SERVICE MANUAL MFZ-KA09NA MFZ-KA12NA MFZ

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SERVICE MANUAL MFZ-KA09NA MFZ-KA12NA MFZ | Manualzz
Revision A:
• OUTLINES AND DIMENSIONS has
been corrected.
• Some descriptions have been modified.
Please void OBH568.
INDOOR UNIT
No. OBH568
REVISED EDITION-A
SERVICE MANUAL
Models
MFZ-KA09NA
MFZ-KA12NA
MFZ-KA18NA
Outdoor unit service manual
MXZ-B NA Series (OBH560)
CONTENTS
MFZ-KA09NA
MFZ-KA12NA
MFZ-KA18NA
1. TECHNICAL CHANGES······································· 2
2. PART NAMES AND FUNCTIONS ····················· 2
3. SPECIFICATION ················································ 4
4. OUTLINES AND DIMENSIONS ························ 5
5. WIRING DIAGRAM············································ 6
6. REFRIGERANT SYSTEM DIAGRAM ··············· 7
7. SERVICE FUNCTIONS ····································· 8
8. MICROPROCESSOR CONTROL ··················· 10
9. TROUBLESHOOTING ····································· 16
10. DISASSEMBLY INSTRUCTIONS ···················· 30
PARTS CATALOG (OBB568)
TM
NOTE:
RoHS compliant products have <G> mark on
the spec name plate.
Revision A:
• OUTLINES AND DIMENSIONS has been corrected.
• Some descriptions have been modified.
1
TECHNICAL CHANGES
MFZ-KA09NA MFZ-KA12NA MFZ-KA18NA
1. New model
2
PART NAMES AND FUNCTIONS
MFZ-KA09NA MFZ-KA12NA MFZ-KA18NA
Front grille
Vertical vane
Fan guard
Air outlet
Horizontal vane
Panel
Catechin air filter
Air cleaning filter
(Anti-Allergy Enzyme
Filter, blue bellows type)
Remote controller
Damper
Air outlet
Vertical vane
Air inlet
Display and operation section (When the front grille is opened)
Operation indicator lamp
Remote control
receiving section
Emergency operation switch
Air outlet selection switch
OBH568A
2
ACCESSORIES
MFZ-KA09NA
MFZ-KA12NA
MFZ-KA18NA
Drain hose
Remote controller holder
Fixing screw for 3.5 x 1.6 mm (Black)
Pipe cover
Band
Battery (AAA) for remote controller
Indoor unit mounting bracket
Fixing screw for 4 x 25 mm
Wood screw for the indoor unit fixation
Washer of
Felt tape (Used for left or left-rear piping)
Wireless remote controller
Air cleaning filter
1
1
2
1
2
2
1
5
4
4
1
1
1
MFZ-KA09NA MFZ-KA12NA MFZ-KA18NA
REMOTE CONTROLLER
Signal transmitting section
Operation display section
OPERATE/STOP
(ON/OFF) button
SMART SET button
FAN SPEED CONTROL button
OPERATION SELECT button
ECONO COOL button
Temperature buttons
RESET button
OFF-TIMER button
ON-TIMER button
TIME SET buttons
FORWARD button
BACKWARD button
CLOCK SET button
VANE CONTROL button
Indication of
remote controller
model is on back
OBH568A
3
3
SPECIFICATION
Indoor model
Power supply
V, phase, Hz
Max. fuse size (time delay)/ Disconnect switch A
COOL Dry CFM
Airflow
(Wet)
Super High - High - Med. Low - Quiet
HEAT Dry CFM
Sound level
Cooling
dB(A)
Super High - High - Med. Heating
dB(A)
Low - Quiet
Cond. drain connection O.D.
in.
W
Dimensions
D
in.
H
Weight
Ib.
External finish
Control voltage (by built-in transformer)
MFZ-KA09NA
314-251-205-169
(303-241-197-163)
332-219-198-177
40-35-30-25
MFZ-KA12NA
208/230, 1, 60
15
321-261-215-177
(309-252-207-170)
335-219-201-184
41-36-31-26
MFZ-KA18NA
394-325-279-251
(379-313-269-241)
434-297-275-261
46-42-38-35
41-36-31-28
47-42-38-35
5/8
27-9/16
7-7/8
23-5/8
32
White
12 - 24 VDC
NOTE: Test conditions are based on ARI 210/240.
3-1. OPERATING RANGE
(1) POWER SUPPLY
Rated voltage
208/230 V
1 phase
60 Hz
Indoor unit
Guaranteed voltage (V)
Min. 198
208
230
Max. 253
(2) OPERATION
Intake air temperature (°F)
Mode
Condition
Indoor
DB
80
90
67
Standard temperature
Maximum temperature
Cooling
Minimum temperature
Maximum humidity
Standard temperature
Heating Maximum temperature
Minimum temperature
Outdoor
WB
67
73
57
DB
95
115
14
60
67
60
47
75
6
78%
70
80
70
WB
—
—
—
—
43
65
5
3-2. OUTLET AIR SPEED AND COVERAGE
Model
MFZ-KA09NA
Mode
Function
HEAT
Dry
Airflow
(CFM)
332
Dry
314
COOL
HEAT
MFZ-KA12NA
COOL
HEAT
MFZ-KA18NA
COOL
OBH568A
● The air coverage is the figure up to the
Air speed
Coverage (ft.)
(ft./s.)
position where the air speed is 1 ft./s.,
when air is blown out horizontally from
6.6
15.4
6.3
14.6
Wet
303
6.1
14.2
Dry
335
6.7
15.6
Dry
321
6.4
15.0
Wet
309
6.2
14.5
Dry
434
8.7
20.0
Dry
395
7.9
18.3
Wet
379
7.5
17.5
4
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.
4
OUTLINES AND DIMENSIONS
MFZ-KA09NA MFZ-KA12NA MFZ-KA18NA
5-5/32
4- 1/4 Hole
5-5/32
9/32
Unit: inch
13-1/8
23-11/32
14-5/16
Installation plate
15/32
Air out
More than
3-7/8
Air in
4-5/8
3-3/4
23-5/8
More than
3-7/8
7-7/8
15/32
1-27/32
More than
3-7/8
1-27/32
8-9/32
Indoor unit
27-9/16
23-29/32
13-9/32
Gas pipe
09, 12: 3/8(flared)
18: 1/2(flared)
Liquid pipe
1/4(flared)
20
drain
5-13/32
4-5/16
15/32
1-25/32
1-6/16
2-3/8
5-1/16
OBH568A
17-7/8
2-27/32
2-3/8
2-3/8
3-5/32
6-1/8
3/4
2-1/8
5
4-15/16
2-3/8
4-27/32
15/32
2-3/8
5-25/32
4-15/16
3/4 2-3/8
Air out
6-1/2
8-1/16
7/16
13-9/32
5
WIRING DIAGRAM
MFZ-KA09NA MFZ-KA12NA MFZ-KA18NA
OBH568A
6
6
REFRIGERANT SYSTEM DIAGRAM
MFZ-KA09NA MFZ-KA12NA MFZ-KA18NA
Unit: inch
Refrigerant pipe 3/8 (MFZ-KA09/12NA)
Refrigerant pipe 1/2 (MFZ-KA18NA)
(with heat insulator)
Indoor
heat
exchanger
Indoor coil
thermistor
RT12 (main)
Distributor
Flared connection
Indoor coil
thermistor
RT12, RT14,
RT15 (main)
RT13 (sub)
Room temperature
thermistor
RT11
Flared connection
Refrigerant pipe 1/4
(with heat insulator)
Refrigerant flow in cooling
Refrigerant flow in heating
OBH568A
7
7
SERVICE FUNCTIONS
MFZ-KA09NA MFZ-KA12NA MFZ-KA18NA
7-1. TIMER SHORT MODE
For service, the following set time can be shortened by bridging of JPG and JPS on the electronic control P.C. board.
(Refer to 9-7.)
Set time: 3-minutes 3-seconds (It takes 3 minutes for the compressor to start operation. However, the starting time is
shortened by bridging of JPG and JPS.)
