Mitsubishi MS-GD80VB-E1 Service Manual

Download

SPLIT-TYPE, AIR CONDITIONERS

INDOOR UNIT

SERVICE MANUAL

Wireless type Model

No. OBH511

MS-GD80VB -

Outdoor unit service manual

MU-GD•VB Series (OBH512)

CONTENTS

1. TECHNICAL CHANGES ··································· 2

2. PART NAMES AND FUNCTIONS ····················· 2

3. SPECIFICATION ················································ 3

4. NOISE CRITERIA CURVES ······························ 3

5. OUTLINES AND DIMENSIONS ························ 4

6. WIRING DIAGRAM ············································ 4

7. REFRIGERANT SYSTEM DIAGRAM ··············· 5

8. SERVICE FUNCTIONS ····································· 6

9. MICROPROCESSOR CONTROL ····················· 8

10. TROUBLESHOOTING ····································· 14

11. DISASSEMBLY INSTRUCTIONS ···················· 22

PARTS CATALOG (OBB511)

NOTE:

RoHS compliant products have <G> mark on the spec name plate.

TECHNICAL CHANGES

MS-GD80VB -

1. New model

PART NAMES AND FUNCTIONS

MS-GD80VB

Air cleaning filter (option) (White bellows type)

Panel

Catechin air filter

Vertical vanes

Front panel

Air inlet

To breaker

Power supply cord

Remote control

receiving section

Operation section

(When the grille is opened)

ACCESSORIES

Horizontal vane

Emergency operation switch

Installation plate

Installation plate fixing screw 4 × 25 mm

Remote controller holder

Fixing screw for × 3.5 × 1.6 mm (Black)

Battery (AAA) for remote controller

Wireless remote controller

Felt tape (Used for left or left-rear piping)

Remote controller

Display section

Operation indicator lamp

Remote control

receiving section

MS-GD80VB

SPECIFICATION

Indoor model

Function

Power supply

Breaker capacity Running current

datamotor

Power input Power factor

Model Fan motor current

Fan Electrical

Dimensions W × H × D

Weight

Air direction

Air flow

(High/Med./Low)

Special

remarks

Sound level Fan speed

(High/Med./Low)

Fan speed regulator

Remote controller model

A W %

rpm

MS-GD80VB

Cooling Single phase 230 V, 50 Hz

0.34 69 88

RC4V40-AA

0.34

1,100 × 325 × 258

954/822/684

47/42/37

1,280/1,130/970

KM04B

NOTE: Test conditions are based on ISO 5151. Cooling: Indoor Dry-bulb temperature 27°C Wet-bulb temperature 19°C Outdoor Dry-bulb temperature 35°C Wet-bulb temperature 24°C Indoor-Outdoor piping length: 5 m

NOISE CRITERIA CURVES

MS-GD80VB

FAN SPEED

High

Test conditions, Cooling : Dry-bulb temperature 27˚C Wet-bulb temperature 19˚C

SPL(dB(A)) LINE

NC-70

NC-60

NC-50

NC-40

INDOOR UNIT

WALL

0.8m

MICROPHONE

APPROXIMATE

THRESHOLD OF HEARING FOR CONTINUOUS

OCTAVE BAND SOUND PRESSURE LEVEL, dB re 0.0002 MICRO BAR

NOISE

63 125 250 500 1000 2000 4000 8000

BAND CENTER FREQUENCIES, Hz

NC-30

NC-20

OUTLINES AND DIMENSIONS

MS-GD80VB

325

162

110 0

791

1068

253

Power supply cord Lead to right 2.0 m

Lead to left 1.0 m

Installation plate

98 173414.5 414.5

Wall hole ø75

258

Air in

Air out

Installation plate

Indoor unit

173

Liquid line ø 9.52- 0.5 m Gas line ø 12-0.43 m

{

Insulation øø50 O.D

Drain hose (Connected part O.D)

Insulation ø28

ø16

Unit: mm

255.547

2.5

32 I.D

7.5

315

Wireless remote controller

WIRING DIAGRAM

MS-GD80VB

REFRIGERANT SYSTEM DIAGRAM

MS-GD80VB

Indoor heat exchanger

Room temperature thermistor RT11

Indoor coil thermistor RT12(main)

Indoor coil thermistor RT13(sub)

Strainer

#50

Refrigerant pipe ø15.88 (with heat insulator)

Flared connection

Refrigerant pipe ø9.52 (with heat insulator)

Unit: mm

Refrigerant flow in cooling

SERVICE FUNCTIONS

MS-GD80VB

8-1. TIMER SHORT MODE

For service, set time can be shortened by short circuit of JPG and JPS on the electronic control P.C. board. The time will be shortened as follows. Set time: 1 minute 1-second Set time: 3 minute 3-second (It takes 3 minutes for the compressor to start operation. However, the starting time is shortened by short circuit of JPG and JPS.)

