Mitsubishi SEZ-KC25VA.W Service Manual

TECHNICAL & SERVICE MANUAL

CONTENTS

1. PART NAMES AND FUNCTIONS········2

2. SPECIFICATIONS·································4

3. OUTLINES AND DIMENSIONS············6

4.WIRING DIAGRAM ·······························7

5.

REFRIGERANT SYSTEM DIAGRAM

·········8

6.TROUBLESHOOTING···························9

7. DISASSEMBLY PROCEDURE···········13

8. PARTS LIST········································18

9. OPTIONAL PARTS·····························21

INDOOR UNIT

Indoor unit
[Model names] [Service Ref.]

SEZ-KC25VA SEZ-KC25VA.W

SPLIT-TYPE, HEAT PUMP AIR CONDITIONERS

WIRED REMOTE

CONTROLLER

ON/OFF

TEMP.

Ceiling Concealed

Series SEZ

R410A

Model name
indication

Note :

•This manual does not cover
outdoor units.When ser vicing
outdoor units, please refer
to the service manual
No.OC322 together with this
manual.

2

1

PART NAMES AND FUNCTIONS

Indoor Unit
SEZ-KC25VA.W

Air outlet duct flange

Air outlet

Air inlet

● Operation buttons

PAR-21MAA

ON/OFF

FILTER

CHECK

OPERATION

CLEAR

TEST

TEMP.

MENU

BACK DAY

MONITOR/SET

CLOCK

ON/OFF

Set Temperature 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
door.

Start/Stop button

Fan Speed button

Filter button
(<return sign> button)

Test Run button

Service button (Clear button)

Airflow Up/Down button

Louver button
(

Operation button)

To preceding operation
number.

Ventilation button
(

Operation button)

To next operation number.

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

Wired remote controller

3

● Display

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

˚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

Identifies the current operation

Shows the operating mode, etc.
* Multilanguage display is sup-

ported.

“Centrally Controlled” indicator

Indicates that operation of 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, shows the time
remaining.

“Sensor” indication

Displayed when the remote controller
sensor is used.

“Locked” indicator

Indicates that remote controller but­tons have been locked.

“Clean The Filter” indicator

Comes 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

Displayed if the airflow is set to
weak and downward during COOL
or DRY mode. (Operation varies
according to model.)
The indicator goes off after one
hour, at which time the airflow di­rection also changes.

Room Temperature display

Shows the room temperature.

Louver display

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

(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.

Caution

● Only the Power display lights when the unit is stopped and power supplied to the unit.

● When power is turned ON for the first time the (Centrally controlled) display appears to go off momentarily but this is not a

malfunction.

● “NOT AVAILABLE” is displayed when the Air speed button are pressed.This indicates that this room unit is not equipped with
the fan direction adjustment function and the louver function.

● When power is turned ON for the first time, it is normal that “PLEASE WAIT” is displayed on the room temperature indication
(For max. 2minutes). Please wait until this “PLEASE W AIT”indication disappear then start the operation.

4

2

SPECIFICATIONS

SEZ-KC25VA.W

Indoor model

Function

Power supply

Single phase

230V , 50Hz

474/288

10

0.45
60
—
97

0.28

CRC4417BB

WHT-BLK : 261 BLK-BLU : 475

YLW-BRN : 294

790✕225✕550

19

1

36/25

2
10
10
10

Cooling

Heating

Air flow (High/Low)
Power outlet
Running current ✽1
Power input Rated frequency
Auxiliary heater
Power factor ✽1
Fan motor current ✽1
Model

Winding
resistance (at20:)

Dimensions W✕H✕D
Weight
Air direction
Sound level (High/Low)
Fan speed regulator
Thermistor RT11 (at 25:)
Thermistor RT12 (at 25:)
Thermistor RT13 (at 25:)

K /h

A
A

W

A(kW)

%

A

Ω

mm

kg

dB(A)

kΩ
kΩ
kΩ

Electrical

data

Fan

motor

Special remarks

Capacity

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. 5:

Outdoor D.B. 7: W.B. 6:
Refrigerant piping length (one way): 5m
✽1 Measured under rated operating frequency.