7-2. 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, both the P.C. boards of remote controller
and the electronic control P.C. boards 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 :
Remote controller model: KM05G
NOTE: For modification, take out the batteries and push the OPERATE/STOP
(ON/OFF) button 2 or 3 times at
first.
After finish modification, put back
the batteries then press the RESET
button.
J1
J2
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
2 units operation
3 units operation
4 units operation
No. 1 unit
No modification
Same as at left
Same as at left
Same as at left
No. 2 unit
–
Solder J1
Same as at left
Same as at left
No. 3 unit
–
–
Solder J2
Same as at left
No. 4 unit
–
–
–
Solder both J1 and J2
How to modify the electronic control P.C. board
Turn OFF the power supply before modification. Cut off “JR05” and “JR06” on the electronic control P.C. board according
to the number of indoor unit as shown in Table 2. (Refer to 9-7.)
Table 2
Indoor electronic
control P.C. Board
JR05
JR06
No modification
No modification
No. 2 unit
Cut off JR05
No modification
No. 3 unit
No modification
Cut off JR06
No. 4 unit
Cut off JR05
Cut off JR06
No. 1 unit
Fuse (F11)
VARISTOR (NR11)
JR05 JR06
IC101
CN1X1 CN1Y1
R111
C111T11
CN151
CN152
CN211
CN212
NOTE: After modification, turn ON the power supply and with the remote controller headed towards the indoor unit, press the
OPERATE/STOP (ON/OFF) button. If 1 or 2 beeps is heard from the indoor unit, modification is completed correctly.
OBH568A
8
7-3. AUTO RESTART FUNCTION
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. The “AUTO RESTART FUNCTION” sets to work the moment
power is restored after power failure. Then, the unit will restart automatically.
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 release “AUTO RESTART FUNCTION”
Turn off the main power for the unit.
Solder the Jumper wire to JR07 on the indoor electronic control P.C. board. (Refer to 9-7.)
F11
CN111 CN112 CN113 CN106
JR07
IC101
CN125
CN151
CN152
C111
T11
CN211
CN212
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
cancelled.
• If the unit has been turned 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 tripping 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 current
by adding to the system that allows the units to start one by one.
OBH568A
9
8
MICROPROCESSOR CONTROL
MFZ-KA09NA MFZ-KA12NA MFZ-KA18NA
WIRELESS REMOTE CONTROLLER
Signal transmitting section
Operation display section
OPERATE/STOP
(ON/OFF) button
Temperature buttons
Indication of
remote controller
model is on back
ra
w.).)
SMART SET button
FAN SPEED CONTROL button
OFF-TIMER button
OPERATION SELECT button
ECONO COOL button
ON-TIMER button
TIME SET buttons
FORWARD button
BACKWARD button
CLOCK SET button
RESET button
VANE CONTROL button
Once the operation mode is set, the same operation mode can be repeated by simply turning OPERATE/STOP (ON/OFF) button ON.
Indoor unit receives the signal with a beep tone.
When the system turns OFF, 3-minute time delay will operate to protect system from overload and compressor will not restart
for 3 minutes.
8-1. 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 61 ~ 88°F (16 ~ 31°C).
OBH568A
10
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 low, low outside temperature operation starts, and the outdoor fan slows or stops.
8-2. 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.
1. Coil frost prevention
Coil frost prevention works the same way as that in COOL mode. (8-1.1.)
The indoor fan maintains the actual speed of the moment.
2. Low outside temperature operation
Low outside temperature operation works the same way as that in COOL mode. (8-1.2.)
NOTE: Even when the damper is closed while cooling or drying operation is performed, the lower fan may rotate intermittently.
8-3. HEAT (
) OPERATION
(1) Press OPERATE/STOP (ON/OFF) 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 (TOO WARM or TOO COOL button) to select the desired temperature.
The setting range is 61 ~ 88°F (16 ~ 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.
The indoor fan operates following the cold air prevention control. 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.
8-4. AUTO CHANGE OVER ··· AUTO MODE OPERATION
Once desired temperature is set, unit operation is switched automatically between COOL and HEAT operation.
Mode selection
(1) Initial mode
When unit starts the operation with AUTO operation from OFF:
• If the room temperature is higher than the set temperature, operation starts in COOL mode.
• If the room temperature is equal to or lower than the set temperature, operation starts in HEAT mode.
(2) Mode change
COOL mode changes to HEAT mode when about 15 minutes have passed with the room temperature 2°F (1°C) below
the set temperature.
HEAT mode changes to COOL mode when about 15 minutes have passed with the room temperature 2°F (1°C) above
the set temperature.
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
), cannot change over to the other operating mode (COOL
HEAT) and becomes a
operating in AUTO (
state of standby.
OBH568A
11
8-5. AUTO VANE OPERATION
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 (approximately 12 V) transmitted from indoor microprocessor.
(2) The horizontal vane angle and mode change as follows by pressing VANE CONTROL button.
(3) Positioning
The vane presses the vane stopper once to confirm the standard position and then moves to the set angle.
Confirming of standard position is performed in case of follows.
(a) When the power supply turns ON.
(b) When the operation starts or finishes (including timer operation).
(c) When the test run starts.
(d) When multi-standby starts or finishes.
(e) When the swing operation finishes.
(4) VANE AUTO (
) mode
The microprocessor automatically determines the vane angle and operation to make the optimum room temperature distribution.
COOL and DRY operation
Vane angle is fixed to Angle 1.
1
HEAT operation
When the upper air outlet is selected with an air outlet
selection switch, vane angle is fixed to Angle 5.
5
1 2
3
4
5
When the upper and lower air outlets are selected with an
air outlet selection switch, vane angle is fixed to Angle 3.
3
(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.
(c) When ON-TIMER is ON standby.
(6) Dew prevention
During COOL or DRY operation with the vane angle at Angle 3 ~ 5 when the compressor cumulative operation time
exceeds 30 minutes to 1 hour, the vane angle automatically changes to Angle 1 for dew prevention.
(7) SWING MODE (
)
By selecting SWING mode with VANE CONTROL button, the horizontal vane swings vertically. The remote controller
". SWING mode is cancelled when VANE CONTROL button is pressed once again.
displays "
(8) Cold air prevention in HEAT operation
The vane angle changes to Horizontal position automatically to prevent cold air blowing on users.
(9) Damper operation
NOTE 1: Be sure to turn OFF the air conditioner before changing the switch setting.
With this function, air comes out simultaneously from the upper and lower air outlets so that the room can be
cooled or heated effectively. This function is set using the switch behind the front grille of the indoor unit. (This
function is available in cooling and heating operation.)
OBH568A
12
1.How to set to blow out air from the upper
and lower air outlets:
Set the air outlet selection switch to
.
2.How to set to blow out air from the upper
air outlet only:
Set the air outlet selection switch to .
Air blows out automatically from the upper and lower air outlets as shown in the table below.
NOTE 2: Set the air outlet selection switch to the end correctly. Otherwise, air outlet cannot be selected as intended.
Description of operation
The direction (opening and closing of the damper) and the volume of the airflow from the lower air outlet are controlled automatically.
Operation
COOL
DRY
HEAT
Air
flow
Upper and lower air flow
Room temperature
and set temperature
Conditions are different.
Upper air flow
Upper air flow only Upper and lower air flow
Room temperature is
close to set temperature, or the air
conditioner has
operated for 1 hour.
Air flow temperature
is high.
Upper air flow
Air flow temperature
is low.
(During defrosting
operation, start of
operation, etc.)
• Be sure to keep the area around the damper of the lower air outlet free of any objects. If any objects block the normal
operation of the damper, the left operation indicator lamp may blink.
Backboard
3-11/32(85)
3/8-25/32(10-20)
Indoor unit
Partition board
Backboard
Indoor temperatur
thermistor
5-1/8
(130)
15-5/32(385)
9/16(14)
2-9/16(65)
Grating
3/8-25/32(10-20)
2-3/8(60)
1-1/32(26)
2-9/16(65)
3-15/16(100)
or more
23-5/8(600)
3-15/16(100) Upper air outlet
or more
Receiver
3-15/16(100) or more
inch(mm)
Partition board
18-11/16(475)
2-1/16(52)
(10) EMBEDDING THE INDOOR UNIT IN A WALL
• When installing a grating, use a grating
with narrow upper and lower horizontal
bars so that the airflow from the upper
and lower air outlets does not contact
the bars. If the horizontal bars will block
the lower air outlet, use a stand, etc., to
adjust the height of the indoor unit. If the
upper or lower air outlet is blocked, the
air conditioner will not be able to cool or
warm the room well.
