Mitsubishi SRK25ZD-S, SRK35ZD-S, SRK50ZD-Sl Technical Manual

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3

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INVERTER WALL MOUNTED TYPE
ROOM AIR-CONDITIONER
( Split system, air to air heat pump type )

Alternative refrigerant R410A use models

SRK25ZD-S, 35ZD-S, 50ZD-S

TECHNICAL MANUAL

Collection data

Manual No. ’04

.

SRK-T

.

039

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1

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CONTENTS

1. GENERAL INFORMATION........................................................................... 1

1.1 Specific features .................................................................................... 1

1.2 How to read the model name................................................................ 1

2. SELECTION DATA........................................................................................ 2

2.1 Specifications ........................................................................................ 2

2.2 Range of usage & limitations ............................................................... 5

2.3 Exterior dimensions .............................................................................. 5

2.4 Piping system ........................................................................................ 7

2.5 Selection chart ....................................................................................... 8

3. ELECTRICAL DATA ..................................................................................... 9

3.1 Electrical wiring ..................................................................................... 9

4. OUTLINE OF OPERATION CONTROL BY MICROCOMPUTER ................11

4.1 Operation control function by remote control switch ........................11

4.2 Back-up Switch ......................................................................................12

4.3 Power blackout auto restart function...................................................12

4.4 Flap control ............................................................................................13

4.5 Comfortable timer setting .....................................................................13

4.6 Outline of heating operation.................................................................14

4.7 Outline of cooling operation.................................................................16

4.8 Outline of dehumidifying operation .....................................................17

4.9 Outline of automatic operation.............................................................19

4.10 Economical operation ...........................................................................19

4.11 Protective control function ...................................................................19

5. APPLICATION DATA ....................................................................................25

5.1 Selection of location for installation.................................................... 26

5.2 Installation of indoor unit......................................................................27

5.3 Installation of outdoor unit ...................................................................29

5.4 Refrigerant piping..................................................................................29

5.5 Test run ...................................................................................................31

5.6 Precautions for wireless remote controller installation and

operation ................................................................................................32

6. MAINTENANCE DATA..................................................................................33

6.1 Troubleshooting procedures for electrical equipment.......................33

6.2 Servicing.................................................................................................51

7. REFRIGERANT PIPING INSTALLATION/SERVICING MANUAL

FOR AIR CONDITIONERS USING R410A ..................................................52

7.1 Outline ....................................................................................................52

7.2 Refrigerant piping installation.............................................................. 53

7.3 Installation, removal and servicing ......................................................59

7.4 Refrigerant recovery..............................................................................64

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1

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Over heat of compressor

Error of signal transmission

Outdoor fan motor error

1 GENERAL INFORMATION

1.1 Specific features

The “Mitsubishi Daiya” room air-conditioner: SRK series are of split and wall mounted type and the unit consists of indoor unit and
outdoor unit with refrigerant precharged in factory. The indoor unit is composed of room air cooling or heating equipment with opera­tion control switch and the outdoor unit is composed of condensing unit with compressor.

(1) Inverter (Frequency converter) for multi-steps power control

¡ Heating/Cooling

The rotational speed of a compressor is changed in step in relation to varying load, interlocked with the indoor and outdoor unit
fans controlled to change frequency, thus controlling the capacity.

¡ Allowing quick heating/cooling operation during start-up period. Constant room temperature by fine-tuned control after the

unit has stabilized.

(2) Fuzzy control

¡ Fuzzy control calculates the amount of v ariation in the dif ference between the return air temperature and the setting temperature

in compliance with the fuzzy rules in order to control the air capacity and the inverter frequency.

(3) Remote control flap

The flap can be automatically controlled by operating wireless remote control.

¡ Air scroll (AUTO): Flap operation is automatically control.
¡ Swing: This will swing the flap up and down.
¡ Memory flap: Once the flap position is set, the unit memorizes the position and continues to operate at the same position from

the next time.

(4) Self diagnosis function

¡ We are constantly trying to do better service to our customers by installing such judges that show abnormality of operation as

follows.

Outdoor heat exchanger liquid
pipe sensor error

Discharge pipe sensor error

Outdoor temperature sensor error

2 time flash

4 time flash

RUN lamp
keeps flashing

1 time flash

OFF

OFF

OFF

Trouble of outdoor unit

Over current

Current cut

2 time flash

3 time flash

RUN lamp

ON

1 time flash

2 time flash

3 time flash

1 time flash

5 time flash 5 time flash

TIMER lamp Outdoor (LED)

R410A models
Series No.
Inverter type
Product capacity
Wall mounted type
Split type room air-conditioner

1.2 How to read the model name

Example : SR K 35 Z D - S

Room temperature sensor error

Indoor fan motor error

Heat exchanger sensor error

2 time flash

6 time flash

TIMER lamp

ON

1 time flash

RUN lamp

Rotor lock

6 time flash 6 time flash

7 time flash ON

(25, 35 type only)

2 time flash 7 time flash

RUN lamp

2 time flash

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Item

Model

SRK25ZD-S SRC25ZD-S

Cooling capacity

(1)

W 2500

Heating capacity

(1)

W 3400

Power source 1 Phase, 220/230/240V, 50Hz

Cooling input kW 0.62
Running current (Cooling) A 3.1/3.0/2.9
Heating input kW 0.94
Running current (Heating) A 4.5/4.3/4.1
Inrush current A 4.5/4.3/4.1
COP Cooling: 4.03 Heating: 3.62

Cooling

Sound level Hi 37, Me 30, Lo 22 44

Noise level

Power level

dB

53 58

Heating

Sound level Hi 39, Me 33, Lo 26 47

Power level 55 61

Exterior dimensions

Height × Width × Depth

mm

250 × 815 × 249 540 × 720 × 290

Color Cool white Stucco white
Net weight kg 9.0 32
Refrigerant equipment

Compressor type & Q’ty

– RM-B5077MD1 (Rotary type) × 1

Motor kW – 0.75

Starting method – Line starting
Heat exchanger Louver fins & inner grooved tubing
Refrigerant control Capillary tubes + Electronic expansion valve
Refrigerant

