Mitsubishi Electronics MUZ-ANA, MXZ-ANA, MS-AWA, MSY-ANA, MU-AWA User Manual

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SERVICE TECHNICAL GUIDE

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

Wireless type Models

MS-A•WA · MU-A•WA MSZ-A•NA · MUZ-A•NA

No. OBT16

· MUZ-A•NA -

MSY-A•NA · MUY-A•NA

Inverter-controlled multi system type Models

· MXZ-A•NA

CONTENTS

1. MS MICROPROCESSOR CONTROL··················3

2. MSZ,MSY MICROPROCESSOR CONTROL·······6

3. MXZ MICROPROCESSOR CONTROL··············20

1. MS MICROPROCESSOR CONTROL ···························································3

Indoor unit models Outdoor unit models

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

1-1. COOL OPERATION················································································3 1-2. DRY OPERATION ··················································································3 1-3. AUTO VANE OPERATION·····································································5

2. MSZ, MSY MICROPROCESSOR CONTROL ···············································6

Indoor unit models Outdoor unit models

MSZ-A09NA MUZ-A09NA MSZ-A12NA MUZ-A12NA MSZ-A15NA MUZ-A15NA MSZ-A17NA MUZ-A17NA MSZ-A24NA MUZ-A24NA MSY-A15NA MUY-A15NA MSY-A17NA MUY-A17NA MSY-A24NA MUY-A24NA

2-1. COOL OPERATION···············································································6 2-2. DRY OPERATION ·················································································7 2-3. HEAT OPERATION ···············································································7 2-4. AUTO CHANGE OVER ··· AUTO MODE OPERATION························9 2-5. OUTDOOR FAN MOTOR CONTROL·················································10 2-6. AUTO VANE OPERATION ··································································10 2-7. INVERTER SYSTEM CONTROL ························································12 2-8. OPERATIONAL FREQUENCY CONTROL OF OUTDOOR UNIT······16 2-9. EXPANSION VALVE CONTROL (LEV CONTROL) ···························17

3. MXZ MICROPROCESSOR CONTROL·······················································20

Outdoor unit models

MXZ-2A20NA MXZ-3A30NA

3-1. INVERTER SYSTEM CONTROL·························································20 3-2. EXPANSION VALVE CONTROL (LEV CONTROL) ····························22 3-3. OPERATIONAL FREQUENCY RANGE···············································27 3-4. HEAT DEFROSTING CONTROL········································· 3-5.

DISCHARGE TEMPERATURE PROTECTION CONTROL ·····BACK PAGE

3-6. OUTDOOR FAN CONTROL················································

BACK PAGE BACK PAGE

ºF

50 59 68 77 86 95

Set temperature

Initial room temperature

Set temperature and initial room temperature in dry mode

ºF

MS MICROPROCESSOR CONTROL

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

1-1. COOL ( ) OPERATION

1. Thermostat control

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

Initial temperature difference Thermostat

Difference between room temperature and set temperature during operation.

Set temperature Room temperature minus set temperature : -1.8 degrees or more·····································ON Room temperature minus set temperature : less than -1.8 degrees···································OFF

2. Indoor fan speed control

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

Initial temperature difference

Fan speed

Difference between room temperature and set temper-

ature during operation ( T)

-1.8deg.

Room temperature minus set temperature : 3.1 degrees or more·······························High Room temperature minus set temperature : Between 1.8 and 3.1 degrees

···················

Room temperature minus set temperature : less than 1.8 degrees ····························Low

3. Coil frost prevention

Med.

1.8 deg.

3.1 deg.

① Temperature control

When the indoor coil thermistor RT12 reads 37 ºF 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 RT12 still reads below 37 ºF this mode prolonged until the RT12 reads over 37 ºF.

② 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 ºF. 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 ºF. However, when two of the above conditions (b.and c.) are satisfied again. Time accumulation is resumed.

-1.3deg.

5.4 deg.

Operation chart

Example

Compressor Outdoor fan

Indoor fan

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.

OFF

(continuously at set speed)

OFF

1. Thermostat control

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

Initial temperature difference Thermostat Room temperature minus set temperature : -1.8 degrees or more·····································ON Room temperature minus set temperature : less than -1.8 degrees···································OFF

2. Indoor fan speed control

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

In AUTO the fan speed is as follows.

Initial temperature difference

Fan speed

Room temperature minus set temperature : 3.1 degrees or more·······························High Room temperature minus set temperature : Between 1.8 degrees and 3.1 degrees

···

Room temperature minus set temperature : less than 1.8 degrees·····························Low

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.

Med.

Difference between room temperature and set temperature during operation

Set temperature

-1.8 deg.

-1.3 deg.

