Mitsubishi MSZ-FA-VA, MSZ-GA-VA, MUZ-GA-VA, MFZ-KA-VA, MUZ-FA-VA Service Technical Manual

SPLIT-TYPE, HEAT PUMP AIR CONDITIONERS FLOOR TYPE, HEAT PUMP AIR CONDITIONERS

Revision A:

● MSZ-GA80VA has been added.

● MUZ-GA•VA - has been added.

● MXZ-A•VA - has been added.

Please void OBT14.

SERVICE TECHNICAL GUIDE

Wireless type Models

No. OBT14

REVISED EDITION-A

MSZ-FA•VA - · MUZ-FA•VA MSZ-GA•VA - · MUZ-GA•VA MFZ-KA•VA -

Inverter-controlled multi system type Models

· MXZ-A•VA -

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CONTENTS

1. MSZ-FA MICROPROCESSOR CONTROL ··········4

2. MSZ-GA MICROPROCESSOR CONTROL ·······22

3. MFZ MICROPROCESSOR CONTROL··············50

4. MXZ MICROPROCESSOR CONTROL··············62

Revision A:

MSZ-GA80VA has been added.

•

• MUZ-GA•VA - has been added.

• MXZ-A•VA - 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

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

15.

OPERATIONAL FREQUENCY CONTROL OF OUTDOOR UNIT ····19

16.

EXPANSION VALVE CONTROL (LEV CONTROL) ···························20

As for outdoor unit MXZ-8A140VA, refer to service manual OC316.

( )

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-8A140A

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

11.

OPERATIONAL FREQUENCY CONTROL OF OUTDOOR UNIT·····33

12.

EXPANSION VALVE CONTROL (LEV CONTROL) ···························34

1 (Refer to OC316)

MSZ-GA·VA

Indoor unit models Outdoor unit models

MSZ-GA50VA MUZ-GA50VA MXZ-A·VA (Refer to 4.) MSZ-GA60VA MUZ-GA60VA MXZ-8A140VA

1 (Refer to OC316)

MSZ-GA71VA MUZ-GA71VA MSZ-GA80VA 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

23.

OPERATIONAL FREQUENCY CONTROL OF OUTDOOR UNIT·····47

24.

EXPANSION VALVE CONTROL (LEV CONTROL) ···························48

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3. MFZ MICROPROCESSOR CONTROL ·······················································50

MFZ-KA·VA

Indoor unit models

MFZ-KA25VA MFZ-KA35VA MFZ-KA50VA

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

4. MXZ MICROPROCESSOR CONTROL·······················································62

As for outdoor units SUZ-KA25VA.TH, SUZ-KA35VA.TH and SUZ-KA50VA.TH,

(

refer to service manual OC323.

)

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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ON-TIMER button

CLOCK SET button

TIME SET buttons FORWARD button BACKWARD button

VANE CONTROL button (Horizontal vane button)

OFF-TIMER button

i-see button

(This diagram shows an overall view.)

PLASMA button

AREA button

RESET button

WIDE VANE button (Vertical vane button)

Signal transmitting section

Operation display section

Temperature buttons

OPERATE/STOP (ON/OFF) button

FAN SPEED CONTROL button

OPERATION SELECT button

ECONO COOL button

(This diagram shows an overall view.)

Indication of remote controller model

MSZ-FA MICROPROCESSOR CONTROL

MSZ-FA25VA MUZ-FA25VA MSZ-FA35VA MUZ-FA35VA

WIRELESS REMOTE CONTROLLER

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 ( ) 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

1. Thermostat control

Thermostat is ON or OFF by difference between room temperature and set temperature

Initial temperature difference Thermostat Room temperature minus set temperature : -1.0 : or more··············································ON Room temperature minus set temperature : less than -1.0 :············································OFF

2. Indoor fan speed control

Indoor fan operates continuously at the set speed by FAN SPEED CONTROLbutton regardless of the thermostat’s OFF-ON. In AUTO the fan speed is as follows.

Room temperature minus set temperature : 1.7

Room temperature minus set temperature : Between 1 and 1.7 :

Initial temperature difference

Fan speed

: or more ········································High

··································

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 and set temperature during operation.

Difference between room temperature and set tempera-

ture during operation ( T)

Set temperature

-1.0 :

1 :

-0.7 :

3 :

1.7 :

Temperature of indoor coil thermistor

10°C or more

Operation frequency

Normal (variable)

8°C to 10°C Raise 6 Hz

6°C to 8°C 3°C to 6°C

Fixed

Lower 3Hz Lower 6Hz

3°C or less

when temperature of indoor coil thermistor continues 3°C or less

Compressor is turned OFF for 5 minutes

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) 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 ( ) OPERATION

10 15 20 25 30 35

Set temperature

Initial room temperature

Set temperature and initial room temperature in dry mode

(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.