• Do not block the receiver with the grating. Otherwise, the grating will interfere
with the remote controller signal and significantly reduce the distance and area
(angle) from which the signals can be
received.
Lower air outlet
Partition board
31/32-1-3/8
(20-35)
JR24
OBH568A
JRFBL
• Use a grating with vertical bars, etc., that has at least 75 % open area. If the grating has horizontal bars or if the open
area is less than 75%, performance could be reduced.
• When the indoor unit is embedded in a wall (built-in), the time it takes for the room temperature to reach the set temperature will increase
Control board
EMBEDDED INDOOR UNIT SETTING
Cut
(MUST BE PERFORMED)
• When embedding the indoor unit in a wall, restrict
the movement of the horizontal vane for the upper air
outlet so that it only operates horizontally.
• If this setting is not performed, heat will build up in the
wall and the room will not be cooled or warmed properly. Cut the wires on both ends.
Cut the JRFBL wires.
• Cut the wires on the left and right sides of JRFBL
using a pair of nippers, etc., as shown here.
13
) operation (ECONOmical operation)
(11) ECONO COOL (
When ECONO COOL button is pressed in COOL mode, set temperature is automatically set 4°F (2°C) higher.
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, 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.
8-6. TIMER OPERATION
1. How to set the time
(1) Check that the current time is set correctly.
NOTE: Timer operation will not work without setting the current time. Initially “0:00 AM” blinks at the current time display
of TIME MONITOR, so set the current time correctly with CLOCK SET button.
How to set the current time
(a) Press the CLOCK set button.
(b) Press the TIME SET buttons (
) to set the current time.
and
• Each time FORWARD button (
) is pressed, the set time increases by 1 minute, and each time BACKWARD button (
) is pressed, the set time decreases by 1 minute.
• Pressing those buttons longer, the set time increases/decreases by 10 minutes.
(c) Press the CLOCK set button.
(2) Press OPERATE/STOP (ON/OFF) button to start the air conditioner.
(3) Set the time of timer.
ON timer setting
(a) Press ON TIMER button (
) during operation.
).
(b) Set the time of the timer using TIME SET buttons (
and
OFF timer setting
(a) Press OFF TIMER button (
) during operation.
).
(b) Set the time of the timer using TIME SET buttons (
and
Each time FORWARD button (
) is pressed, the set time increases by 10 minutes: each time BACKWARD
button (
) is pressed, the set time decreases by 10 minutes.
2. To release the timer
To release ON timer, press ON TIMER button (
).
To release 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. The set time that is reached first will operate first.
• “ ” 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.
PM
PM
AM
PM
NOTE: If the main power is turned OFF or a power failure occurs while ON/OFF timer is active, the timer setting is cancelled. As these models are equipped with an auto restart function, the air conditioner starts operating with timer
cancelled when power is restored.
OBH568A
14
8-7. SMART SET ( ) OPERATION
1. How to SET SMART SET operation
(1) Press OPERATE/STOP (ON/OFF) button.
(2) Select COOL, HEAT or ECONO COOL mode.
(3) Press SMART SET button.
(4) Set the temperature, fan speed, and airflow direction for SMART SET operation.
NOTE: • SMART SET operation cannot be selected during DRY or AUTO mode operation.
• The setting range of HEAT mode in SMART SET operation is 50°F (10°C) and 61 - 88°F (16 - 31°C).
• 2 settings can be saved. (One for COOL/ECONO COOL, one for HEAT)
2. How to cancel operation
• Press SMART SET button again.
• SMART SET operation can also be cancelled by pressing OPERATION SELECT button to change the operation mode.
The same setting is selected from the next time by simply pressing SMART SET button.
8-8. EMERGENCY/TEST OPERATION
In the case of test run operation or emergency operation, use EMERGENCY OPERATION switch on the right side of the
indoor unit. Emergency operation is available when the remote controller is missing or has failed, or when the batteries of
the remote controller are running down. The unit will start and OPERATION INDICATOR lamp will light up.
The first 30 minutes of operation is the test run operation. This operation is for servicing. The indoor fan runs at High
speed and the temperature control does not work.
After 30 minutes of test run operation, the system shifts to EMERGENCY COOL/HEAT MODE with a set temperature of
75°F (24°C). The fan speed shifts to Med.
The coil frost prevention works even in the test run or the emergency operation.
In the test run or emergency operation, the horizontal vane operates in VANE AUTO ( ) mode.
Emergency operation continues until EMERGENCY OPERATION switch is pressed once/ twice or the unit receives any
signal from the remote controller. In the latter case, normal operation will start.
NOTE: Do not press EMERGENCY OPERATION switch during normal operation.
E.O.
SW
EMERGENCY OPERATION switch
Operation mode
Set temperature
Fan speed
Horizontal vane
COOL
24°C
Med.
Auto
• The following indication does not depend on the
shape of lamp.
OPERATION INDICATOR lamp
Lighted
Press once <Cool>
Press again <Heat>
Press once again <Stop>
8-9. Changing temperature indication (°F/°C)
• The preset unit is °F.
• °F → °C: Press RESET button while the temperature
buttons are pressed.
• °C → °F: Press RESET button or remove the batteries .
Press RESET button gently using
a thin instrument.
OBH568A
HEAT
24°C
Med.
Auto
15
Not lighted
9
TROUBLESHOOTING
MFZ-KA09NA MFZ-KA12NA MFZ-KA18NA
9-1. CAUTIONS ON TROUBLESHOOTING
1. Before troubleshooting, check the following
1) Check the power supply voltage.
2) Check the indoor/outdoor connecting wire for miswiring.
2. Take care of the following during servicing
1) Before servicing the air conditioner, be sure to turn OFF the 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 front panel, the cabinet, the top panel, and the P.C. board.
3) When removing the P.C. board, hold the edge of the board with care NOT to apply stress on the components.
4) When connecting or disconnecting the connectors, hold the connector housing. DO NOT pull the lead wires.
Lead wiring
Connector housing
3. Troubleshooting procedure
1) 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 abnormality indication is flashing ON and OFF before starting service work.
2) Before servicing check that the connector and terminal are connected properly.
3) When the 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 9-2, 9-3 and 9-4.
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.
Press RESET button with a thin instrument, and
then use the remote controller.
Insert the negative pole of the
batteries first. Check if the polarity
of the batteries is correct.
RESET button
NOTE: 1. If RESET button is not pressed, the remote controller may not operate correctly.
2. This remote controller has a circuit to automatically reset the microcomputer when batteries are replaced.
This function is equipped to prevent the microcomputer from malfunctioning due to the voltage drop caused by
the battery replacement.
3. Do not use the leaking batteries.
INFORMATION FOR MULTI SYSTEM AIR CONDITIONER
OUTDOOR UNIT: MXZ series
Multi system air conditioner can connect two or more indoor units with one outdoor unit.
•Unit won’t operate in case the total capacity of indoor units exceeds the capacity of outdoor units.
Do not connect indoor units beyond the outdoor unit capacity.
Operation indicator lamp flashes as shown in the figure below.
•When you try to operate two or more indoor units with one outdoor unit simultaneously, one for the cooling and the
other for heating, the operation mode of the indoor unit that operates earlier is selected. The other indoor units will
start the operation later cannot operate, indicating as shown in the figure below. In this case, please set all the indoor
units to the same operation mode.
OPERATION INDICATOR
Lighted (Green)
Blinking (Green or Orange)
Blinking green : Standby for normal operation
Blinking orange : Standby for i-save operation
Not lighted
•When indoor units start operation while the defrosting of outdoor unit is being done, it takes a few minutes (max. 10
minutes) to blow out the warm air.