8-2. P.C. BOARD MODIFICATION FOR INDIVIDUAL OPERATION

A maximum of 4 indoor units with wireless remote controllers can be used in a room. In this case, to operate each indoor unit individually by each remote controller, P.C. boards of remote controller must be modified according to the number of the indoor unit.

How to modify the remote controller P.C. board

Remove batteries before modification. The board has a print as shown below:

NOTE: For modification, take out the bat-

teries and press the OPERATE/ STOP (ON/OFF) button 2 or 3 times at first.

After modification, put back the bat-

teries then press the RESET button.

The P.C. board has the print “J1” and “J2”. Solder “J1” and “J2” according to the number of indoor unit as shown in Table 1. After modification, press the RESET button.

Table 1

1 unit operation

No. 1 unit

No. 2 unit

No. 3 unit

No. 4 unit

How to set the remote controller exclusively for particular indoor unit

After you turn the breaker ON, the first remote controller that sends the signal to the indoor unit will be regarded as the remote controller for the indoor unit. The indoor unit only accepts the signal from the remote controller that has been assigned to the indoor unit once they are set. The setting will be cancelled if the breaker has turned OFF, or the power supply has shut down. Please conduct the above setting once again after the power has restored.

No modification

–

2 units operation

Same as at left

Solder J1

–

3 units operation

Same as at left

Solder J2

–

4 units operation

Same as at left

Solder both J1 and J2

8-3. AUTO RESTART FUNCTION

When the indoor unit is controlled with the remote controller, the operation mode, set temperature, and the fan speed are

memorized by the indoor electronic control P.C. board. The “AUTO RESTART FUNCTION” automatically starts operation in the same mode just before the shutoff of the main power. However if the unit is operated in “I FEEL CONTROL” mode before power failure, the operation is not memorized. In “I FEEL CONTROL” mode, the operation is decided by the initial room temperature.

Operation

If the main power has been cut, the operation settings remain. After the power is restored, the unit restarts automatically

according to the memory. (However, it takes at least 3 minutes for the compressor to start running.)

CN201

C11

CN211

How to release “AUTO RESTART FUNCTION”

Turn OFF the main power for the unit. Solder jumper wire to JR07 on the indoor electronic control P.C.

board. (Refer to 10-6.)

TAB12

CN112

CN111

CN121

RA102

IC101

IC152

CN151

SW1

JR07

NOTE: •The operation settings are memorized when 10 seconds have passed after the remote controller was operated with

the remote controller.

•If main power is turned OFF or a power failure occurs while AUTO START/STOP timer is active, the timer setting is

cancelled.

•If the unit has been OFF with the remote controller before power failure, the auto restart function does not work as the

power button of the remote controller is OFF.

•To prevent breaker OFF due to the rush of starting current, systematize other home appliances not to turn ON at the

same time.

•When some air conditioners are connected to the same supply system, if they are operated before power failure, the

starting current of all the compressors may flow simultaneously at restart.

Therefore, the special counter-measures are required to prevent the main voltage-drop or the rush of the starting cur-

rent by adding to the system that allows the units to start one by one.

MICROPROCESSOR CONTROL

MS-GD80VB

WIRELESS REMOTE CONTROLLER

Signal transmitting section

Operation display section

OPERATE/STOP (ON/OFF) button

VANE button

(Horizontal vane button)

OPERATION SELECT button

ECONO COOL button

WIDE VANE button

(Vertical vane button)

RESET button

ON/OFF

WARM

ON/OFF

WARM

FAN

I FEEL

COOL

VAN E

DRY

FAN

MODE

WIDE VANE

ECONO COOL

LONG

RESET CLOCK

TOO

COOL

TOO

COOL

STOP

START

HR.

MIN.

TEMPERATURE buttons

FAN SPEED CONTROL button

OFF-TIMER button

ON-TIMER button

HR. button

MIN. button

(TIME SET button)

CLOCK SET button

LONG button

NOTE: • The last setting will be stored after the unit is turned OFF with the remote controller.

• Indoor unit receives the signal of the remote controller with beeps.

INDOOR UNIT DISPLAY SECTION

OPERATION INDICATOR lamp

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

The following indication applies regardless of shape of the indicator.

Lighted

Not lighted

Indication

Operation state

This shows that the air conditioner is operating to reach the target temperature. Please wait until the target temperature is obtained.

This shows that the room temperature is approaching the target temperature.

