Mitsubishi Electronics MUZ-ANA - U, MSY-ANA, MUZ-ANA, MUZ-FDNA - U, MUY-ANA User Manual

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Revision B:

• MXZ-2A20NA-

MSZ-D and MSY-D have been added.

Please void OBT16 REVISED EDITION-A.

, MXZ-4A36NA, MSZ-FD,

REVISED EDITION-B

SERVICE TECHNICAL GUIDE

Wireless type Models

No. OBT16

MS-A•WA MSZ-A•NA

· MU-A•WA

· MUZ-A•NA

· MUZ-A•NA MSY-A•NA · MUY-A•NA MSZ-FD•NA

MSZ-D•NA

· MUZ-D•NA -

MSY-D•NA

Inverter-controlled multi system type Models

· MUZ-FD•NA

· MUZ-FD•NA -

· MUZ-D•NA

· MUY-D•NA

· MXZ-A•NA

CONTENTS

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

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

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

Revision A:

• MXZ-3A30NA-

Revision B:

• MXZ-2A20NA-

has been added.

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

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

Indoor unit models Outdoor unit models

MS-A09WA MU-A09WA MS-A12WA MU-A12WA

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-A09NA MSZ-FD09NA MUZ-A09NA MUZ-FD09NA MSZ-A12NA MSZ-FD12NA MUZ-A12NA MUZ-FD12NA MSZ-A15NA MSZ-D30NA MUZ-A15NA MUZ-D30NA MSZ-A17NA MSZ-D36NA MUZ-A17NA MUZ-D36NA MSZ-A24NA MSY-D30NA MUZ-A24NA MUY-D30NA MSY-A15NA MSY-D36NA MUY-A15NA MUY-D36NA MSY-A17NA MUY-A17NA MSY-A24NA MUY-A24NA

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

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

Outdoor unit models

MXZ-2A20NA MXZ-3A30NA MXZ-4A36NA

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 ·······················30 3-6. OUTDOOR FAN CONTROL ································································ 3-7. PRE-HEAT CONTROL ········································································· 3-8.

COOL OPERATION ····················································································31 3-9.

DRY OPERATION ·································································· BACK COVER 3-10. HEAT OPERATION ···························································

BACK COVER

30 30

MS MICROPROCESSOR CONTROL

MS-A•WA MU-A•WA

1-1. COOL ( ) OPERATION

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

Room temperature minus

Thermostat

set temperature (Initial)

ON -1.8 °F or more

-1.8 °F

OFF less

than

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.

Fan speed

Room temperature minus

set temperature (Initial) High 3.1 °F or more Med. between 1.8 and 3.1 °F Low less than 1.8 °F

3. Coil frost prevention

Temperature control When the indoor coil thermistor RT12 reads 37 °F or below the coil frost prevention mode starts immediately. However, the coil frost prevention doesn’t 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, this mode is prolonged until the indoor coil thermistor reads

over 37 °F.

Time control When the three 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. 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.

However, when two of the above conditions (b. and c.) are satisfied again. Time accumulation is resumed.

Room temperature minus set temperature (During operation)

-1.8 °F

-1.3 °F

Room temperature minus set temperature (During operation)

5.4 °F

1.8 °F

3.1 °F

Operation chart Example

Compressor Outdoor fan

Indoor fan

ON OFF

( 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

°F

initial room temperature in dry mode

Set temperature

50 59 68 77 86 95

Initial room temperature

°F

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

Room temperature minus

Thermostat

set temperature (Initial)

ON -1.8 °F or more OFF less

than

-1.8 °F

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 3.1 F or more Med. between 1.8 and 3.1 F Low less than 1.8 F

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 from initial room temperature. Indoor fan and outdoor fan operate in the same cycle as the compressor.