1.5+ 440V
250V 6.3A

ERZV10D471

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

135:i5:

INDOOR UNIT

Item

Model

Indoor fan capacitor
Fuse
Varistor
Terminal block
Indoor fan motor thermal fuse

SEZ-KC25VA.W

(C)

(FUSE)

(ZNR)

(TB)

Specifications and rating conditions of main electric parts

5

NOISE CRITERION CURVES

2m

Aux.duct

1m

1.5m

Measurement location

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

may be bigger than displayed level under actual installation condition by surrounding echoes.The sound level
can be higher by about 2 dB than the displayed level during cooling and heating operation.

SEZ-KC25VA.W

NOTCH

Hi
Lo

<50Hz>

SPL(dB)

36
25

70

60

50

40

30

20

10

OCTAVE BAND PRESSURE LEVEL (dB) 0dB = 20µPa

Appro
Approximate minimum

audible limit on continuous noise

0

63 125 250 500 1000 2000 4000 8000

OCTAVE BAND CENTER FREQUENCIES (Hz)

High speed
Low speed

NC60

NC50

NC40

NC30

NC20

Make the access door at the appointed position properly

for service maintenance.

Ceiling surfaceAccess door

Required space for service and maintenance

Lifting plate

(4-14x30)

Air filter

80

Control box

T erminal bed

(Power source)

Bottom plate

23 664(Lifting bolt pitch)

710

The part air intake duct is attached.(✻3)

(When the air intake duct is used)

610

50

150

790

582

204.5

42.5

30

225(✻2)

15

148

13.55050

510

14127

56.5

(52)

(57)

129

55301 301

189

Detailed chart around the air intake duct frange(✻3)

(Duct and frange should be supplied in the field)

550(✻1)

More than 20mm

More than 20mm

6- ø 3hole

55

50X11=550

16

2X12- ø 3hole

14

459(Lifting bolt pitch)

15

113

Air outlet

Air inlet

450

50~150

300

450

2X3- ø 3hole

25

500

50~150

1

2

3

Note 1. Use M10 screw for the lifting bolt (field supply).

2. Keep the service space for the maintenance from the bottom

when the heat exchanger is cleaned.

3. The direction of air intake can be changed from the bottom to

the rear by attaching the bottom plate to the air intake side.

4. Drain Pan is changeable from right and left.

5. The dimension is changed, in case the optional long-life filter

is attached.

Rear Air-Intake spec. :Depth is increased by 30mm(✻1)

Bottom Air-Intake spec. :Height is increased by 30mm(✻2)

Refrigerant piping flare connection

(gas ø 9.52 copper tube):LP ········1

Refrigerant piping flare connection

(liquid ø 6.35 copper tube):HP ········2

Drain piping connection R1 (External thread) ········3

6

OUTLINES AND DIMENSIONS

3

SEZ-KC25VA.W

7

4

WIRING DIAGRAM

SEZ-KC25VA.W

12

213

131313

1

2

312 4567

1234675

2121

2121

6457321

6457321

TO OUTDOOR UNIT

TH2

TRANS

AC220-240V

CNSK(RED)

DC13.1V

CN2S(WHT)

P.B.

BLU

(CONTROL)

CN3C

ORN

(POWER)

CND

RED

(POWER BOARD)

CNDK

S1S2S3

I.B.

TB4

FUSE

ZNR

X6 X5 X4

WHT

(POWER

BOARD)

CN2D

WHT

(FAN)

FAN

LED1

LED2

LED3

CN32

CN2L

CN51 CN41

CN90

BLK

(2 PHASE)

CN29

RED

(INTAKE)

CN20

WHT

(LIQUID)

CN21

BLU

(REMOCON)

CN22

X6 X5 X4

TH1TH5

1

2

SW2

12345

ON

OFF

5432

OFF

ON

1

SW3

OFF

ON

1

SWE

TB15

TO MA-REMOTE

CONTROLLER

DC8.7-13V

LED1

FUSE

CN90

ZNR

X6

X5

X4

VARISTOR

RELAY (FAN MOTOR HI)

RELAY (FAN MOTOR Lo)

SWE

SW3

RELAY (FAN MOTOR LL)

SWITCH (EMERGENCY OPERATION)

SWITCH (MODE SELECTION)

SW2

LED3

LED2

SWITCH (CAPACITY CODE)

TRANSMISSION (INDOOR-OUTDOOR)

POWER SUPPLY (I.B.)