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

1. Thermostat control

Thermostat is ON or OFF by difference between room temperature and set temperature.

Initial temperature difference Thermostat

temperature and set temperature during operation

Set temperature Room temperature minus set temperature : -1.0 : or more················································ON Room temperature minus set temperature : less than -1.0 :··············································OFF

2. Indoor fan speed control

-1.0 :

Indoor fan operates at the set speed by FAN SPEED CONTROLbutton. When thermostat OFF (compressor OFF) fan speed becomes Very Low.

In AUTO the fan speed is as follows.

Initial temperature difference

Fan speed

Difference between room temperature and set temperature during operation ( T)

Room temperature minus set temperature : 1.7 : or more ········································High Room temperature minus set temperature : Between 1 and 1.7 :

··································

Room temperature minus set temperature : less than 1 : ········································Low

Med.

1 :

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 ( ) 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.

1. Thermostat control

Thermostat is ON or OFF by difference between room temperature and set temperature.

Initial temperature difference Thermostat Room temperature minus set temperature : less than 2.0 :···············································ON Room temperature minus set temperature : 2.0 : or more·················································OFF

2. Indoor fan speed control

(1) Indoor fan operates at the set speed by FAN SPEED CONTROLbutton.

In Auto the fan speed is as follows.

Initial temperature difference

Set temperature minus room temperature: 2 :or more Set temperature minus room temperature:

Between 0.2 and 2 : ·································

Set temperature minus room temperature: less than 0.2

··················································High :··············································

(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.

NOTE : When 3 minutes have passed since the compressor started operation, this control is released regardless of the

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(3) if the temperature of room temperature thermistor RT11 is more than 19°C, the fan operates at Very Low.

temperature of RT11 and RT12.

Fan speed

Med. Low

Difference between room temperature and set temperature during operation

Set temperature

1.7 :

Difference between room temperature and set temperature during operation

0.2 :

1.7 :

-0.7 :

2.0 :

2 :

2.5 :

4 :

set position

set speed

set position

set speed

Indoor fan

Compressor normal

Outdoor fan

R.V. coil

(21S4)

OFF (COOL)

OFF

Maximum frequency

horizontal

Horizontal vane

Very Low (temperature of indoor coil thermistor > 18:)

seconds

5 seconds 5 seconds

seconds

OFF

ON (HEAT)

ON ON

ON (HEAT)

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 sub-

sequent 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)

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1-4. AUTO CHANGE OVER ··· AUTO MODE OPERATION

High

Med.

Low

Super High

time

Rotational frequency

COOL

Fan speed

Down

Mode

HEAT

Compressor frequency

MUZ-FA25 MUZ-FA35

43Hz 33Hz 43Hz 33Hz

54Hz 41Hz 54Hz 41Hz

Down

Fan speed

High

Low

Compressor frequencyMin. Max.

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.

(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.

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Horizontal

position

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

(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.

Vane angle is fixed to Horizontal position.

Vane angle is fixed to Angle 4.

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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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 war m. To warn the area around the feet, set the horizontal vane to (AUTO) or the downwardblowing 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.

To change the air

flow direction

When to use this function?

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.

• Press VANE CONTROL button again to return the

vane to the previously-set position.

The air conditioner starts the cooling or drying operation approx. 3 minutes after the vane has moved to the horizontal position.

•

Pressing and holding VANE CONTROL

button for 2 seconds

or more causes the horizontal vane to reverse and move to horizontal position.

COOL/DRY

HEAT

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.

(9) To change the air flow direction not to blow directly onto your body.

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.

(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

B C D E

F G H

15°C or less 15°C to 17°C 17°C to 18°C

18°C to 20°C

20°C to 21°C 21°C to 22°C 22°C to 24°C

more than 24°C

Downward blow time

(second)

2 5

8 11 14 17 20 23

Horizontal blow time

(second)

23 20 17 14 11

8 5 2

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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.

2 3

4 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.

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

Image of sensing

range

Direction of sensor

Refer to the description on service manual OB371 (8-4. Remote controller) for slide switch settinng.

Installed at left Installed at center Installed at right

Right Center Left

· 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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Enlarged view of i-see Sensor

1-9. AREA ( ) 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:

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.