•When the room temperature is 73 °F 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. 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)

-1.8 °F

-1.3 °F

Room temperature minus set temperature (During operation)

4.5 F

1.8 F

3.1 F

Operation time chart Example

Thermostat

OFF

Indoor fan

OFF

Outdoor fan Compressor

ON 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 higher than that in COOL mode. Also the horizontal vane swings in various cycle according to the temperature of indoor heat exchanger (indoor coil thermistor). SWING operation makes you feel cooler than set temperature. So, even though the set temperature is higher than that in COOL mode, the air conditioner can keep comfort. As a result, energy can be saved. ECONO COOL operation is cancelled when ECONO COOL button is pressed once again or VANE CONTROL button is pressed or change to other operation mode.

<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, the swing operation is performed in table D~H for more cooling. The air conditioner repeats the swing operation in various cycle as follows.

A 59 or less 2 23 B 59 to 63 5 20 C 63 to 64 8 17 D 64 to 68 11 14 E 68 to 70 14 11

F 70 to 72 17 8 G 72 to 75 20 5 H more than 75 23 2

) operation (ECONOmical operation)

Temperature of indoor

coil thermistor (°F)

Downward blow time

(second)

Horizontal blow time

(second)

MSZ,MSY MICROPROCESSOR CONTROL

MSZ-A•NA MSY-A•NA MUZ-A•NA MUY-A•NA MSZ-FD•NA MSY-D•NA MUZ-FD•NA MUY-D•NA MSZ-D•NA MUZ-D•NA

2-1. COOL ( ) OPERATION

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

Room temperature minus

Thermostat

ON -1.8 °F or more OFF less

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.

MSZ-A MSY-A

Fan speed

High 3.1 °F or more Med. between 1.8 and 3.1 °F Low less than 1.8 °F

set temperature (Initial)

-1.8 °F

than

Room temperature minus set temperature (Initial)

Room temperature minus set temperature (During operation)

-1.8 °F

Room temperature minus set temperature (During operation)

1.8 °F

3.1 °F

-1.3 °F

5.4 °F

MSZ-FD MSZ-D MSY-D

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 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 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 rotation 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 10 °F (MUZ-A MUY-A MUZ-D MUY-D), -4 °F (MUZ-FD) 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. (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 64 °F, the unit goes back to the normal COOL mode. If the

outside temperature stays below 64 °F, the unit continues to run in the low outside temperature operation mode.

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

Fan speed

High 2.7 °F or more Med. between Low less than 1.8 °F

Room temperature minus set temperature (Initial)

1.8 and 2.7 °F

Room temperature minus set temperature (During operation)

5.4 °F

1.8 °F

2.7 °F

2-2. 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

°F

initial room temperature in dry mode

Set temperature

50 59 68 77 86 95

Initial room temperature

°F

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

Thermostat

Room temperature minus set temperature (Initial)

Room temperature minus set temperature (During operation)

ON -1.8 °F or more OFF less than

-1.8 °F

-1.3 °F

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.

Fan speed

Room temperature minus set temperature (Initial)

Room temperature minus

set temperature (During operation) High 3.1 F or more Med. between 1.8 and 3.1 F Low less than 1.8 F

1.8 F

4.5 F

3.1 F

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

Thermostat

ON less than 3.6 °F OFF 3.6

2. Indoor fan speed control

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

In Auto the fan speed is as follows.

Fan speed

High Med. between 0.4 and 3.6 °F Low

Room temperature minus set temperature (Initial)

°F or more

Room temperature minus set temperature (Initial)

3.6 °F

or more

less than

0.4 °F

Room temperature minus set temperature (During operation)

3 °F

3.6 °F

Room temperature minus set temperature (During operation)

7.2 °F

0.4 °F

3.6 °F

3 °F

(2) Cold air prevention control

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

When the compressor is not operating,

(

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

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

(

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

(

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

(

When the compressor is operating,

(

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

) if the temperature of indoor coil themistor is less than 104 °F and

(

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

(

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

(

) if the temperature of room temperature thermistor is more than 66 °F, 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.

MSZ-A24

When the compressor is not operating,

) if the temperature of room temperature thermistor is 59 °F or less, or temperature of indoor coil thermistor is

(

less than 64 °F, the fan stops.