(3)

kg R410A 0.9 (Pre-Charged up to the piping length of 15m)
Refrigerant oil R 0.35 (MA68)
Deice control Microcomputer control

Air handling equipment

Fan type & Q’ty

Tangential fan × 1 Propeller fan × 1

Motor W 29 24

(Cooling) 8.0 30

Air flow (at High)

(Heating)

CMM

8.7 25

Air filter, Q’ty Polypropylene net (washable) × 2–

Shock & vibration absorber – Cushion rubber (for compressor)
Electric heater ––
Operation control

Operation switch

Wireless-Remote controller –

Room temperature control Microcomputer thermostat –
Pilot lamp RUN (Green), TIMER (Yellow), HI POWER (Green), ECONO (Orange)

Safety equipment

O.D mm (in) Liquid line: φ6.35 (1/4″) Gas line: φ9.52 (3/8″)
Connecting method Flare connecting
Attached length of piping Liquid line: 0.47 m

Gas line : 0.40 m

–

Insulation Necessary (Both sides)
Drain hose Connectable
Power source cord 2.5 m (3 cores with Earth)

Size × Core number 1.5 mm2 × 4 cores (Including earth cable)

Connection wiring

Connecting method Terminal block (Screw fixing type)
Accessories (included) Mounting kit
Optional parts –

Notes (1) The data are measured at the following conditions.

2 SELECTION DATA

2.1 Specifications

Model SRK25ZD-S (Indoor unit)

SRC25ZD-S (Outdoor unit)

Item Indoor air temperature Outdoor air temperature

Standards

Operation DB WB DB WB

Cooling 27ºC 19ºC 35ºC 24ºC ISO-T1, JIS C9612

Heating 20ºC – 7ºC 6ºC ISO-T1, JIS C9612

(2) The operation data are applied to the 220/230/240V districts respectively.
(3) The refrigerant quantity to be charged includes the refrigerant in 15 m connecting piping.

(Purging is not required even for the short piping.)

Operation data

(1)

Refrigerant

piping

Compressor overheat protection, Heating overload protection (High pressure control), Overcurrent protection,
Frost protection, Serial signal error protection, Indoor fan motor error protection, Cooling overload protection

The piping length is 7.5m.

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Item

Model

SRK35ZD-S SRC35ZD-S

Cooling capacity

(1)

W 3500

Heating capacity

(1)

W 4500

Power source 1 Phase, 220/230/240V, 50Hz

Cooling input kW 1.09
Running current (Cooling) A 5.4/5.2/5.0
Heating input kW 1.24
Running current (Heating) A 5.9/5.7/5.4
Inrush current A 5.9/5.7/5.4
COP Cooling: 3.21 Heating: 3.63

Cooling

Sound level Hi 41, Me 32, Lo 23 48

Noise level

Power level

dB

58 62

Heating

Sound level Hi 45, Me 36, Lo 27 50

Power level 59 64

Exterior dimensions

Height × Width × Depth

mm

250 × 815 × 249 540 × 720 × 290

Color Cool white Stucco white
Net weight kg 9.0 35
Refrigerant equipment

Compressor type & Q’ty

– RM-B5077MD1 [Rotary type] × 1

Motor kW – 0.90

Starting method – Line starting
Heat exchanger Louver fins & inner grooved tubing
Refrigerant control Capillary tubes + Electronic expansion valve
Refrigerant

(3)

kg R410A 1.1 (Pre-Charged up to the piping length of 15m)
Refrigerant oil R 0.35 (MA68)
Deice control Microcomputer control

Air handling equipment

Fan type & Q’ty

Tangential fan × 1 Propeller fan × 1

Motor W 29 24

(Cooling) 8.9 34

Air flow (at High)

(Heating)

CMM

10.3 34

Air filter, Q’ty

Polypropylene net (washable) × 2

–

Shock & vibration absorber – Cushion rubber (for compressor)
Electric heater ––
Operation control

Operation switch

Wireless-Remote controller –

Room temperature control Microcomputer thermostat –
Pilot lamp RUN (Green), TIMER (Yellow), HI POWER (Green), ECONO (Orange)

Safety equipment

O.D mm (in) Liquid line: φ6.35 (1/4″) Gas line: φ9.52 (3/8″)
Connecting method Flare connecting
Attached length of piping Liquid line: 0.47 m

Gas line : 0.40 m

–

Insulation Necessary (Both sides)
Drain hose Connectable
Power source cord 2.5 m (3 cores with Earth)

Size × Core number 1.5 mm2 × 4 cores (Including earth cable)

Connection wiring

Connecting method Terminal block (Screw fixing type)
Accessories (included) Mounting kit
Optional parts –

Notes (1) The data are measured at the following conditions.

Model SRK35ZD-S (Indoor unit)

SRC35ZD-S (Outdoor unit)

Item Indoor air temperature Outdoor air temperature

Standards

Operation DB WB DB WB

Cooling 27ºC 19ºC 35ºC 24ºC ISO-T1, JIS C9612

Heating 20ºC – 7ºC 6ºC ISO-T1, JIS C9612

(2) The operation data are applied to the 220/230/240V districts respectively.
(3) The refrigerant quantity to be charged includes the refrigerant in 15 m connecting piping.

(Purging is not required even for the short piping.)

Operation data

(1)

Refrigerant

piping

Compressor overheat protection, Heating overload protection (High pressure control), Overcurrent protection,
Frost protection, Serial signal error protection, Indoor fan motor error protection, Cooling overload protection

The piping length is 7.5m.