•In heating operation, even though the indoor unit is not in operation, the room may get warm or the sound of refrigerant flowing may be heard. This is not a malfunction. The refrigerant continuously flowing into it causes this.
OBH568A
16
9-2. FAILURE MODE RECALL FUNCTION
Outline of the function
This air conditioner can memorize the abnormal condition which has occurred once.
Even though OPERATION INDICATOR lamp indication listed on the troubleshooting check table (9-4.) disappears, the memorized failure details can be recalled.
This mode is very useful when the unit needs to be repaired for the abnormality which does not recur.
1. Flow chart of failure mode recall function for the indoor/outdoor unit
Operational procedure
The cause of abnormality cannot be found because the abnormality does not recur.
Setting up the failure mode recall function
Turn ON the power supply.
<Preparation of the remote controller>
While pressing both OPERATION SELECT button and TOO COOL button on the
remote controller at the same time, press RESET button.
First, release RESET button.
And release the other two buttons after all LCD in operation display section of the
remote controller is displayed after 3 seconds.
1 Regardless of normal or abnormal condition,
a short beep is emitted once the signal is received.
Press OPERATE/STOP (ON/OFF) button of the remote controller (the set temperature is
displayed) with the remote controller headed towards the indoor unit. 1
Does upper lamp of OPERATION INDICATOR
lamp on the indoor unit blink at the interval of 0.5
seconds?
Blinks: Either indoor or outdoor unit is abnormal.
Beep is emitted at the same timing as the
blinking of upper lamp of OPERATION
INDICATOR lamp. 2
Yes
(Blinks)
Judgment of indoor/outdoor abnormality
Before blinking, does upper lamp of
OPERATION INDICATOR lamp stay ON for 3
seconds?
When it stays ON for 3 seconds (without beep):
The outdoor unit is abnormal.
No
Indoor unit is normal.
But the outdoor unit might be abnormal because there are some abnormalities that cannot be recalled with this way.
No
(OFF)
Yes
The indoor unit is abnormal.
Check the blinking pattern, and identify the abnormal point by referring to the
indoor unit failure mode table. (Refer to 9-2.2)
Make sure to check at least two consecutive blinking cycles. 2
The outdoor unit is abnormal.
Check the blinking pattern, and identify the abnormal point by referring to
the outdoor unit failure mode table. (Refer to outdoor unit service manual.)
Make sure to check at least two consecutive blinking cycles. 3
Releasing the failure mode recall function
Release the failure mode recall function by the following procedures.
Turn OFF the power supply and turn it ON again.
Press RESET button of the remote controller.
Repair the failure parts.
Deleting the memorized abnormal condition
After repairing the unit, recall the failure mode again according to "Setting up the failure mode recall
function" mentioned above.
Press OPERATE/STOP (ON/OFF) button of the remote controller (the set temperature is displayed)
with the remote controller headed towards the indoor unit. 1
Press EMERGENCY OPERATION switch so that the memorized abnormal condition is deleted.
Release the failure mode recall function according to "Releasing the failure mode recall function"
mentioned above.
NOTE: 1. Make sure to release the failure mode recall function after it is set up, otherwise the unit cannot operate properly.
2. If the abnormal condition is not deleted from the memory, the last abnormal condition is kept memorized.
2. Blinking pattern when the indoor unit is abnormal:
Blinking at 0.52.5-second OFF second interval
Blinking at 0.52.5-second OFF second interval
ON
OFF
Beeps
Repeated cycle
Beeps
Repeated cycle
3.Blinking pattern when the outdoor unit is abnormal:
Blinking at 0.52.5-second OFF
3-second ON
second interval
Beeps
Repeated cycle
2.5-second OFF
3-second ON
Blinking at 0.5second interval
ON
OFF
No beep
Repeated cycle
OBH568A
Beeps
No beep
Repeated cycle
17
Beeps
Repeated cycle
2. Indoor unit failure mode table
NOTE: Blinking patterns of this mode differs from the ones of Troubleshooting check table (9-4.).
Left lamp of
Right lamp of
OPERATION
OPERATION
INDICATOR lamp INDICATOR lamp
Not lighted
Abnormal point
(Failure mode)
Not lighted
Check point
Normal
Countermeasure
–
–
1-time flash
every 0.5-second
Not lighted
Room temperature
thermistor
When the room temperature thermistor
short or open circuit is detected every 8
seconds during operation.
2-time flash
2.5-second OFF
Not lighted
Indoor coil thermistor
(Main 1, 2 and sub)
When the indoor coil thermistor short or
open circuit is detected every 8 seconds
during operation.
3-time flash
2.5-second OFF
Not lighted
Serial signal error
When the serial signal from the outdoor unit is Refer to 9-6. "How to check miswiring
and serial signal error".
not received for a maximum of 6 minutes.
Not lighted
Indoor fan motor (Upper)
When the rotational frequency feedback
signal is not emitted during 12-second the
indoor fan operation.
1-time flash
every 0.5-second
Indoor fan motor (Lower)
11-time flash
2.5-second OFF
Refer to the characteristics of the room
temperature thermistor (9-7.).
Refer to the characteristic of the main 1,2
indoor coil thermistor and the sub indoor
coil thermistor (9-7.).
Refer to 9-6 -1 "Check of indoor
fan motor (Upper)"
Refer to 9-6 -2 "Check of indoor
fan motor (Lower)"
12-time flash
2.5-second OFF
Not lighted
Indoor control system
When it cannot be read properly data in the
nonvolatile memory of the indoor electronic
control P.C. board.
Replace the indoor electronic control
P.C. board.
13-time flash
2.5-second OFF
Not lighted
Indoor coil thermistor
(Main 3)
When the indoor coil thermistor short or
open circuit is detected every 8 seconds
during operation.
Replace to the characteristic of the main
3 indoor coil thermistor (9-7.).
14-time flash
2.5-second OFF
Not lighted
Damper
When the damper is not located at the
designated position.
Refer to 9-6.
OBH568A
18
"Check of damper".
9-3. INSTRUCTION OF TROUBLESHOOTING
Start
Indoor unit
operates.
Outdoor unit
does not
operate.
Outdoor unit
operates only
in Test Run
operation.
Check room
temperature
thermistor.
Refer to 9-7.
"Test point
diagram and
voltage".
Indoor unit operates.
Outdoor unit does
not operate normally.
Indoor unit does
not receive
the signal from
remote controller.
Outdoor unit
does not
operate
even in
Test Run
operation.
Unit does
not operate
normal
operation in
COOL or
HEAT mode.
Indoor unit
operates, when
EMERGENCY
OPERATION
switch is pressed.
Refer to
"How to check
inverter/
compressor".
Refer to
"Check of
R.V. coil".
Refer to 9-6.
"Check of
remote controller
and receiver
P.C. board".
OPERATION INDICATOR
lamp on the indoor unit is
flashing ON and OFF.
"Test Run operation" means the
operation within 30 minutes after
EMERGENCY OPERATION switch
is pressed.
1. Check indoor / outdoor
connecting wire.
(Check if the power
is supplied to the
indoor unit.)
2. Refer to 9-6.
"Check of indoor
electronic control
P.C. board and indoor
fan motor".
Left lamp
Flash ON and
OFF at
0.5-second
intervals
Cause:
Indoor/
Outdoor unit
‡0LVZLULQJ
or trouble
of serial signal
Left lamp
2-time flash
Cause:
Indoor unit
‡7URXEOHRI
room temperature/
indoor coil
thermistor
Left lamp
3-time flash
Cause:
Indoor unit
‡7URXEOHRI
indoor fan
motor
Left lamp
4-time flash
Cause:
Indoor unit
‡7URXEOHRI
indoor unit
control
system
Left lamp
5-time flash
Cause:
Outdoor unit
‡2XWGRRU
power
system
abnormality
Left lamp
6-time flash
Cause:
Outdoor unit
‡7URXEOHRI
thermistor
in outdoor
unit
Refer to 9-6.
"How to
check the
miswiring
and serial
signal error
(when
outdoor unit
does not
work)".
Check room
temperature
thermistor
and indoor
coil thermistor.
Refer to 9-7.