(

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

more than 64 °F, the fan operates at Very Low.

When the compressor is operating,

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

( (

) if the temperature of indoor coil themistor is less than 64 °F and

( ) if heating operation starts after defrosting, the fan stops. ( ) if the temperature of room temperature thermistor is 59 °F or less, the fan stops. ( ) if the temperature of room temperature thermistor is more than 59 °F, 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)

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.

When warm air control works, the fan speed changes as follows to blow out warm air gradually.

Gradation of fan speed in initial

<Time condition> <Indoor fan speed> Less than 2 minutes ------------ Low 2 minutes 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 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 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 27 °F or less. b) The cumulative operation time of the compressor has reached any of the set values

(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.

Set value of compressor operation time (here in after referred to as defrost interval)

This is decided by the temperature of defrost thermistor, ambient temperature thermistor, and the previous defrosting

time. For example, the first defrost interval is 40 minutes long, and the second is 45 minutes long. The third and subsequent intervals are set to be longer, and less frequent, depending on defrosting time.

The third and subsequent defrost intervals follow any of the three patterns …5 or 10 to 20 minutes longer, the same,

or 5 or 10 to 20 minutes shorter compared with the previous defrost interval … with the longest 125 minutes and the shortest 40 minutes.

(2) Releasing conditions of defrosting

Defrosting is released when any of the following conditions is satisfied: a) The defrost thermistor continues to read 50 °F or more (MUZ-A09/12 MUZ-D) / 41 °F or more (MUZ-A15/17 MUZ-FD) /

59 °F or more (MUZ-A24) 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)

Horizontal vane

Indoor fan

Compressor normal

Outdoor fan

set position

set speed

seconds

ON ON

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

Very Low (temperature of indoor coil thermistor > 64 °F)

seconds

Maximum frequency

OFF

seconds

5 seconds 5 seconds

horizontal

OFF

seconds

OFF

seconds

set position

set speed

R.V. coil

(21S4)

ON (HEAT)

OFF (COOL)

ON (HEAT)

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 4 °F below the set

temperature.

HEAT mode changes to COOL mode when 15 minutes have passed with the room temperature 4 °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: If two or more indoor units are operating in multi system, there might be a case that the indoor unit, which is

operating in AUTO ( ), cannot change over the other operating mode (COOL HEAT) and becomes a state of standby.

(3) Indoor fan control/ Vane control

As the indoor fan speed and the horizontal vane position depend on the selected operation mode, when the operation mode changes over, they change to the exclusive ones.

2-5. 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 33 44

33 44

MUZ-D MUY-D

39 54

2-6. AUTO VANE OPERATION

1. Horizontal vane

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

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.

Compressor is not operating.

Defrosting is performed. Indoor coil thermistor temperature does not exceed 102 °F 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 doesn’t work in the indoor unit. (2) ECONO COOL ( ) operation (ECONOmical operation) When ECONO COOL button is pressed in COOL mode, set temperature is automatically set 3.6 °F higher than that in

COOL mode.

Also the horizontal vane swings in various cycle according to the temperature of indoor heat exchanger (indoor coil

thermistor).

SWING operation makes you feel cooler than set temperature. So, even though the set temperature is higher than that

in COOL mode, the air conditioner can keep comfort. As a result, energy can be saved.

ECONO COOL operation is cancelled when ECONO COOL button is pressed once again or VANE CONTROL button is

pressed or change to other operation mode.

<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 3.6 °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)

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

POWER SUPPLY

NOISE FILTER CIRCUIT

RESISTOR

RELAY

Downward blow time

(second)

REACTOR

DIODE MODULE1

Horizontal blow time

(second)

CURRENT TRANSFORMER

SMOOTHING CAPACITOR

IPM

COMPRESSOR

DIODE MODULE2

BOOSTER CHOPPER CIRCUIT

SWITCHING POWER TRANSISTOR

Function of main parts

NAME FUNCTION INTELLIGENT POWER MODULE (IPM) It supplies three-phase AC power to compressor. SMOOTHING CAPACITOR It stabilizes the DC voltage and supply 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

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.