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Model SRK50ZD-S (Indoor unit)

SRC50ZD-S (Outdoor unit)

Item

Model

SRK50ZD-S SRC50ZD-S

Cooling capacity

(1)

W 5000

Heating capacity

(1)

W 6300

Power source 1 Phase, 220/230/240V, 50Hz

Cooling input kW 1.66
Running current (Cooling) A 7.6/7.3/7.0
Heating input kW 1.96
Running current (Heating) A 9.0/8.6/8.2
Inrush current A 9.0/8.6/8.2
COP Cooling: 3.01 Heating: 3.21

Cooling

Sound level Hi 48, Me 42, Lo 26 48

Noise level

Power level

dB

61 61

Heating

Sound level Hi 46, Me 40, Lo 34 49

Power level 62 64

Exterior dimensions

Height × Width × Depth

mm

250 × 815 × 249 640 × 850 × 290

Color Cool white Stucco white
Net weight kg 9.0 43
Refrigerant equipment

Compressor type & Q’ty

– 5CS102XFA [Scroll type] × 1

Motor kW – 1.5

Starting method – Line starting
Heat exchanger SLIT fin + Louver fins & inner grooved tubing
Refrigerant control Capillary tubes + Electronic expansion valve
Refrigerant

(3)

kg R410A 1.35 (Pre-Charged up to the piping length of 15m)
Refrigerant oil R 0.36 (RB68A)
Deice control Microcomputer control

Air handling equipment

Fan type & Q’ty

Tangential fan × 1 Propeller fan × 1

Motor W 29 45

(Cooling) 11.5 42

Air flow (at High)

(Heating)

CMM

13.0 42

Air filter, Q’ty

Polypropylene net (washable) × 2

–

Shock & vibration absorber – Cushion rubber (for compressor)
Electric heater ––
Operation control

Operation switch

Wireless-Remote controller –

Room temperature control Microcomputer thermostat –
Pilot lamp RUN (Green), TIMER (Yellow), HI POWER (Green), ECONO (Orange)

Safety equipment

O.D mm (in) Liquid line: φ6.35 (1/4″) Gas line: φ12.7 (1/2″)
Connecting method Flare connecting
Attached length of piping Liquid line: 0.47 m

Gas line : 0.40 m

–

Insulation Necessary (Both sides)
Drain hose Connectable
Power source cord 2.5 m (3 cores with Earth)

Size × Core number 1.5 mm2 × 4 cores (Including earth cable)

Connection wiring

Connecting method Terminal block (Screw fixing type)
Accessories (included) Mounting kit
Optional parts –

Notes (1) The data are measured at the following conditions.

Item Indoor air temperature Outdoor air temperature

Standards

Operation DB WB DB WB

Cooling 27ºC 19ºC 35ºC 24ºC ISO-T1, JIS C9612

Heating 20ºC – 7ºC 6ºC ISO-T1, JIS C9612

(2) The operation data are applied to the 220/230/240V districts respectively.
(3) The refrigerant quantity to be charged includes the refrigerant in 15 m connecting piping.

(Purging is not required even for the short piping.)
If the piping length is longer, when it is 15 to 25m, add 20 g refrigerant per meter.

Operation data

(1)

Refrigerant

piping

Compressor overheat protection, Heating overload protection (High pressure control), Overcurrent protection,
Frost protection, Serial signal error protection, Indoor fan motor error protection, Cooling overload protection

The piping length is 7.5m.

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2.2 Range of usage & limitations

2.3 Exterior dimensions

(1) Indoor unit
Models SRK25ZD-S, 35ZD-S, 50ZD-S

Indoor return air temperature
(Upper, lower limits)

Refrigerant line (one way) length Max. 15m

SRK25ZD-S, 35ZD-S SRK50ZD-S

Refer to the selection chart

Power source voltage Rating ± 10%
Voltage at starting Min. 85% of rating
Frequency of ON-OFF cycle Max. 10 times/h
ON and OFF interval Max. 3 minutes

Outdoor air temperature
(Upper, lower limits)

Vertical height difference between
outdoor unit and indoor unit

Max. 10m (Outdoor unit is higher)
Max. 10m (Outdoor unit is lower)

Max. 25m

Max. 15m (Outdoor unit is higher)
Max. 15m (Outdoor unit is lower)

Item

Models

VIEW A

117.5

580 117.5

148.5

216.5216.5

8.2

44.5

236.1

5.7

450

450

67.5

42.7

47.2

175

44.5

216.5216.5

148.5

53.5

Piping for Gas

Drain hose 540 (ø16)

Piping for Liquid 465.1 (ø6.35)

Piping hole (ø65)

Piping hole (ø65)

( )

25.35: ø9.52
50: ø12.7

397.1

45

14.5

60

788

5

60

45

815

A

250

Unit: mm

Piping hole right(left)

Terminal block

9

60

45

3

249

150

18

56

Remote controller

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6

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(2) Outdoor unit
Models SRC25ZD-S, 35ZD-S

Drain hole

286.4
12

50

290

49.6

43.5

850

203.1

510 136.9

476

Elogated hole
(2-12x16)

314

12

328

Terminal block

Service valve (Liquid)
ø6.35 (1/4'')

Service valve (Gas)
ø12.7 (1/2'')

Ground
terminal

124

34.6

20˚

20˚

42.7

100.3

15

640

14

Model SRC50ZD-S

Unit: mm

290

540

14.4

47.4 42.6

264.5

71

404.5
510

720

17.8

Drain holes

50

12

39.7

99.9

340

312.5

13.5

14

139

2-16x12

61.9

139.3 33.3
Flare connection ø6.35 (1/4")

Service valve (Liquid)

40

°

40

°

Flare connecting ø9.52 (3/8")

Service valve (Gas)