Difference between room temperature and set temper-

ature during operation ( T)

4.5 deg.

1.8 deg.

3.1 deg.

Operation time chart

Example

Thermostat

Indoor fan

Outdoor fan

OFF

Compressor

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 it’s speed becomes the set speed.

1-3. AUTO VANE OPERATION

1. Horizontal vane

ECONO COOL ( ) operation (ECONOmical operation) When ECONO COOL button is pressed in COOL mode, set temperature is automatically set 3.6 degrees higher than that in COOL mode. Also the horizontal vane swings in various cycle according to the temperature of indoor heat exchanger (RT12). SWING operation makes you feel cooler than set temperature. So, even though the set temperature is higher than that

in COOL mode, the air conditioner can keep comfort. As a result, energy can be saved. ECONO COOL operation is cancelled when ECONO COOL button is pressed once again or VANE CONTROL button is pressed or change to other operation mode.

<SWING operation> In swing operation of ECONO COOL operation mode, the initial air flow direction is adjusted to “Horizontal”. According to the temperature of indoor coil thermistor RT12 at starting of this operation, next downward blow time is decided. Then when the downward blow has been finished, next horizontal blow time is decided. For initial 10 minutes the swing operation is performed in table G~H for quick cooling. Also, after 10 minutes when the difference of set temperature and room temperature is more than 3.6 degrees, the swing operation is performed in table D~H for more cooling. The air conditioner repeats the swing operation in various cycle as follows.

Temperature of indoor

coil thermistor RT12

A B C D E F

59°F or less 59°F to 63°F 63°F to 64°F 64°F to 68°F 68°F to 70°F 70°F to 72°F 72°F to 75°F

more than 75°F

Downward blow time

(second)

2 5

8 11 14 17 20 23

Horizontal blow time

(second)

23 20 17 14 11

8 5 2

MSZ,MSY MICROPROCESSOR CONTROL

MSZ-A09NA MSY-A15NA MUZ-A09NA MUY-A15NA MSZ-A12NA MSY-A17NA MUZ-A12NA MUY-A17NA MSZ-A15NA MSY-A24NA MUZ-A15NA MUY-A24NA MSZ-A17NA MUZ-A17NA MSZ-A24NA MUZ-A24NA

2-1. COOL ( ) OPERATION

1. Thermostat control

Thermostat is ON or OFF by difference between room temperature and set temperature Room temperature minus set temperature : -1.8 degrees or more·····································ON

Room temperature minus set temperature : less than -1.8 degrees···································OFF

2. Indoor fan speed control

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

Room temperature minus set temperature : 3.1 degrees or more·······························High Room temperature minus set temperature : Between 1.8 and 3.1 degrees Room temperature minus set temperature : less than 1.8 degrees ····························Low

3. Coil frost prevention

Temperature control When indoor coil thermistor detects following temperature for 90 seconds, operational frequency of compressor is controlled according to the following table.

Temperature of indoor coil thermistor

50°F or more

46°F to 50°F Raise 6Hz 43°F to 46°F 37°F to 43°F

37°F or less

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 enters the low outside temperature operation mode.

<Operation> (1) If the unit enters the low outside temperature operation mode, the outside fan rotation speed gets slow down. (2) Even when the unit is in the "thermostat-off" status under the low outside temperature operation mode, the outside fan

rotation does not stop.

(3) In this mode to detect the exact outside temperature the compressor turns OFF with the outdoor fan ON for 3 minutes

once 1 hour; if the outside temperature rises over 64°F, the unit goes back to the normal COOL mode, and if the outside temperature is still 64°F or less, the unit stays in the low outside temperature operation mode.

(4) Dew drop prevention

When the ambient temperature thermistor RT65 reads 10°F 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.

Initial temperature difference Thermostat

Initial temperature difference

···················

Operation frequency

Compressor is turned OFF for 5 minutes when temperature of indoor coil thermistor continues 37°F or less for 5 minutes or more.

Fan speed

Med.

Normal (variable)

Fixed Lower 3Hz Lower 6Hz

Difference between room temperature and set temperature during operation.

Set temperature

-1.8deg.

Difference between room temperature and set temper-

ature during operation ( T)

1.8deg.

-1.3deg.

5.4deg.

3.1deg.

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

2-2. DRY ( ) OPERATION

ºF

50 59 68 77 86 95

Set temperature

Initial room temperature

Set temperature and initial room temperature in dry mode

ºF

Difference between room

1. Thermostat control

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

Initial temperature difference Thermostat Room temperature minus set temperature : -1.8 degrees or more·······································ON Room temperature minus set temperature : less than -1.8 degrees······································OFF

2. Indoor fan speed control

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

In AUTO the fan speed is as follows.