Difference between target temperature and room temperature

Approximate 2 or more

Approximate 2 or less

9-1. COOL ( ) OPERATION

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

OPERATION INDICATOR lamp of the indoor unit turns on with a beep tone. (2) Select COOL mode with OPERATION SELECT button. (3) Press TEMPERATURE buttons.

(TOO WARM or TOO COOL button) to select the desired temperature.

The setting range is 16 ~ 31˚C

Indoor fan continues to operate regardless of thermostat's OFF-ON at set speed.

1. Coil frost prevention

When the temperature of indoor heat exchanger becomes too low, the coil frost prevention mode works. The indoor fan operates at the set speed and the compressor stops. This mode continues until the temperature of indoor heat exchanger rises.

2. Discharge temperature protection

The compressor is controlled by the temperature of discharge temperature thermistor RT62 for excess rise protection of compressor discharge pressure.

9-2. DRY ( ) OPERATION

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

OPERATION INDICATOR lamp of the indoor unit turns ON with a beep tone. (2) Select DRY mode with OPERATION SELECT button. (3) The set temperature is determined from the initial room temperature. (4) DRY operation will not function when the room temperature is 13˚C or below.

1. Indoor fan speed control

Indoor fan operates at the set speed by FAN SPEED CONTROL button. However, in AUTO fan operation, fan speed becomes Low.

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

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

3. Coil frost prevention

• The operation is as same as coil frost prevention during COOL mode.

• Indoor fan operates at the set speed and the compressor stops for 5 minutes, because protection (Coil frost prevention) has the priority. However, when coil frost prevention works while the compressor is not operating, it's speed becomes Low.

9-3. FAN ( ) OPERATION

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

OPERATION INDICATOR lamp of the indoor unit turns ON with a beep tone. (2) Select FAN mode with OPERATION SELECT button. (3) Select the desired fan speed. When AUTO, it becomes Low.

Only indoor fan operates. Outdoor unit dose not operate.

9-4. "I FEEL CONTROL" ( ) OPERATION

(1) Press OPERATE/STOP (ON/OFF) button on the remote controller. OPERATION INDICATOR lamp of the indoor unit

turns ON with a beep tone. (2) Select "I FEEL CONTROL" mode with OPERATION SELECT button. (3) The operation mode is determined by the room temperature at start-up of the operation.

Initial room temperature

25°C or more

more than 13

less than 25

°C °C

"I FEEL CONTROL"

Mode

COOL mode of

DRY mode of

• Once the mode is fixed, the mode dose not change by room temperature afterwards.

• Under the ON-TIMER (

When the system is stopped on the remote controller, and restarted within 2 hours in " I FEEL CONTROL" ( ) mode, the system operates in previous mode automatically regardless of the room temperature.

) operation, mode is determined as follows.

(4) The initial set temperature is decided by the initial room temperature.

Model Initial room temperature Initial set temperature

COOL mode of

" I FEEL CONTROL"

DRY mode of

" I FEEL CONTROL"

1 When the system is restarted with the remote controller, the system operates with the previous set temperature

regardless of room temperature at restart. The set temperature is calculated by the previous set temperature.

(5) TEMPERATURE buttons

In " I FEEL CONTROL " ( In addition, set temperature can be controlled by TOO WARM or TOO COOL buttons when you feel too cool or too warm. Each time the TOO WARM or TOO COOL button is pressed, the indoor unit receives the signal and emits a beep tone.

• Fuzzy control

When the TOO COOL or TOO WARM button is pressed, the microprocessor changes the set temperature, considering the room temperature, the frequency of pressing TOO COOL or TOO WARM button and the user's preference to heat or cool. So this is called "Fuzzy control", and works only in "I FEEL CONTROL" mode. In DRY mode of "I FEEL CONTROL", the set temperature doesn't change.

more than 13˚C, less than 25˚C Initial room temperature minus 2˚C

) mode, set temperature is decided by the microprocessor based on the room temperature.

26˚C or more 24˚C

25˚C to 26˚C Initial room temperature minus 2˚C

…

To raise the set temperature 1~2˚C

…

To lower the set temperature 1~2˚C

9-5. AUTO VANE OPERATION

1. Horizontal vane

(1) Vane motor drive

These models are equipped with a stepping motor for the horizontal vane. The rotating direction, speed, and angle of the motor are controlled by pulse signals (approximate 12 V) transmitted from indoor microprocessor.

(2) The horizontal vane angle and mode change as follows by pressing the VANE button.

(3) Positioning

To confirm the standard position, the vane moves until it touches the vane stopper. Then the vane is set to the desired

angle.

Confirming of standard position is performed in the following case:

(a) When the power supply turns ON.

(b) When the operation starts or finishes (including timer operation).

(d) When the vane control is changed AUTO to MANUAL (except SWING).

