation starts or finishes (including timer operation).
(c) When the test run starts.
(d) When multi-standby starts or finishes
(4) VANE AUTO (
) mode
In VANE AUTO mode, the microprocessor automatically determines the horizontal vane angle and operation to make
the optimum room-temperature distribution.
(1) In COOL and DRY operation
Vane angle is fixed to Angle 1.
Vane angle is fixed to Angle 4.
(2) In HEAT operation
(5) STOP (operation OFF) and ON-TIMER standby
When the following cases occur, the horizontal vane returns to the closed position.
(a) When OPERATE/STOP (ON/OFF) button is pressed (POWER OFF).
(b) When the operation is stopped by the emergency operation.
(c) When ON-TIMER is ON standby.
(6) Dew prevention
During COOL or DRY operation with the vane angle at Angle 4 or 5 when the compressor cumulative operation time
exceeds 1 hour, the vane angle automatically changes to Angle 1 for dew prevention.
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(7) SWING MODE ( )
By selecting SWING mode with VANE CONTROL button, the horizontal vane swings vertically. The remote controller
displays “ ”. SWING mode is cancelled when VANE CONTROL button is pressed once again.
(8) Cold air prevention in HEAT operation.
When any of the following conditions occurs in HEAT operation, the vane angle changes to Horizontal position automatically to prevent cold air blowing on users.
① Compressor is not operating.
➁ Defrosting is performed.
➂ Indoor coil thermistor RT12 reads 18: or below.
➃ Indoor coil thermistor RT12 temperature is raising from 18°C or below, but it does not exceed 22:.
Indoor coil thermistor RT12 temperature
Horizontal vane
Set position
Released
Cold Air Prevention
18:
22:
Horizontal Position
NOTE1: If the temperature of RT12 reads from 18: to 22: at the air conditioner starting, this control works.
NOTE2: When 2 or more indoor units are operated with multi outdoor unit, even if any indoor unit turns thermostat off,
this control doesn’t work in the indoor unit.
(9) ECONO COOL (
) operation (ECONOmical operation)
When 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 ECONO COOL button is pressed once again or VANE CONTROL
button is pressed or change to other operation mode.
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 horizontal blow time is decided.
For initial 10 minutes the swing operation is performed in table G~H for quick cooling.
Also, after 10 minutes when the difference of set temperature and room temperature is more than 2:, the swing operation is performed in table D~H for more cooling.
The air conditioner repeats the swing operation in various cycle as follows.
Temperature of indoor
coil thermistor RT12
Downward blow time
(second)
Horizontal blow time
(second)
A
15°C or less
2
23
B
15°C to 17°C
5
20
C
17°C to 18°C
8
17
D
18°C to 20°C
11
14
E
20°C to 21°C
14
11
F
21°C to 22°C
17
8
G
22°C to 24°C
20
5
H
more than 24°C
23
2
42
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(10) LONG MODE (
)
By pressing LONG button indoor fan speed becomes faster than setting fan speed on the remote controller, and the horizontal vane moves to the position for LONG mode. The remote controller displays “
”. LONG mode is cancelled
when LONG button is pressed once again or VANE button is pressed or ECONO COOL button is pressed in COOL
mode.
• In the following example, the vertical vane is set to
(front.).
COOL / DRY
HEAT
Fan speed : Faster
Solid arrow : When the LONG mode is used.
Dotted arrow : When the LONG mode is not used.
2. Vertical vane
(1) Vane motor drive
These models are equipped with a stepping motor for the vertical vane. The rotating direction, speed, and angle of the
motor are controlled by pulse signals (approximate 12V) transmitted from microprocessor.
(2) The vertical vane angle and mode change as follows by pressing WIDE VANE button.
1
2
3
4
SWING
5
6
(3) Positioning
The vane presses the vane stopper once to confirm the standard position and then set to the desired angle.
Confirming of standard position is performed in case of follows.
(a) When OPERATE/STOP(ON/OFF) button is pressed (POWER ON/OFF).
(b) When SWING is started or finished.
(c) When the power supply turns ON.
(4) SWING MODE ( )
By selecting SWING mode with WIDE VANE button, the vertical vane swings horizontally. The remote controller displays
“
”. The vane moves right and left in the width of Angle 4 repeatedly.
(5) WIDE MODE (
)
By selecting WIDE mode with WIDE VANE button, indoor fan speed becomes faster than setting fan speed on the
remote controller (W). The remote controller displays “
”.
NOTE : The position of vane angle 3, angle 4 and angle 5 are different in COOL operation and HEAT operation.
W Indoor fan speed becomes faster than setting fan speed on the remote controller even when
selected.
Horizontal AIR FLOW blowing range
About 100COOL and DRY
About 150HEAT
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2-20. 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.
START
(3) Press ON-TIMER button(
) to set ON timer.
Each time the button is pressed, ON timer mode alternates between ON and OFF.
(4) Set the time of the timer using TIME SET buttons (
and
).
Each time FORWARD button(
) is pressed, the set time increases by 10 minutes; each time BACKWARD
button (
) is pressed, the set time decreases by 10 minutes.
STOP
(5) Press OFF-TIMER button (
) to set OFF timer.
Each time the button is pressed, OFF timer mode alternates between ON and OFF.
(6) Set the time of the timer using TIME SET buttons (
and
).
Each time FORWARD button (
) is pressed, the set time increases by 10 minutes; each time BACKWARD (
button is pressed, the set time decreases by 10 minutes.
)
2. Cancel
TIMER setting can be cancelled with ON/OFF TIMER
buttons.
START
To cancel ON timer, press ON-TIMER button (
).
STOP
To cancel OFF timer, press OFF-TIMER button(
).
TIMER is cancelled and the display of set time disappears.
PROGRAM TIMER
• The OFF timer and ON timer can be used in combination. The timer of the set time that is reached first will operate first.
• “ ” and “ ” display shows the order of the OFF timer and the ON timer operation.
(Example 1) The current time is 8:00 PM.
(Example 2) The current time is 11:00 AM.
The unit turns off at 11:00 PM, and on at 6:00 AM.
The unit turns on at 5:00 PM, and off at 9:00 PM.
NOTE : If the main power is turned off or a power failure occurs while AUTO START/STOP timer is active, the timer setting is
cancelled. As these models are equipped with an auto restart function, the air conditioner starts operating with timer
cancelled when power is restored.
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2-21. EMERGENCY / TEST OPERATION
In case of test run operation or emergency operation, use 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 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 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 too.
In the test run or emergency operation, the horizontal vane operates in VANE AUTO (
) mode.
Emergency operation continues until EMERGENCY OPERATION switch is pressed once or twice or the unit receives any
signal from the remote controller. In case of latter normal operation will start.
NOTE : Do not press EMERGENCY OPERATION switch during normal operation.
• The following indication applies
regardless of the shape of lamp.
OPERATION INDICATOR lamp
Press once
<Cool>
Press again
<Heat>
Press once again
<Stop>
Lighted
Not lighted
EMERGENCY
OPERATION switch
2-22. INVERTER SYSTEM CONTROL
2-22-1. Inverter main power supply circuit
POWER BOARD
NOISE FILTER P. C. BOARD
R64A/R64B
V
L
CT1
U
POWER
SUPPLY
N/F
CT61
X64
PFC
MC
U
+CB1
CB2
CB3
W
IPM
V
CT2
W
Function of main parts
SYMBOL
FUNCTION
NAME
IPM
INTELLIGENT POWER MODULE
It supplies three-phase AC power to compressor.
CB1~3
SMOOTHING CAPACITOR
It stabilizes the DC voltage.
CT1~2
CURRENT TRANSFORMER
It measures the current of the compressor motor.
CT61
CURRENT TRANSFORMER
It measures the current of the main power supply circuit.
L
REACTOR
It rectifies AC, controls its voltage and improves the power factor of
PFC
POWER FACTOR CONTROLLER
power supply.
R64A, R64B CURRENT-LIMITING RESISTOR
X64
RELAY
It restricts rush current with the resistance.
It short-circuits the resistance which restricts rush current during the
compressor operates.
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2-22-2. Outline of main power supply circuit
1. At the start of operation
Main power supply circuit is formed when X64 (Relay) is turned ON at compressor startup.
To prevent rush current from running into the circuit when power supply is turned ON, R64A and R64B
(Current-limiting resistor) are placed in sub circuit.
2. At normal operation
1 When AC runs into noise filter P.C. board, its external noise is eliminated in the noise filter circuit.
2 After noise being eliminated from AC, it is rectified to DC by L (Reactor) and PFC (Power factor controller). If the operating
frequency becomes 25Hz or more, DC voltage rises to 370V.
3 DC voltage, to which has AC been rectified by process 2, is stabilized by CB1~3 (Smoothing capacitor) and supplied to
IPM (Intelligent power module).
4 The DC (Bus voltage), which has been stabilized in process 3, is converted to three-phase AC by IPM and supplied to
compressor.
5 CT1 and CT2 (Current Transformer), which are placed in the power supply circuit to compressor, are used to measure the
value of phase current and locate the polar direction of rotor with algorithm. PWM (Pulse width modulation) controls impressed voltage and frequency with those information.
3. Power factor improvement
Booster coil L (Reactor) and PFC rectify AC to DC and control its voltage.
In the motor drive system of sine wave control, power factor can be improved by reducing harmonics PFC and L (Reactor)
stabilize the voltage of DC supplied to inverter circuit and make its waveform smooth.
