Mitsubishi SLZ-KA25VAQ, SLZ-KA35VAQ, SLZ-KA25VAQ2, SLZ-KA50VAQ Service Manual

TECHNICAL & SERVICE MANUAL

SPLIT-TYPE, HEAT PUMP AIR CONDITIONERS

CONTENTS

1. TECHNICAL CHANGES

......................

2

2. REFERENCE SERVICE MANUAL

......

2

3. PART NAMES AND FUNCTIONS

.......

2

4. SPECIFICATIONS

...............................

6

5. OUTLINES AND DIMENSIONS

...........

8

6. WIRING DIAGRAM

............................

10

7.

REFRIGERANT SYSTEM DIAGRAM

.....

11

8. TROUBLESHOOTING

.......................

12

9. 4-WAY AIR FLOW SYSTEM

..............

25

10. DISASSEMBLY PROCEDURE

..........

27

October 2012

No. OCH493

REVISED EDITION-D

WIRED REMOTE CONTROLLER

(Option)

Indoor unit
[Model names] [Service Ref.]

SLZ-KA25VAQ.TH
SLZ-KA25VAQR1.TH
SLZ-KA25VAQ2.TH
SLZ-KA35VAQ.TH
SLZ-KA35VAQR1.TH
SLZ-KA35VAQR2.TH
SLZ-KA50VAQ.TH
SLZ-KA50VAQR1.TH
SLZ-KA50VAQR2.TH

INDOOR UNIT

Model name
indication

ON/OFF

TEMP.

Note:

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

PARTS CATALOG (OCB493)

Revision:

• SLZ-KA25VAQ2.TH and
SLZ-KA35/50VAQR2.TH

have been added in

REVISED EDITION-D.

• Some descriptions have
been modified.

• Please void OCH493
REVISED EDITION-C.

SLZ-KA25VAQ

SLZ-KA25VAQ2
SLZ-KA35VAQ

SLZ-KA50VAQ

2

Auto Air Swing Vane
Disperses airflow up and

down and adjusts the angle
of airflow direction.

Grille

Filter
Removes dust and pollutants

from drawn in air.

Horizontal Air Outlet
Sets horizontal airflow

automatically during
cooling or dehumidifying.

Air Intake
Draws in air from room.

3-1. Indoor unit

3

PART NAMES AND FUNCTIONS

Use the specifi ed refrigerant only

Never use any refrigerant other than that specifi ed.

Doing so may cause a burst, an explosion, or fi re when the unit is being used, serviced, or disposed of.
Correct refrigerant is specifi ed 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.

1

TECHNICAL CHANGES

2

REFERENCE SERVICE MANUAL

2-1. OUTDOOR UNIT’S SERVICE MANUAL

2-2. TECHNICAL DATA BOOK

Service Ref Service Manual No.
SUZ-KA25/50VA3.TH-A OCH511/OCB511

SUZ-KA25/35/50VA2.TH OCH472/OCB472
SUZ-KA25/35/50VA2.TH-A OCH473/OCB473
SUZ-KA25/35/50VA3.TH OCH530/OCB530

SLZ-KA35VAQR1.TH SLZ-KA35VAQR2.TH
SLZ-KA50VAQR1.TH SLZ-KA50VAQR2.TH

• INDOOR CONTROLLER BOARD has been changed.

SLZ-KA25VAQ.TH SLZ-KA25VAQR1.TH
SLZ-KA35VAQ.TH SLZ-KA35VAQR1.TH
SLZ-KA50VAQ.TH SLZ-KA50VAQR1.TH

• TURBO FAN and WASHER have been changed.

Series (Outdoor unit) Data Book No.
SUZ-KA

•

VA

SUZ-KA

•

VAH

OCS03

SUZ-KA

•

VA3 OCS22

OCH493D

33

The main display can be displayed in two different modes: "Full" and "Basic."
The factory setting is "Full."

Fri

Mode Temp. Fan

Room

Cool Auto

Set temp.

Fri

Cool

Mode Temp. Fan

AutoSet temp.

1

2

3

4

5

20

19

4

3

181716

15

14

13

12

6
8

10

1

11

7
9

21

5

2

Fan speed setting appears here.

4 Fan speed

Appears while the units are operated in the
energy-save mode.

Appears while the outdoor units are operated in
the silent mode.

Preset temperature appears here.

Appears when the ON/OFF operation is centrally
controlled.

Current time appears here.

Appears when the buttons are locked.

Indoor unit operation mode appears here.

Appears when the operation mode is centrally
controlled.

15

16

2 Preset temperature

6

12

1 Operation mode

7

Indicates the vane setting.

18

Indicates the louver setting.

Indicates the ventilation setting.

Appears when the On/Off timer or Night setback
function is enabled.

19

20

13

Indicates when filter needs maintenance.

Appears when the filter reset function is centrally
controlled.

Appears when the preset temperature is centrally
controlled.

10

9

8

Appears when the Weekly timer is enabled.

14

Appears when the preset temperature range is
restricted.

21

Functions of the corresponding buttons appear
here.

5 Button function guide

Appears when the built-in thermistor on the
remote controller is activated to monitor the
room temperature (a).

appears when the thermistor on the
indoor unit is activated to monitor the room
temperature.

17

3 Clock

(See the Installation Manual.)

Current room temperature appears here.

11 Room temperature

(See the Installation Manual.)

* All icons are displayed for explanation.

5

6

1234

Press to turn ON/OFF the indoor unit.

1 ON/OFF button

This lamp lights up in green while the unit
is in operation. It blinks while the remote
controller is starting up or when there is
an error.

Press to save the setting.

Main display: Press to change the operation
mode.
Main menu: Press to move the cursor down.

Press to return to the previous screen.

Main

display

: Press to decrease temperature.

Main menu: Press to move the cursor up.

Press to bring up the Main menu.

Main

display

: Press to increase temperature.

Main menu: Press to go to the previous page.

Operation settings will appear.
When the backlight is off, pressing any
button turns the backlight on and it
will stay lit for a certain period of time
depending on the screen.

Main

display

: Press to change the fan speed.

Main menu: Press to go to the next page.

6 ON/OFF lamp

2 SELECT button

7 Function button F1

3 RETURN button

8 Function button F2

4 MENU button

9 Function button F3

5 Backlit LCD

10 Function button F4

Fri

Room

Set temp.

Mode Temp. Fan

Cool Auto

Main

Main display:

Cursor Page

Main menu

Vane·Louver·Vent. (Lossnay)
High power
Timer
Weekly timer
OU silent mode

The functions of the function buttons
change depending on the screen. Refer
to the button function guide that appears
at the bottom of the LCD for the functions
they serve on a given screen.
When the system is centrally controlled,
the button function guide that
corresponds to the locked button will not
appear.

Main display Main menu

Function guide

7890 7890

• When the backlight is off, pressing any button turns the backlight on and
does not perform its function. (except for the ON/OFF button)

• Most settings (except ON/OFF, mode, fan speed, temperature) can be
made from the Menu screen.

Display

Full mode

Basic mode

Controller interface

Function buttons

10987

3-2. Wired remote controller (Option) PAR-30MAA

* The functions which can be used are restricted according to the model.

OCH493D

4

Setting and display items Setting details

Vane · Louver · Vent.
(Lossnay)

Use to set the vane angle.

• Select a desired vane setting from fi ve different settings.

Use to turn ON / OFF the louver.

• Select a desired setting from "ON" and "OFF."

Use to set the amount of ventilation.

• Select a desired setting from "Off," "Low," and "High."

High power Use to reach the comfortable room temperature quickly.

• Units can be operated in the High-power mode for up to 30 minutes.

Timer On/Off timer Use to set the operation On/Off times.

• Time can be set in 5-minute increments.
* Clock setting is required.

Auto-Off timer Use to set the Auto-Off time.

• Time can be set to a value from 30 to 240 in 10-minute increments.

Filter information Use to check the fi lter status.

• The fi lter sign can be reset.

Error information Use to check error information when an error occurs.

• Error code, error source, refrigerant address, unit model, manufacturing number, contact information (dealer's phone

number) can be displayed.

* The unit model, manufacturing number, and contact information need to be registered in advance to be displayed.

Weekly timer Use to set the weekly operation On / Off times.

• Up to eight operation patterns can be set for each day.
* Clock setting is required.
* Not valid when the On/Off timer is enabled.

Energy saving Auto return Use to get the units to operate at the preset temperature after performing energy-save operation for a specifi ed

time period.

• Time can be set to a value from 30 and 120 in 10-minute increments.
* This function will not be valid when the preset temperature ranges are restricted.

Schedule Set the start/stop times to operate the units in the energy-save mode for each day of the week, and set the

energy-saving rate.

• Up to four energy-save operation patterns can be set for each day.

• Time can be set in 5-minute increments.

• Energy-saving rate can be set to a value from 0% and 50 to 90% in 10% increments.
* Clock setting is required.

Night setback Use to make Night setback settings.

•

Select "Yes" to enable the setting, and "No" to disable the setting. The temperature range and the start/stop times can be set.
* Clock setting is required.

Restriction Temp. range Use to restrict the preset temperature range.

• Different temperature ranges can be set for different operation modes.

Operation lock Use to lock selected functions.

• The locked functions cannot be operated.

Maintenance Auto descending panel Auto descending panel (Optional parts) Up / Down you can do.

