Mitsubishi Heavy Industries SRK20HD-S User manual

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3
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WALL MOUNTED TYPE
ROOM AIR-CONDITIONER
(Split system, air to air heat pump type)
SRK20HD-S, SRK28HD-S, SRK40HD-S
(Split system, air cooled cooling only type)
SRK20CD-S, SRK28CD-S, SRK40CD-S
TECHNICAL MANUAL
Collection data
Manual No. ’04
.
SRK-T
.
040

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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 .................................................................. 8
2.3 Exterior dimensions ................................................................................. 8
2.4 Piping system ........................................................................................... 10
2.5 Selection chart .......................................................................................... 11
3. ELECTRICAL DATA ........................................................................................ 12
3.1 Electrical wiring ........................................................................................ 12
4. OUTLINE OF OPERATION CONTROL BY MICROCOMPUTER ................... 14
4.1 Operation control function by remote control switch........................... 14
4.2 Back-up switch ......................................................................................... 15
4.3 Power blackout auto restart function...................................................... 15
4.4 Flap control ............................................................................................... 16
4.5 Comfortable timer setting ........................................................................ 16
4.6 Outline of heating operation.................................................................... 17
4.7 Outline of cooling operation.................................................................... 20
4.8 Outline of dehumidifying operation ........................................................ 21
4.9 Automatic operation................................................................................. 22
4.10 Outline of fan operation ........................................................................... 22
4.11 Protective control function ...................................................................... 23
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 Trouble shooting....................................................................................... 33
6.2 Servicing.................................................................................................... 38

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1
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Serial signal transmission 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 opera-
tion control switch and the outdoor unit is composed of condensing unit with compressor.
(1) Remote control flap
The flap can be automatically controlled by operating wireless remote controller.
¡Air scroll: 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.
(2) Automatic Operation
When the remote control switch is set on “auto( )”, it will either automatically decide operation mode such as cooling, heating
and thermal dry, or operate in the operation mode before it has been turned to automatic control.
(3) 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.
1.2 How to read the model name
Example : SR K 40 H D - S
Room temperature thermistor error
Indoor fan motor error
Heat exchanger thermistor error
2 time flash
6 time flash
TIMER lamp
ON
1 time flash
Outdoor unit heat exchanger
thermistor error
Discharge pipe thermistor error
Outdoor temperature thermistor
error
2 time flash
4 time flash
RUN lamp
keeps flashing
1 time flash
OFF
OFF
OFF
Outdoor unit error
Compressor overheat
Current cut
2 time flash
5 time flash
RUN lamp
ON
1 time flash
2 time flash
5 time flash
1 time flash
6 time flash 6 time flash
RUN lamp TIMER lamp Outdoor (LED)
R410A models
Series No.
H: Heat pump type
C: Cooling only type
Product capacity
Wall mounted type
Split type room air-conditioner

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Item Model SRK20HD-S SRC20HD-S
Cooling capacity(1) W 2050
Heating capacity(1) W 2200
Power source 1 Phase, 220/230/240V, 50Hz
Cooling input kW 0.63
Running current (Cooling) A 3.1/3.0/2.9
Heating input kW 0.6
Running current (Heating) A 3.0/2.9/2.8
Inrush current A 18.9
COP Cooling: 3.21 Heating: 3.61
Cooling sound level Hi 34, Me 28, Lo 26 46
Noise level Power level dB 52 60
Heating sound level Hi 34, Me 31, Lo 27 46
Power level 52 60
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-B5077MNE4 (Rotary type) ×1
Motor kW –0.65
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 R0.35 (MA68)
Deice control MC control
Air handling equipment
Fan type & Q’ty Tangential fan ×1 Propeller fan ×1
Motor W 14 12
(Cooling) 7.5 26
Air flow (at High) (Heating) CMM 7.5 26
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 MC. 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: 0.4 m
Gas line : 0.33 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 SRK20HD-S (Indoor unit)
SRC20HD-S (Outdoor unit)
Item Indoor air temperature Outdoor air temperature Standards
Operation DB WB DB WB
Cooling 27ºC 19ºC 35ºC24ºC ISO-T1, JIS C9612
Heating 20ºC–7ºC6ºC 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 in the short piping.)
Operation data
(1)
Refrigerant
piping
Compressor: Overheat protection, overcurrent protection, Serial signal error protection, Indoor fan mo-
tor error protection, Frost protection
The piping length is 7.5m.