(d) When the SWING is finished (including ECONO COOL). (4) VANE AUTO (

In VANE AUTO mode, the microprocessor automatically determines the horizontal vane angle and operation to make the

optimum room-temperature distribution.

(5) STOP (operation OFF) and ON-TIMER standby

When the following cases occur, the horizontal vane returns to the closed position.

(a) When OPERATE/STOP (ON/OFF) button is pressed (POWER OFF).

(b) When the operation is stopped by the emergency operation.

During COOL or DRY operation at Vane Angle 4 or 5 when the compressor cumulative operation time of compressor

exceeds 1 hour, the vane angle automatically changes to Angle 1 for dew prevention. (7) SWING ( ) mode

By selecting SWING mode with VANE button, the horizontal vane swings vertically. The remote controller displays " ".

SWING mode is cancelled when VANE button is pressed once again.

) mode

(8) ECONO COOL (

When ECONO COOL button is pressed in COOL mode, set temperature is automatically set 2 °C higher.

Also the horizontal vane swings in various cycle.

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

button is pressed or changed to other operation mode. (9) LONG ( ) mode

By pressing LONG button indoor fan speed becomes faster than setting fan speed on the remote controller, and the

horizontal vane moves to the position for LONG mode. The remote controller displays " ". LONG mode is cancelled

when LONG button is pressed once again or VANE button is pressed or ECONO COOL button is pressed in COOL

mode.

• In the following example, the vertical vane is set to (front.).

) operation (ECONOmical operation)

2. Vertical vane

(1) Vane motor drive

These models are equipped with a stepping motor for the vertical vane. The rotating direction, speed, and angle of the motor are controlled by pulse signals (approximate 12 V) transmitted from microprocessor.

(2) The vertical vane angle and mode change as follows by pressing WIDE VANE button.

(3) Positioning

To confirm the standard position, the vane moves until it touches the vane stopper. Then the vane is set to the desired angle. Confirming of standard position is performed in the following case: (a) When OPERATE/STOP (ON/OFF) button is pressed (POWER ON/OFF). (b) When SWING is started or finished. (c) When the power supply turns ON.

(4) SWING (

By selecting SWING mode with WIDE VANE button, the vertical vane swings horizontally. The remote controller displays "

(5) WIDE (

By selecting WIDE mode with WIDE VANE button, indoor fan speed becomes faster than setting fan speed on the remote controller ( ). The remote controller displays " ".

Indoor fan speed becomes faster than setting fan speed on the remote controller even when or is selected.

) mode

".The vane moves right and left in the width of Angle 4 repeatedly.

) mode

9-6. TIMER OPERATION

1. How to set the timer

(1) Press OPERATE/STOP (ON/OFF) button to start the air conditioner. (2) Check that the current time is set correctly.

NOTE: Timer operation will not work without setting the current time. Initially "AM0:00" blinks at the current time display

of TIME MONITOR, so set the current time correctly with CLOCK SET button.

(3) Press ON/OFF TIMER buttons to select the operation.

"ON-TIMER" button…AUTO START operation (ON timer) "OFF-TIMER" button…AUTO STOP operation (OFF timer)

(4) Press HR. and MIN. button to set the timer. Time setting is 10-minute units.

HR. and MIN. button will work when " " or " These marks disappear in 1 minute. After setting the ON timer, check that OPERATION INDICATOR lamp of the indoor unit lights.

NOTE1: Be sure to place the remote controller at the position where its signal can reach the air conditioner even during

TIMER operation, or the set time may deviate within the range of about 10 minutes.

NOTE2: Reset the timer in the following cases, or the set time may deviate and other malfunctions may occur.

• A power failure occurs.

• The circuit breaker functions.

" mark is flashing.

2. Cancel

TIMER setting can be cancelled with ON/OFF TIMER buttons. To cancel ON timer, press "ON-TIMER" button. To cancel OFF timer, press "OFF-TIMER" button. TIMER is cancelled and the display of set time disappears.

PROGRAM TIMER

• OFF timer and ON timer can be used in combination.

• " " and " " display shows the order of OFF timer and ON timer operation. (Example 1) The current time is 8:00 PM.

The unit turns OFF at 11:00 PM, and ON at 6:00 AM.

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

The unit turns ON at 5:00 PM, and OFF at 9:00 PM.

NOTE: TIMER setting will be cancelled by failure or breaker functioning.