Manual vane angle Use to set the vane angle for each vane to a fi xed position.

Initial setting Main/Sub When connecting two remote controllers, one of them needs to be designated as a sub controller.

Clock Use to set the current time.
Main display Use to switch between "Full" and "Basic" modes for the Main display.

• The default setting is "Full."

Contrast Use to adjust screen contrast.

Initial setting Display details Make the settings for the remote controller related items as necessary.

Clock: The factory settings are "Yes" and "24h" format.
Temperature: Set either Celsius (°C) or Fahrenheit (°F).
Room temp. : Set Show or Hide.
Auto mode: Set the Auto mode display or Only Auto display.

Auto mode Whether or not to use the AUTO mode can be selected by using the button.

This setting is valid only when indoor units with the AUTO mode function are connected.

Administrator

pass-

word

The administrator password is required to make the settings for the following items.

• Timer setting • Energy-save setting • Weekly timer setting

• Restriction setting • Outdoor unit silent mode setting • Night set back

Language selection Use to select the desired language.

Service Test run Select "Test run" from the Service menu to bring up the Test run menu.

• Test run • Drain pump test run

Input maintenance Select "Input maintenance Info." from the Service menu to bring up the Maintenance information screen.

The following settings can be made from the Maintenance Information screen.

• Model name input • Serial No. input • Dealer information input

Function setting Make the settings for the indoor unit functions via the remote controller as necessary.
LOSSNAY setting
(City Multi only)

This setting is required only when the operation of City Multi units is interlocked with LOSSNAY units.

Check Error history: Display the error history and execute delete error history.

Refrigerant leak check: Refrigerant leaks can be judged.
Smooth maintenance: The indoor and outdoor maintenance data can be displayed.
Request cord: Details of the operation data including each thermistor temperature and error history can be checked.

Self check Error history of each unit can be checked via the remote controller.
Maintenance password Take the following steps to change the maintenance password.
Remote controller
check

When the remote controller does not work properly, use the remote controller checking function to trouble­shoot the problem.

Main menu list

OCH493D

5

°F°C

°F°C

ERROR CODE

AFTER

TIMER

TIME SUN MON TUE WED THU FRI SAT

ON
OFF

Hr
AFTER

FILTER

FUNCTION

ONLY1Hr.

WEEKLY

SIMPLE

AUTO OFF

PAR-21MAA

ON/OFF

FILTER

CHECK

OPERATION

CLEAR

TEST

TEMP.

MENU

BACK DAY

MONITOR/SET

CLOCK

ON/OFF

Display Section

For purposes of this explanation,
all parts of the display are shown.
During actual operation, only
the relevant items will be lit.

Identifies the current operation

Shows the operating mode, etc.
*Multilanguage display is available.

“Centrally Controlled” indicator

Indicates that operation from the
remote controller has been prohib­ited by a master controller.

“Timer is Off” indicator

Indicates that the timer is off.

Temperature Setting

Shows the target temperature.

Day-of-Week

Shows the current day of the week.

Time/Timer Display

Shows the current time, unless the simple or Auto Off
timer is set.
If the simple or Auto Off timer is set, the time to be
switched off is shown.

“Sensor” indication

Displays when the remote controller
sensor is used.

“Locked” indicator

Indicates that remote controller but­tons have been locked.

“Clean The Filter” indicator

To be displayed on when it is time to
clean the filter.

Timer indicators

The indicator comes on if the corre­sponding timer is set.

Up/Down Air Direction indica­tor

The indicator shows the direc­tion of the outcoming airflow.

“One Hour Only” indicator

Room Temperature display

Shows the room temperature. The room
temperature display range is 8–39.
The display blinks if the temperature
is less than 8 or 39 or more.

Louver display

Indicates the action of the swing louver.
Does not appear if the louver is not
running.

(Power On indicator)

Indicates that the power is on.

Fan Speed indicator

Shows the selected fan speed.

Ventilation indicator

Appears when the unit is running in
Ventilation mode.

Operation Section

Temperature setting buttons

Down
Up

Timer Menu button
(Monitor/Set button)

Mode button (Return button)

Set Time buttons

Back

Ahead

Timer On/Off button
(Set Day button)

Opening the
cover

ON/OFF button

Fan Speed button

Filter button
(<Enter> button)

Test Run button

Check button (Clear button)

Airflow Up/Down button

Louver button
( Operation button)

T o return operation
number

Ventilation button
( Operation button)

To go to next operation
number

Built-in temperature sensor

Displays if the airflow is set to
Low or downward during COOL
or DRY mode. (Operation varies
according to model.)
The indicator goes off in 1 hour,
when the airflow direction also
changes.

3-3. Wired remote controller (Option) PAR-21MAA

Once the controllers are set, the same operation mode can be repeated by simply pressing the ON/OFF button.

* The functions which can be used are restricted according to the model.

OCH493D

6

SPECIFICATIONS

4

NOTE : Test conditions are based on ISO 5151.
Cooling : Indoor D.B. 27: W.B. 19 :
Outdoor D.B. 35: W.B. 24:
Heating : Indoor D.B. 20: W.B. 15:
Outdoor D.B. 7: W.B. 6:
Refrigerant piping length (one way): 5 m
*1 Measured under rated operating frequency

Specifications and rating conditions of main electric parts

SLZ-KA25VAQ.TH

SLZ-KA35VAQ.TH

Indoor service ref.

Function

Power supply

Single phase

230V, 50Hz

600/540/480

10

0.35
75

0.014

0.19

PK6V15-LD

4

37/31/28

650/530/480

3
10
10
10

Cooling90Heating

93

Single phase

230V, 50Hz

660/540/480

10

0.40
85

0.014

0.26

PK6V20-LL

4

38/33/29

690/570/510

3
10
10
10

Cooling

94

Heating

94

Air flow

(High/Medium/Low)
Power outlet
Running current *1
Power input Rated frequency
Dew prevention heater
Power factor *1
Fan motor current *1
Model

Winding
resistance (at 26)

Width
 Height
Depth
Weight
Air direction
Sound level(High/Medium/Low)
Fan speed(High/Medium/Low)
Fan speed regulator
Thermistor TH1(at 25)
Thermistor TH2(at 25)
Thermistor TH5(at 25)

* /h

A
A

W

(kW)

%

A



mm(in)
mm(in)
mm(in)

kg

dB(A)

rpm

k
k
k

Electrical

data

Fan

motor

Special

remarks

Capacity

Dimensions

WHT-BLK : 407
BLK-BLU : 86
BLU-YLW : 30
BRN-RED : 165

UNIT : 570(22-7/16) PANEL : 650(25-9/16)
UNIT : 235(9-1/4) PANEL : 20(13/16)
UNIT : 570(22-7/16) PANEL : 650(25-9/16)
UNIT : 16.5 PANEL : 3

WHT-BLK : 393
BLK-BLU : 164
BLU-YLW : 47
BRN-RED : 319

WHT-BLK : 393
BLK-BLU : 164
BLU-YLW : 47
BRN-RED : 319

SLZ-KA50VAQ.TH

SLZ-KA25VAQR1.TH

SLZ-KA35VAQR2.TH SLZ-KA50VAQR2.TH

SLZ-KA35VAQR1.TH

SLZ-KA25VAQ2.TH

Single phase

230V, 50Hz

660/540/480

10

0.40
85

0.014

0.26

PK6V20-LL

4

38/33/29

690/570/510

3
10
10
10

Cooling

94

Heating

94

SLZ-KA50VAQR1.TH

Single phase

230V, 50Hz

660/540/480

20

0.65
85

0.014

0.27

PK6V20-LM

4

39/34/30

710/590/530

3
10
10
10

Cooling97Heating

97

WHT-BLK : 325
BLK-BLU : 143
BLU-YLW : 47
BRN-RED : 309

1.5440V
250V 6.3A

MSBPC20 12V 250

TO OUTDOOR UNIT : 3P TO WIRED REMOTE CONTROLLER : 2P

141 $ 3

240V AC 15W

INDOOR UNIT

Item

Service ref.

Indoor fan capacitor
Fuse
Vane motor
Terminal block
Indoor fan motor thermal fuse
Cord Heater

SLZ-KA50VAQ.TH
SLZ-KA50VAQR1.TH
SLZ-KA50VAQR2.TH

SLZ-KA25VAQ.TH
SLZ-KA25VAQR1.TH
SLZ-KA25VAQ2.TH

SLZ-KA35VAQ.TH
SLZ-KA35VAQR1.TH
SLZ-KA35VAQR2.TH

(C1)

(FUSE)

(MV)

(TB)

(H2)

OCH493D

77

NOISE CRITERION CURVES

UNIT

1.5 m

MICROPHONE

CEILING

NOTE: The sound level is measured in an anechoic room where echoes are few, when compressor stops. The sound

may be bigger than the indicated level in actual use due to surrounding echoes. The sound level can be higher
by about 2 dB than the indicated level during cooling and heating operation.