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Item Model SRK28HD-S SRC28HD-S
Cooling capacity(1) W 2550
Heating capacity(1) W 2800
Power source 1 Phase, 220/230/240V, 50Hz
Cooling input kW 0.79
Running current (Cooling) A 3.9/3.7/3.5
Heating input kW 0.77
Running current (Heating) A 3.7/3.5/3.3
Inrush current A 17.2
COP Cooling: 3.21 Heating: 3.61
Cooling sound level Hi 39, Me 33, Lo 30 46
Noise level Power level dB 55 60
Heating sound level Hi 40, Me 33, Lo 29 46
Power level 56 60
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 –5PS102DAB [Rotary type] ×1
Motor kW –0.7
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 R0.35 (RB68A)
Deice control MC control
Air handling equipment
Fan type & Q’ty Tangential fan ×1 Propeller fan ×1
Motor W 14 15
(Cooling) 8.0 30
Air flow (at High) (Heating) CMM 8.5 30
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 MC. 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: 0.4 m
Gas line : 0.33 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 SRK28HD-S (Indoor unit)
SRC28HD-S (Outdoor unit)
Item Indoor air temperature Outdoor air temperature Standards
Operation DB WB DB WB
Cooling 27ºC 19ºC 35ºC24ºC ISO-T1, JIS C9612
Heating 20ºC–7ºC6ºC 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 in the short piping.)
Operation data
(1)
Refrigerant
piping
Compressor: Overheat protection, overcurrent protection, Serial signal error protection, Indoor fan
motor error protection, Frost protection
The piping length is 7.5m.

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Model SRK40HD-S (Indoor unit)
SRC40HD-S (Outdoor unit)
Item Model SRK40HD-S SRC40HD-S
Cooling capacity(1) W 3600
Heating capacity(1) W 4000
Power source 1 Phase, 220/230/240V, 50Hz
Cooling input kW 1.12
Running current (Cooling) A 5.3/5.1/4.9
Heating input kW 1.16
Running current (Heating) A 5.5/5.3/5.1
Inrush current A 25.2
COP Cooling: 3.21 Heating: 3.42
Cooling sound level Hi 40, Me 38, Lo 34 49
Noise level Power level dB 56 63
Heating sound level Hi 41, Me 38, Lo 34 50
Power level 57 64
Exterior dimensions
Height ×Width ×Depth mm 250 ×815 ×249 640 ×850 ×290
Color Cool white Stucco white
Net weight kg 9.0 41
Refrigerant equipment
Compressor type & Q’ty –5KS150DBB [Rotary type] ×1
Motor kW –1.1
Starting method –Line starting
Heat exchanger Louver fins & inner grooved tubing
Refrigerant control Capillary tubes + Electronic expansion valve
Refrigerant(3) kg R410A 1.17 (Pre-Charged up to the piping length of 15m)
Refrigerant oil R0.43 (RB68A)
Deice control MC control
Air handling equipment
Fan type & Q’ty Tangential fan ×1 Propeller fan ×1
Motor W 14 35
(Cooling) 9.0 38
Air flow (at High) (Heating) CMM 9.5 38
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 MC. 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: 0.4 m
Gas line : 0.33 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 35ºC24ºC ISO-T1, JIS C9612
Heating 20ºC–7ºC6ºC 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 in the short piping.)
Operation data
(1)
Refrigerant
piping
Compressor: Overheat protection, overcurrent protection, Serial signal error protection, Indoor fan
motor error protection, Frost protection
The piping length is 7.5m.

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Item Model SRK20CD-S SRC20CD-S
Cooling capacity(1) W 2050
Power source 1 Phase, 220/230/240V, 50Hz
Cooling input kW 0.63
Running current (Cooling) A 3.1/3.0/2.9
Inrush current A 18.9
COP Cooling: 3.21
Cooling sound level Hi 34, Me 28, Lo 26 46
Noise level Power level dB 52 60
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-B5077MNE4 (Rotary type) ×1
Motor kW –0.65
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 R0.35 (MA68)
Deice control MC control
Air handling equipment
Fan type & Q’ty Tangential fan ×1 Propeller fan ×1
Motor W 14 12
Air flow (at High) (Cooling) CMM 7.5 26
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 MC. 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: 0.4 m
Gas line : 0.33 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 SRK20CD-S (Indoor unit)
SRC20CD-S (Outdoor unit)
Item Indoor air temperature Outdoor air temperature Standards
Operation DB WB DB WB
Cooling 27ºC 19ºC 35ºC24ºC 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 in the short piping.)
Operation data
(1)
Refrigerant
piping
Compressor: Overheat protection, overcurrent protection, Serial signal error protection, Indoor fan mo-
tor error protection, Frost protection
The piping length is 7.5m.

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Item Model SRK28CD-S SRC28CD-S
Cooling capacity(1) W 2550
Power source 1 Phase, 220/230/240V, 50Hz
Cooling input kW 0.79
Running current (Cooling) A 3.9/3.7/3.5
Inrush current A 17.2
COP Cooling: 3.21
Cooling sound level Hi 39, Me 33, Lo 30 46
Noise level Power level dB 55 60
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 –5PS102DAB [Rotary type] ×1
Motor kW –0.7
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 R0.35 (RB68A)
Deice control MC control
Air handling equipment
Fan type & Q’ty Tangential fan ×1 Propeller fan ×1
Motor W 14 15
Air flow (at High) (Cooling) CMM 8.0 30
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 MC. 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: 0.4 m
Gas line : 0.33 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 SRK28CD-S (Indoor unit)
SRC28CD-S (Outdoor unit)
Item Indoor air temperature Outdoor air temperature Standards
Operation DB WB DB WB
Cooling 27ºC 19ºC 35ºC24ºC 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 in the short piping.)
Operation data
(1)
Refrigerant
piping
Compressor: Overheat protection, overcurrent protection, Serial signal error protection, Indoor fan
motor error protection, Frost protection
The piping length is 7.5m.