"Test point
diagram and
voltage".
Refer to 9-6.
-1, -2
"Check of
indoor fan
motor".
Replace the
indoor
electronic
control
P.C. board.
Refer to
"How to check
the inverter/
compressor".
Refer to
"Check of
outdoor
thermistors".
OBH568A
If blinking of OPERATION
INDICATOR lamp cannot be
checked, it can be checked with
failure mode recall function.
Indoor unit
does not operate,
when
EMERGENCY
OPERATION
switch is pressed.
19
Refer to outdoor unit service manual.
Left lamp
7-time flash
Cause:
Outdoor unit
‡7URXEOHRI
outdoor
control
system
Left lamp
14-time flash
Cause:
Outdoor unit
‡2WKHU
abnormality
Left lamp
15-time flash
Cause:
Indoor unit
‡7URXEOHRI
damper
Replace the
outdoor
electronic
control P.C.
board.
Check
"Flow chart of
the detailed
outdoor unit
failure mode
recall function."
Refer to
9-6.
"Check of
damper".
9-4. TROUBLESHOOTING CHECK TABLE
OPERATION INDICATOR
Lighted
Blinking
· Flashing of OPERATION INDICATOR lamp (left-hand side lamp)
indicates abnormalities.
Not lighted
NOTE: Before taking measures, make sure that the symptom reappears for accurate troubleshooting.
Self check table
No.
Abnormal
point
1
Miswiring
or serial
signal
Operation indicator lamp
Left lamp flashes.
0.5-second ON
Symptom
Check point
Indoor unit
and outdoor
unit do not
operate.
When the serial signal from the outdoor unit is
not received for a maximum of 6 minutes.
‡5HIHUWR+RZWRFKHFN
mis-wiring and serial signal
HUURU
When it cannot properly read data in the
nonvolatile memory of the outdoor electronic
control P.C. board.
‡&KHFNWKHEOLQNLQJSDWWHUQRI
the LED on the outdoor
electronic control P.C. board.
When the indoor coil or the room temperature
thermistor is shorts or opens circuit.
‡5HIHUWRWKHFKDUDFWHULVWLFVRI
indoor coil thermistor, and the
room temperature thermistor
on 9-7.
Indoor unit
and outdoor
unit do not
operate.
When the rotational frequency feedback
signal is not emitted during the indoor fan
operation.
‡5HIHUWR
&KHFNRILQGRRUIDQPRWRU
Indoor unit
and outdoor
unit do not
operate.
When it cannot properly read data in the
nonvolatile memory of the indoor electronic
control P.C. board.
‡5HSODFHWKHLQGRRUHOHFWURQLF
control P.C. board.
Indoor unit
and outdoor
unit do not
operate.
The compressor stops 3 times consecutively
for over current protection or start-up failure
protection within 1 minute after start-up.
Indoor unit
and outdoor
unit do not
operate.
When the outdoor thermistors short or open
circuit during the compressor operation.
‡5HIHUWR&KHFNRIRXWGRRU
WKHUPLVWRU
5HIHUWRRXWGRRUXQLWVHUYLFH
manual.
Indoor unit
and outdoor
unit do not
operate.
When it cannot properly read data in the
nonvolatile memory of the outdoor electronic
control P.C. board.
‡5HSODFHWKHRXWGRRU
electronic control P.C. board.
5HIHUWRRXWGRRUXQLWVHUYLFH
manual.
Indoor unit
and outdoor
unit do not
operate.
An abnormality other than above mentioned is
detected.
‡&KHFNWKHDEQRUPDOLW\LQ
detail using the failure mode
recall function.
5HIHUWRRXWGRRUXQLWVHUYLFH
manual.
Indoor unit
and outdoor
unit do not
operate.
When the damper is not located
at the designated position.
‡5HIHUWR&KHFNRI
GDPSHU
Countermeasure
0.5-second OFF
2
3
4
Outdoor
control
system
Left lamp lights up
Indoor coil
thermistor
Left lamp flashes.
2-time flash
5RRP
temperature
thermistor
Indoor fan
motor
Outdoor unit
does not
operate.
Indoor unit
and outdoor
unit do not
operate.
2.5-second OFF
Left lamp flashes.
3-time flash
2.5-second OFF
5
Indoor
control
system
Left lamp flashes.
4-time flash
2.5-second OFF
6
Outdoor
power
system
Left lamp flashes.
5-time flash
2.5-second OFF
Left lamp flashes.
6-time flash
7
Outdoor
thermistors
‡5HIHUWR&KHFNRILQYHUWHU
FRPSUHVVRU
5HIHUWRRXWGRRUXQLWVHUYLFH
manual.
Check the stop valve.
2.5-second OFF
8
Outdoor
control
system
Left lamp flashes.
7-time flash
2.5-second OFF
9 Other
abnormality
Left lamp flashes.
14-time flash
2.5-second OFF
10 Indoor
damper
Left lamp flashes.
15-time flash
2.5-second OFF
NOTE: When the indoor unit has started operation and the above failures are detected (the first detection after the power ON),
the indoor electronic control P.C. board turns OFF the indoor fan motor with OPERATION INDICATOR lamp flashing.
OBH568A
20
OPERATION INDICATOR
Lighted
Blinking
Not lighted
No.
1
Abnormal
point
MXZ type
Operation
mode
setting
· Flashing of OPERATION INDICATOR lamp (right-hand side lamp) indicates
abnormality.
· OPERATION INDICATOR lamp (left-hand side lamp) is lighted.
Operation indicator lamp
Right lamp flash
2.5-second OFF
Symptom
Check point
Outdoor unit
operates but
indoor unit
does not
operate.
When the operation mode of the each indoor
unit is differently set to COOL(includes DRY)
and HEAT at the same time, the operation
mode of the indoor unit that has operated at
first has the priority.
Countermeasure
• Unify the operation mode.
Refer to outdoor unit
service manual.
NOTE: When the indoor unit has started operation and the above failures are detected (the first detection after the power ON),
the indoor electronic control P.C. board turns OFF the indoor fan motor with OPERATION INDICATOR lamp flashing.
9-5. TROUBLE JUDGEMENT CRITERIA OF MAIN PARTS
MFZ-KA09NA MFZ-KA12NA MFZ-KA18NA
Part name
Room temperature
thermistor (RT11)
Indoor coil thermistor
(RT12 (MAIN1), RT13 (SUB)
RT14 (MAIN2), RT15 (MAIN3))
Check method and criteria
Measure the resistance with a tester. (Part temperature: 10°C ~ 30°C)
Normal
8 kΩ ~ 20 kΩ
Indoor fan motor (Upper)
(MF1)
Check 9-6.
-1.
Indoor fan motor (Lower)
(MF2)
Check 9-6.
-2.
Damper lock motor
Right (ML1)
Damper lock motor
Left (ML2)
Horizontal vane
motor (MV1)
Damper motor
(MV2)
OBH568A
Figure
Measure the resistance between the terminals with a tester.
(Part temperature: 10°C ~ 30°C)
Color of the lead wire
BRN-other one
Normal
235 Ω ~ 255 Ω
Measure the resistance between the terminals with a tester.
(Part temperature: 10°C ~ 30°C)
Color of the lead wire
BRN-other one
Normal
235 Ω ~ 255 Ω
Measure the resistance between the terminals with a tester.
(Part temperature: 10°C ~ 30°C)
Color of the lead wire
BRN-other one (250 Ω)
BRN-other one (300 Ω)
Normal
235 Ω ~ 255 Ω
282 Ω ~ 306 Ω
Measure the resistance between the terminals with a tester.
(Part temperature: 10°C ~ 30°C)
Color of the lead wire
BRN-other one
Normal
282 Ω ~ 306 Ω
21
RED
ROTOR
YLW
BRN
ORN
GRN
9-6. TROUBLESHOOTING FLOW
When the left lamp of OPERATION INDICATOR lamp flashes 3 times and the right lamp of OPERATION INDICATOR
lamp is not lighted.
Indoor fan does not operate.
A -1. Check of indoor fan motor (upper)
The indoor fan motor error has occurred, and the indoor fan doesn't operate.