90

80

70

60

50

40

30

20

10

63 125 250 500 1000 2000 4000 8000

APPROXIMATE
THRESHOLD OF
HEARING FOR
CONTINUOUS
NOISE

NC-60

NC-50

NC-40

NC-30

NC-20

NC-70

OCTAVE BAND SOUND PRESSURE LEVEL, dB (0 dB = 0.0002 μbar)

BAND CENTER FREQUENCIES, Hz

SLZ-KA50VAQ.TH
SLZ-KA50VAQR1.TH
SLZ-KA50VAQR2.TH

High

Medium

39

SPL(dB)34LINE

<50Hz>

NOTCH

Low

30

90

80

70

60

50

40

30

20

10

63 125 250 500 1000 2000 4000 8000

APPROXIMATE
THRESHOLD OF
HEARING FOR
CONTINUOUS
NOISE

NC-60

NC-50

NC-40

NC-30

NC-20

NC-70

OCTAVE BAND SOUND PRESSURE LEVEL, dB (0 dB = 0.0002 μbar)

BAND CENTER FREQUENCIES, Hz

SLZ-KA25VAQ.TH
SLZ-KA25VAQR1.TH

High

Medium

37

SPL(dB)31LINE

<50Hz>

NOTCH

Low

28

90

80

70

60

50

40

30

20

10

63 125 250 500 1000 2000 4000 8000

APPROXIMATE
THRESHOLD OF
HEARING FOR
CONTINUOUS
NOISE

NC-60

NC-50

NC-40

NC-30

NC-20

NC-70

OCTAVE BAND SOUND PRESSURE LEVEL, dB (0 dB = 0.0002 μbar)

BAND CENTER FREQUENCIES, Hz

SLZ-KA25VAQ2.TH
SLZ-KA35VAQ.TH
SLZ-KA35VAQR1.TH
SLZ-KA35VAQR2.TH

High

Medium

38

SPL(dB)33LINE

<50Hz>

NOTCH

Low

29

OCH493D

8

OUTLINES AND DIMENSIONS

5

(Case of Wired remote controller)

Terminal block

Terminal block

Suspension bolt
M10 or 3/8
(procure locally)

Refrigerent
pipe (liquid)

Refrigerent
pipe (gas)

Grille

Drain pipe
VP-25 connection
(O.D. W 32)

Suspension bolt

lower edge

230

18248

Wiring entry

Ceiling surface

235

208

27

+5

0

193

20

93

38~58

66121

17 202

87

15~37 15~37

576~620

570

530

Fresh air
intake

56

57

31

Ceiling hole

Suspension bolt pitch

15~37 15~37576~620

420

570

335

199

352
335

Suspension bolt
pitch

Ceiling hole

Brand label

Vane motor

Drain hole

V/M

Air intake grille

55 35

35 55

Auto vane

Grille

Air intake hole

Air intake hole

Air outlet hole

Air outlet hole

301

301

377

377

650

650

V/M

V/M

V/M

Detail drawing of fresh air intake

Ceiling surface

Cut out hole

W 73.4

Burring hole

3- W 2.8 hole

W 100

118

25

120°

120°

Emergency operation switch (cooling)

Emergency operation switch (heating)

Operation lamp

DEFROST/STAND BY lamp

(WIRELESS PANEL)

Receiver

SLZ-KA50VAQ
SLZ-KA50VAQR1
SLZ-KA50VAQR2

SLZ-KA35VAQ
SLZ-KA35VAQR1
SLZ-KA35VAQR2

SLZ-KA25VAQ
SLZ-KA25VAQR1
SLZ-KA25VAQ2

1/4 F

flared connection

W 6.35mm

1/4 F

flared connection

W 6.35mm

W 9.52mm

flared connection
3/8 F

1/2 F

flared connection

Service ref.

W 6.35mm

flared connection
1/4 F

Refrigerent pipe
(liquid)

Refrigerent pipe
(gas)

W 12.7mm

W 9.52mm

flared connection
3/8 F

Unit : mm

SLZ-KA25VAQ.TH SLZ-KA35VAQ.TH SLZ-KA50VAQ.TH
SLZ-KA25VAQR1.TH SLZ-KA35VAQR1.TH SLZ-KA50VAQR1.TH
SLZ-KA25VAQ2.TH SLZ-KA35VAQR2.TH SLZ-KA50VAQR2.TH

OCH493D

99

WIRED REMOTE CONTROLLER

Unit : mm

PAR-21MAA

PAR-30MAA

130

12083.5

19.5

19

120

120

46

46

83.5

(Option)

OCH493D

10

WIRING DIAGRAM

6

The black square(■)indicates a switch position.<*1>

LED3

LED2

LED1

3

1

FUSE

13579

7
6
3
2
1

10

5

3RED

(D·HEATER)

CNC

X1

X6 X5 X4

X7

RED

(

POWER

BOARD)

CNDK

WHT

(

POWER

BOARD)

CN2D

RED

(INTAKE)

CN20

BLU

(REMOCON)

CN22

WHT

(LIQUID)

CN21

WHT

(DRAIN)

CN31

GRN

(VANE)

CN6V

BLU

WHT

YLW

ORN

RED

CN2L

BLK

(2 PHASE)

CN29

ORN

(

POWER

)

CND

BLU

(D·U·M)

CNP

BLU

(CONTROL)

CN3C

CNSK
(RED)

CN2S
(WHT)

DC13.1V

WHT

(FAN)

FAN

1

31 15

5

14

12

CN32 CN51 CN41

31

31

31 31 31

61

BLU

BLU

BLU

BLU

WHT

YLW

BLK

BRN

BLU

WHT

YLW

YLW
YLW

GRILLE

H2

ORN

RED

WHT

WHT

BLK

YLW

YLW

YLW

YLW

RED

RED

ORN

RED

BLU

ORN

CN90

(WIRELESS)

WHT

9 1

12 12

2

1

12 122

21

3

1

ON
OFF

SWE

ON
OFF

SW2

See fig:*1

12345

20

I.B

M
1

~

M

1

~

DP

MF

P.B

TB4

TO
OUTDOOR
UNIT

S1
S2
S3

TB15

1
2

TB6

1
2

C1

t° t° t°

TH5 TH1 TH2

t°

DS

SW2

MODELS
KA25

KA35

KA50

ON
OFF

12345

ON
OFF

12345

ON
OFF

12345

5
5
5
5

MV

MV
MV
MV

R.B

ON
OFF

SW3

12345

CN105

9

7
6
5
4
3

ORN

YLW

BLU

VLT

GRY

8

PINK

9

SKY BLU

2

RED
BRN

1

9

RU

SW2

SW1

LED1

LED2

BZ

CNB

SKY BLU

PINK

GRY

VLT

BLU

YLW

ORN

RED

BRN

REMOTE
CONTROLLER

W.B

W.R

<fig:*1>

*

Case of wireless model



*

Case of wired model



15

*

For details on how to operate self-diagnosis refer to the technical manuals etc.

SYMBOL NAME SYMBOL NAME

I.B

INDOOR CONTROLLER BOARD

INDOOR POWER BOARD

FUSE (T6.3AL250V)

CONNECTOR (LOSSNAY)
CONNECTOR (REMOTE SWITCH)
CONNECTOR (HA TERMINAL-A)
CENTRALLY CONTROL

POWER SUPPLY (I.B)
POWER SUPPLY (I.B)
TRANSMISSION (INDOOR-OUTDOOR)

DRAIN PUMP/DEW PREVENTION HEATER

SWITCH (EMERGENCY OPERATION)

SWITCH (CAPACITY CODE)

FAN MOTOR (WITH THERMAL FUSE)
VANE MOTOR

DRAIN PUMP
DRAIN SENSOR

TERMINAL BLOCK
(INDOOR/OUTDOOR CONNECTING LINE)

TERMINAL BLOCK (

REMOTE CONTROLLER

TRANSMISSION LINE

)

TERMINAL BLOCK (

REMOTE CONTROLLER

TRANSMISSION LINE

)

ROOM TEMP . THERMIST OR
(0°C / 15kΩ, 25°C / 5.4kΩ DETECT)

PIPE TEMP. THERMISTOR/LIQUID
(0°C / 15kΩ, 25°C / 5.4kΩ DETECT)

COND. / EVA. TEMP. THERMISTOR
(0°C/ 15kΩ, 25°C / 5.4kΩ DETECT)

MF

DEW PREVENTION HEATERH2

FUSE

MV

DP

CAPACITOR (FAN MOTOR)

C1

CN2L

DS

CN32

P.B

CN41
CN51

TB4

LED1

W.B

WIRELESS REMOTE CONTROLLER BOARD

SWITCH (HEATING ON/OFF)

RECEIVING UNIT
BUZZER
LED (RUN INDICATOR)
LED (HOT ADJUST)

SWITCH (COOLING ON/OFF)

SW1

RU
BZ
LED1
LED2

SW2

TB15

LED2

TH1

LED3

X1

RELAY (FAN MOTOR LL)

X4

RELAY (FAN MOTOR Lo)

X5

RELAY (FAN MOTOR Hi)

X6

RELAY (FAN MOTOR Me)

X7

TH2

SW2

SWITCH (MODE SELECTION)

SW3

TH5

TB6

SWE

[LEGEND]

NOTES:

1. Since the outdoor side electric wiring may change be sure to check the
outdoor unit electric wiring for servicing.

2. Indoor and outdoor connecting wires are made with poIarities, make wiring
matching terminal numbers (S1, S2, S3).

3.

SymboIs used in wiring diagram above are, :Connector, :Terminal (block).