Terminal block

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2.4 Piping system

Models SRK25ZD-S, 35ZD-S

Outdoor unitIndoor unit

Room temp.
thermistor

Heat
exchanger

Flare connecting

Heat
exchanger
thermistor

Piping
(Liquid)
ø6.35

Check joint

4 way valve

Service valve (Liquid)

Flare connecting

Discharge temp.
thermistor

Cooling cycle
Heating cycle

Outdoor air
temp. thermistor

Heat
exchanger

Heat exchanger
thermistor

Compressor

Capillary tube

Strainer

Accumulator

Service valve
(Gas)

Electronic
expansion valve

Piping
(Gas)
ø9.52

Model SRK50ZD-S

Outdoor unitIndoor unit

Room temp.
thermistor

Heat
exchanger

Flare connecting

Heat
exchanger
thermistor

Piping
(Liquid)
ø6.35

Check joint

4 way valve

Service valve (Liquid)

Flare connecting

Discharge temp.
thermistor

Cooling cycle
Heating cycle

Outdoor air
temp. thermistor

Heat
exchanger

Heat exchanger
thermistor

Compressor

Capillary tube

Strainer

Strainer

Service valve
(Gas)

Capillary tube

Electronic
expansion valve

Piping
(Gas)

ø12.7

Muffler

Capillary tube

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2.5 Selection chart

Correct the cooling and heating capacity in accordance with the conditions as follows. The net cooling and heating capacity can be
obtained in the following way.

Net capacity = Capacity shown on specification ✕ Correction factors as follows.
(1) Coefficient of cooling and heating capacity in relation to temperatures

(2) Correction of cooling and heating capacity in relation to one way length of refrigerant piping

It is necessary to correct the cooling and heating capacity in relation to the one way piping length between the indoor and outdoor
units.

(3) Correction relative to frosting on outdoor heat exchanger during heating

In additions to the foregoing corrections (1), (2) the heating capacity needs to be adjusted also with respect to the frosting on the
outdoor heat exchanger.

How to obtain the cooling and heating capacity

Example : The net cooling capacity of the model SRK35ZD-S with the piping length of 15m, indoor wet-bulb temperature at 19.0˚C
and outdoor dry-bulb temperature 35˚C is Net cooling capacity = 3500 ✕ 0.975 ✕ 1.0 = 3413 W

SRK35ZD-S Length 15m

Factor by air
temperatures

15

ISO-T1 Standard ConditionOutdoor air W.B. temperature °C W.B.

010-10 -5 5

14 16 18 20 22

15

10

27
25

20
15

20

25

30

35

40

0.6

0.7

0.8

0.9

1.0

1.1

1.2

1.3

43

24

20

ISO-T1 Standard ConditionIndoor air W.B. temperature °C W.B.

Heating

Cooling

Applicable range

Coefficient of cooling &

Heating capacity in

relation to temperature

Cooling operation

Outdoor air D.B.

temperature

°C D.B.

Heating operation

Indoor air D.B.

temperature

°C D.B.

Piping length [m]

Cooling
Heating

7

1.0

1.0

10

0.99

1.0

15

0.975

1.0

20

0.965

1.0

25

0.95

1.0

Air inlet temperature of

outdoor unit in ˚C WB

Adjustment coefficient

-10

0.95-90.94-70.93-50.91-30.88-10.8610.8730.9251.00

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3 ELECTRICAL DATA

3.1 Electrical wiring

Models SRK25ZD-S, 35ZD-S

Power source
1 Phase
220/230/240V 50Hz

Outdoor unit

Indoor unit

HEAT
EXCHANGER

Printed circuit

board

Printed circuit board

BR
BL
Y/GN

BK
WH

RD

RD

1
3
4
5
6

CNU

BK

WH

Y

BL

TB TB

F2 (250V 20A)

F1
250V

3.15A

BK

WH

RD

U
V

W

BK

C2 S.IN R.IN

Re

G

WH
RD
Y/GN

N

ZNR

CNM

CNE CNG

52C3

52C

52C4

J

Th4

Th1 Th2

Th5

Th6

CNB

CNE

CNA

CND

1
2
3

NP

Power

transistor

20S

52C

EEV

FMo

DS

CM

1
2
3

( )

FM

I

SM

Display

Wireless
R-Amp

Black
Brown
Red
Blue
White
Yellow/Green

BK
BR
RD
BL
WH
Y/GN

Color symbol

Meaning of marks
Symbol

Parts name

CM

Compressor motor

F

Fuse

FM

I

F

Fan motor (Indoor)

FMo

F

an motor (Outdoor)

SM
RE

Flap motor
Reactor

Symbol

Parts name

Th

1

Room temp. thermistor

Th

2

Heat exchanger thermistor (Indoor unit)

Th

4

Heat exchanger thermistor (Outdoor unit)

Th

5

Outdoor air temp. thermistor

Th
ZNR

6

Dischar
Varistor

ge temp. thermistor

Symbol

Parts name

20S

4 way valve (coil)

52C

Magnetic contactor

DS

Diode stack

EEV

Electronic expansion valve

-

10

-

Power source
1 Phase
220/230/240V 50Hz

Outdoor unit

Indoor unit

HEAT
EXCHANGER

Printed circuit board

BR
BL
Y/GN

BK
WH

Y

OR

RD

RD
BK

WH

Y

BL

TB TB

F2 (250V 15A)

F1
250V

3.15A

BK

G3 N-1 L-1

CNO.1

WH

RD
Y/GN

N

ZNR

CNM

CNE CNG CNF

52C3

52C

52C4

J

1
2
3

52C

FMo

EEV

CM

CFo

SWITCHING

POWER
CIRCUIT

CNS

PWB1

PWB3

PWB2

1

CNG

2

N_1

N_3

P_1

P_1

RD

RD

RD

OR

OR

BK

BK

GR

N-OUT2

GR

AC.N AC.L

AF_L1

AF_L2

BL

BL

L-OUT2

U
V
W

WH
BK

DC-N

DC-P

CNJ

CNB

CND

CNN

CNG

CNH

CNH

RL

1
2
3

( )