4. Power transistor module
IPM consists of the following components.
· Power Transistors (x6): Converts DC waveform to three-phase AC waveform and outputs it.
· Drive Circuit
: Drives transistors.
· Protection circuit
: Protects transistors from over current.
Since the above components are all integrated in IPM, IPM has a merit that can get the control circuit simplified and miniaturized.
5. Smoothing capacitor
CB1, CB2 and CB3 stabilize the DC voltage and supply it to IPM.
6. Elimination of electrical noise
Noise filter circuit, which is formed by *CMC COILS and capacitors placed on the noise filter P.C. board, eliminates electrical
noise of AC power that is supplied to main power supply circuit. In short, common mode noise is absorbed in this circuit.
Moreover, normal mode noise is absorbed in another noise filter circuit which is formed by *NMC COILS and capacitors.
Both noise filter circuit exists for preventing the electrical noise generated in the inverter circuit from leaking out.
*CMC COILS; Common mode choke coils
*NMC COILS; Normal mode choke coils
2-22-3. Sine wave control
In these air conditioners, compressor equips brushless DC motor which doesn't have Hall element.
In short, the motor is sensorless. However, it's necessary to locate the polar direction of rotor in order to drive brushless DC
motor efficiently. The general detection method of the polar direction for such a DC motor is to locate it from the voltage induced
by unenergized stator.
Therefore, it is necessary to have a certain period of time in which the stator is being unenergized for the rotor position
detection when the voltage of supplied power is impressed.
So the motor has been driven by square wave control (the conventional motor drive system) which energizes the motor only
when the range of electrical angle is within 120_ because it is forced to be unenergized within 30_ at start & end of one heap
in one waveform cycle (180_) when the voltage is impressed.
However, torque pulsation occurs at rotation in this method when the current-carrying phases are switched over to other
phases in sequence. Therefore, sine wave control system is adopted for these air conditioners because it can make the
phase-to-phase current waveform smoother (sine wave) in order to drive the motor more efficiently and smoothly.
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2-22-4. Characteristics of sine wave control in case of brushless DC motor
● Although ordinary three-phase induction motor requires energy to excite the magnetic field of rotor, brushless DC motor
doesn't need it. So, higher efficiency and torque are provided.
● This control provides the most efficient waveform corresponding to the rotation times of compressor motor.
● The rotation can be set to higher compared to the conventional motor drive system. So, the time in which air conditioner
can be operated with energy saved is longer than conventional models. This can save annual electric consumption.
● Compared to square wave control, the torque pulsation is reduced at rotation so that the motor operates more quietly.
● Since response and efficiency are enhanced in sine wave control, finer adjustment can be provided.
DC Motor
Permanent magnet is embedded.
Rotor
AC Motor
Excited by magnetic field of stator
Necessary
Unnecessary
Rotor Position Signal
w In brushless DC motor, permanent magnet is embedded in the rotor. Therefore, it doesn't require energy to excite the rotor
like AC motor does. However, it's necessary to control the frequency of three-phase AC current supplied to the stator
according to the polar direction of magnet embedded in the rotor so as to drive the motor efficiently. Controlling three-phase
AC current frequency also means controlling the timing to switch the polarity of stator. Therefore, the polar direction of rotor
needs to be detected.
2-22-5. Control Method of Rotation Times
Sine wave control makes the current transformers conduct real time detection of the value of the current running into the motor,
locates the rotor position from the detected value and decides if voltage should be impressed and if frequency should be changed.
Compared to the conventional control and rotor position detection method, sine wave control can provide finer adjustment of the
voltage of supplied power. The value of the current running into the motor is determined by each motor characteristic.
2-23. OPERATIONAL FREQUENCY CONTROL OF OUTDOOR UNIT
1. Outline
The operational frequency is as following:
First, the target operational frequency is set based on the difference between the room temperature and the set temperature.
Second, the target operational frequency is regulated by discharge temperature protection, high pressure protection,
electric current protection and overload protection and also by the maximum/minimum frequency.
2. Maximum/minimum frequency in each operation mode.
Applied
COOL
HEAT
DRY
Minimum
frequency
Rated
frequency
Maximum
frequency
Minimum
frequency
Rated
frequency
Maximum
frequency
Minimum
frequency
Maximum
frequency
MUZ-GA50VA
15
71
98
15
81
108
20
98
MUZ-GA60VA
15
87
102
15
96
108
20
102
MUZ-GA71VA
10
62
79
10
66
84
20
79
MUZ-GA80VA
20
76
94
20
76
94
20
94
model
w The operation frequency in COOL mode is restricted the upper limit frequency after 1 hour as shown below for
dew prevention.
It is rated frequency or less.
Maximum
frequency
Upper limit
Rated frequency or less
frequency
1Hr
Time
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2-24. EXPANSION VALVE CONTROL (LEV CONTROL)
standard
specification
(1) Outline of LEV control
The LEV basic control is comprised of setting LEV opening degree to the standard opening degrees set for each operational frequency of the compressor. However, when any change in indoor/outdoor temperatures or other factors cause
air conditioning load fluctuation, the LEV control also works to correct LEV opening degree based on discharge temperature (Shell temperature) of the compressor, developing the unit’s performance.
Control range
from minimum 59 pulse to maximum 500 pulse.
Actuating speed
LEV opens 40 pulse/second and close 90 pulse/second
Opening degree adjustment
LEV opening degree is always adjusted in opening direction.
(When reducing the opening degree, LEV is once overclosed, and then adjusted to the proper degree by opening.
Unit OFF
LEV remains at maximum opening degree (reaches maximum opening degree approximate in 15 minutes after compressor stops)
Remote controller ON
LEV is positioned. (first full-closed at zero pulse and then
positioned.)
COOL · DRY MODE
During 1 to 5 minutes after compressor starts
LEV is fixed to standard opening degree according to operational frequency of compressor.
general operation
HEAT MODE
During 1 to 15 minutes after compressor starts
More than COOL, DRY: 5/ HEAT: 15 minutes have
passed since compressor start-up
LEV opening degree is corrected to get target discharge
temperature of compressor.
(For discharge temperature lower than target temperature,
LEV is corrected in closing direction.)
(For discharge temperature higher than target temperature,
LEV is corrected in opening direction.)
wIt may take more than 30 minutes to reach target temperature, depending on operating conditions.
Thermostat OFF
LEV is adjusted to exclusive opening degree for thermostat
OFF.
Thermostat ON
LEV is controlled in the same way as that after the compressor has started up.
Defrosting in HEAT mode
LEV is adjusted to open 500 pulse.
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(2) Time chart
Air conditioner OFF
(thermostat off)
Air conditioner ON
LEV opening degree
Positioning
Opening degree is
corrected according
to discharge
temperature.
Standard
opening
degree
about 5 minutes <COOL, DRY>
about 15 minutes <HEAT>
Commanded
to open
Operational frequency
of the compressor
Time
ON
OFF Time
(a) Reference value of target discharge temperature
(COOL/HEAT :)
A
B
C
D
E
F
MUZ-GA50VA
60/60
60/63
60/65
63/67
66/70
67/70
MUZ-GA60VB
60/60
60/63
60/65
63/67
64/70
67/70
Applied model
LEV opening degree
(3) Control data
06
05
04
03
02
01
F
E
D
C
B
A(target discharge temperature)
30
MUZ-GA71VA
62/60
62/65
64/67
68/72
74/80
82/85
MUZ-GA80VA
62/60
62/65
64/70
68/75
74/80
82/84
50
70
90
110
(Hz)
Operational frequency of the compressor
In COOL operation, the two indoor coil thermistors (one main and one sub) sense temperature ununiformity (super
heat) at the heat exchanger, and when temperature difference have developed, the indoor coil thermistors adjust
LEV opening degree to get approximate 10 degrees lower temperature than the target temperature in the table
above, thus diminishing super heat.
(b) Reference value of LEV standard opening degree
(COOL/ HEAT pulse)
Applied model
01
02
03
04
05
06
MUZ-GA50VA
150/130 166/150 186/176 206/196 230/210 260/226
MUZ-GA60VA
150/130 166/150 186/170 206/196 230/210 260/226
MUZ-GA71VA
170/140 200/160 240/200 270/220 280/230 290/250
MUZ-GA80VA
140/140 170/160 210/200 250/220 270/230 290/250
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MFZ MICROPROCESSOR CONTROL
MFZ-KA25VA
MFZ-KA35VA
MFZ-KA50VA
WIRELESS REMOTE CONTROLLER
Signal transmitting section
Operation display section
OPERATE/STOP
(ON/OFF) button
Temperature buttons
Indication of
remote controller
model is on back
Open the front lid.
ra shows an overall
verall view.)
.)
(This diagram
view.)
i save button
FAN SPEED CONTROL button
OFF-TIMER button
OPERATION SELECT button
ECONO COOL button
ON-TIMER button
TIME SET buttons
FORWARD button
BACKWARD button
CLOCK SET button
RESET button
VANE CONTROL button
Once the operation mode is set, the same operation mode can be repeated by simply turning 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.
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3-1. COOL (
Page 51
) 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 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
Difference between room
temperature and set temper1. Thermostat control
ature during operation.
Thermostat is ON or OFF by difference between room temperature and set temperature
Set temperature
Initial temperature difference
Thermostat
Room temperature minus set temperature : -1.0 : or more··············································ON
Room temperature minus set temperature : less than -1.0 :············································OFF
-1.0 : -0.7 :
2. Indoor fan speed control
Indoor fan operates continuously at the set speed by FAN SPEED CONTROL button
Difference between room
regardless of the thermostat’s OFF-ON.
temperature and set temperaIn AUTO the fan speed is as follows.