DIODE MODULE 2 BOOSTER CHOPPER CIRCUIT

SWITCHING POWER TRANSISTOR

REACTOR

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

MUZ-A24 MUY-A24 MUZ-D MUY-D

POWER SUPPLY

NOISE FILTER CIRCUIT

RESISTOR

RELAY

REACTOR

PFC

SMOOTHING CAPACITOR

U V

IPM

Function of main parts

NAME FUNCTION INTELLIGENT POWER MODULE (IPM) It supplies three-phase AC power to compressor. SMOOTHING CAPACITOR It stabilizes the DC voltage and supplies it to IPM.

CURRENT TRANSFORMER REACTOR

POWER FACTOR CORRECTION MODULE (PFC)

It measures the current of the compressor motor. It measures the current of the main power supply circuit.

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

CURRENT TRANSFORMER

COMPRESSOR

RESISTOR It restricts rush current with the resistance.

RELAY

It short-circuits the resistance which restricts rush current during the compressor operates.

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

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 three-phase AC by IPM and supplied to COMPRES-

SOR.

CURRENT TRANSFORMER, which is placed in the power supply circuit to COMPRESSOR, are used to measure the val-

ue of phase current and locate the polar direction of rotor with algorithm. PWM (Pulse width modulation) controls impressed voltage and frequency with those information.

3. Purpose of PAM adoption

PAM : Pulse Amplitude Modulation PAM has been adopted for the efﬁ ciency improvement and the adaptation to IEC harmonic current 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.

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

No electricity runs into diode module because the voltage at both sides of smoothing capacitor is higher than input voltage.

Input current

Energized time is short in case L inductance is small.

Owing to the increase of energized time;

· Power factor gets better.

· Harmonic gets suppressed.

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. Elimination of electrical noise 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

MUZ-A24 MUY-A24 MUZ-D MUY-D

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 are placed in sub circuit.

2. At normal operation

When AC runs into noise filter P.C. board, its external noise is eliminated in NOISE FILTER CIRCUIT. After noise being 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 three-phase AC by IPM and supplied to

COMPRESSOR. CURRENT TRANSFORMER, which is 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 im-

pressed voltage and frequency with those information.

3. Power factor improvement Booster coil reactor and power factor controller 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. Power transistor module IPM consists of the following components.

· Power Transistors (x6) : Converts DC waveform to three-phase AC waveform and outputs it.

· Drive Circuit : Drives transistors.

· Protection circuit : Protects transistors from over current. Since the above components are all integrated in IPM, IPM has a merit that can get the control circuit simplified and miniaturized.

5. Elimination of electrical noise NOISE FILTER CIRCUIT, which is formed by *CMC COILS and capacitors placed on the noise filter P.C. board, eliminates electrical noise of AC power that is supplied to main power supply circuit. In short, common mode noise is absorbed in this circuit. Moreover, normal mode noise is absorbed in another NOISE FILTER CIRCUIT which is formed by *NMC COILS and capacitors. Both NOISE FILTER CIRCUIT exists for preventing the electrical noise generated in the inverter circuit from leaking out.

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

2-7-3. Sine wave control

In these air conditioners, compressor equips brushless DC motor which doesn't have Hall element. In short, the motor is sensorless. However, it's necessary to locate the polar direction of rotor in order to drive brushless DC motor 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 three-phase induction motor requires energy to excite the magnetic ﬁ eld of rotor, brushless DC motor

●

doesn't need it. So, higher efﬁ ciency and torque are provided.