FM

I

SM

Display

Wireless
R-Amp

Th1 Th2

Th3

Th4

Th5

Th6

20S

Power

transistor

N

P

L

N1

N2

P2

IC12

DS

L

1
3
4
5
6

CNU

Black
Brown
Red

Blue

White
Yellow/Green

BK
BR
RD

BL

Orange

OR

Green

GR

WH
Y/GN

Color symbol

Meaning of marks
Symbol

Parts name

CFo

Capacitor for FMo

CM

Compressor motor

F

Fuse

FM

I

F

Fan motor (Indoor)

FMo

F

an motor (Outdoor)

SM
RL

L

Flap motor
Inspection lamp

Inductor

Symbol

Parts name

Th

1

Room temp. thermistor

Th

2

Heat exchanger thermistor (Indoor unit)

Th

3

Humidity sensor

Th

4

Heat exchanger thermistor (Outdoor unit)

Th

5

Outdoor air temp. thermistor

Th

6

Discharge temp. thermistor

Symbol

Parts name

ZNR

Varistor

20S

4 way valve (coil)

52C

Magnetic contactor

DS

Diode stack

EEV

Electronic expansion valve

Model SRK50ZD-S

-

11

-

LO

MED

HI

AUTO

HI POWER

ECONO

ON OFF

AM PM

HI POWER

TEMP

ECONO

AIR FLOW

CANCEL

ON OFF

RESERVE

TIMER

TIME

ACL

FAN SPEED

ON

MODE

LO

MED

HI

AUTO

TIME

OFF

HI POWER

ECONO

ON OFF

AM PM

FAN SPEED button

Each time the button is pushed, the
indicator is switched over in turn.

• The above illustration shows all controls, but in practice

only the relevant parts are shown.

OPERATION MODE select button

Each time the button is pushed, the
indicator is switched over in turn.

AIR FLOW button

This button changes the flap mode. When
pressed, this button changes the mode in the
following order:

ON/OFF button

Press for starting operation, press again for
stopping.

HI POWER button

This button changes the HI POWER mode.

ECONOMY button

This button changes the ECONOMY mode.

RESET switch

Switch for resetting microcomputer.

ON TIMER button

This button selects ON TIMER operation.

Clock switch

This switch for setting the clock.

OFF TIMER button

This button selects OFF TIMER operation.

TEMPERATURE button

This button sets the room temperature.
(This button changes the present time and

TIMER time.)

CANCEL button

This button cancels the ON timer and OFF
timer.

RESERVE button

This button sets the present time and
TIMER time.

S Indication section

OPERATION MODE Indicator

Indicates selected operation with lamp.
[

(Auto) • (Cool) • (Heat) • (Dry)]

TEMPERATURE Indicator

Indicates set temperature.
(Does not indicate temperature when operation

mode is on AUTO)

FAN SPEED Indicator

Indicates set air flow rate with lamp.

AIR FLOW Indicator

Shows selected flap mode.

HI POWER MODE indicator

Indicates during Hi power mode operation.

ECONOMY MODE indicator

Indicates during economy mode operation.

ON TIMER Indicator

Indicates during ON TIMER operation.

Clock Indicator

Indicates present time or timer setting time.

OFF TIMER Indicator

Indicates OFF TIMER operation.

Models All models

Remote controller

S Operation section

4 OUTLINE OF OPERATION CONTROL BY MICROCOMPUTER

4.1 Operation control function by remote control switch

(Air scroll) (SWING)

-

12

-

Unit indication section

Models All models

4.2 Back-up switch

When the remote controller batteries become weak, or if the remote controller is lost or malfunctioning, this switch may be used to turn
the unit on and off.

(a) Operation

Push the switch once to place the unit in the automatic mode. Push it once more to turn the unit off.

(b) Details of operation

The unit will go into the automatic mode in which it automatically determines, from room temperature (as detected by sensor),
whether to go into the cooling, thermal dry or heating modes.

Function

Room temperature

Operation mode

setting

Fan speed Flap Timer switch

Cooling About 25ºC
Thermal dry About 25ºC Auto Auto Continuous
Heating About 26ºC

ON/OFF button

ECONOMY light (orange)

Illuminates during ECONOMY operation.

TIMER light (yellow)

Illuminates during TIMER operation.

HI POWER light (green)

Illuminates during HI POWER operation.

RUN (HOT KEEP) light (green)

• Illuminates during operation.

• Flashes at air flow stop due to the ‘HOT KEEP’.

4.3 Power blackout auto restart function

(1) Power blackout auto restart function is a function that records the operational status of the air-conditioner immediately prior to it

being switched off by a power cut, and then automatically resumes operations at that point after the power has been restored.

(2) The following settings will be cancelled:

(a) Timer settings
(b) High-power operations

Notes (1) The power blackout auto restart function is set at on when the air-conditioner is shipped from the

factory. Consult with your dealer if this function needs to be switched off.
(2) When power failure ocurrs, the timer setting is cancelled. Once power is resumed, reset the timer.
(3)

If the jumper wire (J7) “REMOTE/AUTORESTART” is cut, auto restart is disabled. (See the diagram at

right)

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13

-

4.4 Flap control

Control the flap by AIRFLOW button on the wireless remote control.

(1) Air scroll (AUTO)

The flap will be automatically set to the angle of air flow best to operation.

(a) Starting time of operation

(3) Swing flap

Flap moves in upward and downward directions continuously.

(b) When not operating

The flap returns to the position of air flow directly below, when operation has stopped.

(2) Memory flap

While the flap is operating if the AIRFLOW button is pushed once, it stops swinging at an angle.
As this angle is memorized in the microcomputer, the flap will be automatically set to the angle when next operation is started.
¡ Recommendable stopping angle of the flap

Corrects the starting time of next operation by
calculating the temperature difference.