POWER SUPPLY (I.B.)

FUSE (6.3A)

CN51

CN41

CN32

CN2L

CONNECTOR (WIRELESS)

CENTRALLY CONTROL

CONNECTOR (HA TERMINAL-A)

CONNECTOR (REMOTE SWITCH)

CONNECTOR (LOSSNAY)

I.B.

P.B.

SYMBOL

INDOOR CONTROLLER BOARD

NAME

INDOOR POWER BOARD

SYMBOL

C

MF FAN MOTOR

CAPACITOR (FAN MOTOR)

NAME

TB4

TERMINAL BLOCK (INDOOR/OUTDOOR CONNECTING LINE)

TB15

TERMINAL BLOCK (REMOTE CONTROLLER

TRANSMISSION LINE)

TH1

INT AKE AIR TEMP. THERMIST OR

(0˚C/15kΩ. 25˚C/5.2kΩ DETECT)

TH2

PIPE TEMP. THERMIST OR/LIQUID

(0

˚C/15kΩ. 25˚C/5.2kΩ DETECT)

TH5

COND./EVA. TEMP. THERMISTOR

(0

˚C/15kΩ. 25˚C/5.2kΩ DETECT)

C

MF

INSERT

BLU

The motor connector is

connected with 230V,240V

power at factory shipment.

If 220V power is used,

Insert the attachment.

Color/Power source

WHT/230,240V

BLU/220V

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 polarities, make

wiring matching terminal numbers (S1,S2,S3).

3.Symbols used in wiring diagram above are,

: Connector, : Terminal.

4.The wiring between MA-REMOTE CONTROLLER and TB15 is

included in the package.

REFRIGERANT SYSTEM DIAGRAM

5

8

Gas pipe

SEZ-KC25VA.W

ø 9.52<3/8>

mm<in>

Liquid pipe

ø 6.35<1/4>

Capacity

Item

Refrigerant flow in cooling
Refrigerant flow in heating

Pipe temperature
thermistor/liquid
(TH2)

Condenser/evaporator
temperature thermistor
(TH5)

Strainer (#50 mesh)

Heat exchanger

Intake air temperature thermistor TH1

Gas pipe

Flared joints

SEZ-KC25VA.W

9

6

TROUBLESHOOTING

6-1. Cautions on troubleshooting

(1) Before troubleshooting, check the followings:

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

(2) Take care the followings during servicing.

1 Before servicing the air conditioner, be sure to first turn off the remote controller 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.

˚C

˚C

SIMPLE

PAR-21MAA

ON/OFF

FILTER

CHECK

OPERATION

CLEAR

TEST

TEMP.

MENU

BACK DAY

MONITOR/SET

CLOCK

ON/OFF

B

C

A

E D

6-2. Self-check function

Wired remote controller

(1) Tur n on the power.
(2) Press the [CHECK] button twice.
(3) Set refrigerant address with [TEMP] button

if system control is used.

(4) Press the [ON/OFF] button to stop the

self-check.

AA

CHECK button

BB

Refrigerant address

CC

TEMP button

DD

IC : Indoor unit
OC : Outdoor unit

EE

Check code

1 Check code Symptom Remark
P1 Intake sensor error
P2 Pipe (TH2) sensor error
P9 Pipe (TH5) sensor error
E6,E7 Indoor/outdoor unit communication error
P4 Drain sensor error
P5 Drain pump error
P6 Freeing/Overheating safeguard operation
EE Communication error between indoor and outdoor units
P8 Pipe temperature error
E0, E3~E5 Remote controller transmission error
E1, E2 Remote controller control board error
Fb Indoor unit control system error (memory error, etc.)
E9 Indoor/outdoor unit communication error (Transmitting error) (Outdoor unit)
UP Compressor overcurrent interruption
U3,U4 Open/short of outdoor unit thermistors
UF Compressor overcurrent interruption (When compressor locked)
U2 Abnormal high discharging temperature/49C worked/insufficient refrigerant
U1,Ud Abnormal high pressure (63H worked)/Overheating safeguard operation
U5 Abnormal temperature of heat sink
U8 Outdoor unit fan safeguard stop
U6 Compressor overcurrent interruption/Abnormal of power module
U7 Abnormality of super heat due to low discharge temperature
U9,UH Abnormality such as overvoltage or voltage shortage and abnormal synchronous signal to main circuit

/Current sensor error

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
service manual OC322.