Initial temperature difference
Fan speed ture during operation ( T)
Room temperature minus set temperature : 1.7 : or more ········································High
Room temperature minus set temperature : Between 1 and 1.7 : ··································Med.
Room temperature minus set temperature : less than 1 : ········································Low
3:
1 : 1.7 :
3. Coil frost prevention
Temperature control
When indoor coil thermistor detects following temperature for 90 seconds, operational frequency
of compressor is controlled according to the following table.
Temperature of indoor coil thermistor
Operation frequency
10°C or more
Normal (variable)
8°C to 10°C
Raise 6 Hz
6°C to 8°C
Fixed
3°C to 6°C
Lower 3Hz
Lower 6Hz
Compressor is turned OFF for 5 minutes
when temperature of indoor coil thermistor continues 3°C or less
for 5 minutes or more.
3°C or less
The indoor fan maintains the actual speed of the moment.
4. Low outside temperature operation
If the outside temperature falls to 18°C or less during operation in COOL mode, the unit enters the low outside temperature
operation mode.
<Operation>
(1) If the unit enters the low outside temperature operation mode, the outside fan rotation speed gets slow down.
(2) Even when the unit is in the "thermostat-off" status under the low outside temperature operation mode, the outside fan
rotation does not stop.
(3) In this mode to detect the exact outside temperature the compressor turns OFF with the outdoor fan ON for 3 minutes
once 1 hour; if the outside temperature rises over 18°C, the unit goes back to the normal COOL mode, and if the outside
temperature is still 18°C or less, the unit stays in the low outside temperature operation mode.
(4) Dew drop prevention
When the ambient temperature thermistor RT65 reads -12: or less, as coil frost or dew drop from indoor unit may
occur, the compressor turns OFF with the outdoor fan ON for prevention of them.
NOTE: This control can be released by cut of the jumper line JG on the outdoor inverter P.C. board.
Be sure to cut it since user accepts that maker can’t be responsible for coil frost or dew drop from indoor unit.
WOther protections work as well as in the normal COOL mode.
NOTE : Even when the damper is closed while cooling or drying operation is performed, the lower fan may rotate
intermittently.
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3-2. DRY (
Page 52
) 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 OPERATION SELECT button.
(3) The microprocessor reads the room temperature and determines
the set temperature. Set temperature is as shown on the right
chart.
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.
By such controls, indoor flow amounts will be reduced in order to
lower humidity without much room temperature decrease.
Set temperature and
: initial room temperature in dry mode
35
30
Set temperature
OBT14A--2qxp
25
20
15
10
10
35 :
15
20
25
30
Initial room temperature
Difference between room
temperature and set tem1. Thermostat control
perature during operation
Thermostat is ON or OFF by difference between room temperature and set temperature.
Set temperature
Initial temperature difference
Thermostat
Room temperature minus set temperature : -1.0 : or more················································ON
Room temperature minus set temperature : less than -1.0 :··············································OFF
-1.0 : -0.7 :
2. Indoor fan speed control
Indoor fan operates at the set speed by FAN SPEED CONTROL button.
When thermostat OFF (compressor OFF) fan speed becomes Very Low.
In AUTO the fan speed is as follows.
Initial temperature difference
Difference between room
temperature and set temperaFan speed ture during operation ( T)
Room temperature minus set temperature : 1.7 : or more ········································High
Room temperature minus set temperature : Between 1 and 1.7 : ··································Med.
Room temperature minus set temperature : less than 1 : ········································Low
2.5 :
1 : 1.7 :
3. Coil frost prevention
Coil frost prevention is as same as COOL mode. (3-1.3.)
The indoor fan maintains the actual speed of the moment.
4. Low outside temperature operation
Low outside temperature operation is as same as COOL mode. (3-1.4.)
NOTE : Even when the damper is closed while cooling or drying operation is performed, the lower fan may rotate
intermittently.
3-3. HEAT (
) OPERATION
(1) Press OPERATE/STOP(ON/OFF) button.
OPERATION INDICATOR lamp of the indoor unit turns on with a beep tone.
(2) Select HEAT mode with 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.
Difference between room
temperature and set temperature during operation
1. Thermostat control
Thermostat is ON or OFF by difference between room temperature and set temperature.
Initial temperature difference
Thermostat Set temperature
Room temperature minus set temperature : less than 2.0 :···············································ON
Room temperature minus set temperature : 2.0 : or more·················································OFF
1.7 :
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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.
Fan speed
Initial temperature difference
Set temperature minus room temperature: 2 : or more ·················································· High
Set temperature minus room temperature: Between 0.2 and 2 : ································· Med.
Set temperature minus room temperature: less than 0.2 :·············································· Low
Difference between room
temperature and set temperature during operation
2:
0.2 : 1.7 :
4:
(2) Cold air prevention control
1 When the compressor is not operating,
(1) if the temperature of room temperature thermistor RT11 is less than 19°C, the fan stops.
(2) if the temperature of room temperature thermistor RT11 is 19°C or more and
(1) if the temperature of indoor coil thermistor is less than 0°C, the fan stops.
(2) if the temperature of indoor coil thermistor is 0°C or more, the fan operates at Very Low.
2 When the compressor is operating,
(1) if the temperature of indoor coil thermistor is 40°C or more, the fan operates at set speed.
(2) if the temperature of indoor coil thermistor is less than 40°C and
(1) if heating operation starts after defrosting, the fan stops.
(2) if the temperature of room temperature thermistor RT11 is 19°C or less, the fan stops.
(3) if the temperature of room temperature thermistor RT11 is more than 19°C, the fan operates at Very Low.
NOTE : When 3 minutes have passed since the compressor started operation, this control is released regardless of the
temperature of RT11 and indoor coil thermistor.
3. High pressure protection
In HEAT operation the indoor coil thermistor detects the temperature of the indoor heat exchanger. The compressor operational frequency is controlled to prevent the condensing pressure from increasing excessively.
4. Overload starting
When the room temperature thermistor RT11 reads 18°C or more (SUZ-KA25/35) / 25°C or more (SUZ-KA50) , the compressor runs with its maximum frequency regulated for 10 minutes after the start-up.
5. Defrosting
(1) Starting conditions of defrosting
When the following conditions a) ~ c) are satisfied, the defrosting starts.
a) The defrost thermistor reads -3°C or less.
b) The cumulative operation time of the compressor has reached any of the set valuesw [30, 35, 40, 45, 55, 65, 75, 85,
95, 105, 115, 125, 150 minutes (SUZ-KA25/35) / 31, 35, 45, 55, 65, 75, 85, 95, 105, 115, 150 minutes (SUZ-KA50)].
c) More than 5 minutes have passed since the start-up of the compressor.
w Set value of compressor operation time(hereinafter referred to as defrost interval)
This is decided by the temperature of defrost thermistor and ambient temperature thermistor, the previous defrosting
time. For example, the first defrost interval is 40 minutes long, and the second is 45 minutes long. The third and subsequent intervals are set to be longer, and less frequent, depending on defrosting time.
The third and subsequent defrost intervals follow any of the three patterns …5 or 10 to 20 minutes longer, the same,
or 5 or 10 to 20 minutes shorter compared with the previous defrost interval … with the longest 150 minutes and the
shortest 30 minutes.
(2) Releasing conditions of defrosting
Defrosting is released when any of the following conditions is satisfied:
a) The defrost thermistor continues to read 5°C or more (SUZ-KA25) / 10°C or more (SUZ-KA35) / 15°C or more (SUZKA50) for 30 seconds.
b) Defrosting time has exceeded 10 minutes.
c) Any other mode than HEAT mode is set during defrosting.
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Time chart of defrosting in HEAT mode (reverse type)
<indoor unit>
vertical
Horizontal vane
set position
Indoor fan (upper)
Indoor fan (lower)
set speed
set position
Very Low (temperature of indoor coil thermistor > 18:)
OFF
set speed
30
seconds
ON
ON
OFF
Damper
OPEN or CLOSE
OPEN or CLOSE
CLOSE
<outdoor unit>
Maximum frequency
Compressor normal
OFF
40
30
seconds seconds
Outdoor fan
OFF
40
seconds
5 seconds
30
seconds
ON
5 seconds
ON
OFF
R.V. coil
(21S4)
ON (HEAT)
ON (HEAT)
OFF (COOL)
NOTE : When the air outlet selection switch is set to blow out air from the upper air outlet only, the damper
is closed and the lower fan motor is OFF at all times.
3-4. AUTO CHANGE OVER ··· AUTO MODE OPERATION
Once desired temperature is set, unit operation is switched automatically between COOL and HEAT operation.
1. Mode selection
(1) Initial mode
At first indoor unit operates only indoor fan with outdoor unit OFF for 3 minutes to detect present room temperature.
Following the conditions below, operation mode is selected.
1 If the room temperature thermistor RT11 reads more than set temperature, COOL mode is selected.
2 If the room temperature thermistor RT11 reads set temperature or less, HEAT mode is selected.
(2) Mode change
In case of the following conditions the operation mode is changed.
1 COOL mode changes to HEAT mode when 15 minutes have passed with the room temperature 2 degrees below the
set temperature.
2 HEAT mode changes to COOL mode when 15 minutes have passed with the room temperature 2 degrees above the
set temperature.
