Mitsubishi Electronics MFZ-KJ09NA- U1, MFZ-KJ12NA- U1, MFZ-KJ15NA- U1, MFZ-KJ18NA- U1 User Manual

INDOOR UNIT

SERVICE MANUAL

Models

MFZ-KJ09NA MFZ-KJ12NA

Revision A:

• 3. SPECIFICATION and 4. OUTLINES AND DIMENSIONS have been modified.

Please void OBH752.

No. OBH752

REVISED EDITION-A

MFZ-KJ15NA MFZ-KJ18NA

Outdoor unit service manual MUFZ-KJ•NAHZ Series (OBH753) MXZ-C•NA, MXZ-C•NAHZ Series

(OBH702, OCH573)

CONTENTS

1. TECHNICAL CHANGES ··································· 3

2. PART NAMES AND FUNCTIONS ····················· 4

3. SPECIFICATION ················································ 5

4. OUTLINES AND DIMENSIONS ························ 7

5. WIRING DIAGRAM ············································ 8

6. REFRIGERANT SYSTEM DIAGRAM ··············· 9

7. SERVICE FUNCTIONS ··································· 10

8. MICROPROCESSOR CONTROL ··················· 12

9. TROUBLESHOOTING ····································· 21

10. DISASSEMBLY INSTRUCTIONS ···················· 36

PARTS CATALOG (OBB752)

NOTE:

• This service manual describes technical data of the indoor units.

• RoHS compliant products have <G> mark on the spec name plate. For servicing of RoHS compliant products, refer to the RoHS Parts List.

Use the speciﬁ ed refrigerant only

OBH752A

Never use any refrigerant other than that specified.

Doing so may cause a burst, an explosion, or fire when the unit is being used, serviced, or disposed of. Correct refrigerant is specified in the manuals and on the spec labels provided with our products. We will not be held responsible for mechanical failure, system malfunction, unit breakdown or accidents caused by failure to follow the instructions.

Revision A:

• 3. SPECIFICATION and 4. OUTLINES AND DIMENSIONS have been modified.

OBH752A

TECHNICAL CHANGES

MFZ-KJ09NAMFZ-KJ12NAMFZ-KJ15NAMFZ-KJ18NA-

1. New model

OBH752A

PART NAMES AND FUNCTIONS

MFZ-KJ09NA MFZ-KJ12NA MFZ-KJ15NA MFZ-KJ18NA

Air outlet

0XOWLÀRZYDQH

$LUFOHDQLQJ¿OWHU

(Anti-allergy enzyme filter, option)

Front panel

$LU¿OWHU 1DQRSODWLQXP¿OWHU

Display and operation section (When the front panel is opened)

Horizontal vane

Vertical vane

Fan guard

Panel

ACCESSORIES

E.O SW

Remote control receiving section

Operation indicator lamp

MFZ-KJ09NA MFZ-KJ12NA MFZ-KJ15NA MFZ-KJ18NA

Drain hose 1 Remote controller holder 1 Fixing screw for 3.5 x 16 mm (Black) 2 Pipe cover 1 Band 2 Battery (AAA) for remote controller 2 Indoor unit mounting bracket 1 Fixing screw for 4 x 25 mm 5 Wood screw for the indoor unit ﬁ xation 4 Washer of 4 Felt tape (Used for left or left-rear piping) 1 Wireless remote controller 1

Emergency operation switch

OBH752A

1. Single connection

Indoor model MFZ-KJ09NA MFZ-KJ12NA MFZ-KJ15NA MFZ-KJ18NA Power supply V, phase, Hz 208/230, 1, 60 Max. fuse size (time delay)/ Disconnect switch

Airﬂ ow Super High - High - Med. Low - Quiet

Sound level Super High - High - Med. Low - Quiet

Cond. drain connection O.D. in. 5/8

Dimensions

Weight Ib. 33 External ﬁ nish White Control voltage (by built-in transformer) 12 - 24 VDC

NOTE: Test conditions are based on ARI 210/240.