(Example) Heating

Setting temperature

Room temperature

Operation starting time

Time

Setting time

15 min. 10 min. 5 min.
earlier earlier earlier

¡ If the difference (= Setting temperature – Room tempera-

ture) is 4ºC, the correction value is found to be +5 min­utes from the table shown above so that the starting time
of next operation is determined as follows:

15 min. earlier + 5 min. = 20 min. earlier

↑↑

Current operation Correction value
start time

s

During cooling and

t

dry operation

Thick line : Rapid movement
Thin line : Slow movement

Stops for approximately
5 seconds in the
horizontal position.

s

During heating

t

operation

Stops for approximately
5 seconds in this
position.

Thick line : Rapid movement
Thin line : Slow movement

Horizontal
blowing

COOL•DRY

Slant forward
blowing

HEAT

4.5 Comfortable timer setting

If the timer is set at ON when the operation select switch is set at the cooling or heating, or the cooling or heating in auto mode operation
is selected, the comfortable timer starts and determines the starting time of next operation based on the initial value of 15 minutes and the
relationship between the room temperature at the setting time (temperature of room temperature thermistor) and the setting temperature.
(Max. 60 minutes)

Operation mode Operation start time correction value (Min.)

3 < Room temp. – Setting temp. 1 < Room temp. – Setting temp. ≤ 3 Room temp. – Setting temp. ≤ 1

At cooling

+5 No change –5

3 < Setting temp. – Room temp. 2 < Setting temp. – Room temp. ≤ 3 Setting temp. – Room temp. ≤ 2

At heating

+5 No change –5

Notes (1) At 5 minutes before the timer ON time, operation starts regardless of the temperature of the room temperature thermistor (Th1).

(2) This function does not operate when in the Dry or Auto Dry mode.

However, the operation in item (1) does operate in the Auto Dry mode.

(3) During the comfortable timer operation, both the operation lamp and timer lamp illuminate and the timer lamp goes off after expiration of the timer, ON setting

time.

=

=

=

=

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14

-

(c) Hot keep operation

If the hot keep operation is selected during the heating operation, the indoor blower is controlled based on the temperature of
the indoor unit heat exchanger (detected with Th2, indoor unit heat exchanger thermistor) to prevent blowing of cool wind.

Note (1) Refer to the table shown above right for the values A and B.

¡ Normal mode (Normal heating operation, operation after HI POWER completion)

Indoor heat exchanger temp. (˚C)

¡ Values of A, B

AB
At 0 rps command 22 25
Other than 0 rps

17 19

command

AB

25·35ZD: 23°C
50ZD: 20°C

28 29.5 31.5 34 36 37.5 39 40

1st speed

3rd speed

4th speed

5th speed

6th speed

7th speed

OFF

Indoor fan

(3) Details of control at each operation mode (pattern)

(a) Fuzzy operation

Deviation between the room temperature setting correction temperature and the suction air temperature is calculated in
accordance with the fuzzy rule, and used for control of the air capacity and the inverter speed.

(b) Heating thermostat operation

¡ Operating conditions

If the speed obtained with the fuzzy calculation drops below -24 rps during the heating fuzzy operation, the operation
changes to the heating thermostat operation.

¡ Detail of operation

4.6 Outline of heating operation

(1) Operation of major functional components in heating mode

(2) Air flow selection

(a) Speed of inverter changes within the range of selected air flow.

(b) When the defrosting, protection device, etc. is actuated, operation is performed in the corresponding mode.
(c) Outdoor unit blower operates in accordance with the inverter command speed.

Model

SRK25ZD-S, 35ZD-S SRK50ZD -S

Item
Inverter speed 0rps [Comp. stopped] 10 rps [10sec.] → 0rps [Comp. stopped]
Indoor fan Hot keep normal mode → 1st speed
Outdoor fan Stop 2nd speed [1min.] → stop
Flap Horizontal

Model

SRK25ZD-S SRK35ZD-S SRK50ZD-S

Air flow selection

Inverter command speed 30~102rps 15~120rps
Air flow Depends on inverter command speed.
Inverter command speed 30~102rps 15~120rps
Air flow 8th speed fixed 6th/7th speed
Inverter command speed 30~72rps 30~76rps 15~62rps
Air flow 6th speed fixed 4th/5th speed
Inverter command speed 30~42rps 30~46rps 15~38rps
Air flow 4th speed fixed 3rd speed fixed

Auto

HI

MED

LO

Item

Indoor fan motor ON ON OFF

Flaps ON or OFF ON or OFF Stop position control

Display Lights up Lights up Lights up or flashes

52C ON ON OFF after stop mode

Outdoor fan motor

OFF (25, 35 type)

ON

OFF (25, 35 type)

Depending on the stop mode (50 type) Depending on the stop mode (50 type)

4-way valve

Depending on the stop mode

ON

Depending on the stop mode

Electronic expansion valve Depending on the EEV control

When the inverter

speed is 0rps

When the inverter speed

is other than 0rps

When the inverter speed is 0rps

due to an anomalous stop

Functional
components

(25, 35ZD only)

8th speed

(25, 35ZD only)

9th speed

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15

-

Notes (1) Refer to the table shown above right for the values A and B.

Note (2) Values in ( ) are for type 25, 35.

¡ Hot keep M mode [During HI POWER operation (for 15 min.)]

Indoor heat exchanger temp. (˚C)

A B 29 31 32 34 36 43

(40)

(43) (47)

1st speed

3rd speed

4th speed

5th speed

6th speed

7th speed

OFF

Indoor fan

(d) Defrosting operation

(i) Starting conditions (Defrosting operation can be started only when all of the following conditions are met.)