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

• For description of each check code, refer to the following table.

6-3.Test point diagram

6-3-1. Indoor power board

SEZ-KC25VA.W

10

CNSK
Connect to the indoor controller board
(CNDK)
Between

11

to 33220-240V AC

CN2S
Connect to the indoor controller board (CN2D)
Between

11

to

33

12.6-13.7V DC (Pin11(+))

11

6-3.Test point diagram

6-3-2. Indoor controller board

SEZ-KC25VA.W

FAN
Fan motor output

CNDK
Connect to the indoor
power board (CNSK)
(220~240V AC)

FUSE
(6.3A 250V)

CND
Power
supply input
(220~240V AC)

SWE
Emergency operation

SW2
Capacity setting

Jumper connector
J11~J15
Unit setting

CN2L
Connector
(LOSSNAY)

CN51
Centrally control

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

}

}

Non polarity

+

–

+

–

CN41
Connector
(HA terminal-A)

12

6-4.Trouble criterion of main parts
SEZ-KC25VA.W

Intake air temperature
thermistor (TH1)

Condenser/evaporator
temperature thermistor (TH5)

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

Pipe temperature
thermistor/liquid (TH2)

Indoor fan motor
(MF)

Check method and criterion

Part name

Normal

8kΩ~20kΩ

Abnormal

Opened or short-circuited

Measure the resistance between the terminals using a tester. (at 20˚C)

Motor terminal

or

Relay connector

Normal Abnormal

Open or short

White-Black

261

Ω

White-Brown
White-Yellow

White-Blue

294

Ω

389

Ω

475

Ω

White

Orange

Red

Black
Brown

Yellow

Blue

1
2

4
7
5

6

Protector

Relay connector

3

13

DISASSEMBLY PROCEDURE

7

7-1. CONTROL BOX

OPERATING PROCEDURE PHOTOS

1.Removing the control box cover

(1) Remove the fixing screws (two) of the control box (A), and

remove the cover. (Fig. 1)

*At this stage, the following servicing is possible.

1 Connection check of the lead wires (listed below) which

are connected to the controller board.

• Power supply (TB4) lead wire.

• Fan motor (MF) lead wire.

• Intake air sensor (TH1) lead wire

• Liquid

• Cond/Eva piping sensor (TH5) lead wire

piping sensor (TH2) lead wire

2

Control board (I.B.) exchange
3
4

Intake air sensor (TH1) exchange

Terminal block (TB4, TB15) exchange

Be careful on removing heavy parts.

fig.1

fig.2

(A)

14

7-2. FAN and FAN MOTOR

OPERATING PROCEDURE PHOTOS

Be careful on removing heavy parts.

fig.3

fig.5

1.Removing the fan casing and sirocco fan.

(1) Remove the bottom plate B. (fixing screws : six) (Fig. 3)
(2) Remove the fixing screws (three) of the fan cover, and turn

it in direction of arrow. (Fig. 4)

(3) Remove the fixing screws (two) of the fan cover , and loosen

the set screw of the sirocco fan, and remove the fan cover
and sirocco fan. (Fig. 5)

2.Removing the fan motor.

(1) Remove the control box. (fixing screws : two) (Fig. 7)
(2) Move the control box to place that is not block operation.

(Fig. 8)

(3) Remove the fan motor cable connector in the control box,

and remove the screws of the fixing plate. (Fig. 9)

fig.7

fig.9

fig.4

fig.6

fig.8

Fan cover

Bottom plate B

Set screw

Fan motor
cable connector

15

fig.10

fig.11

OPERATING PROCEDURE PHOTOS

1.Removing the drain pan.