R.B

OPTION PART

WIRED REMOTE CONTROLLER BOARD

SLZ-KA25VAQ.TH SLZ-KA35VAQ.TH SLZ-KA50VAQ.TH
SLZ-KA25VAQR1.TH SLZ-KA35VAQR1.TH SLZ-KA50VAQR1.TH
SLZ-KA25VAQ2.TH SLZ-KA35VAQR2.TH SLZ-KA50VAQR2.TH

OCH493D

11

7

REFRIGERANT SYSTEM DIAGRAM

Pipe temperature
thermistor/liquid
(TH2)

Distributor
with strainer
#50

Condenser/evaporator
temperature thermistor
(TH5)

Room temperature
thermistor (TH1)

Refrigerant flow in cooling
Refrigerant flow in heating

Strainer
#50

Strainer
#50

Heat exchanger

Refrigerant GAS pipe connection
(Flare)

Refrigerant LIQUID pipe connection
(Flare)

SLZ-KA25VAQ.TH SLZ-KA35VAQ.TH SLZ-KA50VAQ.TH
SLZ-KA25VAQR1.TH SLZ-KA35VAQR1.TH SLZ-KA50VAQR1.TH
SLZ-KA25VAQ2.TH SLZ-KA35VAQR2.TH SLZ-KA50VAQR2.TH

OCH493D

12

TROUBLESHOOTING

8

8-1. CAUTIONS ON TROUBLESHOOTING

(1) Before troubleshooting, check the followings:

1 Check the power supply voltage.
2 Check that the indoor/outdoor connecting wire is correct.

(2) Take care of the followings during servicing:

1 Before servicing the air conditioner, be sure to turn off the remote controller first to stop the main unit, and then turn

off the breaker.

2 When removing the indoor controller board, hold the edge of the board with care NOT to apply stress on the

components.

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

Lead wire

8-2. MALFUNCTION-DIAGNOSIS METHOD BY REMOTE CONTROLLER

Errors detected by indoor unit

E9

 Check code

Symptom Remark

Wired remote controller

 Check code

Wired remote controller

P1

Intake sensor error

P9 Pipe (TH5) sensor error

P2 Pipe (TH2) sensor error

E6,E7

Indoor/outdoor unit communication error

P4 Drain sensor error
P5 Drain pump error
P6
PL

Freezing/Overheating protection operation

Abnormal refrigerant circuit
EE Communication error between indoor and outdoor units
P8 Pipe temperature error
E4, E5 Remote controller signal receiving error

–
–

–
–

Errors detected by unit other than indoor unit (outdoor unit, etc.)

*1 The check code in the parenthesis indicates PAR-30MAA model.

Symptom Remark

Indoor/outdoor unit communication error
(Transmitting error) (Outdoor unit)

Open/short of outdoor unit thermistors
Compressor overcurrent interruption (When compressor locked)

Abnormal high discharging temperature/49C operated/
insufficient refrigerant

Abnormal high pressure (63H operated)/Overheating
protection operation
Abnormal temperature of heatsink
Outdoor unit fan protection stop

Compressor overcurrent interruption/Abnormal of power module
Abnormality of superheat due to low discharge temperature
Abnormality such as overvoltage or voltage shortage and

abnormal synchronous signal to main circuit/Current sensor error

U2

U5

UP
U3,U4
UF

U1,Ud (UD) *1

U8
U6
U7

U9,UH

Others

–
–

–
–

Other errors (Refer to the technical manual for the outdoor unit.)

For details, check
the LED display
of the outdoor
controller board.
As for outdoor
unit, refer to
outdoor unit’s
service manual.

Fb (FB) *1 Indoor unit control system error (memory error,etc.)
E0, E3
E1, E2 Remote controller control board error

Remote controller transmission error

Compressor overcurrent interruption

continued to the next page.

OCH493D

1313

•

If the unit cannot be operated properly after the test run, refer to the following table to find out the cause.

Symptom

Cause

Wired remote controller

PLEASE WAIT

PLEASE WAIT→ Error code

No messages appear even
when operation switch is turned
ON (operation lamp does not
light up).

For about 2 minutes after power-on

Subsequent to about 2 minutes
after power-on

•

For about 2 minutes after power-on, operation

of the
remote controller is not possible due to system start-up.
(Correct operation)

•Connector for the outdoor unit’s protection device is not
connected.

•Reverse or open phase wiring for the outdoor unit’s
power terminal block

•Incorrect wiring between indoor and outdoor units.
(incorrect polarity of S1, S2, S3)

•Remote controller wire short

Note:
Operation is not possible for about 30 seconds after cancellation of function selection. (Correct operation)

For description of each LED (LED1, 2, 3) provided on the indoor controller, refer to the following table.

LED1 (power for microprocessor)

Indicates whether control power is supplied. Make sure that this LED is
always lit.

LED2 (power for wired remote controller)

Indicates whether power is supplied to the wired remote controller.
This LED lights only in the case of the indoor unit which is connected to the
outdoor unit refrigerant address “0”.

LED3 (communication between indoor and
outdoor units)

Indicates state of communication between the indoor and outdoor units.
Make sure that this LED is always blinking.

• On wired remote controller
Check code displayed in the LCD.

OCH493D

14

8-3. SELF-DIAGNOSIS ACTION TABLE

Note: Refer to the manual of outdoor unit for the details of display
such as F, U, and other E.

Error Code

Abnormal point and detection method

Cause

Countermeasure

P1

Room temperature thermistor (TH1)

1 The unit is in 3-minute resume

prevention mode if short/open of

thermistor is detected. Abnormal if the

unit does not reset normally after 3
minutes. (The unit returns to normal
operation, if it has been reset normally.)

2 Constantly detected during cooling,

drying and heating operation
Short: 90°C or more
Open: -40°C or less

1 Defective thermistor

characteristics

2 Contact failure of connector

(CN20) on the indoor controller
board (Insert failure)

3 Breaking of wire or contact

failure of thermistor wiring

4 Defective indoor controller

board

1–3 Check resistance value of thermistor.

0°C

.....

15.0k"

10°C

.......

9.6k"

20°C

.......

6.3k"

30°C

.......

4.3k"

40°C

.......

3.0k"
If you put force on (draw or bend) the lead wire
with measuring resistance value of thermitor,
breaking of wire or contact failure can be
detected.
2 Check contact failure of connector (CN20)

on the indoor controller board. Refer to 8-5.
Turn the power back on and check restart
after inserting connector again.

4 Check room temperature display on remote

controller.

Replace indoor controller board if there

is abnormal difference with actual room
temperature.

Turn the power off, and on again to operate
after checking.

P2

Pipe temperature thermistor/Liquid
(TH2)

1 The unit is in 3-minute resume

prevention mode if short/open of

thermistor is detected. Abnormal if the

unit does not reset normally after 3 min­utes. (The unit returns to normal opera­tion, if it has been reset normally.)

2 Constantly detected during cooling,

drying, and heating (except defrosting)

operation.
Short: 90°C or more
Open: -40°C or less

1 Defective thermistor

characteristics

2 Contact failure of connector

(CN21) on the indoor controller
board (Insert failure)

3 Breaking of wire or contact

failure of thermistor wiring

4 Defective refrigerant circuit is

causing thermistor temperature
of 90°C or more or -40°C or
less.

5 Defective indoor controller board

1–3 Check resistance value of thermistor.

For characteristics, refer to (P1) above.

2

Check contact failure of connector (CN21)

on the indoor controller board. Refer to 8-5.
Turn the power on and check restart after
inserting connector again.

4 Check pipe <liquid> temperature with remote

controller in test run mode. If pipe <liquid>
temperature is extremely low (in cooling
mode) or high (in heating mode), refrigerant
circuit may have defect.

5 Check pipe <liquid> temperature with

remote controller in test run mode. If there is
extreme difference with actual pipe <liquid>
temperature, replace indoor controller board.

Turn the power off, and on again to operate
after checking.

P4

Drain sensor (DS)

1 Suspensive abnormality, if short/open

of thermistor is detected for 30 seconds

continuously.
Turn off compressor and indoor fan.
2 Short/open is detected for 30 seconds

continuously during suspensive

abnormality.
(The unit returns to normal operation, if it

has been reset normally.)
3 Detect the following condition.

• During cooling and drying operation

• In case that pipe <liquid> temperature ­room temperature < -10 deg

(Except defrosting)

• When pipe <liquid> temperature
or room temperature is short/open
temperature.

• During drain pump operation

1 Defective thermistor

characteristics

2 Contact failure of connector

(CN31) on the indoor controller
board (Insert failure)

3 Breaking of wire or contact

failure of drain sensor wiring

4 Defective indoor controller board

1–3 Check resistance value of thermistor.

0°C

.......

6.0k"

10°C

.......

3.9k"

20°C

.......

2.6k"

30°C

.......

1.8k"

40°C

.......

1.3k"

2 Check contact failure of connector (CN31)

on the indoor controller board. Refer to 8-5.
Turn the power back on and check restart
after inserting connector again.

4 Replace indoor controller board if drain

pump operates with the line of drain sensor
connector CN31-1 and 2 is short-circuited,
and abnormality reappears.

Turn the power off, and on again to operate
after checking.

P5

Malfunction of drain pump (DP)

1 Suspensive abnormality, if thermistor of

drain sensor heats itself and temperature
rises slightly. Turn off compressor and
indoor fan.