2. Multi connection

Indoor model MFZ-KJ09NA MFZ-KJ12NA MFZ-KJ15NA MFZ-KJ18NA Power supply V, phase, Hz 208/230, 1, 60 Max. fuse size (time delay)/ Disconnect switch

Airﬂ ow Super High - High - Med. Low - Quiet

Sound level Super High - High - Med. Low - Quiet

Cond. drain connection O.D. in. 5/8

Dimensions

Weight Ib. 33 External ﬁ nish White Control voltage (by built-in transformer) 12 - 24 VDC

NOTE: Test conditions are based on ARI 210/240.

SPECIFICATION

A15 20

COOL Dry

HEAT Dry CFM 417 - 328 - 254 - 191 - 138

Cooling dB (A) 46 - 41 - 34 - 27 - 21

Heating dB (A) 46 - 40 - 34 - 27 - 21

W D 8-15/32 H 23-5/8

COOL Dry

HEAT Dry CFM 343 - 219 - 180 - 159 - 138

Cooling dB (A) 38 - 34 - 30 - 25 - 21 43 - 40 - 36 - 31 - 28

Heating dB (A) 41 - 32 - 27 - 24 - 21 49 - 39 - 36 - 34 - 29

W D 8-15/32 H 23-5/8

CFM

(Wet)

in.

A15 20

CFM

(Wet)

in.

417 - 360 - 272 - 198 - 138

(354 - 306 - 231 - 168 - 117)

275 - 251 - 208 173 - 138

(234 - 213 - 177 - 147 - 117)

431 - 392 - 311 - 254 - 198

(366 - 333 - 264 - 216 - 168)

470 - 399 - 328 - 268 - 212

47 - 43 - 38 - 33 - 28 50 - 45 - 39 - 33 - 28

49 - 45 - 40 - 35 - 29 49 - 45 - 40 - 35 - 29

29-17/32

374 - 328 - 282 - 237 - 198

(318 - 279 - 240 - 201 - 168)

470 - 325 - 290 - 254 - 212

29-17/32

491 - 420 - 328 - 254 - 198

(417 - 357 - 279 - 216 - 168)

3-1. OPERATING RANGE

OBH752A

(1) POWER SUPPLY

Rated voltage Guaranteed voltage (V)

Indoor unit

208/230 V

1 phase

60 Hz

(2) OPERATION

Mode Condition

Standard temperature 80 67 95 —

Cooling

Heating

Maximum temperature 90 73 115 — Minimum temperature 67 57 14 — Maximum humidity 78% — Standard temperature 70 60 47 43 Maximum temperature 80 67 75 65 Minimum temperature 70 60 -13 -14

3-2. OUTLET AIR SPEED AND COVERAGE

1. Single connection

Model Mode Function

MFZ-KJ09NA MFZ-KJ12NA

MFZ-KJ15NA

MFZ-KJ18NA

HEAT Dry 417 20.3 29.6

COOL

HEAT Dry 470 22.9 33.3

COOL

HEAT Dry 470 22.9 33.3

COOL

Dry 417 20.3 29.6

Wet 354 17.2 25.3

Dry 431 21.0 30.6

Wet 366 17.8 26.2

Dry 491 23.9 34.8

Wet 417 20.3 29.7

Airﬂ ow

(CFM)

Min. 187

DB WB DB WB

208 230 Max. 253

Intake air temperature (°F)

Indoor Outdoor

● The air coverage is the figure up to the

Air speed

(ft./s.)

Coverage

(ft.)

position where the air speed is 1 ft./s., when air is blown out horizontally from the unit properly at the High speed position.

The coverage should be used only as a

general guideline since it varies according to the size of the room and furniture arranged inside the room.