9-7. EMERGENCY/TEST OPERATION

In case of test run operation or emergency operation, use EMERGENCY OPERATION switch on the front of the indoor unit. Emergency operation is available when the remote controller is missing, has failed or batteries of remote controller run down. The unit will start and OPERATION INDICATOR lamp will light. The first 30 minutes of operation is the test run operation. This operation is for servicing. The indoor fan speed runs at High speed and the system is in continuous operation. (The thermostat is ON.) After 30 minutes of test run operation, the system shifts to EMERGENCY COOL MODE with a set temperature of 24˚C. The fan speed shifts to Med. speed. The coil frost prevention works even in emergency operation. In the test run or emergency operation, the horizontal vane operates in VANE AUTO ( Emergency operation continues until EMERGENCY OPERATION switch is pressed again or the unit receives any signal from the remote controller. In case of latter, normal operation will start.

) mode.

NOTE: Do not press EMERGENCY OPERATION switch during normal operation.

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

9-8. 3-MINUTE TIME DELAY OPERATION

When the system turns OFF, compressor will not restart for 3 minutes as 3-minute time delay function operates to protect compressor form overload.

TROUBLESHOOTING

MS-GD80VB

10-1. CAUTIONS ON TROUBLESHOOTING

1. Before troubleshooting, check the following:

(1) Check the power supply voltage. (2) Check the indoor/outdoor connecting wire for mis-wiring.

2. Take care the following during servicing.

(1) Before servicing the air conditioner, be sure to turn OFF the main unit first with the remote controller, and then after confirming the horizontal vane is closed, turn OFF the breaker and/or disconnect the power plug. (2) Be sure to turn OFF the power supply before removing the panel, the cabinet, the top panel, and the electronic control P.C.

board.

(3) When removing the electronic control P.C. board, hold the edge of the board with care NOT to apply stress on the com-

ponents.

(4) When connecting or disconnecting the connectors, hold the housing of the connector. DO NOT pull the lead wires.

Lead wiring

Housing point

3. Troubleshooting procedure

(1) First, check if the OPERATION INDICATOR lamp on the indoor unit is flashing ON and OFF to indicate an abnormality. To make sure, check how many times the OPERATION INDICATOR lamp is flashing ON and OFF before starting serv-

ice work. (2) Before servicing check, that the connector and terminal are connected properly. (3) When the electronic control P.C. board seems to be defective, check the copper foil pattern for disconnection and the

components for bursting and discoloration. (4) When troubleshooting, refer to 10-2. and 10-3.

4. How to replace batteries

Weak batteries may cause the remote controller malfunction. In this case, replace the batteries to operate the remote controller normally.

Remove the front lid and insert batteries.

Then reattach the front lid.

FAN

Insert the negative pole of the batteries first. Check if the polarity of the batteries is correct.

Press the RESET button with tip end of ball point

pen or the like, and then use the remote controller.

FAN

RESET button

NOTE: If the RESET button is not pressed, the remote controller may not operate correctly.

10-2. INSTRUCTION OF TROUBLESHOOTING

Start

Indoor unit operates. Outdoor unit doesn't operate.

Outdoor unit operates only in “Test run operation”.

Check room temperature thermistor. Refer to 10-6. "Test point diagram and voltage".

Outdoor unit doesn't operate even in “Test run operation”.

Refer to "Check of outdoor unit".

Indoor unit operates. Outdoor unit doesn't operate normally.

Outdoor unit doesn't stop even if indoor unit stops.

Refer to "Check of outdoor unit".

Indoor unit doesn't receive the signal from remote controller.

Indoor unit operates when the EMERGENCY OPERATION switch is pressed.

Refer to 10-5. "Check of remote controller and receiver P.C. board".

OPERATION INDICATOR lamp on the indoor unit is flashing ON and OFF.

Indoor unit doesn't operate when the EMERGENCY OPERATION switch is pressed.

1. Check indoor / outdoor connecting wire.

2. Refer to 10-5. "Check of indoor electronic control P.C. board".

Flash ON and OFF at 0.5second intervals Cause: Indoor/ outdoor unit

• Mis-wiring

Refer to 10-5. "How to check mis-wiring (When outdoor unit doesn't work)".

Refer to outdoor unit service manual.

"Test run operation" means the operation within 30 minutes after EMERGENCY OPERATION switch is pressed.

2-time flash Cause: Indoor unit

• Trouble of room temp erature/ indoor coil thermistor

Check room temperature thermistor and indoor coil thermistor. Refer to 10-6. "Test point diagram and voltage".

3-time flash Cause: Indoor unit

• Trouble of indoor fan motor

Refer to 10-5. "Check of indoor fan motor".

4-time flash Cause: Indoor unit

• Trouble of indoor unit control system

Replace the indoor electronic control P.C. board.

6-time flash Cause: Outdoor unit

• Trouble of thermistor in outdoor unit

Refer to "Check of outdoor thermistor".

7-time flash Cause: Outdoor unit

• Trouble of outdoor control system

Replace the deicer P.C. board.