2 Drain pump is abnormal if the condition

above is detected during suspensive
abnormality.

3 Constantly detected during drain pump

operation

1 Malfunction of drain pump
2 Defective drain

Clogged drain pump
Clogged drain pipe
3 Attached drop of water at the

drain sensor

• Drops of drain trickles from
lead wire

• Clogged filter is causing
wave of drain.

4 Defective indoor controller board

1 Check if drain pump works.
2 Check drain function.
3 Check the setting of lead wire of drain sen-

sor and check clogs of the filter.

4 Replace indoor controller board if drain

pump operates with the line of drain sensor
connector CN31-1 and 2 is short-circuited
and abnormality reappears.

Refer to 8-5.
Turn the power off, and on again to operate

after checking.

OCH493D

15

Error Code

Abnormal point and detection method

Cause

Countermeasure

P6

Freezing/overheating protection is oper­ating

1 Freezing protection (Cooling mode)

The unit is in 6-minute resume prevention
mode if pipe <liquid or condenser/evap­orator> temperature stays under -15°C
for 3 minutes after the compressor start­ed. Abnormal if it stays under 15°C for
3 minutes again within 16 minutes after
6-minute resume prevention mode.

2 Overheating protection (Heating mode)

The units is in 6-minute resume pre­vention mode if pipe <condenser /
evaporator> temperature is detected as
over 70°C after the compressor started.
Abnormal if the temperature of over
70°C is detected again within 10 min­utes after 6-minute resume prevention
mode.

P8

1 Slight temperature difference

between indoor room
temperature and pipe <liquid
or condenser / evaporator>
temperature thermistor

• Shortage of refrigerant

• Disconnected holder of pipe
<liquid or condenser /

evaporator> thermistor

• Defective refrigerant circuit

2 Converse connection of
extension pipe (on plural units

connection)
3 Converse wiring of indoor/
outdoor unit connecting wire

(on plural units connection)
4 Defective detection of indoor

room temperature and pipe

<condenser / evaporator>
temperature thermistor
5 Stop valve is not opened
completely.

(Cooling or drying mode)

1 Clogged filter (reduced airflow)
2 Short cycle of air path
3 Low-load (low temperature)

operation out of the tolerance
range

4 Defective indoor fan motor

• Fan motor is defective.

• Indoor controller board is

defective.

5 Defective outdoor fan control
6 Overcharge of refrigerant
7 Defective refrigerant circuit

(clogging)

(Heating mode)

1 Clogged filter (reduced airflow)
2 Short cycle of air path
3 Overload (high temperature)

operation out of the tolerance
range

4 Defective indoor fan motor

• Fan motor is defective.

• Indoor controller board is

defective.

5 Defective outdoor fan control
6 Overcharge of refrigerant
7 Defective refrigerant circuit

(clogging)

8 Bypass circuit of outdoor unit

is defective.

(Cooling or drying mode)

1 Check clogging of the filter.
2 Remove blockage.

4 Measure the resistance of fan motor's winding.

Measure the output voltage of fan's connector

(FAN) on the indoor controller board.

WThe indoor controller board should be

normal when voltage of AC 220 - 240V is
detected while fan motor is connected.

Refer to 8-5.

5 Check outdoor fan motor.
67 Check operating condition of refrigerant

circuit.

(Heating mode)

1 Check clogs of the filter.
2 Remove blockage.

4 Measure the resistance of fan motor's

winding.

Measure the output voltage of fan's connector

(FAN) on the indoor controller board.

W The indoor controller board should be

normal when voltage of AC 220 - 240V is
detected while fan motor is connected.

Refer to 8-5.

5 Check outdoor fan motor.
6~8 Check operating condition of refrigerant

circuit.

Pipe temperature

<Cooling mode>
Detected as abnormal when the pipe tem­perature is not in the cooling range 3 min­utes after compressor start and 6 minutes
after the liquid or condenser/evaporator pipe
is out of cooling range.
Note 1) It takes at least 9 min. to detect.
Note 2) Abnormality P8 is not detected in

drying mode.
Cooling range : -3 deg ] (TH-TH1)
TH: Lower temperature between liquid pipe

temperature (TH2) and condenser/
evaporator temperature (TH5)

TH1: Intake temperature
<Heating mode>

When 10 seconds have passed after the
compressor starts operation and the hot
adjustment mode has finished, the unit is
detected as abnormal when condenser/
evaporator pipe temperature is not in heat­ing range within 20 minutes.

Note 3) It takes at least 27 minutes to

detect abnormality.
Note 4) It excludes the period of defrosting

(Detection restarts when defrosting

mode is over)
Heating range : 3 deg [ (TH5-TH1)

23Check converse connection of extension
pipe or converse wiring of indoor/outdoor
unit connecting wire.

1~4Check pipe <liquid or condenser /

evaporator> temperature with room
temperature display on remote controller
and outdoor controller circuit board.

Pipe <liquid or condenser / evaporator>

temperature display is indicated by

setting SW2 of outdoor controller circuit

board as follows.

Conduct temperature check with outdoor
controller circuit board after connecting
‘A-Control Service Tool(PAC-SK52ST)’.

(

)

OCH493D

16

Error Code

Abnormal point and detection method

Cause

Countermeasure

P9

Pipe temperature thermistor / Condenser
/ Evaporator (TH5)

1 The unit is in 3-minute resume protec-

tion mode if short/open of thermistor is
detected. Abnormal if the unit does not
get back to normal within 3 minutes. (The
unit returns to normal operation, if it has
been reset normally.)

2 Constantly detected during cooling,

drying, and heating operation (except

defrosting)
Short: 90°C or more
Open: -40°C or less

1 Defective thermistor

characteristics

2 Contact failure of connector

(CN29) on the indoor controller
board (Insert failure)

3 Breaking of wire or contact

failure of thermistor wiring

4 Temperature of thermistor is

90°C or more or -40°C or less
caused by defective refrigerant
circuit.

5 Defective indoor controller

board

1–3 Check resistance value of thermistor.
For characteristics, refer to (P1) above.
2 Check contact failure of connector (CN29)

on the indoor controller board.
Refer to 8-5.
Turn the power on and check restart after

inserting connector again.
4 Operate in test run mode and check pipe

<condenser/evaporator> temperature with

outdoor controller circuit board. If pipe

<condenser/evaporator> temperature is

extremely low (in cooling mode) or high (in

heating mode), refrigerant circuit may have

defect.
5 Operate in test run mode and check pipe

<condenser/evaporator> temperature

with outdoor control circuit board. If there

is extreme difference with actual pipe

<condenser/evaporator> temperature replace

indoor controller board.
There is no abnormality if none of above

comes within the unit.
Turn the power off and on again to operate.

E0

or

E4

Remote controller transmission
error(E0)/signal receiving error(E4)

1 Abnormal if main or sub remote con-

troller cannot receive any transmission
normally from indoor unit of refrigerant

address “0” for 3 minutes.
(Error code : E0)
2 Abnormal if sub-remote controller could

not receive for any signal for 2 minutes.

(Error code: E0)
1 Abnormal if indoor controller board

cannot receive normally any data from

remote controller board or from other

indoor controller board for 3 minutes.

(Error code: E4)
2 Indoor controller board cannot receive

any signal from remote controller for 2

minutes. (Error code: E4)

1 Check disconnection or looseness of indoor

unit or transmission wire of remote controller.

2 Set one of the remote controllers “main”, if

there is no problem with the action above.

3 Check wiring of remote controller.

• Total wiring length: max. 500 m
(Do not use cable × 3 or more)

• The number of connecting indoor units:
max. 16 units

• The number of connecting remote
controller: max. 2 units

When the above-mentioned problem of 1~3
are not seen.
4 Diagnose remote controllers.

a) When “RC OK” is displayed, remote

controllers have no problem.
Turn the power off, and on again to check.
If abnormality generates again, replace
indoor controller board.

b) When “RC NG” is displayed, replace

remote controller.

c)

When “RC E3” or “ERC 00-66” is displayed,
noise may be causing abnormality.

1 Contact failure at transmission

wire of remote controller

2 All remote controllers are set

as “sub” remote controller. In
this case, E0 is displayed on
remote controller, and E4 is
displayed at LED (LED1, LED2)
on the outdoor controller circuit
board.

3 Miswiring of remote controller
4 Defective transmitting/receiving

circuit of remote controller

5 Defective transmitting/receiving

circuit of indoor controller board
of refrigerant address “0”

6 Noise has entered into the

transmission wire of remote
controller.

In case of checking pipe temperature
with outdoor controller circuit board,
be sure to connect A-control service
tool (PAC-SK52ST).

(

)

PL

Abnormal refrigerant circuit

During Cooling, Dry, or Auto Cooling

operation, when the following are
regarded as failures when detected for
one second.

a) The compressor continues to run for 30

or more seconds.

b) The liquid pipe temperature or the

condense/evaporator temperature is
75°C or more.

* These detected errors will not be

cancelled until the power source is
reset.

1 Abnormal operation of 4-way

valve

2 Disconnection of or leakage in

refrigerant pipes

3 Air into refrigerant piping
4 Abnormal operation (no rotation)

of indoor fan

· Defective fan motor.

· Defective indoor control
board.

5 Defective refrigerant circuit

(clogging)

1 When this error occurs, be sure to

replace the 4-way valve.