2. Multi connection

Model Mode Function

MFZ-KJ09NA MFZ-KJ12NA

MFZ-KJ15NA MFZ-KJ18NA

Airﬂ ow

(CFM)

HEAT Dry 343 16.7 24.5

COOL

HEAT Dry 470 22.9 33.3

COOL

Dry 275 13.4 19.8

Wet 234 11.4 16.9

Dry 374 18.2 26.7

Wet 318 15.5 22.8

Air speed

(ft./s.)

Coverage

(ft.)

OBH752A

OUTLINES AND DIMENSIONS

MFZ-KJ09NA MFZ-KJ12NA MFZ-KJ15NA MFZ-KJ18NA

Unit: inch

OBH752A

MFZ-KJ09NA MFZ-KJ12NA MFZ-KJ15NA MFZ-KJ18NA

WIRING DIAGRAM

Indoor heat exchanger

Flared connection

Room temperature thermistor RT11

Indoor coil thermistor RT12, RT14, RT15 (main) RT13 (sub)

Flared connection

Refrigerant flow in cooling Refrigerant flow in heating

Refrigerant pipe 3/8 ( 9.52) (MFZ-KJ09/12) 1/2 ( 12.7) (MFZ-KJ15/18) (with heat insulator)

Refrigerant pipe 1/4 ( 6.35) (with heat insulator)

Distributor

OBH752A

REFRIGERANT SYSTEM DIAGRAM

MFZ-KJ09NA MFZ-KJ12NA MFZ-KJ15NA MFZ-KJ18NA

Unit: inch (mm)

OBH752A

SERVICE FUNCTIONS

MFZ-KJ09NA MFZ-KJ12NA MFZ-KJ15NA MFZ-KJ18NA

7-1. TIMER SHORT MODE

For service, the following set time can be shortened by bridging the timer short mode point on the electronic control P.C.

• board. (Refer to 9-7.)

The set time for the ON/OFF timer can be reduced to 1 second for each minute.

• After the breaker is turned on, the time for starting the compressor, which normally takes 3 minutes, can be reduced to 3

• seconds. Restarting the compressor, which takes 3 minutes, cannot be reduced.

7-2. HOW TO SET REMOTE CONTROLLER EXCLUSIVELY FOR A PARTICULAR INDOOR UNIT

A maximum of 4 indoor units with wireless remote controllers can be used in a room. To operate the indoor units individually with each remote controller, assign a number to each remote controller according to the number of the indoor unit.

This setting can be set only when all the following conditions are met:

• The remote controller is powered OFF.

• Weekly timer is not set.

• Weekly timer is not being edited.

1. How to modify the electronic control P.C. board

Turn OFF the power supply before modification. To assign a number to each indoor unit , cut off “JR05” and “JR06” on the electronic control P.C. board as shown in Table 1. (Refer to 9-7.)

Table 1

Indoor electronic control P.C. Board

Fuse (F11)

Unit No. 1

Unit No. 2

Unit No. 3

Unit No. 4

JR05

No modification

Cut off JR05

No modification

Cut off JR05

JR06

No modification

Cut off JR06

VARISTOR (NR11)

R111

JR05 JR06

CN211

2. How to set the remote controller

(1) Hold down (2) Press Each press of

(3) Press

After the setting, turn ON the power supply and with the remote controller headed towards the indoor unit, press the

STOP/OPERATE (OFF/ON) button. If 1 or 2 beeps are heard from the indoor unit, the setting is completed correctly.

The remote controller that first sends a signal to an indoor unit will be regarded as the remote controller for the indoor

unit.

Once they are set, the indoor unit will only receive the signal from the assigned remote controller afterwards.

button on the remote controller for 2 seconds to enter the pairing mode.

button again and assign a number to each remote controller.

button advances the number in the following order: 1 → 2 → 3 → 4.

button to complete the pairing setting.

CN151

7-3. AUTO RESTART FUNCTION

OBH752A

When the indoor unit is controlled with the remote controller, the operation mode, the set temperature, and the fan speed are memorized by the indoor electronic control P.C. board. “AUTO RESTART FUNCTION” automatically starts operation in the same mode just before the shutoff of the main power.