Pay careful attention to the high voltage on
the fan motor connector CN211.
Turn OFF the power supply.
Is there anything that interferes the
rotation of the line flow fan?
Turn ON the power supply, wait 5 seconds or more, and then press
EMERGENCY OPERATION switch.
Measure the supply voltage as follows within 12 seconds
after EMERGENCY OPERATION switch is pressed.
If more than 12 seconds passes by, turn OFF the power supply and
turn it ON again, then measure the voltage.
1) Measure the voltage between CN211 (+) and (-).
2) Measure the voltage between CN211 (+) and (-).
No
Yes
If more than 12 seconds passes after EMERGENCY OPERATION switch
is pressed, the voltage mentioned in above 2) goes 0 VDC although the
indoor electronic control P.C. board is normal.
Remove the object and
adjust the line flow fan.
Is there 311 VDC between
CN211 (+) and (-), and does
the voltage between CN211 (+)
and (-) rise to the range between 3
and 6 VDC within 12 seconds after
EMERGENCY OPERATION switch
is pressed?
Yes
Indoor electronic
control P.C. Board
Replace the indoor fan motor.
Fuse (F11)
VARISTOR (NR11)
No
JR05 JR06
IC101
CN1X1 CN1Y1
R111
C111T11
Replace the indoor electronic control P.C. board.
CN151
CN152
CN211
CN212
The indoor fan motor error has occurred, and the indoor fan repeats "12-second ON and 30-second OFF" 3 times, and then stops.
Measure the voltage between CN211
(+) and (-) while the fan
motor is rotating.
Is 0 VDC or 15 VDC
held unchanged?
Yes
(Unchanged)
Replace the indoor fan motor.
OBH568A
22
No
(Changed)
Replace the indoor electronic control P.C. board.
When the left lamp of OPERATION INDICATOR lamp flashes 3 times and the right lamp of OPERATION INDICATOR
lamp flashes ON and OFF every 0.5-second.
Indoor fan does not operate.
A -2. Check of indoor fan motor (lower)
The indoor fan motor error has occurred, and the indoor fan does not operate.
Pay careful attention to the high voltage on
the fan motor connector CN212.
Turn OFF the power supply.
Is there anything that interferes the
rotation of the line flow fan?
Turn ON the power supply, wait 5 seconds or more, and then press
EMERGENCY OPERATION switch.
Measure the supply voltage as follows within 12 seconds
after EMERGENCY OPERATION switch is pressed.
If more than 12 seconds passes by, turn OFF the power supply and
turn it ON again, then measure the voltage.
1) Measure the voltage between CN212 (+) and (-).
2) Measure the voltage between CN212 (+) and (-).
No
Yes
If more than 12 seconds passes after EMERGENCY OPERATION switch
is pressed, the voltage mentioned in above 2) goes 0 VDC although the
indoor electronic control P.C. board is normal.
Remove the object and
adjust the line flow fan.
Is there 311 VDC between
CN211 (+) and (-), and does
the voltage between CN212 (+)
and (-) rise to the range between 3
and 6VDC within 12 seconds after
EMERGENCY OPERATION switch
is pressed?
Yes
Indoor electronic
control P.C. Board
Replace the indoor fan motor.
Fuse (F11)
VARISTOR (NR11)
No
JR05 JR06
IC101
CN1X1 CN1Y1
R111
C111T11
Replace the indoor electronic control P.C. board.
CN151
CN152
CN211
CN212
The indoor fan motor error has occurred, and the indoor fan repeats "12-second ON and 30-second OFF" 3 times, and then stops.
Measure the voltage between CN212
(+) and (-) while the fan
motor is rotating.
Is 0 VDC or 15 VDC
held unchanged?
Yes
(Unchanged)
Replace the indoor fan motor.
OBH568A
23
No
(Changed)
Replace the indoor electronic control P.C. board.
B Check of remote controller and indoor electronic control P.C. board
Check if the remote controller is exclusive for this air conditioner.
Switch on the remote controller.
Is the LCD display on the remote
controller visible?
No
Replace the batteries. (Refer to 9-1.4.)
1 Look at the image of the signal transmitting section of
the remote controller through the monitor of a digital
camera or a camera phone. It is normal if the LED of
the signal transmitting section lights up when the OPERATE/STOP (ON/OFF) button on the remote controller is pressed. However, it may be difficult to see the
illuminated LED of the signal transmitting section with a
smartphone camera.
(not clear)
Yes
Remove the batteries, then set them back
and press RESET button. (Refer to 9-1.4.)
Check if the unit operates with the remote
controller.
Does the unit operate with the
remote controller?
No
Turn ON a radio to AM and press OPERATE/STOP (ON/OFF) button on the remote
controller. 1
Yes
OK
Is noise heard from radio?
2 If the inverter fluorescent light is turned on when the
room is cool, the unit may have difficulty receiving the
signal from the remote controller or may not be able to
operate with it; if the inverter fluorescent light is turned
on when the room is warm, the unit may be able to
operate with the remote controller.
No
Replace the remote controller.
Yes
Are there any fluorescent lights of
inverter or of rapid-start type within
the range of 1 m?
2
No
Replace the indoor electronic
control P.C. board.
OBH568A
24
Yes
Reinstall the unit away from lights.
Attach a filter on receiving part.
The unit cannot be operated with the remote controller.
Also, OPERATION INDICATOR lamp does not light up by pressing EMERGENCY OPERATION switch.
C Check of indoor P.C. board and indoor fan motor
Turn OFF the power supply.
Remove indoor fan motor connector CN211/ CN212 and
vane motor connector CN151/ CN152 from the indoor
electronic control P.C. board and turn ON the power
supply.
Turn OFF the power supply.
Measure the resistance between CN211/
CN212 and
of the indoor fan motor
connector.
Short/ open circuit:
Replace the indoor fan motor.
Yes
Does the unit operate with the remote controller?
Does OPERATION INDICATOR lamp light up by
pressing EMERGENCY OPERATION switch?
Turn OFF the power supply.
Measure the resistance of the horizontal vane
motor coil.
Refer to 9-5.
Short/ open circuit:
Replace the horizontal vane motor and the indoor
electronic control P.C. board.
No
Replace the varistor (NR11) and fuse (F11).
Yes
Are the varistor (NR11) burnt
and the fuse (F11) blown?
Turn OFF the power supply.
Check both “parts side” and “pattern
side” of the indoor electronic control P.C.
board visually.
No
Be sure to check both the fuse
and the varistor in any case.
Is the fuse (F11) blown only?
No
Yes
Measure the resistance between
(+) and (-) of the indoor fan
motor connector (to CN211/CN212
on the indoor electronic control
P.C. board).
,VWKHUHVLVWDQFH0Ÿ
or more?
1. The fan motor connector's
lead wire is red, whereas
is black.
2. Connect "+" of the tester to fan motor connector's lead
wire, and "-" to lead wire, otherwise the resistance cannot be
measured properly.
No
Replace the fuse (F11) and the indoor fan motor.
Yes
Replace the fuse (F11).
Is the resistance
approximately 4Ÿ?
Measure the cement resistance R111 on
the indoor electronic control P.C. board.
No
Yes
Replace the indoor electronic control P.C. board.
OBH568A
25
Replace the indoor electronic control P.C. board
and the indoor fan motor.
When the left lamp of OPERATION INDICATOR lamp flashes ON and OFF in every 0.5-second.
Outdoor unit does not operate.
D How to check miswiring and serial signal error
Turn OFF the power supply.
Is there rated voltage of
230 VAC in the power
supply?
No
Check the power
supply.
Yes
Turn ON the power supply.
Is there 230 VAC between
No
outdoor terminal block S1 and
S2?
Yes
Press EMERGENCY OPERATION switch once.
Check the wiring.
Does the left lamp of OPERATION INDICATOR
lamp light up? <Confirmation of the power
supply to the indoor unit>
Yes
No
Is the serial signal error indicated 6 minutes later?
No
Yes
Is there any miswiring,
poor contact, or wire
disconnection of the
indoor/outdoor
connecting wire?
Yes
Make them sure.
No
A
Turn OFF the power supply.
