Mitsubishi Electronics MSY-A15, MSZ-A09, MSZ-D30, MUZ-FE09, MUZ-FD09 User Manual

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SPLIT-TYPE AIR CONDITIONERS

Revision G:

CONFIDENTIAL (FOR INTERNAL USE ONLY)

• MSZ-FE18NA, MSZ-GE24NA and MSY-GE24NA have been added.

Please void OBT16 REVISED EDITION-F.

REVISED EDITION-G

SERVICE TECHNICAL GUIDE

Models

MS-A•WA · MU-A•WA MSZ-A•NA · MUZ-A•NA, MSY-A•NA · MUY-A•NA MSZ-FD•NA · MUZ-FD•NA, -

No. OBT16

MSZ-FE•NA · MUZ-FE•NA MSZ-D•NA · MUZ-D•NA, -

MSY-D•NA · MUY-D•NA MSZ-GA•NA · MUZ-GA•NA, MSY-GA•NA · MUY-GA•NA MSZ-GE•NA · MUZ-GE•NA MSY-GE•NA · MUY-GE•NA

MFZ-KA•NA

· MXZ-A•NA, -

· MXZ-B•NA, -

CONTENTS

1. MS MICROPROCESSOR CONTROL ·················· 4

2. MSZ, MSY MICROPROCESSOR CONTROL ······7

3. MXZ MICROPROCESSOR CONTROL ··············21

4. MFZ MICROPROCESSOR CONTROL ·············· 35

, -

Revision A:

• MXZ-3A30NA-

has been added.

Revision B:

• MXZ-2A20NA-

, MXZ-4A36NA, MSZ-FD, MSZ-D and MSY-D have been added.

Revision C:

• MXZ-2A20NA-2 has been added.

Revision D:

• MSZ-GA•NA and MSY-GA•NA have been added.

Revision E:

• MSZ-FE•NA, MSZ-GE•NA, MSY-GE•NA and MXZ-B•NA have been added.

Revision F:

• MXZ-2B20NA- 1, MXZ-3B24NA, MXZ-3B30NA, MXZ-4B36NA and MFZ-KA09/12/18NA have been added.

Revision G:

• MSZ-FE18NA, MSZ-GE24NA and MSY-GE24NA have been added.

1. MS MICROPROCESSOR CONTROL ··················································································································· 4

Indoor unit models Outdoor unit models

MS-A09/12WA MU-A09/12WA

1-1. COOL OPERATION ······································································································································· 4 1-2. DRY OPERATION ·········································································································································· 4 1-3. AUTO VANE OPERATION ····························································································································· 6

2. MSZ, MSY MICROPROCESSOR CONTROL ······································································································· 7

Indoor unit models Outdoor unit models

MSZ-A09/12/15/17/24NA MUZ-A09/12/15/17/24NA MSY-A15/17/24NA MUY-A15/17/24NA MSZ-FD09/12NA MUZ-FD09/12NA MSZ-FE09/12/18NA MUZ-FE09/12/18NA MSZ-D30/36NA MUZ-D30/36NA MSY-D30/36NA MUY-D30/36NA MSZ-GA24NA MUZ-GA24NA MSY-GA24NA MUY-GA24NA MSZ-GE06/09/12/15/18/24NA MUZ-GE09/12/15/18/24NA MSY-GE09/12/15/18/24NA MUY-GE09/12/15/18/24NA

2-1. COOL OPERATION ······································································································································· 7 2-2. DRY OPERATION ·········································································································································· 8 2-3. HEAT OPERATION ········································································································································ 8 2-4. AUTO CHANGE OVER ··· AUTO MODE OPERATION ··············································································· 10 2-5. OUTDOOR FAN MOTOR CONTROL ·········································································································· 11 2-6. AUTO VANE OPERATION ··························································································································· 11 2-7. INVERTER SYSTEM CONTROL ················································································································· 12 2-8. OPERATIONAL FREQUENCY CONTROL OF OUTDOOR UNIT ······························································17 2-9. EXPANSION VALVE CONTROL (LEV CONTROL) ····················································································18 2-10. PRE-HEAT CONTROL ·································································································································

3. MXZ MICROPROCESSOR CONTROL ··············································································································· 21

Outdoor unit models

MXZ-2A20NA MXZ-3A30NA MXZ-4A36NA MXZ-2B20NA MXZ-3B24NA MXZ-3B30NA MXZ-4B36NA

3-1. INVERTER SYSTEM CONTROL ················································································································· 21 3-2. EXPANSION VALVE CONTROL (LEV CONTROL) ····················································································23 3-3. OPERATIONAL FREQUENCY RANGE ······································································································ 29 3-4. HEAT DEFROSTING CONTROL ················································································································· 3-5.

DISCHARGE TEMPERATURE PROTECTION CONTROL ·················································································· 31 3-6. OUTDOOR FAN CONTROL ························································································································ 3-7. PRE-HEAT CONTROL ································································································································· 3-8.

COOL OPERATION ···············································································································································33 3-9.

DRY OPERATION ··················································································································································34 3-10. HEAT OPERATION ······································································································································

4. MFZ MICROPROCESSOR CONTROL ··············································································································· 35

Indoor unit models

32 33

MFZ-KA09NA MFZ-KA12NA MFZ-KA18NA

4-1. COOL OPERATION ···································································································································· 35 4-2. DRY OPERATION ······································································································································· 35 4-3. HEAT OPERATION ····································································································································· 36 4-4. AUTO CHANGE OVER ··· AUTO MODE OPERATION ············································································· 37 4-5. INDOOR FAN MOTOR CONTROL ············································································································· 37 4-6. AUTO VANE OPERATION ·························································································································· 38

MS MICROPROCESSOR CONTROL

1-1. COOL ( ) OPERATION

1. Thermostat control

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

Room temperature minus

Thermostat

set temperature (Initial)

ON -1.8°F(-1°C) or more OFF less than -1.8°F(-1°C)

2. Indoor fan speed control

Indoor fan operates continuously at the set speed by FAN SPEED CONTROL button regardless of the thermostat's OFFON. In AUTO the fan speed is as follows.

Room temperature minus

Fan speed

set temperature (Initial) High 3.15°F(1.75°C) or more Med. between 1.8 and 3.15°F Low

less than 1.8°F(1°C)

3. Coil frost prevention

Temperature control

When the indoor coil thermistor RT12 reads 37°F (3°C) or below the coil frost prevention mode starts immediately. However, the coil frost prevention does not work for 5 minutes since the compressor has started. The indoor fan operates at the set speed and the compressor stops for 5 minutes. After that, if the indoor coil thermistor still reads below 37°F (3°C), this mode is prolonged until the indoor coil thermistor reads over 37°F (3°C).

Time control

When the 3 conditions as follows have been satisfied for 1 hour and 45 minutes, compressor stops for 3 minutes. a. Compressor has been continuously operating. b. Indoor fan speed is Low or Med. c. Room temperature is below 79°F (26°C). When compressor stops, the accumulated time is cancelled and when compressor restarts, time counting starts from the beginning. Time counting also stops temporarily when the indoor fan speed becomes High or the room temperature exceeds 79°F (26°C). However, when two of the above conditions (b. and c.) are satisfied again, time accumulation is resumed.

Operation chart Example

Compressor Outdoor fan

OFF

Room temperature minus set temperature (During operation)

-1.8°F (-1°C)

-1.35°F

(-0.75°C)

Room temperature minus set temperature (During operation)

5.4°F

1.8°F (1°C)

3.15°F (1.75°C)

(3°C)

Indoor fan

( Continuously at set speed)

1-2. DRY ( ) OPERATION

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

Set temperature (°F)

50 59 68 77 86 95

Initial room temperature (°F)

1. Thermostat control

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

Room temperature minus

Thermostat

set temperature (Initial)

ON -3.6°F(-2°C) or more OFF less than -3.6°F(-2°C)

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.

Room temperature minus

Fan speed

set temperature (Initial) High 3.15°F(1.75°C) or more Med. between 1.8 and 3.15°F Low

less than 1.8°F(1°C)

3. The operation of the compressor and indoor/outdoor fan

Compressor operates by room temperature control and time control. Set temperature is controlled to fall 4°F (2°C) from initial room temperature. Indoor fan and outdoor fan operate in the same cycle as the compressor.

• When the room temperature is 73°F (23°C) or over:

• When The Thermostat is ON, the compressor repeats 8 minutes ON and 3 minutes OFF.

• When The thermostat is OFF, the compressor repeats 4 minutes OFF and 1 minute ON.

• When the room temperature is under 73°F (23°C).

• When The Thermostat is ON, the compressor repeats 2 minutes ON and 3 minutes OFF.