This control provides the most efﬁ cient 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 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 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 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 Rotation Times

Sine wave control makes the current transformers conduct real time detection of the value of the current running into the motor, locates the rotor position from the detected value, and decides if voltage should be impressed and if frequency should be changed. Compared to the conventional control and rotor position detection method, sine wave control can provide 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 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 HEAT (MUZ)DRY

Unit: Hz

Applied model

MUZ-A09 32 70 32 76 32 57 MUZ-A12 32 73 32 71 32 57

MUZ-A15 MUY-A15

MUZ-A17 MUY-A17

MUZ-A24 MUY-A24

MUZ-FD09 10 52 10 100 10 41 MUZ-FD12 10 62 10 100 10 41 MUZ-D30 20 84 20 87 20 83 MUY-D36 20 79 — — 20 79 MUZ-D36 20 91 20 94 20 83 MUY-D36 20 92 — — 20 79

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.

Minimum

frequency

10 82 15 93 10 68 10 87 15 93 10 68 15 110 15 108 15 102

Maximum frequency

Minimum

frequency

Maximum frequency

Minimum

frequency

Maximum frequency

Upper limit 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 °F set for each operational

frequency of the compressor. However, when any change in indoor/outdoor temperatures or other factors cause air conditioning load fluctuation, the LEV control also works to correct LEV opening degree based on discharge temperature (Shell temperature) of the compressor, developing the unit’s performance.

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

59 pulse (MUZ-A24 MUY-A24)

Control range

Maximum : 500 pulse Actuating speed Opening degree adjustment LEV opening degree is always adjusted in opening direction.

Standard specification

Unit OFF LEV remains at maximum opening degree (reaches maximum

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

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

Open : 40 pulse/second Close : 90 pulse/second.

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

opening degree approximate in 15 minutes after compressor stops)

tioned.) LEV is fixed to standard opening degree according to opera-

tional frequency of compressor.

54 pulse (MUZ-FD) 58 pulse (MUZ-D MUY-D)

HEAT MODE During 1 to 15 minutes after compressor starts

More than 5 (COOL, DRY), 15 (HEAT (MUZ)) minutes have passed since compressor start-up

General operation

Thermostat OFF

Thermostat ON

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

LEV opening degree is corrected to get target discharge temperature of compressor. (For lower discharge temperature than target temperature, LEV is corrected in closing direction.) (For higher discharge temperature than target temperature, LEV is corrected in opening direction.)

It may take more than 30 minutes to reach target tempera-

ture, depending on operating conditions.

LEV is adjusted to exclusive opening degree for thermostat OFF.

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

(2) Time chart

Air conditioner ON

Air conditioner OFF (thermostat off)

LEV opening degree

of the compressor

Operational frequency

(3) Control data

06 05 04 03 02

LEV opening degree

Positioning

Standard opening degree

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

Opening degree is corrected according to discharge temperature.

A(target discharge temperature)

Time

OFF Time

Commanded to open

30 50 70

Operational frequency of the compressor

90 110 130

(Hz)

(a) Reference value of target discharge temperature (COOL / HEAT (MUZ) F)

Applied model A B C D E F

MUZ-A09/12 MUZ-A15/17

MUY-A15/17 MUZ-A24

MUY-A24 MUZ-FD MUZ-D

MUY-D

COOL 122 127 140 151 158 158

HEAT 113 126 138 154 169 169

COOL 129 136 147 158 158 158

HEAT 120 136 151 165 180 185

COOL 140 140 140 145 147 153

HEAT 140 145 149 153 158 158

COOL 120 131 142 153 162 169

HEAT 109 124 138 156 167 176

COOL 126 135 149 167 183 187

HEAT 131 140 149 154 162 167

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 (pulse)