Check once again if the indoor/outdoor
connecting wire is not wrongly connected.
B
Bridge the outdoor terminal block S2
and S3.
1
1. Miswiring may damage indoor electronic control
P.C. board during operation.
Be sure to confirm the wiring is correct before the
operation starts.
Turn ON the power supply of the outdoor unit.
Inverter P.C. board
(Parts side)
LED
Blinking
A
· Turn OFF inverter-controlled lighting
equipment.
· Turn OFF the power supply and then
turn it ON again.
· Press EMERGENCY OPERATION
switch.
Is the serial
signal error
indicated 6
minutes later?
Yes
B
· Reinstall
either the
unit or the
light away
No from each
other.
· Attach a filter
on receiving
section of
the indoor
unit.
OBH568A
In 3 minutes after turning ON the
power supply of the outdoor unit, does
the LED on the outdoor electronic control
P.C. board repeat quick blinking
"3.6-second-OFF and 0.8-second-ON"?
Be sure to check above in 3 minutes
after turning ON. After 3 minutes, LED
blinks 6 times. When the inverter P.C.
board is normal, LED also blinks 6
times after 3 minutes.
No
(Lighting)
Replace the outdoor
electronic control P.C.
board.
2
2 Be careful of the residual
voltage of smoothing capacitor.
Yes
Remove the bridge between
outdoor terminal block S2 and S3.
Is there amplitude of 10 to 20 VDC
between outdoor terminal block S2
and S3? <Confirmation of serial
signal>
No
Is there any error of the
indoor/outdoor connecting wire,
such as the damage of the wire,
intermediate connection, poor
contact to the terminal block?
Yes
Replace the
indoor/outdoor
connecting.
No
Yes
Is there 230 VAC between outdoor
terminal block S1 and S2?
<Confirmation of power voltage>
Yes
No
Is there any error of the
indoor/outdoor connecting wire,
such as the damage of the wire,
intermediate connection, poor
contact to the terminal block?
No
Replace the indoor electronic control P.C. board.
Be sure to release the failure-mode recall function after checking.
As for outdoor unit, refer to outdoor unit service manual.
26
Yes Replace the
indoor/outdoor
connecting.
When the left lamp of OPERATION INDICATOR lamp flashes 15-time.
Indoor unit and outdoor unit do not operate.
E Check of damper
After performing the check, make sure to release the failure mode recall function.
Turn OFF the power supply.
Is there anything that interferes the opening
or closing movement of the damper?
Yes
Remove the object.
No
Turn ON the power supply.
While pressing both OPERATION SELECT
button and TOO COOL button on the remote controller
at the same time, press RESET button.
First, release RESET button.
And release the other two buttons after all LCD except the
set temperature in operation display section of the remote
controller is displayed after 3 seconds.
< Set up the failure mode recall function >
Turn ON the power supply.
While pressing both OPERATION SELECT
button and TOO COOL button on the remote controller at the same
time, press RESET button.
First, release RESET button.
And release the other two buttons after all LCD except the set
temperature in operation display section of the remote controller is
displayed after 3 seconds.
Press OPERATE/STOP (ON/OFF) button of the remote controller (the set temperature
is displayed) with the remote controller headed towards the indoor unit. 1
1. Regardless of normal or abnormal, a short
beep is emitted once as the signal is received.
With the remote controller headed towards the indoor unit,
press VANE CONTROL button.
Indoor electronic
control P.C. Board
Fuse (F11)
Does the damper open and close?
(Normally, the damper opens and closes
each time VANE CONTROL button is pressed.)
JR05 JR06
VARISTOR (NR11)
Yes
IC101
CN1X1 CN1Y1
No
Turn OFF the power supply.
Measure the resistance according to 9-5.
1.Measure the resistance of the damper lock motors (ML1, ML2).
2.Measure the resistance of the damper motor (MV2).
Make the damper open by pressing
VANE CONTROL button.
1) Measure the voltage between CN1X1
2) Measure the voltage between CN1Y1
No
C111 T11
R111
(+) and
(+) and
CN151
CN152
CN211
CN212
(-).
(-).
Is the resistance value normal each?
1) No
Yes
Replace the motor
that indicates the
abnormal value.
1) Is there 0V DC between CN1X1
(+) and
(-)?
2) Is there 5V DC between CN1Y1
(+) and
(-)?
Replace the indoor
electronic control
P.C. board.
2) No
Yes
Replace either or both damper
limit switches (open, close) as
follows.
1) No : Replace the damper
limit switch (open) .
2) No : Replace the damper
limit switch (close) .
Make the damper close by pressing
VANE CONTROL button.
1) Measure the voltage between CN1X1
2) Measure the voltage between CN1Y1
(+) and
(+) and
(-).
(-).
1) No
1) Is there 5V DC between CN1X1
(+) and
(-)?
2) Is there 0V DC between CN1Y1
(+) and
(-)?
2) No
Yes
Replace the indoor electronic control
P.C. board.
OBH568A
27
Replace either or both damper
limit switches (open, close) as
follows.
1) No : Replace the damper
limit switch (open) .
2) No : Replace the damper
limit switch (close) .
F Electromagnetic noise enters into TV sets or radios
Is the unit earthed?
No
Earth the unit.
Yes
Is the distance between the
antennas and the indoor
unit within 3 m, or is the
distance between the
antennas and the outdoor
unit within 3 m?
Yes
Extend the distance between
the antennas and the indoor
unit, or the antennas
and the outdoor unit.
No
Is the distance between the
TV sets or radios and the
indoor unit within 1m, or is
the distance between the TV
sets or radios and the
outdoor unit within 3 m?
Yes
Extend the distance between
the TV sets or radios and the
indoor unit, or the TV
sets or radios and the
outdoor unit.
No
Are the antennas damaged?
Is the coaxial cable damaged?
Is there any poor contact in
the antenna wiring?
Yes
Replace or repair the antenna.
Replace or repair the coaxial cable.
No
Is the indoor/outdoor
connecting wire of the air
conditioner and the wiring of
the antennas in close?
Yes
Extend the distance between
the indoor/outdoor connecting
wire of the air conditioner and
the wiring of the antennas.
No
Even if all of the above conditions is fulfilled, the electromagnetic noise may enter, depending on
the electric field strength or the installation condition (combination of specific conditions such as
antennas or wiring).
Check the followings before asking for service.
1.Devices affected by the electromagnetic noise
TV sets, radios (FM/AM broadcast, shortwave)
2.Channel, frequency, broadcast station affected by the electromagnetic noise
3.Channel, frequency, broadcast station unaffected by the electromagnetic noise
4.Layout of ;
indoor/outdoor unit of the air conditioner, indoor/outdoor wiring, grounding wire, antennas, wiring
from antennas, receiver
5.Electric field intensity of the broadcast station affected by the electromagnetic noise
6.Presence or absence of amplifier such as booster
7.Operation condition of air conditioner when the electromagnetic noise enters in.
1)Turn OFF the power supply once, and then turn ON the power supply. In this situation check for
the electromagnetic noise.
2)Within 3 minutes after turning ON the power supply, press OPERATE/STOP (ON/OFF) button
on the remote controller for power ON, and check for the electromagnetic noise.
3)After a short time (3 minutes later after turning ON), the outdoor unit starts running. During
operation, check for the electromagnetic noise.
4)Press OPERATE/STOP (ON/OFF) button on the remote controller for power OFF, when the
outdoor unit stops but the indoor/outdoor communication still runs on. In this situation check for
the electromagnetic noise.
After checking the above, consult the service representative.
OBH568A
28
9-7. TEST POINT DIAGRAM AND VOLTAGE
MFZ-KA09NA
MFZ-KA12NA
MFZ-KA18NA
Indoor electronic control P.C. board
Room temperature
thermistor RT11
FUSE (F11)
T3.15AL250V Power supply
input 208/230 VAC
5 VDC
Indoor coil thermistor RT14 (MAIN 2)
Indoor coil thermistor RT13 (SUB)
Indoor coil thermistor RT12 (MAIN 1)
Indoor coil thermistor RT15 (MAIN 3)
Release of Auto restart function
Solder the Jumper wire to JR07.