• When The thermostat is OFF, the compressor repeats 4 minutes OFF and 1 minute ON.

Room temperature minus set temperature (During operation)

-3.6°F (-2°C)

-1.35°F

(-0.75°C)

Room temperature minus set temperature (During operation)

4.5°F

(2.5°C)

3.15°F

1.8°F (1.75°C)

(1°C)

Operation time chart Example

Thermostat

OFF

Indoor fan

OFF

Outdoor fan Compressor

OFF

8 minutes

3 minutes

4 minutes

1 minute

4. 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. However, when coil frost prevention works while the compressor is not operating, its speed becomes the set speed.

1-3. AUTO VANE OPERATION

1. Horizontal vane

ECONO COOL ( When ECONO COOL button is pressed in COOL mode, set temperature is automatically set 3.6°F (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. To cancel this operation, select a different mode or press one of the following buttons in ECONO COOL operation: ECONO COOL or VANE CONTROL button.

<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 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 3.6°F (2°C), the swing operation is performed in table D~H for more cooling. The air conditioner repeats the swing operation in various cycle as follows.

) operation (ECONOmical operation)

Temperature of indoor

coil thermistor (°F/°C) A 59/15 or less 2 23 B 59/15 to 63 /17 5 20 C 63/17/ to 64/18 8 17 D 64/18 to 68/20 11 14 E 68/20 to 70/21 14 11 F 70/21 to 72/22 17 8 G 72/22 to 75/24 20 5 H more than 75/24 23 2

Downward blow time

(second)

Horizontal blow time

(second)

MSZ, MSY MICROPROCESSOR CONTROL

2-1. COOL ( ) OPERATION

1. Thermostat control

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

Room temperature minus

Thermostat

ON -1.8°F(-1°C) or more OFF less than -1.8°F(-1°C)

2. Indoor fan speed control

Indoor fan operates continuously at the set speed by FAN SPEED CONTROL button regardless of the thermostat's OFF-

ON.

In AUTO the fan speed is as follows.

Fan speed

High 3.15°F(1.75°C) or more Med. between 1.8 and 3.15°F Low

3. Coil frost prevention

The compressor operational frequency is controlled to prevent the temperature of indoor heat exchanger from falling excessively. The compressor is turned OFF for 5 minutes when the temperature of indoor coil thermistor continues 37°F (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 64°F (18°C) or less during operation in COOL mode, the unit will switch to the low outside temperature operation mode. <Operation> (1) Outdoor fan control

The outdoor fan rotational speed slows down to maintain sufficient cooling capacity. NOTE: Even when the unit is in the "thermostat-off" status under the low outside temperature operation mode, the out-

door fan rotation does not stop. (2) Dew drop prevention When the ambient temperature thermistor reads 14°F (-10°C) or less (the set temperature is different depending on the

models), as coil frost or dew drop from indoor unit may occur, the compressor turns OFF with the outdoor fan OFF for

prevention of them. (3) Outdoor temperature detecting control To detect the exact outdoor temperature in this mode, the compressor turns OFF but the outdoor fan stays ON for 3

minutes once 1 hour. If the outdoor temperature rises over about 64°F (18°C), the unit goes back to the normal COOL

mode. If the outside temperature stays below about 64°F (18°C), the unit continues to run in the low outside tempera-

ture operation mode.

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

set temperature (Initial)

Room temperature minus set temperature (Initial)

less than 1.8°F(1°C)

Room temperature minus set temperature (During operation)

-1.8°F (-1°C)

Room temperature minus set temperature (During operation)

5.4°F

1.8°F (1°C)

3.15°F (1.75°C)

(3°C)

-1.35°F

(-0.75°C)

2-2. DRY ( ) OPERATION

High 3.15°F(1.75°C) or more Med. between 1.8 and 3.15°F Low

less than 1.8°F(1°C)

3.15°F (1.75°C)

4.5°F

(2.5°C)

1.8°F (1°C)

Fan speed

Room temperature minus set temperature (Initial)

Room temperature minus set temperature (During operation)

ON less than 3.6°F(2°C) OFF 3.6°F(2°C) or more

3.15°F

(1.75°C)

3.6°F (2°C)

Thermostat

Room temperature minus set temperature (Initial)

Room temperature minus set temperature (During operation)

High Med. Low

Fan speed

Set temperature minus room temperature (During operation)

Set temperature minus room temperature (Initial)

Between 0.45 and 3.6°F

3.6°F(2°C) or more

Less than 0.45°F(0.25°C)

0.45°F

(0.25°C)

3.15°F

(1.75°C)

3.6°F (2°C)

7.2°F (4°C)

ON less than 1.8°F(1°C) OFF 1.8°F(1°C) or more

1.35°F

(0.75°C)

1.8°F (1°C)

Thermostat

Room temperature minus set temperature (Initial)

Room temperature minus set temperature (During operation)

Set temperature is as shown on the right chart.

Set temperature and initial room temperature in dry mode

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.

1. Thermostat control

Set temperature (°F)

50 59 68 77 86 95

Initial room temperature (°F)

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

Thermostat

Room temperature minus set temperature (Initial)

Room temperature minus set temperature (During operation)

ON -3.6°F(-2°C) or more OFF less than -3.6°F(-2°C)

2. Indoor fan speed control

Indoor fan operates at the set speed by FAN SPEED CONTROL button. When the thermostat turns OFF (compressor OFF), fan speed becomes Very Low. In AUTO the fan speed is as follows.

-3.6°F (-2°C)

-1.35°F

(-0.75°C)

3. Coil frost prevention

4. Low outside temperature operation

Low outside temperature operation is as same as COOL mode. (2-1.4.)

2-3. HEAT ( ) OPERATION (MSZ)

1. Thermostat control

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

(MSZ-FE18 MSZ-GE24)

(Other models)

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.

(2) Cold air prevention control

MSZ-A09/12/15/17 MSZ-FD MSZ-FE MSZ-D MSZ-GE

When the compressor is not operating,

) if the temperature of room temperature thermistor is less than 66°F (19°C), the fan stops.

( ( ) if the temperature of room temperature thermistor is 66°F (19°C) or more and

( ) if the temperature of indoor coil thermistor is less than 32°F (0°C), the fan stops.

) if the temperature of indoor coil thermistor is 32°F (0°C) or more, the fan operates at Very Low.

(

When the compressor is operating,

(

) if the temperature of indoor coil thermistor is 104°F (40°C) or more, the fan operates at set speed.

(

) if the temperature of indoor coil thermistor is less than 104°F (40°C) and

) if heating operation starts after defrosting, the fan stops.

(

) if the temperature of room temperature thermistor is 66°F (19°C) or less, the fan stops.

(

)

if the temperature of room temperature thermistor is more than 66°F (19°C), the fan operates at Very Low.

(

NOTE: When 4 minutes (

MSZ-FE18 MSZ-GE24)/

3 minutes (Other models) have passed since the compressor started

operation, this control is released regardless of the temperature of room temperature thermistor and indoor coil thermistor.

MSZ-A24 MSZ-GA

When the compressor is not operating,

(

) if the temperature of room temperature thermistor is 59°F (15°C) or less, or temperature of indoor coil thermis-

tor is less than 64°F (18°C), the fan stops.

) if the temperature of room temperature thermistor is more than 59°F (15°C), or temperature of indoor coil

(

thermistor is more than 64°F (18°C), the fan operates at Very Low.

When the compressor is operating,

(

) if the temperature of indoor coil thermistor is 64°F (18°C) or more, the fan operates at set speed.

(

) if the temperature of indoor coil thermistor is less than 64°F (18°C) and

) if heating operation starts after defrosting, the fan stops.

(

) if the temperature of room temperature thermistor is 59°F (15°C) or less, the fan stops.

(

)

if the temperature of room temperature thermistor is more than 59°F (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 room temperature thermistor and indoor coil thermistor.

(3) Warm air control (MSZ-FD MSZ-FE MSZ-GE)

When the following any condition of (a. ~ c.) and the condition of

are satisfied at the same time, warm air control

works.

a.) Fan speed is used in MANUAL. b.) When cold air prevention has been released. c.) When defrosting has been finished.

When the temperature of indoor coil thermistor is less than 104°F (40°C). When warm air control works, the fan speed changes as follows to blow out warm air gradually.

Gradation of fan speed in initial

(MSZ-FE18 MSZ-GE24)

<Time condition> <Indoor fan speed> Less than 4 minutes ------------ Low 4 to 8 minutes -------------------- Med. More than 8 minutes ----------- High

(Other models)

<Time condition> <Indoor fan speed> Less than 2 minutes ------------ Low 2 to 4 minutes -------------------- Med. More than 4 minutes ----------- High or Super high

The upper limit of the fan speed in MANUAL is the set speed. When the temperature of indoor coil thermistor has been 104°F (40°C) or more, or when the set speed has been changed, this control is released and the fan speed is the set speed.