In the other cases than the above conditions, the present operation mode is continued.
NOTE1: Mode selection is performed when multi standby (refer to NOTE2) is released and the unit starts operation with
ON-timer.
NOTE2: If two or more indoor units are operating in multi system, there might be a case that the indoor unit, which is
operating in AUTO (
), cannot change over the other operating mode (COOL
HEAT) and becomes a
state of standby.
(3) Indoor fan control/ Vane control
As the indoor fan speed and the horizontal vane position depend on the selected operation mode, when the operation
mode changes over, they change to the exclusive ones.
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3-5. INDOOR 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 (Super High, High,
Med., Low), the microprocessor 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.
Rotational frequency
Super High
Super High
High
Med.
Low
time
(2) Fan motor lock-up protection
When the rotational frequency feedback signal has not output for 12 seconds, (or when the microprocessor cannot
detect the signal for 12 seconds) energizing to the fan motor is stopped. Then the microprocessor retries detection 3
times every 30 seconds. If the microprocessor still cannot detect the signal, the fan motor is regarded locked-up. When
the fan motor lock-up, POWER lamp flashes on and off to show the fan motor abnormality.
3-6. OUTDOOR FAN MOTOR CONTROL
Fan speed is switched according to the compressor frequency.
Fan speed
Down
High
Up
Low
Min.
Compressor frequency
Max.
<Relation between compressor frequency and fan speed.>
Mode
COOL
HEAT
Fan speed
SUZ-KA25
Compressor frequency
SUZ-KA35
SUZ-KA50
Up
54Hz
43Hz
44Hz
Down
41Hz
33Hz
33Hz
Up
54Hz
43Hz
52Hz
Down
41Hz
33Hz
42Hz
3-7. AUTO VANE OPERATION
Horizontal vane
(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 (approximate 12V) transmitted from indoor microprocessor.
(2) The horizontal vane angle and mode change as follows by pressing VANE CONTROL button.
(3) Positioning
The vane presses the vane stopper once to confirm the standard position and then moves to the set angle.
Confirming of standard position is performed in case of follows.
(a) When the power supply turns on.
(b) When the operation starts or finishes (including timer operation).
(c) When the test run starts.
(d) When multi-standby starts or finishes.
(e) When the swing operation finishes.
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(4) VANE AUTO (
) mode
In VANE AUTO mode, the microprocessor automatically determines the vane angle and operation to make the optimum
room-temperature distribution.
(1) In COOL and DRY operation
1
1 2
Vane angle is fixed to Angle 1.
(2) In HEAT operation
3
4
5
4
When air comes out from upper
air outlet, vane angle is fixed to
Angle 4.
2
When air comes out from upper
and lower air outlets, vane angle
is fixed to Angle 2.
(5) STOP (operation OFF) and ON-TIMER standby
When the following cases occur, the horizontal vane returns to the closed position.
(a) When OPERATE/STOP (ON/OFF) button is pressed (POWER OFF).
(b) When the operation is stopped by the emergency operation.
(c) When ON-TIMER is ON standby.
(6) Dew prevention
During COOL or DRY operation with the vane angle at Angle 2 ~ 5 when the compressor cumulative operation time
exceeds 30 minutes to 1 hour, the vane angle automatically changes to Angle 1 for dew prevention.
(7) SWING MODE ( )
By selecting SWING mode with VANE CONTROL button, the horizontal vane swings vertically. The remote controller
displays “
”. SWING mode is cancelled when VANE CONTROL button is pressed once again.
(8) Cold air prevention in HEAT operation.
When any of the following conditions occurs in HEAT operation, the vane angle changes to Horizontal position 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 39:.
Indoor coil thermistor RT12 temperature
Horizontal vane
Set position
Released
Cold Air Prevention
24:
39:
Horizontal Position
NOTE : When 2 or more indoor units are operated with multi outdoor unit, even if any indoor unit turns thermostat off,
this control doesn’t work in the indoor unit.
NOTE : The horizontal vane automatically moves in certain intervals to determine its position, and then it returns to the
set position.
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(9) Damper operation
NOTE 1 : Be sure to turn off the air conditioner before changing the switch setting.
With this function, air comes out simultaneously from the upper and lower air outlets so that the room
can be cooled or heated effectively. This function is set using the switch behind the front grille of the
indoor unit. (This function is available in cooling and heating operation.)
1.How to set to blow out air from the upper
2.How to set to blow out air from the upper
and lower air outlets:
air outlet only:
Set the air outlet selection switch to
Set the air outlet selection switch to .
.
Air blows out automatically from the upper and lower air outlets as shown in the table below.
NOTE 2 : Set the air outlet selection switch to the end correctly. Otherwise, air outlet cannot be selected as intended.
Description of operation
The direction (opening and closing of the damper) and the volume of the airflow from the lower air
outlet are controlled automatically.
Operation
COOL
DRY
HEAT
Air
flow
Upper and lower air flow
Room temperature
and set temperature
Conditions are different.
Upper air flow
Upper air flow only Upper and lower air flow
Room temperature is
close to set temperature, or the air
conditioner has
operated for 1 hour.
Air flow temperature
is high.
Upper air flow
Air flow temperature
is low.
(During defrosting
operation, start of
operation, etc.)
• Be sure to keep the area around the damper of the lower air outlet free of any objects. If any objects block the normal
operation of the damper, the left operation indicator lamp may blink.
Indoor fan motor (Lower) in COOL OPERATION
Difference between room temperature and
set temperature during operation
Damper
Difference between
room temperature and
set temperature
during operation
OPEN
CLOSE
2:
7:
Indoor fan motor (Lower) in HEAT OPERATION
Indoor coil thermistor temperature
Damper
OPEN
Indoor coil thermistor
temperature
CLOSE
35:
40:
• As for indoor fan motor (upper), refer to "Indoor fan speed control (3-1.2, 3-2.2, 3-3.2)" and
"INDOOR FAN MOTOR CONTROL (3-5.)".
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(10) EMBEDDED INDOOR UNIT SETTING (MUST BE PERFORMED)
• When installing a grating, use a grating with narrow upper and lower horizontal bars so that the airflow from
the upper and lower air outlets does not contact the bars. If the horizontal bars will block the lower air outlet,
use a stand, etc., to adjust the height of the indoor unit. If the upper or lower air outlet is blocked, the air
conditioner will not be able to cool or warm the room well.
• Do not block the receiver with the grating. Otherwise, the grating will interfere with the remote controller
signal and significantly reduce the distance and area (angle) from which the signals can be received.
• Use a grating with vertical bars, etc., that has at least 75% open area. If the grating has horizontal bars or if
the open area is less than 75%, performance could be reduced.
• When the indoor unit is embedded in a wall (built-in), the time will inclease for the room temperature to reach the
set temperature.
100 or more
Upper air outlet
100 or more
Receiver
Indoor unit
Grating
100 or
more
65
65
475
14
52
26 60
Lower air outlet
20 to 35
EMBEDDED INDOOR UNIT SETTING (MUST BE PERFORMED)
• When embedding the indoor unit in a wall, restrict the movement of the horizontal vane for the upper air outlet
so that it only operates horizontally.
• If this setting is not performed, heat will build up in the wall and the room will not be cooled or warmed
properly.
• Cut the wires on the left and right sides of JRFBL using a pair of nippers, etc., as shown below.
Control board
Cut
JR24
JRFBL
Cut the wires on both ends.
Cut the JRFBL wires.
(11) ECONO COOL (
) operation (ECONOmical operation)
When 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(indoor coil thermistor).
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 ECONO COOL button is pressed once again or VANE CONTROL
button is pressed or change to other operation mode.
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<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 horizontal blow time is decided.
For initial 10 minutes the swing operation is performed in table G~H for quick cooling.
Also, after 10 minutes when the difference of set temperature and room temperature is more than 2:, the swing operation is performed in table D~H for more cooling.
The air conditioner repeats the swing operation in various cycle as follows.
Temperature of indoor
coil thermistor RT12
Downward blow time
(second)
Horizontal blow time
(second)
A
15°C or less
2
23
B
15°C to 17°C
5
20
C
17°C to 18°C
8
17
D
18°C to 20°C
11
14
E
20°C to 21°C
14
11
F
21°C to 22°C
17
8
G
22°C to 24°C
20
5
H
more than 24°C
23
2
3-8 i-save OPERATION
1.How to set i-save operation
To start i-save operation:
(1) Press OPERATE/STOP(ON/OFF) button to start the air conditioner.
i-save operation
(2) Press OPERATION SELECT button to select COOL or HEAT mode.
OPERATION INDICATOR lamp
i-save operation can only be set during cooling or heating operation
(Not available in dry operation or auto mode operation).
(3) Press i-save button.
The operation indicator lamp on the right side of the indoor unit lights in orange.
To set the temperature, fan speed, and air flow direction for i-save operation:
(1) Press the temperature buttons to set the desired temperature.
(Green ) : Lighted
(2) Press VANE CONTROL button to set the desired air flow direction.
(3) Press FAN SPEED CONTROL button to set the desired fan speed.
(Orange) : Lighted
The next time i-save button is pressed, the air conditioner starts operating
with the above settings for temperature, fan speed, and air flow direction.
To change the settings, repeat steps(1)–(3).
NOTE:
• ECONO COOL operation can be set together with COOL mode for i-save operation.
• Timer operation can be used even if i-save operation is set.