(AUTO) (LEFT) (RIGHT) Cancel

The indoor unit delivers warm air detecting the cold area in the room.

· 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

Moving of horizontal air flow direction

Indoor unit

display

NOTE

· 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.

Indication of AREA setting

Day

Night

Warm area Cold area

Lighted Not lighted

i-see Sensor moves intermittenly, measuring the floor and wall temperature.

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(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 Installed at center Installed at right

LEFT RIGHT LEFT 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

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

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.

Installed at center

Installed at left

Installed at right

AREA

Press AREA button to select LEFT.

T o 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.

Operation and operating range

i-see sensor moves 30 degrees from the center in both right and left side.

To air-condition mainly the right area of the room

Press AREA button to select RIGHT.

Approx. 150 degrees

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 AREAsetting made with the remote controller.

“AUTO” in AREAsetting; 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 AREAsetting; 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 AREAsetting; 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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PLASMA/WASH lamp

Blinking Not lighted

Lighted

WASH reset switch

WASH

reset

E.O.

Each time this b utton is pressed, the oper ation mode of PLASMA is changed in sequence:

Cancel (The sign of PLASMA oper ation disappears .)

PLASMA/WASH lamp tur ns on in the displa y section of the indoor unit and PLASMA DEODORIZING and/or PLASMA AIR PURIFYING unit is energyz ed. Adjust the air flow to your desired speed.

(1) Press OPERATE/STOP (ON/OFF) button to start the air conditioner. (2) Press PLASMA button to set PLASMA DUO operation.

(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.

1-10. PLASMA DUO ( ) OPERATION

● 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.

PLASMA/WASH lamp

Not lighted

Lighted

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.

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.

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START

STOP

START

STOP

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

(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

(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. To cancel ON timer, press ON-TIMER button ( ). To cancel OFF timer, press OFF-TIMER button( ). TIMER is cancelled and the display of set time disappears.

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EMERGENCY OPERATION switch

WASH

reset

E.O.

Operation mode COOL HEAT Set temperature

24:

24: Fan speed Medium Medium Horizontal vane Auto Auto Vertical vane Straight Straight

The operation mode is indicated by the Operation Indicator lamp on the indoor unit as following figure.

Operation Indicator lamp

NOTE: This is the indication of EMERGENCY OPERATION mode. AREA setting is not available during EMERGENCY OPERATION.

Press again <Heat>

Press once <Cool>

Lighted Not lighted

Press once again <Stop>

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.

The unit turns off at 11:00 PM, and on at 6:00 AM.

(Example 2) The current time is 11:00 AM.

The unit turns on at 5:00 PM, and off at 9:00 PM.

NOTE : 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.

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1-14. INVERTER SYSTEM CONTROL

POWER P.C. BOARD

Power supply

INVERTER P.C. BOARD

R64A R64B

TR821

DB65

X64

L62 L63

C63A C63B C63C

DB61

L61

CT761

CT781

IPM

Booster chopper circucuit

SYMBOL IPM C63A/C63B/C63C CT761/CT781

CT DB61 R64A, R64B

X64 DB65

TR821 L61

NAME INTELLIGENT POWER MODULE SMOOTHING CAPACITOR CURRENT TRANSFORMER

CURRENT TRANSFORMER DIODE MODULE CURRENT-LIMITING RESISTOR

RELAY DIODE MODULE

SWITCHING POWER TRANSISTOR REACTOR

FUNCTION

It supplies three-phase AC power to compressor. It stabilizes the DC voltage. It measures the current of the compressor motor. 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 normal operation after the compressor startup.

Booster chopper circuit

Function of main parts

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.

1-14-1. Inverter main power supply circuit

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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

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 Input current waveform with PAM

Due to the time of no electricity;

· Power factor gets worse.

· Harmonic gets increased. Input voltage

Release of energy stored in L

Energized time is extended by optimization of L inductance.

Peak gets down.

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.

Input current

Owing to the increase of energized time;

· Power factor gets better.

· Harmonic gets suppressed.

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.

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 hour

Time

Maximum frequency

Upper limit frequency

Rated frequency or less

1-15. OPERATIONAL FREQUENCY CONTROL OF OUTDOOR UNIT

Rotor Rotor Position Signal

Permanent magnet is embedded. Necessary

DC Motor

Excited by magnetic field of stator Unnecessary

AC Motor

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.