1 After start of heating operation → When it elapsed 35 minutes. (Accumulated operation time)
2 After end of defrosting operation → When it elapsed 35 minutes. (Accumulated compressor operation time)
3 Outdoor unit heat exchanger thermistor (Th4) temperature → When the temperature has been below –5ºC for 3

minutes continuously.

4 When the temperature difference between the outdoor air thermistor temperature and the outdoor unit heat exchanger

thermistor temperature exceeded 25 type: 7.0°C, 35 type: 5.0°C, 50 type: 4.0°C

5 During continuous compressor operation

In addition, when the speed command from the indoor controller of the indoor unit during heating operation has
counted 0 rps 10 times or more and all conditions of 1, 2 and 3 abov e are satisfied (note that when the temperature
for Th4 is -5°C or less: 62 rps or more, -4°C or less: less than 62 rps), defrost operation is started.

(ii) Operation of functional components during defrosting operation

¡ 25, 35 type

Indoor fan

Operation lamp

Corresponding
to speed

OFF

ON

Flashing

(Hot keep)

Outdoor fan

Inverter
command

Fuzzy calculated

value

70 rps

0

Corresponding

to speed

OFF

OFF

ON

(1)

4-way valve

Final defrost operation

Defrost control

Hot keep

Indoor unit

Outdoor unit

60 sec.

Hot keep

50 sec.

Normal heating operation restored

Defrost end

(Th4 ≥ 13˚C, 10 minutes)

Defrost operation

Defrost operation
preparation

6th speed 6th speed

¡ Values of A, B

AB
At 0 rps command 22 25
Other than 0 rps

17 19

command

8th speed

9th speed

(25, 35ZD only)

(25, 35ZD only)

Note (1) When outdoor unit heat exchanger thermistor (Th4) temperature becomes 2°C or higher, inverter command changes 70 rps to

50 rps.

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16

-

(iii) Ending conditions (Operation returns to the heating cycle when either one of the following is met.)

1 Outdoor heat exchanger thermistor (Th4) temperature: 13ºC or higher (50 type: 20°C or higher)
2 Continued operation time of defrosting → For more than 10 min.

Indoor fan

Operation lamp

Corresponding
to speed

OFF

ON

Flashing

(Hot keep)

Outdoor fan

Inverter
command

Fuzzy calculated

value

70 rps

(1)

0

Corresponding

to speed

OFF

OFF

ON

4-way valve

Final defrost operation

Defrost control

Hot keep

Indoor unit

Outdoor unit

75 sec.

Hot keep

60 sec.

Normal heating operation restored

Defrost end

(Th4≥20°C, 10 minutes)

Defrost operation

Defrost operation
preparation

2nd speed 2nd speed

(e) Heating “HI POWER” operation (HI POWER button on remote controller: ON)

Operation is maintained for 15 minutes with a higher blow out air temperature.

¡ Detail of operation

Model

SRK25, 35ZD-S SRK50ZD-S

Item
Inverter speed 102 rps 120 rps
Indoor fan Hot keep M mode (max 8th speed) Hot keep M mode (max 7th speed)
Outdoor fan 4th speed 2nd speed

Notes (1) Room temperature is not adjusted during the HI POWER operation.

(2) Protective functions will actuate with priority even during the HI POWER operation.

4.7 Outline of cooling operation

(1) Operation of major functional components in Cooling mode

¡ 50 type

Item

Indoor fan motor ON ON OFF

Flaps ON or OFF ON or OFF Stop position control

Display Lights up Lights up Lights up or flashes

52C ON ON OFF after stop mode

Outdoor fan motor

OFF (25, 35 type)

ON

OFF (25, 35 type)

Depending on the stop mode (50 type) Depending on the stop mode (50 type)

4-way valve

Depending on the stop mode

ON

Depending on the stop mode

Electronic expansion valve Depending on the EEV control

When the inverter

speed is 0rps

When the inverter speed

is other than 0rps

When the inverter speed is 0rps

due to an anomalous stop

Functional
components

Note (1) When outdoor unit heat exchanger thermistor (Th4) temperature becomes 7°C or higher, inverter instruction changes 70 rps

to 50 rps.

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17

-

(3) Detail of control in each mode (Pattern)

(a) Fuzzy operation

During the fuzzy operation, the air flow and the inv erter speed are controlled by calculating the difference between the room
temperature setting correction temperature and the suction air temperature.

(b) Cooling thermostat operation

(i) Operating conditions

During the cooling fuzzy operation or when the speed obtained by the fuzzy calculation is less than -24 rps.

(ii) Detail of operation

(2) Air flow selection

(a) Speed of inverter changes within the range of selected air flow.

(b) When any protective function actuates, the operation is performed in the mode corresponding to the function.
(c) Outdoor blower is operated in accordance with the inverter command speed.

(c) Cooling “HI POWER” operation (HI POWER button on remote controller: ON)

The unit is operated continuously for 15 minutes regardless of the setting temperature.
(i) Detail of operation

Model

SRK25, 35ZD-S SRK50ZD-S

Item
Inverter speed 0 rps [Comp. stopped] 10rps [10sec.] → 0rps [Comp. stopped]
Indoor fan Corresponds to fan speed switch.
Outdoor fan Stop 2nd speed [1min.] → stop

Notes (1) Protective functions will actuate with priority even during the “HI POWER” operation.

(2) Room temperature is not adjusted during the “HI POWER” operation

4.8 Outline of dehumidifying operation

(1) After operating the indoor blower for 20 seconds from immediately after the start of operation, the indoor temperature is checked

and, based on the result of check, the cooling oriented dehumidifying or heating oriented dehumidifying is selected.

Heating oriented dehumidifying Cooling oriented dehumidifying

Low –3 High

Room temperature - Setting temperature (deg)
Cooling or heating oriented dehumidifying is selected again one hour after the first selection of the cooling or heating oriented
dehumidifying.