3. Overload starting

When the room temperature thermistor reads 64°F (18°C) or more, the compressor runs with its maximum frequency regulated for 10 minutes after the start-up.

4. Defrosting

(1) Starting conditions of defrosting

When the following conditions a) ~ c) are satisfied, the defrosting starts. a) The defrost thermistor reads about 30.2°F (-1°C) or less. b) The cumulative operation time of the compressor has reached any of the set values

(defrost interval: 40-150 min-

utes).

c) More than 5 minutes have passed since the start-up of the compressor.

The defrost interval is decided by the previous defrosting time. The next defrost interval extends or shortens 0-20

minutes compared with the previous defrost interval.

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 > 64 °F)

seconds

5 seconds 5 seconds

seconds

OFF

(39°C)

(18°C)

OFF

ON (HEAT)

ON ON

ON (HEAT)

horizontal (temperature of indoor coil thermistor < 102 °F)

(2) Releasing conditions of defrosting

Defrosting is released when any one of the following conditions is satisfied: a) The defrost thermistor continues to read "Defrost finish temperature" for 30 seconds.

Refer to "CHANGE IN DEFROST SETTING of SERVICE FUNCTIONS in OUTDOOR UNIT SERVICE MANUAL". 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)

2-4. AUTO CHANGE OVER ··· AUTO MODE OPERATION (MSZ)

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.

If the room temperature thermistor reads more than set temperature, COOL mode is selected. If the room temperature thermistor reads set temperature or less, HEAT mode is selected.

(2) Mode change

In case of the following conditions, the operation mode is changed.

COOL mode changes to HEAT mode when 15 minutes have passed with the room temperature 2 - 4°F (1 - 2°C)

below the set temperature.

HEAT mode changes to COOL mode when 15 minutes have passed with the room temperature 2 - 4°F (1 - 2°C)

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: When two or more indoor units are operating simultaneously, the indoor unit, which is operating in AUTO ( ),

might not be able to change over the operating mode (COOL ↔ HEAT) and becomes the standby state.

(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.

2-5. OUTDOOR FAN MOTOR CONTROL

Fan speed is switched according to the compressor frequency.

Fan speed

High

Low

Down Up

Compressor frequencyMin. Max.

Compressor frequency (Hz)

Down Up

MUZ-A MUY-A

MUZ-FD

MUZ-FE09/12

MUZ-GA MUY-GA

MUZ-GE12/15/18 MUY-GE12/15/18

MUZ-D MUY-D

MUZ-GE09 MUY-GE09

MUZ-FE18

MUZ-GE24 MUY-GE24

33 44

39 54

33 43

2-6. AUTO VANE OPERATION

1. Horizontal vane

(1) Cold air prevention in HEAT operation (MUZ)

When any of the following conditions occur in HEAT operation, the vane angle changes to Horizontal position automatically to prevent cold air blowing on users.

Compressor is not operating. Defrosting is performed. Indoor coil thermistor temperature does not exceed 102°F (39°C) within 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 does not work in the indoor unit.

(2) ECONO COOL ( ) operation (ECONOmical operation) (Excluding MSZ-FD and MSZ-FE09/12)

When ECONO COOL button is pressed in COOL mode, set temperature is automatically set 3.6°F (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. To cancel this operation, select a different mode or press one of the following buttons in ECONO COOL operation: ECONO COOL or VANE CONTROL button.

POWER SUPPLY

NOISE FILTER CIRCUIT

RESISTOR

SWITCHING POWER TRANSISTOR

RELAY

SMOOTHING CAPACITOR

CURRENT TRANSFORMER

COMPRESSOR

DIODE MODULE1

DIODE MODULE2

REACTOR

IPM

BOOSTER CHOPPER CIRCUIT

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 3.6°F (2°C), 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 (°F/°C)

Downward blow time

(second)

Horizontal blow time

(second)

A 59/15 or less 2 23 B 59/15 to 63/17 5 20 C 63/17 to 64/18 8 17 D 64/18 to 68/20 11 14 E 68/20 to 70/21 14 11 F 70/21 to 72/22 17 8 G 72/22 to 75/24 20 5 H more than 75/24 23 2

2-7. INVERTER SYSTEM CONTROL

2-7-1. Inverter main power supply circuit

MUZ-A09/12/15/17 MUY-A15/17 MUZ-FD MUZ-FE09/12 MSZ-GE06/09/12/15/18 MUY-GE09/12/15/18

Function of main parts

NAME FUNCTION

INTELLIGENT POWER MODULE (IPM) It supplies 3-phase AC power to compressor.

SMOOTHING CAPACITOR It stabilizes the DC voltage and supplies it to IPM.

CURRENT TRANSFORMER It measures the current of the compressor motor.

DIODE MODULE 1 It converts the AC voltage to DC voltage.

RESISTOR

RELAY

BOOSTER CHOPPER CIRCUIT

DIODE MODULE 2

SWITCHING POWER TRANSISTOR

It absorbs the rush current not to run into the main power supply circuit when the electricity turns ON.

It keeps the RESISTOR, which restricts rush current, short-circuited while the compressor is operating.

It improves power factor. It controls the bus-bar voltage.

REACTOR

MUZ-A24 MUY-A24 MUZ-D MUY-D MUZ-FE18 MUZ-GA MUY-GA MUZ-GE24 MUY-GE24

POWER SUPPLY

NOISE FILTER CIRCUIT

RESISTOR

RELAY

REACTOR

PFC

SMOOTHING CAPACITOR

IPM

Function of main parts

NAME FUNCTION

INTELLIGENT POWER MODULE (IPM) It supplies 3-phase AC power to compressor.

SMOOTHING CAPACITOR It stabilizes the DC voltage and supplies it to IPM.

CURRENT TRANSFORMER It measures the current of the compressor motor.

CURRENT TRANSFORMER

COMPRESSOR

REACTOR

It rectiﬁ es AC, controls its voltage and improves the power factor of power supply.

POWER FACTOR CORRECTION MODULE (PFC)

RESISTOR

RELAY

It absorbs the rush current not to run into the main power supply circuit when the electricity turns ON.

It keeps the RESISTOR, which restricts rush current, short-circuited while the compressor is operating.

2-7-2. Outline of main power supply circuit MUZ-A09/12/15/17 MUY-A15/17 MUZ-FD MUZ-FE09/12 MUZ-GE09/12/15/18 MUY-GE09/12/15/18

1. At the start of operation

Main power supply circuit is formed when RELAY is turned ON at COMPRESSOR startup. To prevent rush current from running into the circuit when power supply is turned ON, RESISTOR is placed in sub circuit.

2. At normal operation

When AC runs into POWER P.C. board, its external noise is eliminated in NOISE FILTER CIRCUIT. After noise is eliminated from AC, it is rectiﬁ ed to DC by DIODE MODULE 1. DC voltage, to which AC has been rectiﬁ ed by process , is stabilized by SMOOTHING CAPACITOR and supplied to IPM. DC voltage, which has been stabilized in process

, is converted to 3-phase AC by IPM and supplied to COMPRESSOR.

CURRENT TRANSFORMER, which is placed in the power supply circuit to COMPRESSOR, is 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 pieces of information.

3. Purpose of PAM adoption

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

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

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.

PAM (Pulse Amplitude Modulation) has been adopted for the efﬁ ciency improvement and the adaptation to IEC harmonic cur- rent emission standard

Outline of simple partial switching method

In conventional inverter models, DIODE MODULE rectiﬁ es 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 BOOSTER CHOPPER CIRCUIT 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 satisﬁ ed. Since the switching synchronized with the zero cross point, this simple partial switching method has the feature of lower energy loss compared to active ﬁ lter method. In addition, output and efﬁ ciency is enhanced by combining with vector-controlled inverter in order to boost the voltage of power supplied to IPM.

4. Intelligent power module

IPM consists of the following components

· IGBT (x6): Converts DC waveform to 3-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. Elimination of electrical noise

NOISE FILTER CIRCUIT, which is formed by *CMC COILS and capacitors placed on the POWER P.C. board, eliminates electrical noise of AC power that is supplied to main power supply circuit. This circuit also prevents the electrical noise generated in the inverter circuit from leaking out.