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 chan ged. 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. 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

MUZ-FA25VA

MUZ-FA35VA

Minimum frequency

28 70

Rated frequency

Maximum frequency

Minimum frequency

HEAT

Rated frequency

77 105

73 98 28

Maximum frequency

Minimum frequency

DRY

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.

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Maximum frequency

1-16. EXPANSION VALVE CONTROL (LEV CONTROL)

(1) Outline of LEV control The LEV basic control is comprised of setting LEV opening degree to the standard opening degrees set for each opera-

tional 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.

standard

specification

Unit OFF LEV remains at maximum opening degree (reaches maxi-

Remote controller ON LEV is positioned. (first full-closed at zero pulse and then

(When reducing the opening degree, LEV is once overclosed, and then adjusted to the proper degree by opening.

mum opening degree approximate in 15 minutes after compressor stops)

positioned.)

COOL · DRY MODE During 1 to 5 minutes after compressor starts

HEAT MODE During 1 to 15 minutes after compressor starts

More than COOL, DRY: 5/ HEAT: 15 minutes have passed since compressor start-up

general operation

Thermostat OFF LEV is adjusted to exclusive opening degree for thermostat

Thermostat ON

Defrosting in HEAT mode LEV is adjusted to open 500 pulse.

LEV is fixed to standard opening degree according to operational frequency of compressor.

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.

OFF.

LEV is controlled in the same way as that after the compressor has started up.

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(2) Time chart

OFF Time

Time

Operational frequency

of the compressor

Commanded to open

Standard opening degree

Opening degree is corrected according to discharge temperature.

Positioning

Air conditioner ON

Air conditioner OFF (thermostat off)

LEV opening degree

about 5 minutes <COOL, DRY> about 15 minutes <HEAT>

06 05 04 03 02

LEV opening degree

A(target discharge temperature)

30 50 70

Operational frequency of the compressor

90 110 130

(Hz)

(3) Control data

(a) Reference value of target discharge temperature

(COOL/HEAT :)

Applied model

MUZ-FA25VA

MUZ-FA35VA

47/41B53/48C58/55

50/45

53/52 60/59

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-FA25VA

MUZ-FA35VA

150/110

130/100

190/11003240/15004280/17005310/20006340/230

190/130 240/170

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63/60

66/68

260/210

67/65F67/65

70/76 70/76

260/230

Approximate 2 : or more

Difference between target temperature and room temperature

Approximate 2 : or less

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.

Operation stateIndication

Lighted

Not lighted

•The following indication applies regardless of shape of the indicator.

Operation Indicator

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

(This diagram shows an overall view.)

Temperature buttons

Indication of remote controller model is on back

FAN SPEED CONTROL button

OPERATION SELECT button

ECONO COOL button

RESET button

OFF-TIMER button

ON-TIMER button

TIME SET buttons FORWARD button BACKWARD button

CLOCK SET button

VANE CONTROL button

INDOOR UNIT DISPLAY SECTION

Operation Indicator lamp

The operation indicator at the right side of the indoor unit indicates the operation state.

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2-1. COOL ( ) OPERATION

(1) Press OPERATE/STOP(ON/OFF) button.

OPERATION INDICATOR lamp of the indoor unit turns on with a beep tone. (2) Select COOL mode with OPERATION SELECT button. (3) Press TEMPERATURE buttons (TOO WARM or TOO COOL button)to select the desired temperature.

The setting range is 16 ~ 31°C

1. Thermostat control

Thermostat is ON or OFF by difference between room temperature and set temperature

Initial temperature difference Thermostat

Room temperature minus set temperature : -1.0 : or more··············································ON Room temperature minus set temperature : less than -1.0 :············································OFF

2. Indoor fan speed control

Indoor fan operates continuously at the set speed by FAN SPEED CONTROLbutton regardless of the thermostat’s OFF-ON. In AUTO the fan speed is as follows.

Initial temperature difference

Fan speed

··································

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

10°C or more

Operation frequency

Normal (variable)

8°C to 10°C Raise 6Hz

6°C to 8°C 3°C to 6°C

Fixed Lower 3Hz Lower 6Hz

3°C or less

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 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.

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

(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.

Difference between room temperature and set temperature during operation.

Set temperature

-0.7 :

-1.0 :

Difference between room temperature and set tempera-

ture during operation ( T)

3 :

1.7 :

1 :

WOther protections work as well as in the normal COOL mode.

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Mitsubishi MSZ-FA-VA, MSZ-GA-VA, MUZ-GA-VA, MFZ-KA-VA, MUZ-FA-VA Service Technical Manual

Specifications and Main Features

Frequently Asked Questions

User Manual