Applied model A B C D E F

MUZ-A09/12 MUZ-A15/17

MUY-A15/17 MUZ-A24

MUY-A24 MUZ-FD MUZ-D

MUY-D

COOL 130 190 240 260 260 260

HEAT 100 130 170 210 230 230

COOL 290 300 350 350 370 370

HEAT 130 150 220 250 280 300

COOL 150 166 186 206 230 260

HEAT 130 150 170 196 210 226

COOL 180 240 300 320 320 320

HEAT 130 180 240 270 300 300

COOL 150 170 210 250 280 300

HEAT 100 120 140 190 240 280

MXZ MICROPROCESSOR CONTROL

MXZ-A•NA

3-1. INVERTER SYSTEM CONTROL

3-1-1. Inverter main power supply circuit

CURRENT

REACTOR

POWER SUPPLY

NOISE FILTER CIRCUIT

RESISTOR

RELAY

PFC

SMOOTHING CAPACITOR

Function of main parts

NAME FUNCTION INTELLIGENT POWER MODULE (IPM) It supplies three-phase AC power to compressor. SMOOTHING CAPACITOR It stabilizes the DC voltage and supplies it to IPM.

CURRENT TRANSFORMER REACTOR

POWER FACTOR CORRECTION MODULE (PFC)

It measures the current of the compressor motor. It measures the current of the main power supply circuit.

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

U V

IPM

TRANSFORMER

COMPRESSOR

RESISTOR It restricts rush current with the resistance.

RELAY

It short-circuits the resistance which restricts rush current during the compressor operates.

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 being 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 three-phase AC by IPM and supplied to

COMPRESSOR. CURRENT TRANSFORMER, which is placed in the power supply circuit to COMPRESSOR, are used to measure the val-

ue of phase current and locate the polar direction of rotor with algorithm. PWM (Pulse width modulation) controls impressed

voltage and frequency with those information.

3. Power factor improvement Booster coil 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. Power transistor module IPM consists of the following components.

· Power Transistors (x6) : Converts DC waveform to three-phase AC waveform and outputs it.

· Drive Circuit : Drives transistors.

· Protection circuit : Protects transistors from over current. Since the above components are all integrated in IPM, IPM has a merit that can get the control circuit simpliﬁ ed and miniatur- ized.

5. Elimination of electrical noise

NOISE FILTER CIRCUIT, which is formed by *CMC COILS and capacitors placed on the noise ﬁ lter P.C. board, eliminates electrical noise of AC power that is supplied to main power supply circuit. In short, common mode noise is absorbed in this circuit. Moreover, normal mode noise is absorbed in another NOISE FILTER CIRCUIT which is formed by *NMC COILS and capacitors. Both NOISE FILTER CIRCUIT exists for preventing the electrical noise generated in the inverter circuit from leaking out.

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

3-1-3. Sine wave control

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

Although ordinary three-phase induction motor requires energy to excite the magnetic ﬁ eld of rotor, brushless DC motor

●

doesn't need it. So, higher efﬁ ciency and torque are provided.

This control provides the most efﬁ cient 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 efﬁ ciency 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 doesn't require energy to excite the rotor

3-1-5. Control Method of Rotation Times

Sine wave control makes the current transformers conduct real time detection of the value of the current running into the motor, locates the rotor position from the detected value and decides if voltage should be impressed and if frequency should be changed. Compared to the conventional control and rotor position detection method, sine wave control can provide 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 pulse in 15 minutes

When outdoor unit is operating,

some indoor units stop and some

operate.

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

:(MXZ-3A30NA-

/ 4A ) : 100 → 59 pulse

Thermostat OFF in COOL or DRY

mode

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

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

Thermostat ON in COOL or DRY

mode

• After starting operation, adjustment in accordance with intake super heat, discharge temperature is included in standard opening.

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 pulse.

Thermostat OFF in HEAT mode

• When the outdoor unit stops. (When the other indoor unit stops or thermo off) : Maintain LEV opening before stop → 500 pulse in 15 minutes. “

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

Thermostat ON in HEAT mode

Ex.) Opening 120 pulse in standard opening 1 → Minimum 70 pulse, Maximum 165 pulse. (Capacity code 4 at 1 unit operation) (Capacity code 1 at 3 units operation)

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

1 “

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

(MXZ-3A30NA-

/ 4A).

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 have developed, the indoor coil thermistors adjust LEV opening to diminish the super heat. This action is called Evaporation Temperature Protection.