2 Check refrigerant pipes for disconnection or

leakage.

3 After the recovery of refrigerant, vacuum

dry the whole refrigerant circuit.

4 Refer to section 8-7.
5 Check refrigerant circuit for operation.

* To avoid entry of moisture or air into

refrigerant circuit which could cause
abnormal high pressure, purge air in
refrigerant circuit or replace refrigerant.

OCH493D

17

E6

1 Contact failure, short circuit or,

miswiring (converse wiring) of
indoor/outdoor unit connecting
wire

2 Defective transmitting/receiv-

ing circuit of indoor controller
board

3 Defective transmitting/receiving

circuit of indoor controller board

4 Noise has entered into indoor/

outdoor unit connecting wire.

1 Check disconnection or looseness of indoor/

outdoor unit connecting wire of indoor unit or
outdoor unit.

Check all the units in case of twin indoor unit

system.

2-4 Turn the power off, and on again to

check. If abnormality generates again,
replace indoor controller board or outdoor
controller circuit board.

* Other indoor controller board may have

defect in case of twin indoor unit system.

E7

Indoor/outdoor unit communication
error (Transmitting error)

Abnormal if “1” receiving is detected 30
times continuously though indoor controller
board has transmitted “0”.

1 Defective transmitting receiving

circuit of indoor controller board

2 Noise has entered into power

supply.

3 Noise has entered into outdoor

control wire.

1-3 Turn the power off, and on again to check.

If abnormality generates again, replace
indoor controller board.

Indoor/outdoor unit communication
error (Signal receiving error)

1 Abnormal if indoor controller board

cannot receive any signal normally for 6
minutes after turning the power on.

2 Abnormal if indoor controller board

cannot receive any signal normally for 3
minutes.

3 Consider the unit abnormal under the

following condition: When 2 or more
indoor units are connected to one
outdoor unit, indoor controller board
cannot receive a signal for 3 minutes
from outdoor controller circuit board, a
signal which allows outdoor controller
circuit board to transmit signals.

Error Code

Abnormal point and detection method

Cause

Countermeasure

Fb

(FB)*

Indoor controller board

Abnormal if data cannot be normally read
from the nonvolatile memory of the indoor
controller board.

1 Defective indoor controller

board

1 Replace indoor controller board.

* The check code in the parenthesis indicates

PAR-30MAA model.

E1

or

E2

Remote controller control board

1 Abnormal if data cannot be normally

read from the nonvolatile memory of the
remote controller control board.

(Error code: E1)
2 Abnormal if the clock function of remote

controller cannot be normally operated.

(Error code: E2)

1 Defective remote controller 1 Replace remote controller.

E3

or

E5

Remote controller transmission
error(E3)/signal receiving error(E5)

1 Abnormal if remote controller could not

find blank of transmission path for 6

seconds and could not transmit.
(Error code: E3)
2 Remote controller receives transmitted

data at the same time, compares the

data, and when detecting it, judges

different data to be abnormal 30

continuous times. (Error code: E3)
1 Abnormal if indoor controller board could

not find blank of transmission path.
(Error code: E5)
2 Indoor controller board receives

transmitted data at the same time,

compares the data, and when detecting

it, judges different data to be abnormal

30 continuous times. (Error code: E5)

1 Set a remote controller to main, and the

other to sub.

2 Remote controller is connected with only one

indoor unit.

3 The address changes to a separate setting.
4~6 Diagnose remote controller.

a) When “RC OK” is displayed, remote con-

trollers have no problem.
Turn the power off, and on again to check.
When becoming abnormal again, replace

indoor controller board.
b) When “RC NG” is displayed, replace

remote controller.
c)

When “RC E3” or “ERC 00-66” is displayed,

noise may be causing abnormality.

1 2 remote controllers are set as

“main.”

(In case of 2 remote controllers)

2 Remote controller is connected

with 2 indoor units or more.

3 Repetition of refrigerant

address

4 Defective transmitting/receiving

circuit of remote controller

5 Defective transmitting/receiving

circuit of indoor controller board

6

Noise has entered into transmis­sion wire of remote controller.

OCH493D

18

PA
(2502)
(2500)

Forced compressor stop
(due to water leakage abnormality)

1 When the intake temperature subtracted

from liquid pipe temperature is less than

-10°C, drain sensor detects whether it is
soaked in the water or not at the interval
of 90 seconds. (Drain pump will start
operating when the drain sensor detects
to be soaked in the water.)

2 The unit has a water leakage abnormality

when the following conditions, a) and b),
are satisfied while the above-mentioned
detection is performed.

a) The drain sensor detects to be

soaked in the water 10 times in a row.

b) The intake temperature subtracted

from liquid pipe temperature is
detected to be less than -10°C for a
total of 30 minutes.
(When the drain sensor detects to
be NOT soaked in the water, the
detection record of a) and b) will be
cleared.)

3 The drain sensor detection is performed

in operations other than cooling. (When
the unit stops operating, during heating
or fan operation, when the unit stops
because of some abnormality)

* Once the water leakage abnormality is

detected, abnormality state will not be
released until the main power is reset.

1 Drain pump trouble
2 Drain defective

· Drain pump clogging

· Drain pipe clogging
3 Open circuit of drain sensor

side heater

4 Contact failure of drain sensor

connector

5 Dew condensation on drain

sensor

· Drain water trickles along lead
wire.

· Drain water waving due to filter
clogging

6 Extension piping connection

difference at twin, triple,
quadruple system

7 Miswiring of indoor/outdoor

connecting at twin, triple,
quadruple system

8 Room temperature thermistor/

liquid pipe temperature
themistor detection is defective.

1 Check the drain pump.
Performance

2 Please check whether water can be drained.

3 Check the resistance of the drain sensor side

heater.

4 Check the connector contact failure.

5 Check the drain sensor lead wire mounted.
Check the filter clogging.

6 Check the piping connection.

7 Check the indoor/outdoor connecting wires.

8 Check the room temperature display of

remote controller.
Check the indoor liquid pipe temperature
display of outdoor controller board.

Error Code

Abnormal point and detection method

Cause

Countermeasure

OCH493D

19

8-4. TROUBLESHOOTING OF PROBLEMS

Note: Refer to the manual of outdoor unit for the detail of remote

controller.

Phenomena

Cause

Countermeasure

(1) LED2 on indoor controller board

is off.

• When LED1 on indoor controller board is also off.
1 Power supply of rated voltage is not supplied to out-

door unit.

2 Defective outdoor controller circuit board

3 Power supply of 220~240V is not supplied to indoor

unit.

4 Defective indoor power board

5 Defective indoor controller board

1 Check the voltage of outdoor power

supply terminal block (L, N) or (L

3, N).

• When AC 220-240V is not detected,
check the power wiring to outdoor unit
and the breaker.

• When AC 220-240V is detected, check

2 (below).

2 Check the voltage between outdoor

terminal block S1 and S2.

• When AC 220-240V is not detected,

—check the fuse on outdoor controller

circuit board.

—check the wiring connection.

• When AC 220-240V is detected, check

3 (below).

3 Check the voltage between indoor terminal

block S1 and S2.

• When AC 220-240V is not detected,
check indoor/outdoor unit connecting
wire for miswiring.

• When AC 220-240V is detected, check

4 (below).

4 Check voltage output from CN2S on indoor

power board (DC13.1V). Refer to 8-5.

• When no voltage is output, check the
wiring connection.

• When output voltage is between
DC12.5V and DC13.7V, check 5
(below).

5 Check the wiring connection between

indoor controller board and indoor power
board. Check the fuse on indoor controller
board. If no problems are found, indoor
controller board is defective.

• When LED1 on indoor controller board is lit.
1 Mis-setting of refrigerant address for outdoor unit
(There is no unit corresponding to refrigerant
address “0”.)

1 Check the setting of refrigerant address

for outdoor unit.

Set the refrigerant address to “0”.

(For grouping control system under which
2 or more outdoor units are connected,
set one of the units to “0”.)
Set refrigerant address using SW1 (3-6)
on outdoor controller circuit board.

(2) LED2 on indoor controller board

is blinking.

• When LED1 on indoor controller board is also blinking.
Connection failure of indoor/outdoor unit connecting

wire

• When LED1 is lit
1 Miswiring of remote controller wires

Under twin indoor unit system, 2 or more indoor

units

2 Refrigerant address for outdoor unit is wrong or not

set.

Under grouping control system, there are some units

whose refrigerant address is 0.

3 Short-cut of remote controller wires
4 Defective remote controller

Check indoor/outdoor unit connecting wire
for connection failure.

1 Check the connection of remote

controller wires in case of twin triple
indoor unit system. When 2 or more
indoor units are wired in one refrigerant
system, connect remote controller wires
to one of those units.

2 Check the setting of refrigerant address

in case of grouping control system. If
there are some units whose refrigerant
addresses are 0 in one group, set one
of the units to 0 using SW1 (3-6) on out­door controller circuit board.

34 Remove remote controller wires and

check LED2 on indoor controller board.

• When LED2 is blinking, check the
short-cut of remote controller wires.

• When LED2 is lit, connect remote
controller wires again and:

if LED2 is blinking, remote controller is
defective;
if LED2 is lit, connection failure of remote
controller terminal block etc. has returned
to normal.