*CMC COILS: Common mode choke coils

MUZ-A24 MUY-A24 MUZ-D MUY-D MUZ-FE18 MUZ-GA MUY-GA MUZ-GE24 MUY-GE24

1. At the start of operation

2. At normal operation

When AC runs into noise filter P.C. board, its external noise is eliminated in NOISE FILTER CIRCUIT. After noise is eliminated from AC, it is rectified to DC by REACTOR and PFC. If the operating frequency becomes 25 Hz or

more, DC voltage rises to 370 V. DC voltage, to which has AC been rectified by process , is stabilized by SMOOTHING CAPACITOR and supplied to IPM. The DC (Bus voltage), which has been stabilized in process , is converted to 3-phase AC by IPM and supplied to COM-

PRESSOR. CURRENT TRANSFORMER, which is placed in the power supply circuit to COMPRESSOR, is 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 pieces of information.

3. Power factor improvement

Booster coil 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 reactor stabilize the voltage of DC supplied to inverter circuit and make its waveform smooth.

4. Intelligent power module

IPM consists of the following components.

· IGBT (x6): Converts DC waveform to 3-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 to make the control circuit simplified and miniaturized.

5. Elimination of electrical noise

NOISE FILTER CIRCUIT, which is formed by *CMC COILS, *NMC COILS and capacitors placed on the POWER P.C. board, eliminates electrical noise of AC power that is supplied to main power supply circuit. This circuit also prevents the electrical noise generated in the inverter circuit from leaking out.

*CMC COILS: Common mode choke coils *NMC COILS: Normal mode choke coils

2-7-3. Sine wave control

In these air conditioners, compressor equips brushless DC motor which does not have Hall element. In short, the motor is sensorless. However, it is necessary to locate the polar direction of rotor in order to drive brushless DC motor efﬁ ciently. 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 efﬁ ciently and smoothly.

2-7-4. Characteristics of sine wave control in case of brushless DC motor

Although ordinary 3-phase induction motor requires energy to excite the magnetic ﬁ eld of rotor, brushless DC motor does not

●

need it. So, higher efﬁ ciency and torque are provided.

This control provides the most efﬁ cient waveform corresponding to the rotational speed 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 less energy 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 the response and efﬁ ciency of motor are enhanced in sine wave control, ﬁ ner adjustment can be provided.

●

DC Motor AC Motor

Rotor Permanent magnet is embedded. Excited by magnetic ﬁ eld of stator

Rotor Position Signal Necessary Unnecessary

In brushless DC motor, permanent magnet is embedded in the rotor. Therefore, it does not require energy to excite the rotor

like AC motor does. However, it is necessary to control the frequency of 3-phase AC current supplied to the stator according to the polar direction of magnet embedded in the rotor so as to drive the motor efﬁ ciently. Controlling 3-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.

2-7-5. Control Method of Rotational speed

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 ﬁ ner adjustment of the voltage of supplied power. The value of the current running into the motor is determined by each motor characteristic.

2-8. 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 tempera-

ture.

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.

Operational frequency (Hz)

Applied model

MUZ-A09 32 70 32 76 32 57 MUZ-A12 32 73 32 71 32 57 MUZ-A15 MUY-A15 10 82 15 93 10 68 MUZ-A17 MUY-A17 10 87 15 93 10 68 MUZ-A24 MUY-A24 15 110 15 108 15 102 MUZ-FD09 10 52 10 100 10 41 MUZ-FD12 10 62 10 100 10 41 MUZ-FE09 10 52 10 100 10 41 MUZ-FE12 10 62 10 100 10 41 MUZ-FE18 26 120 26 124 26 120 MUZ-D30 20 84 20 87 20 83 MUZ-D36 20 91 20 94 20 83 MUY-D30 20 79 — — 20 79 MUY-D36 20 92 — — 20 79 MUZ-GA24 MUY-GA24 15 101 15 108 15 101 MUZ-GE09 MUY-GE09 28 93 30 105 28 48 MUZ-GE12 MUY-GE12 20 98 30 98 30 55 MUZ-GE15 MUY-GE15 15 90 15 102 15 54 MUZ-GE18 MUY-GE18 15 98 15 108 15 83 MUZ-GE24 MUY-GE24 26 120 26 124 26 120

The operation frequency in COOL mode is restricted by the upper limit frequency after 1 hour or 0.5 ~ 1 hour as shown

below for dew prevention.

It is rated frequency or less.

COOL HEAT (MUZ)DRY

Minimum Maximum Minimum Maximum Minimum Maximum

Upper limit frequency

Maximum frequency

1 hour

0.5~1 hour

Rated frequency or less

Time

2-9. 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.

Minimum: 33 pulses (MUZ-A09/12/15/17 MUY-A15/17)

MUZ-A24 MUY-A24 MUZ-GA MUY-GA

Control range

59 pulses ( 54 pulses (MUZ-FD MUZ-FE MUZ-GE MUY-GE) 58 pulses (MUZ-D MUY-D)

Maximum: 500 pulses

Actuating speed

Open: 40 pulses/second Close: 90 pulses/second

Opening degree adjustment LEV opening degree is always adjusted in opening direction. (When reduc-

Standard specification

ing the opening degree, LEV is once over-closed, 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 pulses and then positioned.) During 1 to 15 minutes after compressor

starts

More than about 15 minutes have passed since compressor start-up

LEV is fixed to standard opening degree according to operational frequen-

cy of compressor.

LEV opening degree is corrected to get target discharge temperature of

compressor.

(For lower discharge temperature than target temperature, LEV is correct-

ed in closing direction.)

(For higher discharge temperature than target temperature, LEV is cor-

rected in opening direction.)

General operation

It may take more than 30 minutes to reach target temperature, depend-

ing 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 pulses

)

(2) Time chart

Air conditioner ON

Positioning

Standard opening degree

LEV opening degree

About 15 minutes

of the compressor

Operational frequency

Opening degree is corrected according to discharge temperature. (Refer to (3))

Air conditioner OFF (thermostat off)

Commanded to open

Time

OFF Time

(3) Control data

F E

D C B

Target discharge temperature

23 38 53 69 84 99 30 50 70 90 110 130

(MUZ-FE18 MUZ-GE24 MUY-GE24)

(Hz) (Hz)

(Other models)

Operational frequency of the compressor

(a) Reference value of target discharge temperature

COOL / HEAT (MUZ) °F/°C

Applied model A B C D E F

MUZ-A09/12

MUZ-A15/17 MUY-A15/17

MUZ-A24 MUY-A24 MUZ-GA MUY-GA

MUZ-FD MUZ-FE09/12

MUZ-FE18 MUZ-GE24 MUY-GE24

MUZ-D MUY-D

MUZ-GE09 MUY-GE09

MUZ-GE12 MUY-GE12

MUZ-GE15 MUY-GE15

MUZ-GE18 MUY-GE18

COOL 122/50 127/53 140/60 151/66 158/70 158/70

HEAT 113/45 126/52 138/59 154/68 169/76 169/76

COOL 129/54 136/58 147/64 158/70 158/70 158/70

HEAT 120/49 136/58 151/66 165/74 180/82 185/85

COOL 140/60 140/60 140/60 145/63 147/64 153/67

HEAT 140/60 145/63 149/65 153/67 158/70 158/70

COOL 120/49 131/55 142/61 153/67 162/72 169/76

HEAT 109/43 124/51 138/59 156/69 167/75 176/80

COOL 131/55 142/61 151/66 162/72 171/77 178/81

HEAT 115/46 133/56 151/66 167/75 181/83 187/86

COOL 126/52 135/57 149/65 167/75 183/84 187/86

HEAT 131/55 140/60 149/65 154/68 162/72 167/75

COOL 126/52 136/58 149/65 153/67 158/70 160/71

HEAT 109/43 122/50 131/55 138/59 149/65 156/69

COOL 127/53 140/60 147/64 153/67 162/72 169/76

HEAT 109/43 124/51 138/59 156/69 167/75 176/80

COOL 120/49 131/55 147/64 153/67 162/72 169/76

HEAT 109/43 124/51 138/59 156/69 167/75 176/80

COOL 135/57 140/60 144/62 153/67 165/74 178/81

HEAT 140/60 149/65 158/70 167/75 167/75 167/75

In COOL operation, the indoor coil thermistors (main and sub) sense temperature ununiformity (super heat) at the heat exchanger, and when temperature difference develops, the indoor coil thermistors adjust LEV opening degree to get approximate 18°F (10°C) lower temperature than the target temperature in the table above, thus diminishing super heat.

Power ON

OFF

Compressor ON

OFF

Pre-heat ON

OFF

Breaker ON

69.8°F (21°C)

Stop operation

Start operation

Defrost thermistor

30 minutes 30 minutes 30 minutes 30 minutes 30 minutes 30 minutes

15 minutes

30minutes

When the defrost thermistor reads

69.8°F(21°C) or more

2-10. PRE-HEAT CONTROL MUZ-FD MUZ-FE MUZ-GE

1. Outline Compressor is energized to improve the start-up of compressor at a low outside temperature even when compressor is

stopped.