10-time flash Cause: Outdoor unit

• Trouble of low discharge temperature protection

Refer to "Check of LEV".

10-3. TROUBLESHOOTING CHECK TABLE

• Before taking measures, make sure that the symptom reappears for accurate troubleshooting. When the indoor unit has started operation and the following detection method has detected an abnormality (the first detection after the power ON), the indoor electronic control P.C. board turns OFF the indoor fan motor with the OPERATION INDICATOR lamp flashing.

Abnormal

No.

Mis-Wiring

Indoor coil thermistor

Room temperature thermistor

Indoor

control system

point

Indoor fan motor

Outdoor thermistor

Lighted

Not lighted

0.5-second ON

0.5-second OFF

2-time flash

2.5-second OFF

3-time flash

2.5-second OFF

4-time flash

2.5-second OFF

6-time flash

2.5-second OFF

· Flashing of the OPERATION INDICATOR lamp (the left-hand side lamp) indicates possible abnormalities.

SymptomOperation indicator lamp Condition Correspondence

Outdoor unit does not operate.

Indoor fan repeats 12 seconds ON and 3 minutes OFF. When the indoor fan breaks, the fan keeps stopping.

Outdoor unit does not operate.

3 minutes after power supply turns ON, serial signal is not received.

Indoor coil/room temperature thermistor detects short or open circuit every 8 seconds during operation.

The rotational frequency feedback signal is not sent out for 12 seconds after indoor fan motor is operated.

It cannot properly read data in the nonvolatile memory of the indoor electronic control P.C. board.

<Thermistor short> Thermistors are abnormal when they short after compressor start-up. <Thermistor open> Thermistors are abnormal when they open after compressor start-up. However, discharge temperature thermistor is abnormal when open circuit is detected more than 10 minutes after compressor start-up.

• Refer to 10-5. "How to check mis-wiring ".

• Refer to the characteristics of indoor coil thermistor, and room temperature thermistor

on 10-6.

• Refer to 10-5. "Check of indoor fan motor".

• Check the indoor electronic

control P.C. board.

• Check the deicer P.C.

board.

• Reconnect the connector.

Refer to "Check of outdoor thermistor". Refer to outdoor service manual.

Outdoor

control system

Low discharge

temperature protection

7-time flash

2.5-second OFF

10-time flash

2.5-second OFF

Outdoor unit does not operate.

It cannot properly read data in the nonvolatile memory of the deicer P.C. board, outdoor unit stops.

Discharge temperature has been 50°C or less on cool operation.

• Check the deicer P.C. board.

Refer to outdoor service manual.

• Refer to "Check of LEV".

• Check refrigerant circuit and refrigerant amount.

Refer to outdoor service

manual.

10-4. TROUBLE CRITERION OF MAIN PARTS

MS-GD80VB

Part name

Room temperature thermistor (RT11)

Indoor coil thermistor (RT12 (main), RT13 (sub))

Indoor fan motor (MF)

INNER PROTECTOR 135± 5 °C OPEN

Horizontal vane motor (MV1) Vertical vane motor (MV2)

Check method and criterion

Measure the resistance with a tester. (Part temperature 10°C ~ 30°C)

Refer to 10-6."Test point diagram and voltage", "Indoor electronic control P.C. board", the chart of thermistor.

Measure the resistance between the terminals with a tester. (Part temperature 10°C ~ 30°C)

Color of lead wire

Motor part

WHT – BLK BLK – RED

Normal

132 Ω ~ 144 Ω 152 Ω ~ 166 Ω

Measure the voltage power ON.

Color of lead wire

BRN – YLW

Normal

4.5 ~ 5.5 V

(When fan revolved one time)

YLW – GRY

Sensor part

0 V → 5 V → 0 V

(Approx.)

Measure the resistance between the terminal with a tester.

°C

(Part temperature 10

~ 30°C)

Normal

282 Ω ~ 306 Ω

Figure

MAIN

AUX.

BLK

YLW

BRN

GRY

RED

YLW BRN

ROTOR

:INNER PROTECTOR

RED

WHT

GRNORN

10-5. TROUBLESHOOTING FLOW

When OPERATION INDICATOR lamp flashes 3-time. Indoor fan motor doesn’t operate.

Check of indoor fan motor

Reconnect the lead wires.

Are lead wires connected?

Disconnect lead wires from connector CN211 on the indoor electronic control P.C. board. Measure resistance between lead wires No.1 and No.4 and then No.3 and No.4.

Is resistance 0 (short circuit) or (open circuit)?

Repair or replace the indoor fan motor.

Turn OFF the power supply. Check connector CN211 visually.

Yes

Yes ( 0 or )

Is soldered point of the connector correctly soldered?