Initial temperature difference

Fan speed

Room temperature minus set temperature : 3.1 degrees or more·······························High Room temperature minus set temperature : Between 1.8 and 3.1 degrees

···················

Med.

Room temperature minus set temperature : less than 1.8 degrees ····························Low

3. Coil frost prevention

4. Low outside temperature operation

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

temperature and set temperature during operation

Set temperature

-1.8deg.

-1.3deg.

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

4.5deg.

1.8deg.

3.1deg.

2-3. HEAT ( ) OPERATION (MSZ)

1. Thermostat control

Thermostat is ON or OFF by difference between room temperature and set temperature. Room temperature minus set temperature : less than 3.6 degrees····································ON

Room temperature minus set temperature : 3.6 degrees or more······································OFF

2. Indoor fan speed control

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

In Auto the fan speed is as follows. Set temperature minus room temperature:

Set temperature minus room temperature: Set temperature minus room temperature: less than

Difference between room temperature and set temperature during operation

Initial temperature difference Thermostat

Set temperature

3deg.

3.6deg.

Difference between room temperature and set temper-

Initial temperature difference

3.6 degrees

or more

······································ High

Between 0.4 and 3.6 degrees ····················

0.4 degrees····································

Fan speed

Med.

Low

ature during operation

3.6deg.

0.4deg.

3deg.

7.2deg.

(2) Cold air prevention control

MSZ-A09/12/15/17

1 When the compressor is not operating,

(1) if the temperature of room temperature thermistor RT11 is less than 66°F, the fan stops. (2) if the temperature of room temperature thermistor RT11 is 66°F or more and

1) if the temperature of RT12 is less than 32°F, the fan stops.

(

2 When the compressor is operating,

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

MSZ-A24

1 When the compressor is not operating,

2 When the compressor is operating,

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

3. Overload starting

When the room temperature thermistor RT11 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 valuesw (40, 45, 55, 65, 75, 85, 95, 105,

115, 125, 150 minutes(MUZ-A09/12/15/17))/(31,35,45,55,65,75,85,95,105,115,150minutes(MUZ-A24)). c) More than 5 minutes have passed since the start-up of the compressor. w Set value of compressor operation time (here in after referred to as defrost interval)

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

time. For example, the first defrost interval is 40 minutes long, and the second is 45 minutes long. The third and subse-

quent 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) / 41°F or more (MUZ-A15/17) / 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.

(2) if the temperature of RT12 is 32°F or more, the fan operates at Very Low.

(1) if the temperature of RT12 is 104°F or more, the fan operates at set speed. (2) if the temperature of RT12 is less than 104°F and

(1) if heating operation starts after defrosting, the fan stops. (2) if the temperature of room temperature thermistor RT11 is 66°F or less, the fan stops. (3) if the temperature of room temperature thermistor RT11 is more than 66°F, the fan operates at Very Low.

temperature of RT11 and RT12.

(1) if the temperature of room temperature thermistor RT11 is 59°F or less, or RT12 is less than 64°F,

the fan stops.

(2) if the temperature of room temperature thermistor RT11 is more than 59°F, or RT12 is more than 64°F,

the fan operates at Very Low.

(1) if the temperature of RT12 is 64°F or more, the fan operates at set speed. (2) if the temperature of RT12 is less than 64°F and

(1) if heating operation starts after defrosting, the fan stops. (2) if the temperature of room temperature thermistor RT11 is 59°F or less, the fan stops. (3) if the temperature of room temperature thermistor RT11 is more than 59°F, the fan operates at Very Low.

temperature of RT11 and RT12.

Time chart of defrosting in HEAT mode (reverse type)

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

ON (HEAT)

ON ON

ON (HEAT)

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

1. Mode selection

Once desired temperature is set, unit operation is switched automatically between COOL and HEAT operation.

(1) Initial mode

At first indoor unit operates only indoor fan with outdoor unit OFF for 3 minutes to detect present room temperature. Following the conditions below, operation mode is selected.

1 If the room temperature thermistor RT11 reads more than set temperature, COOL mode is selected. 2 If the room temperature thermistor RT11 reads set temperature or less, HEAT mode is selected.

(2) Mode change

In case of the following conditions the operation mode is changed. 1 COOL mode changes to HEAT mode when 15 minutes have passed with the room temperature 4 degrees below the

set temperature.

2 HEAT mode changes to COOL mode when 15 minutes have passed with the room temperature 4 degrees above the

set temperature. In the other cases than the above conditions, the present operation mode is continued. NOTE1: Mode selection is performed when multi standby (refer to NOTE2) is released and the unit starts operation with

ON-timer.

NOTE2: If two or more indoor units are operating in multi system, there might be a case that the indoor unit, which is

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

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