2. Pre-heat control

Compressor

OFF

Pre-heat control

Outside temperature

Pre-heat control ON condition

OFF

68°F (20°C)

30 minutes 1 hour

(1) Compressor is not operating. (However, pre-heat control is still OFF for 30 minutes after compressor is stopped, regardless

of the outside temperature.)

(2) Outside temperature is 68°F (20°C) or below. Outside temperature is monitored hourly, and when outside temperature is

68°F (20°C) or below, pre-heat control is turned ON. When pre-heat control is turned ON, compressor is energized about 50 W (40-60 W). (Compressor and fan are not operated.)

MUZ-D MUY-D

1. Outline The compressor is energized even while it is not operating. This is to generate heat at the winding to improve the compressor's start-up condition.

2. Pre-heat control ON condition (1) Pre-heat control is turned ON for 15 or 30 minutes after the breaker is turned ON. (2) 30 min. after the unit is stopped, pre-heat control is turned ON for 15 or 30 minutes and turned OFF for 30 minutes. This

is repeated as shown in the graph until the breaker is turned OFF.

When the defrost thermistor reads less than 69.8°F (20°C), pre-heat control is ON for 30 minutes. When the defrost

thermistor reads 69.8°F (21°C) or more, pre-heat control is ON for 15 minutes.

NOTE: When the unit is started with the remote controller, pre-heat control is turned OFF. Compressor uses 50 W when pre-

heat control is turned ON.

MXZ MICROPROCESSOR CONTROL

3-1. INVERTER SYSTEM CONTROL

3-1-1. Inverter main power supply circuit

REACTOR

POWER SUPPLY

NOISE FILTER CIRCUIT

RESISTOR

RELAY

PFC

SMOOTHING CAPACITOR

Function of main parts

NAME FUNCTION

INTELLIGENT POWER MODULE (IPM) It supplies 3-phase AC power to compressor.

SMOOTHING CAPACITOR It stabilizes the DC voltage and supplies it to IPM.

CURRENT TRANSFORMER It measures the current of the compressor motor.

IPM

CURRENT TRANSFORMER

COMPRESSOR

REACTOR

It rectiﬁ es AC, controls its voltage and improves the power factor of power supply.

POWER FACTOR CORRECTION MODULE (PFC)

RESISTOR

RELAY

It absorbs the rush current not to run into the main power supply circuit when the electricity turns ON.

It keeps the RESISTOR, which restricts rush current, short-circuited while the compressor is operating.

3-1-2. Outline of main power supply circuit

1. At the start of operation

2. At normal operation

When AC runs into noise ﬁ lter P.C. board, its external noise is eliminated in NOISE FILTER CIRCUIT. After noise is eliminated from AC, it is rectiﬁ ed to DC by REACTOR and PFC. If the operating frequency becomes 25 Hz or

more, DC voltage rises to 370 V.

DC voltage, to which has AC been rectiﬁ ed by process , is stabilized by SMOOTHING CAPACITOR and supplied to IPM. The DC (Bus voltage), which has been stabilized in process , is converted to 3-phase AC by IPM and supplied to COM-

PRESSOR.

CURRENT TRANSFORMER, which is placed in the power supply circuit to COMPRESSOR, is 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 pieces of information.

3. Power factor improvement

4. Intelligent power module

IPM consists of the following components.

· IGBT (x6): Converts DC waveform to 3-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 to make the control circuit simpliﬁ ed and miniaturized.

5. Elimination of electrical noise

NOISE FILTER CIRCUIT, which is formed by *CMC COILS, *NMC COILS and capacitors placed on the P.C. board, eliminates electrical noise of AC power that is supplied to main power supply circuit. This circuit also prevents the electrical noise generated in the inverter circuit from leaking out. *CMC COILS: Common mode choke coils *NMC COILS: Normal mode choke coils

3-1-3. Sine wave control

In these air conditioners, compressor equips brushless DC motor which does not have Hall element. In short, the motor is sensorless. However, it is necessary to locate the polar direction of rotor in order to drive brushless DC motor efﬁ ciently. 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 and 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 efﬁ ciently and smoothly.

3-1-4. Characteristics of sine wave control in case of brushless DC motor

Although ordinary 3-phase induction motor requires energy to excite the magnetic ﬁ eld of rotor, brushless DC motor does not

●

need it. So, higher efﬁ ciency and torque are provided.

This control provides the most efﬁ cient waveform corresponding to the rotational speed 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 less energy 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 the response and efﬁ ciency of motor are enhanced in sine wave control, ﬁ ner adjustment can be provided.

●

DC Motor AC Motor

Rotor Permanent magnet is embedded. Excited by magnetic ﬁ eld of stator

Rotor Position Signal Necessary Unnecessary

In brushless DC motor, permanent magnet is embedded in the rotor. Therefore, it does not require energy to excite the rotor

3-1-5. Control Method of Rotational speed

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 ﬁ ner adjustment of the voltage of supplied power. The value of the current running into the motor is determined by each motor characteristic.

3-2. EXPANSION VALVE CONTROL (LEV CONTROL)

Linear expansion valve (LEV) is controlled by “Thermostat ON” commands given from each unit.

Indoor unit status LEV opening Stop of all indoor unit Opening before stop → 500 pulses in 15 minutes

When outdoor unit is operating, some indoor units stop and some operate.

COOL: 5 pulses (full closed) HEAT: (MXZ-2A/3A30NA/2B): 140 pulses (slightly opened)

: (MXZ-3A30NA- 1/4A/3B/4B): 100 → 59 pulses

Thermostat OFF in COOL or DRY mode

When the outdoor unit operates (When the other indoor unit operates): 5 pulses When outdoor unit stops. (When the other indoor unit stops or thermo OFF): Maintain LEV opening before stop → 500 pulses in 15 minutes

• LEV opening for each indoor unit is determined by adding adjustment according to the number of operating unit and the capacity class to standard opening, based on the operation frequency: e.g.) Opening 130 pulses in standard opening 1 → Minimum 80 pulses/Maximum 205 pulses (Capacity code 4 at 1 unit operation) (Capacity code 1 at 3 units operation)

Thermostat ON in COOL or DRY mode

• After starting operation, adjustment according to intake super heat, discharge temperature is included in standard opening. 1

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 3-3. 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): 140 pulses

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 pulses in 15 minutes “

• LEV opening for each indoor unit is determined by adding adjustment according to the number of operating unit and the capacity class to standard opening, based on the operation frequency:

Thermostat ON in HEAT mode

e.g.) Opening 120 pulses in standard opening 1 → Minimum 70 pulses/Maximum 165 pulses (Capacity code 4 at 1 unit operation) (Capacity code 1 at 3 units operation)

• After starting operation, opening becomes the one that adjustment according to discharge temperature was added to basic opening.

1 “

1 LEV opening when the outdoor unit is operating: Upper limit 500 pulses, Lower limit 53 pulses (MXZ-2A/3A30NA/2B)/59

pulses (MXZ-3A30NA-

/4A/3B/4B).

MXZ-2A20NA/3A30NA

The table below shows the role of Exclusive LEV and Receiver LEV in each operation mode.

Discharge

Temperature

Protection

High Pressure

Protection

COOL

HEAT

Exclusive LEV

Receiver LEV

Exclusive LEV

Receiver LEV

Circulation Amount

Control

Capacity Distribution

○○○○ ○

××○○ ○ × ○○○ ○ × ○○

Evaporation

Temperature Protection

— —

Indoor heat

exchanger

(MXZ-3A30NA)

Exclusive

LEV

Receiver

Outdoor heat exchanger

Receiver

LEV

In COOL mode, the two indoor coil thermistors (one main and one sub) sense temperature ununiformity (super heat) at the heat exchanger, and when temperature difference develops, 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-2A20NA>

Standard No.

Number of

operating

indoor units

COOL HEAT

1 unit 2 units 1 unit 2 units

LEV opening (pulse)

1 200 150 120 120 2 300 320 140 140 3 400 360 160 160 4 450 410 220 220 5 500 500 280 280

<MXZ-3A30NA>

Standard No.

1 150 250 250 250 250 250 2 250 320 320 300 300 300 3 350 360 370 450 380 380 4 400 410 420 460 400 390 5 450 460 470 470 450 440

Number of

operating

indoor units

LEV opening (pulse)

COOL HEAT

1 unit 2 units 3 units 1 unit 2 units 3 units

23 54 69 84 100 115 131 14638 14 32 41 50 59 68 77 86

MXZ-2A/2B MXZ-3A/4A23

Compressor operating frequency (Hz)

4Hz

LEV Opening (code)

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 or 3 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 out-

put opening is in a range from 59 to 500 pulses.