Model

SRK25ZD-S SRK35ZD-S SRK50ZD-S

Item
Inverter speed 62 70 84
Indoor fan 7th speed 7th speed
Outdoor fan 4th speed 2nd speed

Model

SRK25ZD-S SRK35ZD-S SRK50ZD-S

Air flow selection

Inverter command speed 20~62rps 20~70rps 15~84rps
Air flow Depends on inverter command speed.
Inverter command speed 20~62rps 20~70rps 15~84rps
Air flow 7th speed fixed 5th~7th speed
Inverter command speed 20~52rps 20~58rps 15~60rps
Air flow 5th speed fixed 3rd~5th speed
Inverter command speed 20~34rps 20~38rps 15~30rps
Air flow 2nd speed fixed

Auto

HI

MED

LO

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18

-

D range C range B range A range

(b) Heating oriented dehumidifying

After interrupting the compressor operation for 3 minutes (by the 3-minute timer) following the determination of heating
oriented dehumidifying, the unit begins in the heating operation. If the room temperature exceeds the setting temperature by
2ºC or more, the unit checks the room temperature at 5-minute intervals and, depending on the result, determines the range of
heating oriented dehumidifying operation.

Operation range

D C B A

Low –1 0 +2 High

Room temperature – Setting temperature (deg)

(D) (C) (C) (B)

OFF

3rd speed

25 sec.

OFF

0

25, 35 type : 38

50 type : 24

25, 35 type : 50

50 type : 40

50 type :
4th speed

25, 35 type : 30

50 type : 15

5th speed

2nd speed

1st speed

50 type :
1st speed

50 type :
1st speed

50 type :
1st speed

Inverter speed

Indoor fan

Outdoor fan

Determination of cooling
oriented dehumidifying
operation range

Temperature check

5 min. 5 min. 5 min. 5 min.

Operation pattern

O L M

Low –1 0 High

Room temperature – Setting temperature (deg)

Operation range

Heating operation O range L range M range

OFF

4th speed

2nd speed

1st speed

OFF

3rd speed

50 type :
1st speed

50 type :
1st speed

50 type :
1st speed

25, 35 type : 38

50 type : 28

25, 35 type : 30

50 type : 15

25, 35 type : 48

50 type : 44

0

25 sec.

Inverter speed

Indoor fan

Outdoor fan

Determination of heating
oriented dehumidifying
operation range

Temperature check

5 min. 5 min. 5 min.

Depends on
the operation
condition

Operation pattern

Note (1) Figures in the parentheses

( ) show the values at
economical operation.

Note (1) Figures in the parentheses

( ) show the values at
economical operation.

(2) Outline of control

(a) Cooling oriented dehumidifying

Room temperature is checked at 5-minute intervals after selecting the cooling or heating oriented dehumidifying in order to
determine the operation range.

(O) (L) (L)

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19

-

4.9 Outline of automatic operation

(1) Determination of operation mode

The unit checks the room temperature and the outdoor air temperature after operating the indoor and outdoor blowers for 20
seconds, determines the operation mode and the room temperature setting correction value, and then begins in the automatic
operation.

Heating

Dehumidifying

Cooling

Room temperature (˚C)

Outdoor temperature (˚C)

27.5

25.5

19.5

18

30

(2) The unit checks the temperature every hour after the start of operation and, if the result of check is not same as the previous

operation mode, changes the operation mode.

(3) When the unit is started again within one hour after the stop of automatic operation or when the automatic operation is selected

during heating, cooling or dehumidifying operation, the unit is operated in the previous operation mode.

(4) Setting temperature can be adjusted within the following range. There is the relationship as shown below between the signals of the

wireless remote controller and the setting temperature.

Signals of wireless remote controller (Display)

–6 –5 –4 –3 –2 –1 ±0+1+2+3+4+5+6

Setting

Cooling 19 20 21 22 23 24 25 26 27 28 29 30 31

temperature

Dehumidifying 19 20 21 22 23 24 25 26 27 28 29 30 31
Heating 20 21 22 23 24 25 26 27 28 29 30 31 32

4.10 Economical operation

(ECONO button on remote controller: ON)

(1) The set temperature is raised by 1.5ºC (0.5ºC every one hour) at cooling operation and lowered by 2.5ºC (Steps of 1ºC, 1ºC and

0.5ºC every one hour) at heating operation to continue the operation with the following contents.

(2) Detail of operation

4.11 Protective control function

(1) Frost prevention for indoor heat exchanger (During cooling or dehumidifying)

(a) Operating conditions

(i) Indoor heat exchanger temperature (detected with Th2) is lower than 5ºC.
(ii) 10 minutes after reaching the inverter command speed except 0 rps.

(b) Detail of anti-frost operation

5°C or lower 2.5°C or lower

Item
Indoor command speed 20 rps (Type 50: 15 rps) 0rps

Indoor fan Depends on operation mode

25·35ZD: Max 2nd
50ZD: Max 3rd

Outdoor fan Depends on operation mode OFF
4-way valve OFF Depends on stop mode

(c) Reset conditions: 20 rps (Type 50: 15 rps) After 5 minutes of operation,

the indoor heat exchanger temperature (Th2) is 8ºC or higher.

Model

SRK25ZD-S SRK35ZD-S SRK50ZD-S

Item
Operation mode Cooling Heating Cooling Heating Cooling Heating
Inverter command speed 20~52rps 30~72rps 20~58rps 30~76rps 15~60rps 15~62rps
Indoor fan 2nd, 5th speed 4th, 6th speed 2nd, 5th speed 4th, 6th speed 3rd~5th speed 4th, 5th speed
Outdoor fan 3rd speed 1st speed

Indoor heat exchanger

temperature

Indoor heat exchanger

temperature (°C)

2.5 5 8

0 rps

20 rps

(Type 50: 15rps)

Inverter

command

speed