The opening pulse of the Receiver LEV is fixed to the standard No.3 in cooling operation, and so is that of each Exclusive LEV in heating operation. However the opening pulse will be changed to the standard No.4 or No.5 when the discharge temperature protection or highpressure protection is working.

In addition to that, it will also be changed to standard No.2 or No.1 when the opening pulse of the each Exclusive LEV becomes 100 pulse or less in cooling operation or so does that of Receiver LEV in heating operation.

<MXZ-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

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 pulse.

4Hz

10 09 08 07 06 05 04 03

LEV Opening (code)

02 01

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

Compressor operating frequency (Hz)

MXZ-2A MXZ-3A/4A23

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-

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-

MXZ-4A36NA

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)

Operation number

Difference in operation number

4(MXZ-4A)

COOL 28 56 84

HEAT -45 -60 -60

Capacity code 4 7 9 10 12

Indoor unit 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-1 and MXZ-4A36NA are excluded.

●

—

●

MXZ-2A20NA

Operation frequency

of compressor (Hz)

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

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

1 unit 2 units 1 unit 2 units

COOL HEAT

Target discharge temperature (°F)

Number of operating unit

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

Target discharge temperature (°F)

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.

COOL HEAT

Number of operating unit

4 units

(MXZ-4A36)

1 unit 2 unit 3 units

4 units

(MXZ-4A36)

MXZ-2A

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

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

∆RT 2

10.8

LEV opening

correction (pulse)

7.2 ∆RT < 10.8 1 ∆RT < 7.2 1

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

∆ RT

∆RT 18

10.8

Temperature to be

decreased (°F)

7.2 ∆RT< 10.8 9 ∆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-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)

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 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-4A

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

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

105, 115, 150 minutes).

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

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

The third and subsequent defrost intervals follow any of the three patterns …5 or 10 to 20 minutes longer, the same,

or 5 or 10 to 20 minutes shorter compared with the previous defrost interval … with the longest 125 minutes and the shortest 40 minutes.

(2) Releasing conditions of defrosting

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

(31, 35, 45, 55, 65, 75, 85, 95,

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)/ 212 °F (3A30NA-

/4A) or 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.

3-6. OUTDOOR FAN CONTROL

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

Fan speed

High

Down

Low

Compressor frequencyMin. Max.

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.

Compressor frequency (Hz)

Down Up

MXZ-2A

MXZ-3A30NA

MXZ-4A

30 40 40 50

3-7. PRE-HEAT CONTROL MXZ-2A20NA-

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.

Power ON

Compressor ON

Outside temperature

MXZ-3A30NA-1 MXZ-4A36NA

OFF

68 °F

Pre-heat ON

OFF

30min.

Breaker ON

Start operation

30 min. 30 min. 30 min. 30 min. 30 min. 15 min. 30 min.15 min. 30 min.

Stop operation

When outside temperature is above 68 °F

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

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

When outside temperature is 68 °F or below, pre-heat control is ON for 30 min."

When outside temperature is 69.8 °F or above, pre-heat control is ON for 15 min."

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

Room temperature minus

Thermostat

set temperature (Initial)

ON -1.8 °F or more OFF less

than

-1.8 °F

Room temperature minus set temperature (During operation)

-1.8 °F

-1.3 °F

2. Coil frost prevention

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

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

Thermostat

Room temperature minus set temperature (Initial)

Room temperature minus set temperature (During operation)

ON -1.8 °F or more OFF less

than

-1.8 °F

-1.3 °F

2. Coil frost prevention

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

3-10. HEAT OPERATION

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

Thermostat

ON less than 3.6 OFF 3.6

Room temperature minus set temperature (Initial)

°F

°F or more

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 °F

3.6 °F

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

Copyright 2006 MITSUBISHI ELECTRIC ENGINEERING CO.,LTD 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 Feb. 2008 Specifications subject to change without notice.

Mitsubishi Electronics MUZ-ANA - U, MSY-ANA, MUZ-ANA, MUZ-FDNA - U, MUY-ANA User Manual

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