MXZ-2A20NA

Standard opening (pulse)

LEV Opening (code)

12345678910

COOL 120 130 136 146 156 160 170 180 190 200

HEAT 100 110 120 130 146 160 170 180 190 200

Difference in capacity

Code3,4 Code5,6 Code7,8

Code9,10 Code11,12 Code13,14

Code15or above

Difference in operation number

COOL 3 6 9 12 15 25 35 -20

HEAT 3 6 9 52 55 65 75 0

MXZ-3A30NA

Standard opening (pulse)

LEV Opening (code)

12345678910

COOL 126 130 134 138 140 142 182 228 296 310

HEAT 140 146 150 170 180 200 224 244 272 280

Difference in capacity

Code3,4 Code5,6 Code7,8

Code9,10 Code11,12 Code13,14

Code15or above

Difference in operation number

COOL 3 6 9 12 15 25 35 -20 -30

HEAT 3 6 9 52 55 65 75 0 0

MXZ-2A20NA-

1,2

MXZ-2B20NA

MXZ-2B20NA-

Exclusive LEV

Standard opening (pulse)

LEV Opening (code)

12345678910

COOL 120 130 136 146 156 160 170 180 190 200

HEAT 248 248 258 266 274 280 286 292 300 306

Difference in capacity

Code3,4 Code5,6 Code7,8

Code9,10 Code11,12 Code13,14

Code15or above

Difference in operation number

COOL 3 6 9 12 15 25 35 -20

HEAT 3 6 9 52556575 30

Receiver LEV

Standard opening (pulse)

LEV Opening (code)

12345678910

COOL 140 150 160 170 180 190 200 200 200 200

HEAT 80 84 90 110 120 130 140 150 160 170

Operation number

Difference in operation number

COOL -20

HEAT 30

MXZ-3A30NA-1 MXZ-4A36NA MXZ-3B24NA MXZ-3B30NA MXZ-4B36NA

Exclusive LEV

Standard opening (pulse)

LEV Opening (code)

12345678910

COOL 126 130 134 138 150 160 170 180 190 200

HEAT 248 248 258 266 274 280 286 292 300 306

Difference in capacity

Code3,4 Code5,6 Code7,8

Code9,10 Code11,12 Code13,14

Code15or above

Difference in operation number

COOL 3 6 9 12 15 25 35 -20 -30 -30

HEAT 3 6 9 52 55 65 75 -4 -8 -12

Receiver LEV

Standard opening (pulse)

LEV Opening (code)

12345678910

COOL 270 280 290 300 310 320 330 340 350 360

HEAT 140 152 160 170 180 200 224 244 274 280

4(MXZ-4A/4B)

Operation number

Difference in operation number

4(MXZ-4A/4B)

COOL 28 56 84

HEAT -45 -60 -60

Capacity code 3 4 7 9 10 12

Indoor unit 06 09 12 15 17 24

COOL DRY HEAT

Discharge temperature

Each correction

• (Each gas pipe temperature thermistor - Minimum gas pipe temperature thermistor) 1

• (Main indoor coil thermistor - Sub indoor coil thermistor)

1 Perform this, when number of operation units is 2 units or more.

(MXZ-2A20NA

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-3A30NA only)

and

●

—

●

MXZ-2A20NA

Operation frequency

of compressor (Hz)

Minimum ~ 23 95 136.4 122 122

24 ~ 38 104 140 132.8 122 39 ~ 54 120.2 149 140 132.8 55 ~ 69 136.4 154.4 140 140 70 ~ 85 149 158 140 140

86 ~ Maximum 158 158 140 140

1 unit 2 units 1 unit 2 units

COOL HEAT

Target discharge temperature (°F)

Number of operating unit

MXZ-2A20NA-

Operation frequency

of compressor (Hz)

Minimum ~ 23 95 136.4 122 122

24 ~ 38 104 140 132.8 122 39 ~ 54 120.2 149 140 132.8 55 ~ 69 136.4 154.4 145.4 140 70 ~ 85 149 158 150.8 140

86 ~ Maximum 158 158 152.6 140

MXZ-2B20NA MXZ-2B20NA-

1,2

COOL HEAT

1 unit 2 units 1 unit 2 units

Target discharge temperature (°F)

Number of operating unit

MXZ-3A30NA

Target discharge temperature (°F)

Operation frequency

of compressor (Hz)

1 unit 2 units 3 units 1 unit 2 unit 3 units

Minimum ~ 14 95 131 134.6 125.6 143.6 122

15 ~ 23 104 131 134.6 136.4 150.8 131 24 ~ 32 120.2 136.4 145.4 149 165.2 140 33 ~ 41 136.4 140 149 154.4 172.4 152.6 42 ~ 50 149 149 158 154.4 172.4 161.6 51 ~ 59 154.4 154.4 163.4 154.4 172.4 168.8 60 ~ 68 158 158 167 154.4 172.4 168.8 69 ~ 77 167 163.4 176 154.4 172.4 168.8 78 ~ 86 167 167 179.6 154.4 172.4 168.8

87 ~ Maximum 167 176 179.6 172.4 172.4 168.8

COOL HEAT

Number of operating unit

MXZ-3A30NA-1 MXZ-4A36NA

Operation frequency

of compressor (Hz)

1 unit 2 units 3 units

Minimum ~ 14 95 131 134.6 140 125.6 143.6 122 122

15 ~ 23 107.6 131 134.6 140 136.4 150.8 131 122 24 ~ 32 120.2 136.4 145.4 140 149 165.2 140 122 33 ~ 41 136.4 140 149 143.6 154.4 172.4 152.6 122 42 ~ 50 149 149 158 149 154.4 172.4 161.6 131 51 ~ 59 154.4 154.4 163.4 158 154.4 172.4 168.8 140 60 ~ 68 158 158 167 158 154.4 172.4 168.8 140 69 ~ 77 167 163.4 176 161.6 154.4 172.4 168.8 140 78 ~ 86 167 167 179.6 161.6 154.4 172.4 168.8 140

87 ~ Maximum 167 176 179.6 161.6 172.4 172.4 168.8 140

Correct the LEV opening according to the difference between target discharge temperature and discharge temperature.

MXZ-3B24NA MXZ-3B30NA MXZ-4B36NA

Target discharge temperature (°F)

COOL HEAT

Number of operating unit

4 units

(MXZ-4A/4B)

1 unit 2 unit 3 units

4 units

(MXZ-4A/4B)

MXZ-2A MXZ-2B

Discharge temperature (°F)

More than Target discharge temperature+18 5 8 Target discharge temperature + 18 to Target discharge temperature + 9 4 3 Target discharge temperature + 9 to Target discharge temperature + 3.6 2 1 Target discharge temperature + 3.6 to Target discharge temperature - 3.6 0 0 Target discharge temperature - 3.6 to Target discharge temperature - 9 -1 -1 Target discharge temperature - 9 to Target discharge temperature - 18 -3 -2 Target discharge temperature - 18 or less -4 -3

LEV opening correction (pulse)

COOL HEAT

MXZ-3A MXZ-4A MXZ-3B MXZ-4B

Discharge temperature (°F)

More than Target discharge temperature + 21.6 4 6 Target discharge temperature + 21.6 to Target discharge temperature + 9 2 2 Target discharge temperature + 9 to Target discharge temperature + 5.4 1 1 Target discharge temperature + 5.4 to Target discharge temperature - 5.4 0 0 Target discharge temperature - 5.4 to Target discharge temperature - 9 -1 -1 Target discharge temperature - 9 to Target discharge temperature - 21.6 -3 -2 Target discharge temperature - 21.6 or less -8 -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.

Calculate each super heat of the unit from the expression below;

(Super heat) = (Each gas pipe temperature) - (Minimum gas pipe temperature)

Separate correction is performed according to each super heat in the table below.

MXZ-2A20NA

Superheat

More than 16.2 3

10.8 to 16.2 2

5.4 to 10.8 1

5.4 or less 0

correction (pulse)

LEV opening

MXZ-3A30NA

Superheat

More than 16.2 12

10.8 to 16.2 8

5.4 to 10.8 4

5.4 or less 0

LEV opening correction (pulse)

COOL HEAT

LEV opening

correction (pulse)

b) Correct the LEV separately by temperature difference “ ∆RT” between main/sub indoor coil thermistor.

∆RT

10.8

∆RT 2

LEV opening

correction (pulse)

7.2 ∆RT < 10.8 1 ∆RT < 7.2 1

In addition, decrease the target discharge temperature corresponding ∆RT.