2. cancel
Press i-save button again.
i-save operation can also be cancelled by pressing OPERATION SELECT button to change the operation mode.
i-save operation has been successfully cancelled if the operation indicator lamp on the right side of the indoor unit turns
off or changes from orange to green.
Usage of i-save operation:
1.Using as a low-energy mode
i-save operation can be used as a low-energy mode by setting the temperature 2–3: warmer than the normal cooling
temperature or 2–3: cooler than the normal heating temperature. This is good to use if a room is unoccupied or while
you are sleeping.
■ Before leaving the room unoccupied:
• Press i-save button to switch to the low-energy mode before leaving the room.
• When you return to the room, the temperature will not be too hot or too cold.
• Press i-save button again and the air conditioner will operate with the normal settings for temperature, fan speed,
and air flow direction for a comfortable, air-conditioned environment.
■ Before sleeping:
• Before going to sleep, press i-save button, and then go to your bedroom.
• While you are sleeping, the room will be air-conditioned using the low-energy mode until the following morning.
• In the morning, press i-save button again, and the air conditioner will operate with the normal settings for temperature, fan speed, and air flow direction. The set room temperature will be obtained quicker than if the air conditioner was
stopped while you were sleeping.
2.Using as a mode for frequent settings
If you often switch between two groups of settings for temperature, fan speed, and air flow direction in the same operation
mode, save one group of settings using i-save button. This will allow you to select the desired group of settings simply
by pressing i-save button, avoiding the troublesome remote controller operations.
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3-9. 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.
ON timer setting
START
(1) Press ON-TIMER button(
) to set ON timer.
Each time the button is pressed, ON timer mode alternates between ON and OFF.
(2) Set the time of the timer using TIME SET buttons (
and
).
Each time FORWARD button(
) is pressed, the set time increases by 10 minutes; each time BACKWARD
button (
) is pressed, the set time decreases by 10 minutes.
OFF timer setting
STOP
(1) Press OFF-TIMER button (
) to set OFF timer.
Each time the button is pressed, OFF timer mode alternates between ON and OFF.
(2) Set the time of the timer using TIME SET buttons (
and
).
Each time FORWARD button (
) is pressed, the set time increases by 10 minutes; each time BACKWARD (
button is pressed, the set time decreases by 10 minutes.
)
2. Cancel
TIMER setting can be cancelled with ON/OFF TIMER
buttons.
START
To cancel ON timer, press ON-TIMER button (
).
STOP
To cancel OFF timer, press OFF-TIMER button(
).
TIMER is cancelled and the display of set time disappears.
PROGRAM TIMER
• The OFF timer and ON timer can be used in combination. The timer of the set time that is reached first will operate first.
• “ ” and “ ” display shows the order of the OFF timer and the ON timer operation.
(Example 1) The current time is 8:00 PM.
(Example 2) The current time is 11:00 AM.
The unit turns off at 11:00 PM, and on at 6:00 AM.
The unit turns on at 5:00 PM, and off at 9:00 PM.
NOTE : If the main power is turned off or a power failure occurs while AUTO START/STOP timer is active, the timer setting is
cancelled. As these models are equipped with an auto restart function, the air conditioner starts operating with timer
cancelled when power is restored.
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3-10. EMERGENCY / TEST OPERATION
In case of test run operation or emergency operation, use 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 the remote
controller run down. The unit will start and 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 in ON).
After 30 minutes of test run operation the system shifts to EMERGENCY COOL / HEAT MODE with a set temperature of
24°C. The fan speed shifts to Med.
The coil frost prevention works even in emergency operation, and defrosting too.
In the test run or emergency operation, the horizontal vane operates in VANE AUTO (
) mode.
Emergency operation continues until EMERGENCY OPERATION switch is pressed once or twice or the unit receives any
signal from the remote controller. In case of latter normal operation will start.
NOTE : Do not press EMERGENCY OPERATION switch during normal operation.
Operation mode
Set temperature
Fan speed
E.O.
SW
EMERGENCY OPERATION switch
Horizontal vane
COOL
HEAT
24:
24:
Medium
Medium
Auto
Auto
• The following indication does not depend on the
shape of lamp.
OPERATION INDICATOR lamp
Lighted
Press once <Cool>
Not lighted
Press again <Heat>
Press once again <Stop>
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4
Page 62
MXZ MICROPROCESSOR CONTROL
MXZ-2A52VA MXZ-4A71VA
MXZ-3A54VA MXZ-4A80VA
4-1. INVERTER SYSTEM CONTROL
4-1-1. MXZ-2A52VA
4-1-1-1. Inverter main power supply circuit
POWER P.C. BOARD
L61
L62
INVERTER P.C. BOARD
CT61
X64
L64
DB61
Power
supply
R64A R64B
U
P
+ C63A
C63B
V
C63C
N
W
CT761
U
W
IPM CT781
MC
V
TR821
DB65
Booster chopper circucuit
Function of main parts
NAME
SYMBOL
IPM
INTELLIGENT POWER MODULE
FUNCTION
It supplies three-phase AC power to compressor.
C63A/C63B/C63C SMOOTHING CAPACITOR
It stabilizes the DC voltage.
CT761/CT781 CURRENT TRANSFORMER
It measures the current of the compressor motor.
CT61
CURRENT TRANSFORMER
DB61
DIODE MODULE
R64A, R64B CURRENT-LIMITING RESISTOR
It measures the value of current which is supplied to the main power
supply circuit.
It converts the AC voltage to DC voltage.
It absorbs the rush current not to run into the main power supply circuit
when the electricity turns ON.
It short-circuits the resistance which restricts rush current during the
X64
RELAY
DB65
DIODE MODULE
Booster
TR821
SWITCHING POWER TRANSISTOR
chopper
L64
REACTOR
circuit
normal operation after the compressor startup.
It improves power factor.
It rectifies AC and controls its voltage.
4-1-1-2. Outline of main power supply circuit
1. At the start of operation
Main power supply circuit is formed when X64 (Relay) is turned ON at compressor startup.
To prevent rush current from running into the circuit when power supply is turned ON,
R64A and R64B (Current-limitting resistor) are placed in sub circuit.
2. At normal operation
1 When AC runs into POWER P.C. board, its external noise is eliminated in the noise filter circuit.
2 After noise is eliminated from AC, it is rectified to DC by DB61 (Diode module).
3 DC voltage, to which AC has been rectified by process 2, is stabilized by C63A, C63B and C63C (Smoothing capacitor)
and supplied to IPM (Intelligent power module).
4 DC voltage, which has been stabilized in process 3, is converted to three-phase AC by IPM and supplied to
compressor.
5 CT761 and CT781 (Current Transformer), which are placed in the power supply circuit to compressor, are used to
measure the value of phase current and locate the polar direction of rotor with algorithm. PWM (Pulse width modulation)
controls impressed voltage and frequency with those information.
3. Purpose of PAM adoption
PAM : Pulse Amplitude Modulation
PAM has been adopted for the efficiency improvement and the adaptation to IEC harmonic current emission standard.
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Outline of simple partial switching method
In conventional inverter models, diode module rectifies AC voltage to DC voltage, smoothing capacitor makes its DC waveform
smooth, and IPM converts its DC voltage to imitated AC voltage again in order to drive the compressor motor.
However, it has been difficult to meet IEC harmonic current emission standard by above circuit because harmonic gets
generated in the input current waveform and power factor gets down. The simple partial switching method with PAM, which has
been adopted this time, places and utilizes the booster chopper circuit (L64, DB65 and TR821) before rectifying AC voltage in
the general passive-method converter circuit. As harmonic gets suppressed and the peak of waveform gets lower by adding
booster chopper circuit as mentioned above and by synchronizing the timing of switching with the zero-cross point of
waveform, the input current waveform can be improved and the requirement of IEC harmonic current emission standard can be
satisfied. Since the switching times is twice by synchronizing with the zero cross point, this simple partial switching method
has the feature of lower energy loss compared to active filter method. In addition, output and efficiency is enhanced by
combining with vector-controlled inverter in order to boost the voltage of power supplied to IPM.
Input current waveform without PAM
Due to the time of no electricity;
· Power factor gets worse.
· Harmonic gets increased.
Input voltage
Input current
Input current waveform with PAM
Owing to the increase of energized time;
· Power factor gets better.
· Harmonic gets suppressed.
Release of energy stored in L
Peak gets down.
Energized time is
extended by optimization
of L inductance.
Energized time is short in
case L inductance is small.
No electricity runs into
diode module because the
voltage at both sides of smoothing
capacitor is higher than input voltage.
Compulsory energizing
by switching.
4. Intelligent power module
IPM consists of the following components
· IGBT (x6)
: Converts DC waveform to three-phase AC waveform and outputs it.
· Drive Circuit
: Drives transistors.
· Protection circuit
: Protects transistors from overcurrent.
Since the above components are all integrated in IPM, IPM has a merit to make the control circuit simplify and miniaturize.
5. Smoothing capacitor
C63A, C63B and C63C stabilize the DC voltage and supply it to IPM.
6. Elimination of electrical noice
Noise filter circuit, which is formed by *CMC COILS capacitors placed on the POWER P.C. board, eliminates electrical
noise of AC power that is supplied to main power supply circuit. And this circuit prevents the electrical noise generated in
the inverter circuit from leaking out.
*CMC COILS; Common mode choke coils
Sine wave control
In these air conditioners, compressor equips brushless DC motor which doesn't have Hall element.