Yes

Turn ON the power supply. Stop it if the unit operate. Insert screwdriver into air outlet to rotate indoor fan motor slowly for 1 revolution or over, and measure

(others)

voltage between No.2(+) and No.3(-) on CN121.

Does voltage repeat 0 V DC and 5 V DC?

Replace the indoor electronic control P.C. board.

Resolder it.

Yes

Indoor unit operates by pressing the EMERGENCY OPERATION switch, but doesn’t operate with the remote controller.

Check of remote controller and receiver P.C. board

Check if the remote controller is exclusive for this air conditioner.

Press OPERATE/STOP (ON/OFF) button on the remote controller.

Is LCD display on the remote controller visible?

Yes

Remove the batteries, then set them back and press the RESET button. Check if the unit operates with the remote controller.

Does the unit operate with the remote controller?

Yes

No (not clear)

Replace the batteries. (Refer to 10-1.4.)

Turn ON a radio to AM and press OPERATE/STOP (ON/OFF) button on the remote controller.

Is noise heard from radio?

Yes

Are there any fluorescent lights of inverter or rapid-start type within the range of 1 m?

Measure the voltage between receiver P.C. board connector CN301 No.2(+) and No.1(-) when the remote controller button is pressed.

Is the voltage approx. 4 V DC?

No (5 V or 0 V DC)

Yes

Replace the remote controller.

Reinstall the unit away from lights. Attach a filter on receiving part.

Replace the indoor electronic control P.C. board.

Replace the receiver P.C. board.

The unit doesn’t operate with the remote controller. Also, the OPERATION INDICATOR lamp doesn’t light up by pressing the EMERGENCY OPERATION switch.

Check of indoor electronic control P.C. board

Check the both “parts side” and “pattern side” of indoor electronic control P.C. board visually.

Turn OFF the power supply. Remove indoor fan motor connector CN211 and vane motor connector CN151 from the indoor electronic control P.C. board and turn ON the power supply.

Does the unit operate with the remote controller? Does the OPERATION INDICATOR lamp light up by pressing the EMERGENCY OPERATION switch?

Yes

Turn OFF the power supply.

Replace the vane motor.

Yes

Is winding resistance of vane motor 0 Ω?

Is winding resistance of fan motor 0 Ω?

Yes

Replace the fan motor.

Turn OFF the power supply.

Replace the fuse.

Yes

Is fuse (F11) blown?

Is varistor (NR11) burnt?

Yes

Replace the varistor.

Fuse (F11)

Indoor electronic control P.C. board

Varistor (NR11)

Replace the indoor electronic control P.C. board.

When OPERATION INDICATOR lamp flashes ON and OFF in every 0.5-second. Outdoor unit doesn’t operate.

How to check mis-wiring

Short circuit of JPG and JPS on the indoor electronic control P.C. board enables self -check to be displayed in 3 seconds.

Start

• Turn ON the power supply. (indoor/outdoor unit)

• Press EMERGENCY OPERATION switch once.

After 3 minutes, mis-wiring is indicated (0.5-second ON, 0.5-second OFF) on OPERATION INDICATOR lamp on indoor unit.

Correct them.

Yes

1. Turn OFF the power supply (indoor/outdoor unit) and disconnect indoor and outdoor connecting wire at the terminal block

2. Short-circuit terminal block

3. Turn ON the power supply (indoor unit) and press EMERGENCY OPERATION switch once.

Is this mis-wiring, poor contact, or wire disconnection?

□

-□

Is there 20 V DC between both ends of R132 on the indoor electronic control P.C. board ? ( By tester, the stylus is between 0 ~ 20 V. )

• Turn OFF the power supply.

• Disconnect the lead wire that terminal block short-circuited.

• Connect indoor/outdoor connecting wire.

Turn ON the power supply. (outdoor unit)

Is there 230 V AC between on the outdoor terminal block?

Is there 5 V DC between J101 + -J401 on the deicer P.C. board?

During EMERGENCY OPERATION, is there 10 V DC between both ends of R601 on the deicer P.C. board? (By tester, the stylus is between 5 ~10 V.)

Replace the deicer P.C. board.

of the indoor unit.

of indoor unit by lead wire.

Yes

(indoor unit)

□

-□

of the indoor unit is

□

Yes

-□

Replace the indoor electronic control P.C. board.

Check the outdoor power supply and connection of wiring.

Replace the deicer P.C. board.

Make the wiring between CN730

on the deicer P.C. board and outdoor terminal block correct.

Refer to outdoor unit service manual.