∆ RT

10.8

∆RT 18

∆RT< 10.8 9

7.2

Temperature to be

decreased (°F)

∆RT < 7.2 9

3-3. OPERATIONAL FREQUENCY RANGE

MXZ-2A20NA

Number of operating

unit

Capacity code

COOL (Hz)

Min. Max. Min. Max. Defrost

DRY (Hz)

4 206525489292 7 208530489292

9,10 20 100 75 48 100 100

12 20 100 75 48 100 100

8 ~ 10 30 105 52 58 112 100

11 ~ 13 30 105 52 58 112 100

14 ~ 16 30 105 52 58 112 100

17 ~ 20 105 100 58 112 100

HEAT (Hz)

MXZ-2A20NA-

Number of operating

unit

MXZ-2A20NA-

Number of operating

unit

Capacity code

COOL (Hz)

Min. Max. Min. Max. Defrost

DRY (Hz)

HEAT (Hz)

4 206535489292 7 208534489292

9,10 20 93 75 48 92 92

12 20 93 75 48 92 92

8 ~ 10 30 93 52 58 110 101 11 ~ 13 30 93 52 58 110 101 14 ~ 16 30 93 52 58 110 101

17 ~ 30 93 93 58 110 101

Capacity code

COOL (Hz)

Min. Max. Min. Max. Defrost

DRY (Hz)

HEAT (Hz)

4 206525309292 7 208534309292

9,10 20 93 75 30 92 92

12 20 93 75 30 92 92

8 ~ 10 40 93 53 58 112 100 11 ~ 13 40 93 53 58 112 100 14 ~ 16 40 93 53 58 112 100

17 ~ 40 93 93 58 112 100

MXZ-2B20NA

Number of operating

unit

Capacity code

COOL (Hz)

Min. Max. Min. Max. Defrost

DRY (Hz)

HEAT (Hz)

3, 4 206525309292

7 208534309292

9, 10 20 93 75 30 92 92

12 20 93 75 30 92 92

2 ~ 7 30 93 53 58 112 100

8 ~ 10 30 93 53 58 112 100 11 ~ 13 30 93 53 58 112 100 14 ~ 16 30 93 53 58 112 100

17 ~ 30 93 93 58 112 100

MXZ-2B20NA-

Number of operating

unit

MXZ-3A30NA

Number of operating

unit

3 12 ~ 52 90 65 39 94 58

Capacity code

COOL (Hz)

Min. Max. Min. Max. Defrost

DRY (Hz)

HEAT (Hz)

3, 4 206530309292

7 208530309292

9, 10 20 93 38 30 92 92

12 20 93 62 30 92 92

5 ~ 7 30 93 58 58 112 99

8 ~ 10 30 93 58 58 112 99 11 ~ 13 30 93 58 58 112 99 14 ~ 16 30 93 58 58 112 99

17 ~ 30 93 58 58 112 99

Capacity code

COOL (Hz)

Min. Max. Min. Max. Defrost

DRY (Hz)

HEAT (Hz)

4 155820224848 7 155825224848

9,10 15 62 44 22 62 58

12 15 68 44 22 90 58

8 ~ 10 24 80 31 35 70 58 11 ~ 13 24 80 31 35 90 58 14 ~ 16 24 80 31 35 94 58

17 ~ 24 80 59 35 94 58

MXZ-3A30NA-1 MXZ-4A36NA

Number of operating

unit

Capacity code

COOL (Hz)

Min. Max. Min. Max. Defrost

DRY (Hz)

HEAT (Hz)

4 255825207058

7 255825207058

9,10 25 71 25 20 80 58

12 25 80 35 20 80 58

8 ~ 10 25 80 31 20 80 58

11 ~ 13 25 80 31 20 80 58 14 ~ 16 25 80 42 20 80 58

17 ~ 25 80 42 20 80 58

3 (MXZ-3A) 12 ~ 25 80 52 20 80 58 3 (MXZ-4A) 12 ~ 25 90 52 20 103 58 4 (MXZ-4A) 16 ~ 25 90 52 20 113 58

MXZ-3B24NA MXZ-3B30NA MXZ-4B36NA

Number of operating

unit

Capacity code

COOL (Hz)

Min. Max. Min. Max. Defrost

DRY (Hz)

HEAT (Hz)

3,4 15 58 22 25 70 70

7 155822257070

9,10 15 71 31 25 80 80

12 15 80 42 25 80 80

5 ~ 7 25 80 35 35 80 80

8 ~ 10 25 80 35 35 80 80

11 ~ 13 25 80 35 35 80 80

14 ~ 16 25 80 35 35 80 80

17 ~ 25 80 52 35 80 80

3 (MXZ- 3B) 9 ~ 52 80 52 39 80 80

3 (MXZ-4B) 9 ~ 52 90 52 39 103 80 4 (MXZ-4B) 12 ~ 62 90 70 52 113 80

3-4. HEAT DEFROSTING CONTROL

(1) Starting conditions of defrosting

When the following conditions a) ~ c) are satisfied, the defrosting starts. a) The defrost thermistor reads 26.6°F or less. b) The cumulative operation time of the compressor has reached any of the set values

utes).

c) More than 5 minutes have passed since the start-up of the compressor.

The defrost interval is decided by the previous defrosting time. The next defrost interval extends or shortens 0-20

minutes compared with the previous defrost interval.

(2) Releasing conditions of defrosting

Defrosting is released when any one of the following conditions is satisfied: a) The defrost thermistor continues to read 50.7°F. b) Defrosting time exceeds 10 minutes. c) Any other mode than HEAT mode is set during defrosting.

(defrost interval: 40-150 min-

3-5. 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 240.8°F, the control stops the compressor. When temperature of the discharge temperature thermistor is 176°F (2A/3A30NA/2B)/ 212°F (3A30NA-

less, the controls starts the compressor. (2) Compressor operation frequency When temperature of the discharge temperature thermistor is expected to be higher than 240.8°F, the control decreases

12 Hz from the current frequency. When temperature of the discharge temperature thermistor is expected to be higher than 231.8°F and less than 240.8°F,

the control decreases 6 Hz from the current frequency. When temperature of the discharge temperature thermistor is expected to be higher than 219.2°F and less than 231.8°F,

the control is set at the current frequency.

/4A/3B/4B) or

3-6. OUTDOOR FAN CONTROL

Down

Fan speed

High

Low

Compressor frequency

Min.

Max.

Down

Fan speed

High

Low

Compressor frequency

Min.

Max.

Fan speed is switched according to the number of operating indoor unit and the compressor frequency.

MXZ-2B20NA

Compressor frequency (Hz)

Down Up

MXZ-2B20NA 30 40

NOTE: When the indoor coil thermistor is 134.6 ˚F or more on HEAT operation, fan speed is fixed to Low speed.

Or, the indoor coil thermistor is 113 ˚F or less on HEAT operation, fan speed is back to normal.

MXZ-2B20NA-1 MXZ-3B MXZ-4B

COOL

Fan speed changes so that the condensing temperature stays within the target range.

Revolution per minutes (rpm)

Fan speed

1 100 100 2 150 150 3 200 200 4 250 250 5 300 300 6 350 350 7 400 400 8 450 450

9 500 500 10 550 550 11 600 600 12 650 650 13 700 700 14 750 750

HEAT Fan speed is switched according to the compressor frequency.

Fan speed

Up 30 50

Down 23 40

MXZ-2B20NA-

Compressor speed (Hz)

MXZ-2B20NA-

MXZ-3B MXZ-4B

Frequency (Hz) Target condensing temperature (ºF)

~24 88-95 25~34 91-99 35~44 95-102 45~54 99-106 55~64 99-106

65~ 99-106

3-7. PRE-HEAT CONTROL

Power ON

OFF

Compressor

ON OFF

Pre-heat ON

OFF

Breaker ON

69.8°F (21°C)

Stop operation

Start operation

Defrost thermistor

30 minutes 30 minutes 30 minutes 30 minutes 30 minutes 30 minutes

15 minutes

30minutes

When the defrost thermistor reads

69.8°F(21°C) or more

MXZ-2A20NA-

MXZ-3A30NA-1 MXZ-4A36NA MXZ-2B20NA MXZ-2B20NA-

1,2

MXZ-3B24NA MXZ-3B30NA MXZ-4B36NA

The compressor is energized even while it is not operating. This is to generate heat at the winding to improve the compressor's start-up condition.

1. Pre-heat control is turned ON for 15 or 30 minutes, after the breaker is turned ON.

2. 30 minutes after the unit is stopped, pre-heat control is turned ON for 15 or 30 minutes and turned OFF for 30 minutes. This is repeated as shown in the graph until the breaker is turned OFF.

NOTE: When the unit is started with the remote controller, pre-heat control is turned OFF. Compressor uses 50 W when pre-heat control is turned ON.