In short, the motor is sensorless. However, it's necessary to locate the polar direction of rotor in order to drive brushless DC
motor efficiently. The general detection method of the polar direction for such a DC motor is to locate it from the voltage induced
by unenergized stator.
Therefore, It is necessary to have a certain period of time in which the stator is being unenergized for the rotor position
detection when the voltage of supplied power is impressed.
So the motor has been driven by square wave control (the conventional motor drive system) which energizes the motor only
when the range of electrical angle is within 120_ because it is forced to be unenergized within 30_ at start & end of one heap
in one waveform cycle (180_) when the voltage is impressed.
However, torque pulsation occurs at rotation in this method when the current-carrying phases are switched over to other
phases in sequence. Therefore, sine wave control system is adopted for these air conditioners because it can make the
phase-to-phase current waveform smoother (sine wave) in order to drive the motor more efficiently and smoothly.
4-1-1-3. Characteristics of sine wave control in case of brushless DC motor
● Although ordinary three-phase induction motor requires energy to excite the magnetic field of rotor, brushless DC motor
doesn't need it. So, higher efficiency and torque are provided.
● This control provides the most efficient waveform corresponding to the rotation times of compressor motor.
● The rotation can be set to higher compared to the conventional motor drive system. So, the time in which air conditioner
can be operated with energy saved is longer than conventional models. This can save annual electric consumption.
● Compared to square wave control, the torque pulsation is reduced at rotation so that the motor operates more quietly.
● Since response and efficiency of motor are enhanced in sine wave control, finer adjustment can be provided.
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Rotor
DC Motor
Permanent magnet is embedded.
AC Motor
Excited by magnetic field of stator
Rotor Position Signal
Necessary
Unnecessary
w In brushless DC motor, permanent magnet is embedded in the rotor. Therefore, it doesn't require energy to excite the rotor
like AC motor does. However, it's necessary to control the frequency of three-phase AC current supplied to the stator
according to the polar direction of magnet embedded in the rotor so as to drive the motor efficiently. Controlling three-phase
AC current frequency also means controlling the timing to switch the polarity of stator. Therefore, the polar direction of rotor
needs to be detected.
4-1-1-4. Control Method of Rotation Times
Sine wave control makes the current transformers conduct real time detection of the value of the current running into the motor,
locates the rotor position from the detected value, and decides if voltage should be impressed and if frequency should be changed.
Compared to the conventional control and rotor position detection method, sine wave control can provide finer adjustment of the
voltage of supplied power. The value of the current running into the motor is determined by each motor characteristic.
4-1-2. MXZ-3A54VA
MXZ-4A71/80VA
4-1-2-1. Iverter main power supply circuit
POWER BOARD
NOISE FILTER P. C. BOARD
R64A/R64B
V
L
CT1
U
POWER
SUPPLY
N/F
CT61
X64
PFC
MC
U
+CB1
CB2
CB3
W
IPM
V
CT2
W
Function of main parts
SYMBOL
FUNCTION
NAME
IPM
INTELLIGENT POWER MODULE
It supplies three-phase AC power to compressor.
CB1~3
SMOOTHING CAPACITOR
It stabilizes the DC voltage.
CT1~2
CURRENT TRANSFORMER
It measures the current of the compressor motor.
CT61
CURRENT TRANSFORMER
It measures the current of the main power supply circuit.
L
REACTOR
It rectifies AC, controls its voltage and improves the power factor of
PFC
POWER FACTOR CONTROLLER
power supply.
R64A, R64B CURRENT-LIMITING RESISTOR
X64
RELAY
It restricts rush current with the resistance.
It short-circuits the resistance which restricts rush current during the
compressor operates.
4-1-2-2. Outline of main power supply circuit
1. At the start of operation
Main power supply circuit is formed when X64 (Relay) is turned ON at compressor startup.
To prevent rush current from running into the circuit when power supply is turned ON, R64A and R64B
(Current-limiting resistor) are placed in sub circuit.
2. At normal operation
1 When AC runs into noise filter P.C. board, its external noise is eliminated in the noise filter circuit.
2 After noise being eliminated from AC, it is rectified to DC by L (Reactor) and PFC (Power factor controller). If the operating
frequency becomes 25Hz or more, DC voltage rises to 370V.
3 DC voltage, to which has AC been rectified by process 2, is stabilized by CB1~3 (Smoothing capacitor) and supplied to
IPM (Intelligent power module).
4 The DC (Bus voltage), which has been stabilized in process 3, is converted to three-phase AC by IPM and supplied to
compressor.
5 CT1 and CT2 (Current Transformer), which are placed in the power supply circuit to compressor, are used to measure the
value of phase current and locate the polar direction of rotor with algorithm. PWM (Pulse width modulation) controls impressed voltage and frequency with those information.
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3. Power factor improvement
Booster coil L (Reactor) and PFC rectify AC to DC and control its voltage.
In the motor drive system of sine wave control, power factor can be improved by reducing harmonics PFC and L (Reactor)
stabilize the voltage of DC supplied to inverter circuit and make its waveform smooth.
4. Power transistor module
IPM consists of the following components.
· Power Transistors (x6): Converts DC waveform to three-phase AC waveform and outputs it.
· Drive Circuit
: Drives transistors.
· Protection circuit
: Protects transistors from over current.
Since the above components are all integrated in IPM, IPM has a merit that can get the control circuit simplified and miniaturized.
5. Smoothing capacitor
CB1, CB2 and CB3 stabilize the DC voltage and supply it to IPM.
6. Elimination of electrical noise
Noise filter circuit, which is formed by *CMC COILS and capacitors placed on the noise filter P.C. board, eliminates electrical
noise of AC power that is supplied to main power supply circuit. In short, common mode noise is absorbed in this circuit.
Moreover, normal mode noise is absorbed in another noise filter circuit which is formed by *NMC COILS and capacitors.
Both noise filter circuit exists for preventing the electrical noise generated in the inverter circuit from leaking out.
*CMC COILS; Common mode choke coils
*NMC COILS; Normal mode choke coils
4-1-2-3. Sine wave control
In these air conditioners, compressor equips brushless DC motor which doesn't have Hall element.
In short, the motor is sensorless. However, it's necessary to locate the polar direction of rotor in order to drive brushless DC
motor efficiently. The general detection method of the polar direction for such a DC motor is to locate it from the voltage induced
by unenergized stator.
Therefore, it is necessary to have a certain period of time in which the stator is being unenergized for the rotor position
detection when the voltage of supplied power is impressed.
So the motor has been driven by square wave control (the conventional motor drive system) which energizes the motor only
when the range of electrical angle is within 120_ because it is forced to be unenergized within 30_ at start & end of one heap
in one waveform cycle (180_) when the voltage is impressed.
However, torque pulsation occurs at rotation in this method when the current-carrying phases are switched over to other
phases in sequence. Therefore, sine wave control system is adopted for these air conditioners because it can make the
phase-to-phase current waveform smoother (sine wave) in order to drive the motor more efficiently and smoothly.
4-1-2-4. Characteristics of sine wave control in case of brushless DC motor
● Although ordinary three-phase induction motor requires energy to excite the magnetic field of rotor, brushless DC motor
doesn't need it. So, higher efficiency and torque are provided.
● This control provides the most efficient waveform corresponding to the rotation times of compressor motor.
● The rotation can be set to higher compared to the conventional motor drive system. So, the time in which air conditioner
can be operated with energy saved is longer than conventional models. This can save annual electric consumption.
● Compared to square wave control, the torque pulsation is reduced at rotation so that the motor operates more quietly.
● Since response and efficiency are enhanced in sine wave control, finer adjustment can be provided.
Rotor
DC Motor
Permanent magnet is embedded.
AC Motor
Excited by magnetic field of stator
Necessary
Unnecessary
Rotor Position Signal
w In brushless DC motor, permanent magnet is embedded in the rotor. Therefore, it doesn't require energy to excite the rotor
like AC motor does. However, it's necessary to control the frequency of three-phase AC current supplied to the stator
according to the polar direction of magnet embedded in the rotor so as to drive the motor efficiently. Controlling three-phase
AC current frequency also means controlling the timing to switch the polarity of stator. Therefore, the polar direction of rotor
needs to be detected.
4-1-2-5. Control Method of Rotation Times
Sine wave control makes the current transformers conduct real time detection of the value of the current running into the motor,
locates the rotor position from the detected value and decides if voltage should be impressed and if frequency should be changed.
Compared to the conventional control and rotor position detection method, sine wave control can provide finer adjustment of the
voltage of supplied power. The value of the current running into the motor is determined by each motor characteristic.
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4-2. EXPANSION VALVE CONTROL (LEV CONTROL)
Linear expansion valve (LEV) is controlled by "Thermostat ON" commands given from each unit.
LEV opening
Indoor unit status
Stop of all indoor unit
Opening before stop ➝ 500 pulse in 15 minutes
When outdoor unit is operating,
some indoor units stop and
some operate.
COOL : 5 pulse (full closed)
HEAT (MXZ-2A) : 59 pulse (slightly opened)
(MXZ-3A/4A) :140 pulse (slightly opened)
Thermostat OFF in
COOL or DRY mode
When the outdoor unit operates (When the other indoor unit operates): 5 pulse.