(1) Remove the fixing screw (one) of the drain pan. (Fig. 10).
(2) Slide the drain pan in the order of arrow ①,➁,③, and remove

the drain pan. (Fig. 11)

Be careful on removing heavy parts.

7-3. DRAIN PAN

Drain pan

Drain pan

1

2

3

16

OPERATING PROCEDURE PHOTOS

(1) Remove the drainpan with procedure 7-3.
(2) Remove the bottom plate A (fixing screws : six), and remove

the plate.(Fig. 12)

(3) Remove the thermistors from the thermistor holders which

are installed on the piping.(Fig. 13)

(liquid piping : fine piping )

fig.12

fig.13

Be careful on removing heavy parts.

1.Removing the thermistors.

7-4.THERMISTOR (Liquid piping temperature detection)

Bottom plate A

Thermistor

17

7-5. HEAT EXCHANGER

OPERATING PROCEDURE PHOTOS

1.Removing the heat exchanger.

(1) Remove the drainpan with procedure 7-3.
(2) Remove the bottom plate A with procedure 7-4.
(3) Remove the heat exchanger cover.(fixing screws : four)

(Fig. 14)

(4) Remove the heat exchanger.(fixing screws : three)

(Fig. 15),(Fig. 16)

fig.14

fig15

fig.16

Be careful on removing heavy parts.

Heat exchanger cover

18

101

R61 Y85 481 Heat exchanger ass'y 1 W273547

G06
102 R61 Y18 201 Thermistor (2phase) TH5 1 W848734G11
103 R61 Y19 201 Thermistor (liquid) TH2 1 W848734G10
104 R61 Y13 661 Bottom plate A 1 W635907G02
105 R61 Y14 661

Bottom plate B 1 W877415G02
106 R61 Y10 529 Drain pan 1 W877416G01
107 R61 Y06 501 Filter 1 W634781H01
108 R61 151 326 Lifting plate 4 W398770H02

Dwg. No. Price

No.

Part No. Part Name Spec.

-KC25VA

107

108

105

106

104

101.102.103

PARTS LIST

8

EXTERNAL PARTS
SEZ-KC25VA.W

19

201

R61 Y14 140 Fan stand 1 W267214G01
202 R61 370 130 Motor support 1 W234925H06
203 R61 220 044 Rubber bush 2 W837244H01
204 R61 652 131 Fixing plate 2 W353715H01
205

R61 Y38 221

Motor P20L

CRC4417BB1ø23W<MF>

1 P714880X01

206

R61 Y16 118 Fan cover 1 W879404G03
207 R40 045 103 Sirocco fan ass'y 1 W234904G01

Dwg. No. Price

No.

Part No. Part Name Spec.

-KC25VA

BLOWER PARTS
SEZ-KC25VA.W

201

202

203

204203 205

206

207

301

R61 Y08 715 Terminal bed <3P(S1,S2,S3)> 1 P436157X01

302 R61 435 246 Terminal bed <2P(1,2)>

440V 1.5µF

Intake air

1 A73S950H02

303 R61 Y65 281 Controller board ass'y

1 P785032X01
304 R61 R92 281 Power supply board ass'y 1 P785020X01
305 R61 Y01 287 Thermistor 1 W891304G16
306 R61 Y14 252 Capacitor 1 P412234X01

Dwg. No. Price

No.

Part No. Part Name Spec.

-KC25VA

306

303

304

305

301

302

S1

1

2

S2

S3

FAN

CNDK

CND

CN3C

CN2D

CN20

CN22

20

CONTROL BOX PARTS
SEZ-KC25VA.W

21

Applied unit

SEZ-KC25VA.W

Models Pipe length

Pipe size O.D.mm (in.)

Cross-section A-Gas

9.52
(3/8)

6.35
(1/4)

27

21

B-liquid

Insulation

CD

3m
5m
7m

10m

MAC-440PI
MAC-441PI
MAC-442PI
MAC-443PI

9

OPTIONAL PARTS

9-1. REFRIGERANT PIPES

The air conditioner has flared connections.
Please use the optional extension pipe as follows.

MEE04K350
Issued in Mar. 2005
Printed in Japan

New publication, effective Mar. 2005.
Specifications subject to change without notice.

TM

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