3-8. COOL OPERATION

1. Thermostat control

2. Coil frost prevention

When the defrost thermistor reads less than 69.8°F, pre-heat control is ON for 30 minutes.

When the defrost thermistor reads 69.8°F or more, pre-heat control is ON for 15 minutes.

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

Thermostat

ON -1.8°F(-1°C) or more OFF less than -1.8°F(-1°C)

Room temperature minus set temperature (Initial)

Room temperature minus set temperature (During operation)

-1.8°F (-1°C)

-1.35°F

(-0.75°C)

The compressor operational frequency is controlled to prevent the indoor heat exchanger temperature from falling excessively. Compressor is turned OFF for 5 minutes when temperature of indoor coil thermistor continues 37.4°F or less for 5 minutes or more.

3-9. DRY OPERATION

ON less than 3.6°F(2°C) OFF 3.6°F(2°C) or more

1.35°F

(0.75°C)

1.8°F (1°C)

Thermostat

Room temperature minus set temperature (Initial)

Room temperature minus set temperature (During operation)

1. Thermostat control

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

Thermostat

Room temperature minus set temperature (Initial)

Room temperature minus set temperature (During operation)

ON -3.6°F(-2°C) or more OFF less than -3.6°F(-2°C)

-3.6°F (-2°C)

-1.35°F

(-0.75°C)

2. Coil frost prevention

Coil frost prevention is as same as COOL mode. (3-8.2.)

3-10. HEAT OPERATION

1. Thermostat control

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

MXZ-2A/3A/4A

Thermostat

Room temperature minus

set temperature (Initial) ON less than 3.6°F(2°C) OFF 3.6°F(2°C) or more

MXZ-2B/3B/4B

2. 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.

Room temperature minus set temperature (During operation)

3.15°F

(1.75°C)

3.6°F (2°C)

°F

50 59 68 77 86 95

Set temperature

Initial room temperature

Set temperature and initial room temperature in dry mode

°F

High 3.15°F(1.75°C) or more Med. between 1.8 and 3.15°F Low

less than 1.8°F(1°C)

3.15°F (1.75°C)

5.4°F (3°C)

1.8°F (1°C)

Fan speed

Room temperature minus set temperature (Initial)

Room temperature minus

set temperature (During operation) High 3.15°F(1.75°C) or more Med. between 1.8 and 3.15°F Low

less than 1.8°F(1°C)

3.15°F (1.75°C)

4.5°F

(2.5°C)

1.8°F (1°C)

Fan speed

Room temperature minus set temperature (Initial)

Room temperature minus

set temperature (During operation)

MFZ MICROPROCESSOR CONTROL

4-1. COOL ( ) OPERATION

1. Thermostat control Refer to MXZ MICROPROCESSOR CONTROL, COOL OPERATION (3-8.1.).

2. Indoor fan speed control

Indoor fan operates continuously at the set speed by FAN SPEED CONTROL button regardless of the thermostat's OFF-

ON. In AUTO the fan speed is as follows.

3. Coil frost prevention

Refer to MXZ MICROPROCESSOR CONTROL, COOL OPERATION (3-8.2.).

4-2. DRY (

) OPERATION

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.

1. Thermostat control Refer to MXZ MICROPROCESSOR CONTROL, DRY OPERATION (3-9.1.).

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.

3. Coil frost prevention

Coil frost prevention is as same as COOL mode. (4-1.3.) The indoor fan maintains the actual speed of the moment.

4-3. HEAT ( ) OPERATION

High Med. Low

Fan speed

Set temperature minus room temperature (During operation)

Set temperature minus room temperature (Initial)

Between 0.45 and 3.6°F

3.6°F(2°C) or more

Less than 0.45°F(0.25°C)

0.45°F

(0.25°C)

3.15°F

(1.75°C)

3.6°F (2°C)

7.2°F (4°C)

1. Thermostat control Refer to MXZ MICROPROCESSOR CONTROL, HEAT OPERATION (3-10.1.).

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.

(2) Cold air prevention control

When the compressor is not operating: ( ) If the temperature of room temperature thermistor RT11 is less than 66.2°F, the fan stops. ( ) If the temperature of room temperature thermistor RT11 is 66.2°F or more and

( ) if the temperature of indoor coil thermistor is less than 32°F, the fan stops. (

) if the temperature of indoor coil thermistor is 32°F or more, the fan operates at Very Low.

When the compressor is operating: ( ) If the temperature of indoor coil thermistor is 104°F or more, the fan operates at set speed. ( ) If the temperature of indoor coil thermistor is less than 104°F and

( ) if heating operation starts after defrosting, the fan stops.

) if the temperature of room temperature thermistor RT11 is 66.2°F or less, the fan stops.

( (

) if the temperature of room temperature thermistor RT11 is more than 66.2°F, the fan operates at Very Low.

NOTE: • When 2 or more indoor units are operated with a multi type outdoor unit, the fan operates intermittently at Very Low or stops in the thermostat-OFF units while at least one unit is thermostat-ON.

• 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. Defrosting Refer to MXZ MICROPROCESSOR CONTROL, HEAT DEFROSTING CONTROL (3-4.).

Time chart of defrosting in HEAT mode (reverse type)

Horizontal vane

Indoor fan (upper)

Indoor fan (lower)

Damper

set position

set speed

OPEN or CLOSE

Very Low (temperature of indoor coil thermistor > 64.4°F)

seconds

vertical

OFF

set position

set speed

OPEN or CLOSE

4-4. 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.

If the room temperature thermistor RT11 reads more than set temperature, COOL mode is selected. 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.

COOL mode changes to HEAT mode when 15 minutes have passed with the room temperature 35.6°F below the set

temperature.

HEAT mode changes to COOL mode when 15 minutes have passed with the room temperature 35.6°F 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: When two or more indoor units are operating simultaneously, the indoor unit, which is operating in AUTO ( might not be able to change over the operating mode (COOL HEAT) and becomes the standby state.

(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.

4-5. 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 feed-

back 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

High

Med.

Low

Super High

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 locks up, OPERATION INDICATOR lamp flashes ON and OFF to show the fan motor abnormality.

4-6. AUTO VANE OPERATION

35.6°F (2°C)

44.6°F (7°C)

Difference between room temperature and set temperature during operation

Damper

OPEN

95°F

(35°C)

104°F

(40°C)

Indoor coil thermistor temperature

Damper

OPEN

Difference between room temperature and set temperature during operation

Indoor coil thermistor temperature

Horizontal vane

(1) Cold air prevention in HEAT operation

When any of the following conditions occurs in HEAT operation, the vane angle changes to Vertical position automatically to prevent cold air blowing on users.

Compressor is not operating. Defrosting is performed. Indoor coil thermistor reads 75.2°F or below. Indoor coil thermistor temperature is raising from 75.2°F or below, but it does not exceed 102.2°F.

Indoor coil thermistor temperature

Released

Cold Air Prevention

75.2°F (24°C)

Horizontal vane

102.2°F (39°C)

Set position

Vertical Position

NOTE: The horizontal vane automatically moves in certain intervals to determine its position, and then it returns to the set

position.

Indoor fan motor (Lower) in COOL OPERATION

Indoor fan motor (Lower) in HEAT OPERATION

• As for indoor fan motor (upper), refer to "Indoor fan speed control (2-1.2, 2-2.2, 2-3.2)" and "INDOOR FAN MOTOR CONTROL (2-5.)".

<SWING operation> In swing operation of ECONO COOL operation mode, the initial airflow direction is adjusted to "Horizontal". According to the temperature of indoor coil thermistor 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 35.6°F, 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 (°F)

59 or less 2 23

More than 75 23 2

Downward blow time (second) Horizontal blow time (second)

59 to 63 5 20

63 to 64 8 17

64 to 68

11 14

68 to 70 14 11

70 to 72 17 8

72 to 75 20 5

HEAD OFFICE: TOKYO BLDG.,2-7-3, MARUNOUCHI, CHIYODA-KU, TOKYO 100-8310, JAPAN

© Copyright 2006 MITSUBISHI ELECTRIC CO.,LTD Distributed in Sep. 2010. No. OBT16 REVISED EDITION-G 6 Distributed in Mar. 2010. No. OBT16 REVISED EDITION-F 6 Distributed in Sep. 2009. No. OBT16 REVISED EDITION-E 5 Distributed in Mar. 2009. No. OBT16 REVISED EDITION-D 4 Distributed in Jul. 2008. No. OBT16 REVISED EDITION-C 6 Distributed in Feb. 2008. No. OBT16 REVISED EDITION-B 6 Distributed in May 2007. No. OBT16 REVISED EDITION-A 7 Distributed in Apr. 2006. No. OBT16 7 Made in Japan

New publication, effective Sep. 2010. Specifications subject to change without notice.

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