When outdoor unit stops. (When the other indoor unit stops or thermo off):
Maintain LEV opening before stop ➝ 500 pulse in 15 minutes
Thermostat ON in
COOL or DRY mode
• LEV opening for each indoor unit is determined by adding adjustment in accordance
with the number of operating unit and the capacity class to standard opening, based
on the operation frequency:
Ex.) Opening 130 pulse in standard opening 1 ➝ Minimum 80 pulse, Maximum 205
pulse. (Capacity code 4 at 1 unit operation) (Capacity code 1 at 4 units operation)
• After starting operation, adjustment in accordance with intake super heat, discharge
temperature is included in standard opening. w1
Note: LEV opening in each frequency at DRY operation and COOL operation is the
same. However, velocity and compressor operation frequency controls are
different. See 2-3. OPERATIONAL FREQUENCY RANGE
(As far as the indoor unit velocity control goes, refer to DRY operation in
MICROPROCESSOR CONTROL in indoor unit.)
• When the outdoor unit operates. (When the other indoor unit operates): 59 pulse
(MXZ-2A), 140pulse (MXZ-3A/4A).
Thermostat OFF in HEAT mode • When the outdoor unit stops. (When the other indoor unit stops or thermo off):
Maintain LEV opening before stop ➝ 500 pulse in 15 minutes.
Thermostat ON in HEAT mode
• LEV opening for each indoor unit is determined by adding adjustment in accordance
with the number of operating unit and the capacity class to standard opening, based
on the operation frequency:
Ex.) Opening 120 pulse in standard opening 1 ➝ Minimum 70 pulse, Maximum 165
pulse. (Capacity code 4 at 1 unit operation) (Capacity code 1 at 4 units operation)
• After starting operation, opening becomes the one that adjustment in accordance
with discharge temperature was added to basic opening. w1
w1 LEV opening when the outdoor unit is operating: Upper limit 500 pulse, Lower limit 59 pulse(MXZ-2A),
53pulse (MXZ-3A/4A).
Determination of LEV standard opening in each indoor unit
• The standard opening is on the straight line, which connects an each standard point in the section where divided
into seven according to the operation frequency of compressor as shown in the figure below.
(LEV opening is controlled in proportion to the operation frequency.)
Note: Opening is adjusted at the standard opening according to the indoor unit conditions.
However, inclination of standard opening in each point of opening does not change with the original curve.
• Add opening provided in Difference in Capacity in the table below to the standard opening from 1 to 8,
when capacity of the indoor unit is excluding code 1.
• Add opening provided in Difference in Operation number in the table below to determined LEV opening for
each indoor unit, when 2, 3 or 4 indoor units are operated at the same time.
Note: Even when the adjusted standard opening exceeds the driving range from 59 to 500 pulse, actual
driving output opening is in a range from 59 to 500 pulse.
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MXZ-3A/4A
The table below shows the role of Exclusive LEV and Receiver LEV in each operation mode.
High
Circulation
Discharge
Capacity
Pressure
Amount
Temperature
Distribution
Protection
Control
Protection
COOL Exclusive LEV
Receiver LEV
Exclusive LEV
HEAT Receiver LEV
Indoor heat
exchanger
Exclusive
LEV
wEvaporation
Temperature
Protection
Outdoor
heat
exchanger
Receiver
Receiver
LEV
(MXZ-4A71VA, MXZ-4A80VA)
wIn COOL mode, the two indoor coil thermistor (one main and one sub) sense temperature ununiformity (super heat) at the
heat exchanger, and when temperature difference have developed, the indoor coil thermistors adjust LEV opening to diminish the super heat.This action is called Evaporation Temperature Protection.
The opening pulse of the Receiver LEV is fixed to the standard No.3 in cooling operation, and so is that of each Exclusive
LEV in heating operation.
However the opening pulse will be changed to the standard No.4 or No.5 when the discharge temperature protection or highpressure protection is working.
In addition to that, it will also be changed to standard No.2 or No.1 when the opening pulse of the each Exclusive LEV
becomes 100 pulse or less in cooling operation or so does that of Receiver LEV in heating operation.
<MXZ-3A54VA
MXZ-4A71VA>
Number of
operating
indoor units
Standard No.
1
2
3
4
5
LEV opening (pulse)
COOL
HEAT
1 unit
2 units
3 units
4 units
(MXZ-4A71VA)
1 unit
2 units
3 units
(MXZ-4A71VA)
4 units
200
300
400
450
500
150
320
360
410
500
250
320
370
420
500
250
320
380
430
500
120
140
160
220
280
120
140
160
220
280
120
140
160
220
280
120
140
160
220
280
<MXZ-4A80VA>
Number of
operating
indoor units
Standard No.
1
2
3
4
5
LEV opening (pulse)
COOL
HEAT
1 unit
2 units
3 units
4 units
1 unit
2 units
3 units
4 units
150
250
350
400
450
250
320
360
410
460
250
320
370
420
470
250
320
380
430
480
250
300
450
460
470
250
300
380
400
450
250
300
380
390
440
240
290
380
390
430
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LEV Opening (code)
4Hz
10
09
08
07
06
05
04
03
02
01
8
5
23
14
38
23
54
32
69
41
84 100 115 131 146 MXZ-2A/3A/4A71VA
50 59 68 77 86 MXZ-4A80VA
Compressor operating frequency (Hz)
MXZ-2A52VA
LEV Opening(code) 01
COOL
240
HEAT
200
02
260
220
03
280
250
Standard opening (pulse)
04
05
06
07
300 330 350 370
280 300 320 340
08
390
360
09
400
380
10
410
400
Difference in capacity
Code3,4
10
5
COOL
HEAT
MXZ-3A54VA
Code7,8
30
15
Code5,6
20
10
Difference in operation number
2
-60
-100
MXZ-4A71VA
Standard opening (pulse)
LEV Opening(code) 01
COOL
120
HEAT
100
02
130
110
03
136
120
04
146
130
05
156
146
06
160
160
07
170
170
08
180
180
09
190
190
10
200
200
Difference in capacity
COOL
HEAT
Difference in operation number
Code3,4 Code5,6 Code7,8 Code9,10 Code11,12 Code13,14 Code15or above
9
3
6
12
15
25
35
9
3
6
52
55
65
75
2
-20
0
3
-30
0
4
-40
0
MXZ-4A80VA
Standard opening (pulse)
LEV Opening(code) 01
COOL
126
HEAT
140
02
130
146
03
134
150
04
138
170
05
140
180
06
142
200
07
182
224
08
228
244
09
296
272
10
310
280
Difference in capacity
COOL
HEAT
Capacity code
Indoor unit
capacity(kw)
Code3,4 Code5,6 Code7,8 Code9,10 Code11,12 Code13,14 Code15or above
12
9
3
6
15
25
35
52
9
3
6
55
65
75
3
4
7
10
12
13
2.2
2.5
3.5
5.0
6.0
7.1
68
Difference in operation number
2
-20
0
3
-30
0
4
-40
0
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<Correction>
1 Discharge temperature
2 Each correction
• (Each gas pipe temperature thermistor - Minimum gas pipe temperature thermistor)w 1
• (Main indoor coil thermistor - Sub indoor coil thermistor)
COOL
DRY
HEAT
•
•
•
•
•
w2
w2
-
w 1 Perform this, when number of operation units is 2 units or more.
MXZ-2A52VA is excluded.
w 2 Correct the LEV opening by discharge temperature.
(1) LEV opening correction by discharge temperature
The target discharge temperature is determined according to frequency zone and number of operation unit of the
compressor.
MXZ-2A52VA
Target discharge temperature (:)
Operation frequency
of compressor (Hz)
Minimum ~ 23
24 ~ 38
39 ~ 54
55 ~ 69
70 ~ 85
86 ~ 100
101 ~ Maximum
COOL
Number of operating unit
2 units
1 unit
60
56
61
69
64
59
67
60
67
61
69
62
70
63
HEAT
Number of operating unit
2 units
1 unit
51
57
58
63
64
69
71
75
77
80
83
86
90
90
MXZ-3A54VA MXZ-4A71VA
Operation frequency
of compressor (Hz)
Minimum ~ 23
24 ~ 38
39 ~ 54
55 ~ 69
70 ~ 85
86 ~ 100
101 ~ Maximum
Target discharge temperature (:)
COOL
HEAT
Number of operating unit
Number of operating unit
3 units
2 units
1 unit
4 units
3 units
2 units
1 unit
4 units
50
50
50
50
62
62
58
55
55
55
50
56
65
65
60
60
60
60
56
60
70
70
65
62
60
60
60
60
70
70
68
68
60
60
60
60
72
72
70
70
60
60
60
60
72
72
70
70
60
60
60
60
72
72
70
70
MXZ-4A80VA
Operation frequency
of compressor (Hz)
Minimum ~ 14
15 ~ 23
24 ~ 32
33 ~ 41
42 ~ 50
51 ~ 59
60 ~ 68
69 ~ 77
78 ~ 86
87 ~ Maximum
Target discharge temperature (:)
COOL
HEAT
Number of operating unit
Number of operating unit
3 units
2 units
1 unit
4 units
3 units
2 units
1 unit
4 units
50
50
62
52
59
57
55
55
55
55
66
58
60
57
55
55
60
60
74
65
65
63
58
55
67
67
78
68
67
65
60
60
72
72
78
68
72
70
65
65
76
76
78
68
74
73
68
68
76
76
78
68
75
75
70
70
76
76
78
68
80
80
73
75
76
76
78
68
84
82
75
75
76
76
78
78
84
82
80
75
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Correct the LEV opening according to the difference between target discharge temperature and discharge temperature.