OCH493D

20

8-5. TEST POINT DIAGRAM

8-5-1. Indoor power board

SLZ-KA25VAQ.TH SLZ-KA35VAQ.TH SLZ-KA50VAQ.TH
SLZ-KA25VAQR1.TH SLZ-KA35VAQR1.TH SLZ-KA50VAQR1.TH

CNSK
Connect to the indoor controller board
(CNDK)
between 1 to 3 220-240V AC

CN2S
Connect to the indoor controller board (CN2D)
between 1 to 2 12.6-13.7V DC (Pin1 (+))

CNSK
Connect to the indoor controller board
(CNDK)
between 1 to 3 220-240V AC

CN2S
Connect to the indoor controller board (CN2D)
between 1 to 2 12.6-13.7V DC (Pin1 (+))

SLZ-KA25VAQ2.TH SLZ-KA35VAQR2.TH SLZ-KA50VAQR2.TH

OCH493D

21

8-5-2. Indoor controller board

SLZ-KA25VAQ.TH SLZ-KA35VAQ.TH SLZ-KA50VAQ.TH
SLZ-KA25VAQR1.TH SLZ-KA35VAQR1.TH SLZ-KA50VAQR1.TH
SLZ-KA25VAQ2.TH SLZ-KA35VAQR2.TH SLZ-KA50VAQR2.TH

FAN
Fan motor output

CNP
Drain-pump
output (DP)
(208/230V AC)

CNC
Dew prevention
heater (H2)
(208/230V AC)

CNDK
Connect to the
indoor power
board (CNSK)
(208/230V AC)

FUSE
(6.3A 250V)

CND
Power
supply input
(208/230V AC)

SWE
Emergency operation

SW2
Capacity setting

Jumper connector
J11~J15
Unit setting

CN2L
Connector (LOSSNAY)

CN51
Centrally control

1-2 : Control signal

13V pulse input (1 : +)

3-4 : Operation indicator

13VDC (3 : +)

3-5 : Malfunction indicator

13VDC (3 : +)

CN6V
Vane motor output (MV)

CN90
Connect to the wire­less remote controller
board (CNB)

CN31
Drain sensor (DS)

CN29
Condenser/evaporator
temperature thermistor (TH5)

CN21
Pipe temperature
thermistor/Liquid (TH2)

CN20
Room temperature
thermistor (TH1)

CN22
Remote controller
connecting wire
(10.4~14.6V DC)

LED3
Transmission
(Indoor/outdoor)

LED2
Power supply
(R.B)

LED1
Power supply
(I.B)

CN2D
Connector to the indoor
power board (CN2S)
(12.5~13.7V DC)

CN3C
Transmission
(Indoor/outdoor)
(0~24V DC)

SW3
Mode selection

}

}

+

–

+

–

CN41
Connector
(HA terminal-A)

CN105
(CN92)

OCH493D

22

8-6. FUNCTIONS OF DIP SWITCH AND JUMPER WIRE

Each function is controlled by the dip switch on control P.C. board.
Model setting and capacity setting are memorised in the nonvolatile memory of the indoor controller board.

The black square (■) indicates a switch position.

Setting by the dip switch and jumper wire

Functions

Jumper wire

Capacity
setting

Remarks

SW2

Function
setting

SW3

Setting
SLZ-KA25VAQ
SLZ-KA25VAQ2

Models

ON
OFF

12345

ON
OFF

12345

ON
OFF

12345

SLZ-KA35VAQ

SLZ-KA50VAQ

Action by switch opration

OFF

Available

Extra low

Not available

ON

Not available

Stop

Available

Dip switch Function

SW3-1

SW3-2

SW3-3

SW3-4

SW3-5*

Power failure
automatic recovery

Set temperature in
heating mode (4 deg up)

Fan speed when the
thermostat is OFF
(during heating mode)

SW3 function

OFF

ON

ON
OFF

12345

<Initial setting>
SW3

• Function setting becomes effective when the Dip switch SW3-5 is ON.
* Switch off SW3-5 when the function setting is done by wired remote controller.

OCH493D

23

8-7. TROUBLE CRITERION OF MAIN PARTS
SLZ-KA25VAQ.TH SLZ-KA35VAQ.TH SLZ-KA50VAQ.TH
SLZ-KA25VAQR1.TH SLZ-KA35VAQR1.TH SLZ-KA50VAQR1.TH
SLZ-KA25VAQ2.TH SLZ-KA35VAQR2.TH SLZ-KA50VAQR2.TH

Measure the resistance between the terminals with a tester.
Measure the resistance after 3 minutes have passed since the power supply was intercepted.
(At the ambient temperature 0 °C ~ 60 °C)

(Refer to the next page for a detail.)

Abnormal

Open or short

Normal

0.6k ~ 6.0k

BLK RED ORNYLW

BLU

BRN

WHT

P

Room temperature
thermistor
(TH1)

Condenser/evaporator
temperature thermistor
(TH5)

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

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

Pipe temperature
thermistor/liquid
(TH2)

Indoor fan motor
(MF)

Check method and criterion

Part name

Normal

KA25VAQ

Normal

WHT-BLK
BLK-BLU
BLU-YLW

BRN-RED

386~428

81~91
28~32

157~174

KA35VAQ

KA25VAQ2

373~413
155~172

44~49

302~335

KA50VAQ

308~341
135~151

44~49

293~324

4.3k ~ 9.6k

Abnormal

Abnormal

Opened or

short-circuited

Opened or short-circuited

Measure the resistance between the terminals with a tester.
(At the ambient temperature 20 °C ~ 30 °C)

Measure the resistance between the terminals with a tester.
(At the ambient temperature 20 °C ~ 30 °C)

Vane motor (MV)

Drain pump (DP)

Drain sensor (DS)

1
2

Yellow

Yellow

1
2
3

NormalConnector Abnormal

300 Open or short

Normal Abnormal

290 Open or short

Orange

Red

White

# : Thermal fuse 141 ± 3°C

Red — Yellow
Red — Blue
Red — Orange
Red — White

Blue

Yellow









M

Relay
connector

OCH493D

24

<Thermistor Characteristic graph>

• Room temperature thermistor (TH1)

• Pipe temperature thermistor/liquid (TH2)

• Condenser/evaporator temperature
thermistor (TH5)

Thermistor R

0=15kΩ ± 3%

Fixed number of B=3480 ± 2%
Rt=15exp { 3480( ) }
0: 15kΩ

10: 9.6kΩ
20: 6.3kΩ
25: 5.2kΩ
30: 4.3kΩ
40: 3.0kΩ

Thermistor R0=6.0kΩ ±5%
Fixed number of B=3390 ± 2%

Rt=6exp { 3390( ) }
0: 6.0kΩ

10: 3.9kΩ
20: 2.6kΩ
25: 2.2kΩ
30: 1.8kΩ
40: 1.3kΩ
60: 0.6kΩ

Thermistor for
lower temperature

1

273+t

1

273

1

273+t

1

273

Thermistor for
drain sensor

0

10

20

30

40

50

-20-100 1020304050

< Thermistor for lower temperature >

Temperature ()

Resistance (k)

-20 0 20 40 60 80

< Thermistor for drain sensor >

Temperature ()

0

1

2

3

4

5

6

7

8

9

10

Resistance (k)

OCH493D

2525

9 4-WAY AIR FLOW SYSTEM

9-1. FRESH AIR INTAKE (LOCATION FOR INSTALLATION)

At the time of installation, use the duct holes (cut out) located at the positions shown in following diagram, as and when required.

Detail drawing of fresh air intake

Ceiling surface

Refrigerant pipe

Drain pipe

Electrical Box

Cut out hole

:73.4

Burring hole

3-:2.8 hole

:100

118

25

120°

120°

Fresh air intake

SLZ-KA25VAQ.TH SLZ-KA35VAQ.TH SLZ-KA50VAQ.TH
SLZ-KA25VAQR1.TH SLZ-KA35VAQR1.TH SLZ-KA50VAQR1.TH
SLZ-KA25VAQ2.TH SLZ-KA35VAQR2.TH SLZ-KA50VAQR2.TH

9-2. FRESH AIR INTAKE AMOUNT & STATIC PRESSURE CHARACTERISTICS

● Whenever the indoor unit operates, the
duct fan operates.

(1) Connect the optional multiple

remote controller adapter (PAC­SA88HA-E) to the connector CN51
on the indoor controller board.

(2) Drive the relay after connecting the

12V DC relay between the Yellow
and Orange connector wires.

Use a nonpolar relay of 1W or smaller.

MB: Electromagnetic switch power

relay for duct fan.

X: Auxiliary relay (12V DC LY-1F)

Multiple remote
controller adapter
PAC-SA88HA-E

Indoor controller board

Distance between indoor
controller board and relay
must be within 10m.

Be sure to secure insulation
material by tape, etc.

5

Green

Yellow

Orange

Connector (5P)

Indoor unit side

Multiple remote
controller adapter
PAC-SA88HA-E

Be sure to secure insulation
material by tape, etc.

Installation at site

CN51
on
indoor unit
board

Red

Brown

1

~

CN51

MB

+

CN51(WHT)

9-3. OPERATION IN CONJUNCTION WITH DUCT FAN (BOOSTER FAN)

Static pressure : P [Pa]

Air flow : Q [m

3

/min]

50

-50

-100

-150

-200

-250

-300

0

0.5 1.0 1.5 2.0 2.5 3.0 3.5

Taking air into the unit

Q

0

B

A

C

1

Curve in the
left graphs

Duct characteristics
at site

Q

A

EC

2

Q

Qa

AD

3

NOTE: Fresh air intake amount should be 20% or less of

whole air amount to prevent dew dripping.