10-6. TEST POINT DIAGRAM AND VOLTAGE

MS-GD80VB Indoor electronic control P.C. board

Fuse (F11) T3.15AL250V

R132

Fan motor power supply

Power supply input

}

230 V AC

5 V DC

}

Room temperature thermistor (RT11)

Indoor coil thermistor (RT12 (main))

Receiver P.C. board

Release of “Auto restart function” Solder jumper wire to JR07. (Refer to 8-3.)

Indoor coil thermistor (RT13 (sub))

Emergency operation switch

Timer short mode point (JPS, JPG) (Refer to 8-1.)

}

12 V DC

Indoor coil thermistor (RT12(main), RT13 (sub))

Room temperature thermistor (RT11)

Resistance(kΩ)

DISASSEMBLY INSTRUCTIONS

<"Terminal with locking mechanism" Detaching points>

The terminal which has the locking mechanism can be detached as shown below. There are two types ( Refer to (1) and (2)) of the terminal with locking mechanism. The terminal without locking mechanism can be detached by pulling it out. Check the shape of the terminal before detaching.

(1) Slide the sleeve and check if there is a locking lever or not.

Sleeve

Slide the sleeve.

○

Pull the terminal while

○

Locking lever

pushing the locking lever.

MS-GD80VB

OPERATING PROCEDURE PHOTOS

1. Removing the panel

(1) Remove the screw caps of the panel. Remove the screws of the panel. (2) Pull the panel down to your side slightly and unhook the

catches at the top. (3) Remove the screw of the corner box. Remove the corner box.

(2) The terminal with this connector has the locking mechanism.

Hold the sleeve, and

○

pull out the terminal slowly.

Connector

Photo 1

2. Removing the electronic control P.C. board, the receiver P.C. board and the display P.C. board

(1) Remove the panel and the corner box. (Refer to 1.) (2) Remove the screw of the electrical cover. Remove the electrical cover. (3) Remove the screws of the V.A. clamp. Remove the V.A. clamp. (4) Remove the screw of the terminal block. (5) Remove the screws of the earth wire. (6) Disconnect all the connectors and all the lead wires on the

electronic control P.C. board. (7) Remove the R.L holder. (8) Remove the electronic control P.C. board. (9) Open the R.L holder, remove the receiver P.C. board and

the display P.C. board.

Photo 2

R.L holder

Screws of the panel

Screws of the earth wire

Screw of the terminal block

Receiver P.C. board

Screw of the corner box

Fan motor connectors

Vane motor connector

Indoor electronic control P.C. board

Screw of the electrical cover

Screw of the V.A. clamp

OPERATING PROCEDURE

PHOTOS

3. Removing the electrical box

(1) Remove the panel and the corner box. (Refer to 1.) (2) Remove the electrical cover. (Refer to 2.) (3) Disconnect the connector of the indoor coil thermistor. (4) Disconnect the motor connector (CN211 and CN121) and

the vane motor connector (CN151) on the electronic control P.C. board. (5) Remove the screws of earth wire. (6) Remove the fan motor lead wire and indoor coil thermistor

from the electrical box. (7) Remove the lead wire of vane motor from the bottom of

electrical box. (8) Remove the screw of the electrical box and remove the

electrical box.

4. Removing the vane motor

(1) Remove the panel and the corner box. (Refer to 1.) (2) Remove the electrical cover. (Refer to 2.) (3) Remove the lead wire of vane motor. (Refer to 3.) (4) Remove the R.L. holder. (5) Pull out the drain hose from the nozzle assembly and

remove the nozzle assembly.

(6) Remove the screws of the vane motor and disconnect the

connector.

(7) Remove the vane motor.

Photo 5

Screws of the vane motor

Photo 3

Photo 4

Screws of the earth wire

Vane motors

Screw of the electrical cover

Screw of the electrical box

Screws of the vane motor

Vane motor

5. Removing the line flow fan and the indoor fan motor

(1) Remove the panel and the corner box. (Refer to 1.) (2) Remove the electrical box. (Refer to 3.) (3) Pull out the drain hose from the nozzle assembly and

remove the nozzle assembly. (4) Remove the water cut. (5) Slide the hole cover and remove the hole cover. (6) Remove the hexagon socket set screw from the line flow

fan. (7) Remove the screws of the fan motor and remove the fan

motor. (Be careful not to drop the fan motor because it is

heavy.) (8) Remove the screws of the left side of the heat exchanger. (9) Lift the left side of the heat exchanger.

) Remove the line flow fan.

(

Photo 8

Hole cover

Photo 6

Screws of the left side of the heat exchanger

Photo 7

Indoor coil thermistor

Water cut

Screws of the fan motor

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

New publication, effective Apr. 2008 Specifications subject to change without notice.

Mitsubishi MS-GD80VB-E1 Service Manual

Specifications and Main Features

Frequently Asked Questions

User Manual