MXZ-2A52VA
LEV opening
correction (pulse)
Discharge temperature (:)
More than Target discharge temperature+10
Target discharge temperature+10 to Target discharge
Target discharge temperature+5 to Target discharge
Target discharge temperature+2 to Target discharge
Target discharge temperature-2 to Target discharge
Target discharge temperature-5 to Target discharge
Target discharge temperature-10 or less
MXZ-3A54VA
temperature+5
temperature+2
temperature-2
temperature-5
temperature-10
COOL
5
4
2
0
-1
-3
-4
HEAT
8
3
1
0
-1
-2
-3
MXZ-4A71VA
LEV opening
correction (pulse)
Discharge temperature (:)
More than Target discharge temperature+10
Target discharge temperature+10 to Target discharge
Target discharge temperature+5 to Target discharge
Target discharge temperature+2 to Target discharge
Target discharge temperature-2 to Target discharge
Target discharge temperature-5 to Target discharge
Target discharge temperature-10 or less
temperature+5
temperature+2
temperature-2
temperature-5
temperature-10
COOL
5
4
2
0
-1
-3
-4
HEAT
8
3
1
0
-1
-2
-3
MXZ-4A80VA
LEV opening
correction (pulse)
Discharge temperature (:)
More than Target discharge temperature+12
Target discharge temperature+12 to Target discharge
Target discharge temperature+5 to Target discharge
Target discharge temperature+3 to Target discharge
Target discharge temperature-3 to Target discharge
Target discharge temperature-5 to Target discharge
Target discharge temperature-12 or less
temperature+5
temperature+3
temperature-3
temperature-5
temperature-12
COOL
4
2
1
0
-1
-3
-8
HEAT
6
2
1
0
-1
-2
-8
(2) Separate correction (COOL,DRY)
(Correction by the separate super heat)
a) Correct the LEV separately by temperature difference between each gas pipe temperature and the minimum gas pipe
temperature of all.
1 Calculate each super heat of the unit from the expression below;
(Super heat) = (Each gas pipe temperature) - (Minimum gas pipe temperature)
2 Separate correction is performed according to each super heat in the table below.
MXZ-3A54VA MXZ-4A71VA
MXZ-4A80VA
Superheat
LEV opening
correction (pulse)
Superheat
LEV opening
correction (pulse)
more than 9
6 to 9
3 to 6
3 or less
3
2
1
0
more than 9
6 to 9
3 to 6
3 or less
12
8
4
0
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b) Correct the LEV separately by temperature difference “
RT
LEV opening
correction (pulse)
6[ RT
4[ RT< 6
RT<4
2
1
0
RT” between main/sub indoor coil thermistor.
In addition, decrease the target discharge temperature corresponding
RT
Temperature to be
decreased (:)
6[ RT
4[ RT< 6
RT<4
-10
-5
-5
RT.
4-3. OPERATIONAL FREQUENCY RANGE
MXZ-2A52VA
Number of
operating
unit
Capacity
code
1, 2, 3, 4
5, 6
7
2, 3, 4, 5, 6, 7
8, 9, 10
11, 12, 13
14
1
2
MXZ-3A54VA
Number of
operating
unit
1
2
3
4
COOL (Hz)
Min.
Max.
20
65
20
65
20
65
20
100
20
100
20
100
30
100
DRY
(Hz)
25
25
30
75
75
75
75
Min.
30
30
30
30
30
30
30
HEAT (Hz)
Max.
Defrost
63
63
63
63
63
63
100
100
100
100
100
100
100
100
MXZ-4A71VA
Capacity
code
1, 2, 3, 4
5, 6
7, 8
9, 10
11, 12
13, 14
15 or above
2, 3, 4, 5, 6, 7
8, 9, 10
11, 12, 13
14, 15, 16
17, 18, 19, 20, 21
22, 23, 24 or above
3, 4, 5, 6, 7, 8, 9, 10
11, 12, 13, 14, 15
16, 17, 18, 19, 20
21, 22, 23, 24, 25
26, 27, 28, 29
30 or above
4, 5, 6, 7, 8, 9, 10
11, 12, 13, 14, 15
16, 17, 18, 19, 20
21, 22, 23, 24, 25
26, 27, 28, 29, 30
31, 32, 33, 34, 35
36 or above
COOL (Hz)
Min.
Max.
20
65
20
65
20
65
20
100
20
100
20
100
30
100
30
105
30
105
30
105
30
105
DRY
(Hz)
25
25
30
75
75
75
75
52
52
52
52
Min.
30
30
30
30
30
30
30
58
58
58
58
HEAT (Hz)
Max.
Defrost
63
63
63
63
63
63
100
100
100
100
100
100
100
100
100
100
100
100
100
100
112
100
30
105
100
58
112
100
40
105
105
66
112
100
40
105
105
66
112
100
52
105
105
88
112
100
52
105
105
88
112
100
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MXZ-4A80VA
Number of
operating
unit
1
2
3
4
Capacity
code
1, 2, 3, 4
5, 6
7, 8
9, 10
11, 12
13, 14
15 or above
2, 3, 4, 5, 6, 7
8, 9, 10
11, 12, 13
14, 15, 16
17, 18, 19, 20, 21
22, 23, 24 or above
3, 4, 5, 6, 7, 8, 9, 10
11, 12, 13, 14, 15
16, 17, 18, 19, 20
21, 22, 23, 24, 25
26, 27, 28, 29
30 or above
4, 5, 6, 7, 8, 9, 10
11, 12, 13, 14, 15
16, 17, 18, 19, 20
21, 22, 23, 24, 25
26, 27, 28, 29, 30
31, 32, 33, 34, 35
36 or above
COOL (Hz)
Min.
Max.
15
58
15
58
15
58
15
62
15
62
15
62
15
65
24
80
24
80
24
80
24
80
DRY
(Hz)
20
20
25
44
44
44
44
31
31
31
31
Min.
22
22
22
22
22
22
22
35
35
35
35
HEAT (Hz)
Max.
Defrost
37
37
37
37
37
37
90
80
90
80
90
80
90
80
58
58
58
58
90
80
94
80
24
80
59
35
94
80
52
90
65
39
94
80
52
90
65
39
94
80
63
94
65
52
94
80
63
94
65
52
94
80
4-4. HEAT DEFROSTING CONTROL
(1) Conditions to enter defrosting mode
1. When temperature of defrosting thermistor is -3: or less.
2. When specified non-defrosting time, is counted in the control p.c. board is satisfied.
(Total time of compressor operating)
Going to defrosting mode at both condition of 1 and 2.
(2) Defrosting operation
1. Compressor stops for 50 seconds, Indoor fan is off, Defrosting lamp lights.
2. 4-way valve reverses flow, Compressor operates by the frequency in heat defrosting control.
3. After compressor stops for 35 seconds, 4-way valve reverses flow, then defrosting finishes.
(3) Conditions to finish defrosting mode
1. When the defrosting thermistor temperature is 13.2: or more.
2. When it has spent 10 minutes for defrosting.
Defrosting finishes at condition of 1 or 2.
4-5. DISCHARGE TEMPERATURE PROTECTION CONTROL
This protection controls the compressor ON/OFF and operation frequency according to temperature of the discharge
temperature thermistor.
(1) Compressor ON/OFF
When temperature of the discharge temperature thermistor exceeds 116:, the control stops the compressor.
When temperature of the discharge temperature thermistor is 80: or less, the controls starts the compressor.
(2) Compressor operation frequency
When temperature of the discharge temperature thermistor is expected to be higher than 116:, the control decreases 12Hz
from the current frequency.
When temperature of the discharge temperature thermistor is expected to be higher than 111: and less than 116:, the control decreases 6Hz from the current frequency.
When temperature of the discharge temperature thermistor is expected to be higher than 104: and less than 111:, the control is set at the current frequency.
4-6. REFRIGERANT RECOVERY CONTROL ON HEATING
MXZ-2A52VA
<Control status>
The control performs when the all the following status are satisfied;
• When one or more indoor units are operating in HEAT mode. (Excluding thermostat OFF)
• When discharge temperature becomes 107: or more.
• When it passed 60 minutes or more since the operation has started or the last refrigerant recovery has controlled.
<Control details>
LEV opening of indoor unit not operating is controlled to be 80 pulse.
<Control finish status>
The control finishes either as follows. However, the LEV opening is considered to be 59 pulse.
• When it passed 60 seconds since the control has started.
• When the discharge temperature is 90: or less.
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4-7. OUTDOOR FAN CONTROL
Fan speed is switched according to the number of operating indoor unit and the compressor frequency.
Fan speed
Down
High
Up
Low
Min.
Compressor frequency
Max.
<Relation between compressor frequency and fan speed.>
Mode
COOL
HEAT
Fan speed Compressor frequency
Up
40Hz
Down
30Hz
Up
40Hz
Down
30Hz
Note
• When the indoor coil thermistor is 57: or more on HEAT operation, fan speed is fixed to Low speed.
Or, the indoor coil thermistor is 45: or less on HEAT operation, fan speed is back to normal.
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Page 74
HEAD OFFICE: TOKYO BLDG.,2-7-3, MARUNOUCHI, CHIYODA-KU, TOKYO100-8310, JAPAN
C Copyright 2005 MITSUBISHI ELECTRIC ENGINEERING CO.,LTD
Distributed in Jan. 2006. No. OBT14 REVISED EDITION-A 7
Distributed in Aug. 2005. No. OBT14 8
Made in Japan
New publication, effective Jan. 2006
Specifications subject to change without notice.
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