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.)

How to disable “AUTO RESTART FUNCTION”

Turn off the main power for the unit. Cut the Jumper wire to JR77 on the indoor electronic control P.C. board. (Refer to 9-7.)

CN201 F11

L101

JR77

CN211

CN 111

C111

CN104

T111

CN105

CN123

NOTE:

• The operation settings are memorized when 10 seconds have passed after the indoor unit 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 can-

celled.

• 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 appliance 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.

OBH752A

MICROPROCESSOR CONTROL

MFZ-KJ09NA MFZ-KJ12NA MFZ-KJ15NA MFZ-KJ18NA

WIRELESS REMOTE CONTROLLER

Signal transmitting section

Distance of signal : About 20 ft. (6 m)

Beep(s) is (are) heard from the indoor unit when the signal is received.

OPERATION SELECT button

ECONO COOL button

Operation display section

SLEEP button

SMART SET button

FAN SPEED CONTROL button

POWERFUL button

VANE CONTROL button

TIME, TIMER set buttons FORWARD button BACKWARD button

TEMPERATURE buttons

STOP/OPERATE (OFF/ON) button

Indication of remote controller model is on back

WEEKLY TIMER set buttons

RESET button

CLOCK button

Lid Slide the lid down to open the remote controller. Slide it down further to get to the weekly timer buttons.

NOTE: 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 indication.

Indication Operation state Room temperature

The unit is operating to reach the set temperature

The room temperature is approaching the set temperature

About 4 °F (2°C) or more away from set temperature

About 2 to 4 °F (1 to 2°C) from set temperature

Lighted

Blinking

Not lighted

Standby mode (only during multi system operation)

—

8-1. COOL ( ) OPERATION

OBH752A

(1) Press STOP/OPERATE (OFF/ON) 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 TEMP

- 31°C).

1. Coil frost prevention

The compressor operational frequency is controlled by the temperature of the indoor heat exchanger to prevent the coil

from frosting.

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. Low outside temperature operation

When the outside temperature is lower, low outside temperature operation starts, and the outdoor fan slows or stops.

3. Indoor fan speed control

When the thermostat turns OFF, the indoor fan operates at the setting fan speed.

or button to select the desired temperature. The setting range is 61 - 88°F (16

8-2. DRY ( ) OPERATION

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

1. Coil frost prevention

Coil frost prevention works the same way as that in COOL mode. (8-1.1.)

2. Low outside temperature operation

Low outside temperature operation works the same way as that in COOL mode. (8-1.2.)

3. Indoor fan speed control

Indoor fan speed control works the same way as that in COOL mode. (8-1.3.) However in AUTO setting, the fan speed changes.

8-3. FAN ( ) OPERATION

(1) Press STOP/OPERATE (OFF/ON) 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 does not operate.

NOTE: Temperature cannot be set during FAN mode.

8-4. HEAT ( ) OPERATION

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

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

- 31°C).

1. Cold air prevention control

When the compressor is not operating or is starting, and the temperature of indoor heat exchanger and/or the room temperature is low or when defrosting is being done, the indoor fan will stop or rotate in Very Low speed.

2. High pressure protection

The compressor operational frequency is controlled by the temperature of the indoor heat exchanger to prevent the condensing pressure from increasing excessively. When the temperature of indoor heat exchanger becomes too high, the high pressure protection works. This mode continues until the temperature of indoor heat exchanger falls.

3. Defrosting

Defrosting starts when the temperature of outdoor heat exchanger becomes too low.

The compressor stops once, the indoor/outdoor fans stop, the 4-way valve reverses, and the compressor re-starts.

This mode continues until the temperature of outdoor heat exchanger rises or the fixed time passes.

or button to select the desired temperature. The setting range is 61 - 88°F (16

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