(Refer to 7-3.)
short mode point
} Timer
JPG, JPS (Refer to 7-1.)
Varistor
NR11
Display receiver P.C. board
Emergency
1FAN/2FAN
change switch operation
switch
Horizontal vane motor CN151
Damper lock motor Right CN151
Damper motor CN152
Damper lock motor Left CN152
Indoor fan motor (Upper) CN211
(+) 0/15 V
(+) 3-6 VDC
15 VDC
(-) GND (high voltage DC)
325 VDC
Indoor fan motor (Lower) CN212
JR05 JR06
GND DC
(+) 0/15 V
(+) 3-6 VDC
15 VDC
(-) GND (high voltage DC)
325 VDC
12 VDC
}
Modification point for
individual operation
(Refer to 7-2.)
Resistance (kΩ)
Indoor coil thermistor [RT12,RT14,RT15 (MAIN), RT13 (SUB)]
Room temperature thermistor (RT11)
OBH568A
Temperature (°C)
29
10
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
Locking lever
(2) The terminal with this connector has the
locking mechanism.
Slide the sleeve.
Pull the terminal while
pushing the locking
lever.
Hold the sleeve, and
pull out the terminal
slowly.
Connector
MFZ-KA09NA MFZ-KA12NA MFZ-KA18NA
INDOOR UNIT
NOTE: Turn OFF the power supply before disassembly.
PHOTOS
OPERATING PROCEDURE
1. Removing the panel
(1) Push both sides of the upper part of the front grille and
pull the front grille open, and then remove the front grille
from the panel. (See Photo 1.)
(2) Remove the screws of the panel. (See Photo 2.)
(3) Open the horizontal vane and push the left, right and
middle of the upper part of the panel, and pull the panel
toward you. (See Photo 2.)
(4) Lift up the panel and remove it from the box.
Photo 1
Push
Push
Grille
Screws of the panel
Photo 2
Horizontal
vane
Push
OBH568A
30
Push
Push
OPERATING PROCEDURE
PHOTOS
2. Removing the electronic control P.C. board and the
display receiver P.C. board
(1) Remove the panel. (Refer to 1.)
(2) Remove the screw of the electrical cover, and then the
electrical cover. (See Photo 3.)
(3) Remove the screw of the indoor/outdoor connecting wire,
and then the indoor/outdoor connecting wire.
(4) Unhook the lamp cover from the catch. (See Photo 4.)
(5) Open the lamp cover. Pull out the display receiver P.C.
board, and disconnect the connector on the display
receiver P.C. board.
(6) Remove the screw of the wire connected from the
electronic control P.C. board, and then the wire.
(See Photo 4.)
(7) Pull the electronic control P.C. board slightly toward you
from the electrical box, and disconnect all the connectors
on the electronic control P.C. board.
(8) Pull out the electronic control P.C. board from the electrical
box.
Photo 3
Screw of the
electrical cover
Lamp cover
Photo 4
Screw of the wire
connected from the
electronic control
P.C. board
NOTE: Skip (4) and (5) when the display receiver P.C. board
dose not have to be removed.
Screw of the
ground wire
Screw of the wire
connected from the
heat exchanger
Screw of the
electrical box
3. Removing the electrical box
(1) Remove the panel. (Refer to 1.)
(2) Remove the electrical cover. (Refer to 2.)
(3) Remove the screw of the indoor/outdoor connecting wire,
and then the indoor/outdoor connecting wire. Remove the
ground wire as well.
(4) Remove the screw of the conduit plate, and then the
conduit plate. (Refer to Photo 4.)
(5) Remove the screws of the wires connected from
the heat exchanger and the box assembly, and then both
the wires. (See Photo 4.)
(6) Pull the electronic control P.C. board slightly toward you.
Disconnect the following connectors on the electronic
control P.C. board. (See Photo 5.)
•Fan motor connectors < CN211, CN212 >
•Horizontal vane motor connector < CN151 >
•Damper motor connector < CN152 >
•Display receiver P.C. board connectors < CN106, CN125 >
•Indoor coil thermistor connectors < CN112, CN113 >
•Room temperature thermistor connector < CN111 >
•Damper limit switch connectors < CN1X1, CN1Y1 >
•Upper nozzle assembly relay connector.
(7) Remove the screw of the electrical box. (See Photo 4.)
(8) Unhook the electrical box from the upper catch and pull out
the electrical box from the box.
OBH568A
31
Screws of the
conduit plate
Photo 5
Screw of the wire
connected from the
box assembly
Indoor coil thermistor
connector CN112,
CN113
Display receiver P.C.
board connector
CN106
Display receiver P.C.
board connector
CN125
Horizontal vane
motor connector
CN151
Damper motor
connector CN152
Fan motor
connector CN211
Fan motor
connector CN212
Upper nozzle assembly
relay connector
OPERATING PROCEDURE
PHOTOS
Photo 6
4. Removing the horizontal vane motor unit
(1) Remove the panel. (Refer to 1.)
(2) Remove the screws of the horizontal vane motor unit and
pull out the horizontal vane motor unit. (See Photo 6.)
(3) Disconnect the connector from the horizontal vane motor
unit.
Screw of the horizontal
vane motor unit
5. Removing the indoor fan motor (upper)
(1)
(2)
(3)
(4)
Remove the panel. (Refer to 1.)
Remove the electrical box. (Refer to 3.)
Remove the nozzle (upper). (See Photo 7.)
Unhook the water cover from the catches and remove the
water cover. (See Photo 7.)
(5) Removing the screw of the motor band, and then the motor
band. (See Photo 8.)
(6) Remove the line flow fan and the indoor fan motor (upper)
from the box.
Photo 7
Nozzle <Upper>
Water cover
Photo 8
Screw of the motor band
OBH568A
32
OPERATING PROCEDURE
PHOTOS
6. Removing the damper lock motor, the damper motor
and the damper limit switch
(1) Remove the panel. (Refer to 1.)
(2) Remove the screws of the nozzle assembly (lower). (See
Photo 9.)
(3) Remove the drain hose from the nozzle assembly (lower)
and pull out the nozzle assembly (lower) toward you.
(4) Remove the tape fixing the lead wires of the damper motor
and the damper lock motor from the nozzle assembly
<lower>. (See Photo 10.)
(5) Remove the screws of the damper lock motor. (See Photo
11 and 12.)
(6) Lift the nozzle slightly and remove the lock shaft from with
in the nozzle and remove the damper lock motors (ML1,
ML2).
(7) Remove the screws of the damper motor support, and
then the damper motor support.
(8) Remove the screws of the damper motor, and then the
damper motor from the damper motor support.
(9) Disconnect the connector from the damper motor.
(10) Remove the damper limit switches (LS1, LS2).
Photo 9
Screw of
the nozzle
Screw of
the nozzle
Drain
hose
Photo 10
Lead wires of the damper motor
and the damper lock motor
Photo 11
7. Removing the indoor fan motor (lower)
Screw of the
damper motor
support
(1) Remove the panel. (Refer to 1.)
(2) Remove the nozzle assembly (lower) and the drain hose.
(Refer to 6.)
(3) Remove the screw of the ground wire of the indoor fan
motor (lower), and then the ground wire. (See Photo 13.)
(4) Remove the screw of the motor band, and then the motor
band. (See Photo 13.)
(5) Remove the line flow fan and the indoor fan motor (lower)
from the box.
Screws of the
damper motor
Screw of the damper
motor support
Photo 13
Photo 12
Screw of
the motor band
OBH568A
Screws of the
damper
lock motor (Left)
Screws of the damper lock motor (Right)
Screw of the
ground wire
33
HEAD OFFICE: TOKYO BLDG., 2-7-3, MARUNOUCHI, CHIYODA-KU, TOKYO 100-8310, JAPAN
© Copyright 2010 MITSUBISHI ELECTRIC CO.,LTD
Distributed in Dec. 2014. No. OBH568 REVISED EDITION-A
Distributed in Jan. 2010. No. OBH568 7
Made in Japan
New publication, effective Dec. 2014
Specifications are subject to change without notice.

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