How to read curves

Q…Designed amount of fresh air intake
<m3/min>
A…Static pressure loss of fresh air

intake duct system with air flow
amount Q <Pa>

B…Forced static pressure at air condi-

tioner inlet with air flow amount Q
<Pa>
C…Static pressure of booster fan with

air flow amount Q <Pa>
D…Static pressure loss increase

amount of fresh air intake duct

system for air flow amount Q <Pa>
E…Static pressure of indoor unit with

air flow amount Q <Pa>
Qa…Estimated amount of fresh air

intake without D <m3/min>

Unit : mm

OCH493D

26

9-4. FIXING HORIZONTAL VANE

Horizontal vane of each air outlet can be fixed according to the environment where it is installed.

Setting procedure

1) Turn off a main power supply (Turn off a breaker).

2) Remove the vane motor connector in the direction of the arrow shown below with pressing the unlocking button as in the
figure below.

Insulate the disconnected connector with the plastic tape.

Vane motor

Horizontal vane

Connector

Unlocking button

Vane motor

3) Set the vertical vane of the air outlet by hand slowly within the range in the table below.

Measured standard
position of the grille

Horizontal vane

< Specified range >

Up/down airflow

direction

Horizontal 30° Downward 45° Downward 55° Downward 70°

A

21 mm 25 mm 28 mm 30 mm

The vanes can be set between 21mm and 30 mm.

Caution:
Do not set the up/down vanes passed the specified range. Condensation could form and drop from the ceiling,
or the unit could malfunction.

OCH493D

2727

10 DISASSEMBLY PROCEDURE

OPERATING PROCEDURE PHOTOS & ILLUSTRATIONS

1. Removing the air intake grille

(1) Slide the knob of air intake grille to the direction of the

arrow 1 to open the air intake grille.

(2) Remove the string hook from the panel to prevent the grille

from dropping.

(3) Slide the hinge of the intake grille to the direction of the

arrow 2 and remove the air intake grille.

4. Removing the electrical parts

(1) Remove the 2 screws and the control box cover.

<Electrical parts in the control box>

• Indoor controller board (I.B)

• Terminal block (TB4)

• Indoor power board (P.B)

Be careful when removing heavy parts.

Photo 3

Figure 1

Air intake grille

Grille

2. Removing the fan guard

(1) Open the air intake grille.
(2) Remove the 3 screws of fan guard.

Air intake grille knob

3. Removing the panel

(1) Remove the air intake grille. (Refer to Procedure 1)

Corner panel (See Figure 2)

(1) Remove the screw of the corner.

(2) Slide the corner panel to the direction of the arrow 3, and

remove the corner panel.

Panel (See Photo 2)

(1) Disconnect the connector that connects with the unit.

(2) Remove the 2 screws from the panel and loose another

2 screws, which are fixed to the oval hole, have different
diameter.

(3) Rotate the panel a little to remove the screws. (Slide the

panel so that the screw comes to a larger diameter of the
oval hole, which has 2 different diameters.)

Photo 1

Screws

Air intake grille

Photo 2

Figure 2

Corner
panel

Screw

Corner
panel

Panel

Panel

Screws

Connectors

Screws

Fan guard

Indoor power board (P.B)

Terminal block
(TB4)

Indoor controller board
(I.B)

SLZ-KA25VAQ.TH SLZ-KA35VAQ.TH SLZ-KA50VAQ.TH
SLZ-KA25VAQR1.TH SLZ-KA35VAQR1.TH SLZ-KA50VAQR1.TH
SLZ-KA25VAQ2.TH SLZ-KA35VAQR2.TH SLZ-KA50VAQR2.TH

OCH493D

28

OPERATING PROCEDURE

PHOTOS & ILLUSTRATIONS

7. Removing the pipe temperature thermistor/liquid (TH2)
and condenser/evaporator temperature thermistor (TH5)

(1) Remove the panel. (Refer to Procedure 3)
(2) Remove the drain pan. (Refer to Procedure 6)
(3) Disconnect the indoor coil thermistor from the holder.
(4) Remove the 3 screws fixed to the piping cover, and remove

the piping cover. (See Photo 9)

(5) Remove the 2 screws fixed to the control box cover, and

remove the control box cover.

Pipe temperature thermistor/liquid (TH2)

(6) Remove the connector (CN21) from the indoor controller

board, and disconnect the pipe temperature thermistor/liquid.

Condenser/evaporator temperature thermistor (TH5)

(6) Remove the connector (CN29) from the indoor controller

board, and disconnect the condenser/evaporator temperature
thermistor.

8. Removing the fan motor (MF)

(1) Remove the panel. (Refer to Procedure 3)
(2) Remove the drain pan. (Refer to Procedure 6)
(3) Remove the nut and the washer from the turbo fan, and

remove the turbo fan.

(4) Remove the 2 screws fixed to the control box cover, and

remove the control box cover.

(5) Disconnect the connectors of the (fan 1) and the (fan 2)

from the indoor controller board.

(6) Remove the 3 screws fixed to the piping cover, and remove

the piping cover. (See Photo 9)

(7) Remove the 6 screws fixed to the flat plate, and remove

the flat plate.

(8) Disconnect the lead wires to the direction of the fan motor,

and remove the 3 nuts of the fan motor.

Photo 5

6. Removing the drain pan

(1) Remove the panel. (Refer to Procedure 3)
(2) Remove the room temperature thermistor and the 2 lead

wires held with fastener; wireless controller board relay
connector (9P red) and panel relay connector (10P white).

(3) Remove the 4 screws fixed to the drain pan, and remove

the drain pan.

(4) Remove the fan guard. (Refer to Procedure 2)

Photo 4

Control box

Pipe temperature
thermistor/liquid
(TH2)

Screw

Screw

Screw

Screw

Room
temperature
thermistor
(TH1)

Drain pan

Control box

Photo 6

Fan motor
(MF)

Nut

Flat plate

Screws

Nut

Lead
wires

Nut

Screw

Screw

5. Removing the room temperature thermistor (TH1)

(1) Remove the panel. (Refer to Procedure 3)
(2) Pull out the room temperature thermistor from the drain

pan.

(3) Remove the 2 screws fixed to the control box cover, and

remove the control box cover.

(4) Remove the connector (CN20) from the indoor controller

board, and disconnect the room temperature thermistor.

Fan guard

Drain plug

Connectors

Screws

Condenser/evaporator
temperature thermistor
(TH5)

OCH493D

29

OPERATING PROCEDURE PHOTOS & ILLUSTRATIONS

10. Removing the heat exchanger

(1) Remove the panel. (Refer to Procedure 3)
(2) Remove the drain pan. (Refer to Procedure 6)
(3) Remove the nut and the washer from the turbo fan, and

remove the turbo fan.

(4) Remove the 2 screws fixed to the control box cover, and

remove the control box cover.

(5) Disconnect the connector of the (fan) from the indoor con-

troller board.

(6) Remove the 3 screws fixed to the piping cover, and remove

the piping cover. (See Photo 9)

(7) Remove the pipe temperature thermistor/liquid and

condenser/evaporator temperature thermistor. (Refer to

Procedure 7)
(8) Disconnect the lead wires to the direction of the fan motor.
(9) Remove the 1 coil support screw, the 2 inside coil screws

(See Photo 10), and the 4 outside coil screws (See Photo 9)

from the heat exchanger, and remove the heat exchanger.

9. Removing the drain pump (DP) and drain sensor (DS)

(1) Remove the panel. (Refer to Procedure 3)
(2) Remove the drain pan. (Refer to Procedure 6)
(3) Remove the 2 screws fixed to the control box cover, and

remove the control box cover.

(4) Remove the connectors of the (CNP) and the (CN31)

from the indoor controller board.

(5) Remove the 1 screw fixed to the cover, and remove the

cover.

(6) Disconnect the lead wires to the direction of the drain

pump. (See Photo 7)
(7) Remove the 3 screws of the drain pump.
(8) Cut the drain hose band, pull out the drain hose from the

drain pump.
(9) Pull out the drain pump.
(10) Remove the drain sensor and the holder.

Photo 7

Screw

Screws

Drain sensor (DS) Drain pump (DP)

Drain
hose

Fixing band

Photo 9

Photo 10

Heat exchanger

Coil screws

Coil
support

Coil
support
screw

Control box

Cover

Screw

Control
box

Photo 8

Screws of
piping cover

Coil
screws

Control box

Piping cover

Coil
screws

Lead wires

Lead wires

OCH493D

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

CCopyright 2010 MITSUBISHI ELECTRIC CORPORATION
Distributed in Oct. 2012 No.OCH493 REVISED EDITION-D
Distributed in Feb. 2012 No.OCH493 REVISED EDITION-C
Distributed in Dec. 2011 No.OCH493 REVISED EDITION-B
Distributed in Mar. 2011 No.OCH493 REVISED EDITION-A
Distributed in Dec. 2010 No.OCH493
Made in Japan

New publication, effective Oct. 2012
Specifications are subject to change without notice.