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Item Model SRK40CD-S SRC40CD-S
Cooling capacity(1) W 3600
Power source 1 Phase, 220/230/240V, 50Hz
Cooling input kW 1.12
Running current (Cooling) A 5.3/5.1/4.9
Inrush current A 25.2
COP Cooling: 3.21
Cooling sound level Hi 40, Me 38, Lo 34 49
Noise level Power level dB 56 63
Exterior dimensions
Height ×Width ×Depth mm 250 ×815 ×249 640 ×850 ×290
Color Cool white Stucco white
Net weight kg 9.0 41
Refrigerant equipment
Compressor type & Q’ty –5KS150DBB [Rotary type] ×1
Motor kW –1.1
Starting method –Line starting
Heat exchanger Louver fins & inner grooved tubing
Refrigerant control Capillary tubes + Electronic expansion valve
Refrigerant(3) kg R410A 1.17 (Pre-Charged up to the piping length of 15m)
Refrigerant oil R0.43 (RB68A)
Deice control MC control
Air handling equipment
Fan type & Q’ty Tangential fan ×1 Propeller fan ×1
Motor W 14 35
Air flow (at High) (Cooling) CMM 9.0 38
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 MC. 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: 0.4 m
Gas line : 0.33 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 SRK40CD-S (Indoor unit)
SRC40CD-S (Outdoor unit)
Item Indoor air temperature Outdoor air temperature Standards
Operation DB WB DB WB
Cooling 27ºC 19ºC 35ºC24ºC 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 in the short piping.)
Operation data
(1)
Refrigerant
piping
Compressor: Overheat protection, overcurrent protection, Serial signal error protection, Indoor fan
motor error protection, Frost protection
The piping length is 7.5m.

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2.2 Range of usage & limitations
2.3 Exterior dimensions
Indoor return air temperature
(Upper, lower limits)
Refrigerant line (one way) length Max. 15m
All models
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)
Item
Models
(1) Indoor unit
Models All 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)
( )
20.28:ø9.52
40:ø12.7 397.1
45
14.5
60
788
560
45
815
A
250
Unit: mm
Piping hole right(left)
Terminal block
960
45
3
249

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(2) Outdoor unit
Models SRC20HD-S, 28HD-S, 20CD-S, 28CD-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 (Liquide)
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
Models SRC40HD-S, 40CD-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 connecting 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 SRK20HD-S, 28HD-S, 40HD-S
Models SRK20CD-S, 28CD-S
Model SRK40CD-S
Outdoor unitIndoor unit
Heat
exchanger
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
thermistor
Compressor
Capillary tube
Strainer
Accumulator
Service valve
(Gas)
Capillary tube
Electronic
expansion valve
( )
Piping
(Gas)
20, 28 : ø9.52
40 : ø12.7
Outdoor unitIndoor unit
Room temp.
thermistor
Heat
exchanger
Flare connecting
Heat
exchanger
thermistor
Piping
(Liquid)
ø6.35
Check joint
Service valve (Liquid)
Flare connecting
Discharge temp.
thermistor
Cooling cycle Outdoor air
temp. thermistor
Heat
exchanger
Heat exchanger
thermistor
Compressor
Capillary tube
Strainer
Accumulator
Service valve
(Gas)
Capillary tube
Electronic
expansion valve
Piping
(Gas)
ø9.52
Outdoor unitIndoor unit
Room temp.
thermistor
Heat
exchanger
Flare connecting
Heat
exchanger
thermistor
Piping
(Liquid)
ø6.35
Check joint
Service valve (Liquid)
Flare connecting
Discharge temp.
thermistor
Cooling cycle Outdoor air
temp. thermistor
Heat
exchanger
Heat exchanger
thermistor
Compressor
Capillary tube
Accumulator
Service valve
(Gas)
Electronic
expansion valve
Piping
(Gas)
ø12.7

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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 SRK40HD-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 = 3600 ✕0.975 ✕1.0 =3510 w
SRK40HD-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
Air inlet temperature of
outdoor unit in ˚CWB
Adjustment coefficient
-10
0.95
-9
0.94
-7
0.93
-5
0.91
-3
0.88
-1
0.86
1
0.87
3
0.92
5
1.00

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12
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3 ELECTRICAL DATA 3.1 Electrical wiring
Models SRK20HD-S, 28HD-S, 40HD-S
Power source
1 Phase
220/230/240V 50Hz
Outdoor unit
Indoor unit
LB
CNW
CF I
WH
HEAT
EXCHANGER
CNM
CNU
CNC
Tr
F
(250V 3.15A)
52C-3
52C
52C
Printed circuit
board
Printed circuit
board
1
1
1
5
3
3
52X1
CFO
52X2
52X3
52X3
52X2
52X1
52C-4
N
ZNR
IC8
3
5
1
WH
2/N
3
Y/GN
SM
FM
I
FMo
CM
20S
EEV
LB
BR
BK
RD
Y/GN
RD
WH
BR
TB TB
RD
J
Y/GN
G
LNJ
F
(250V 3.15A)
ZNR
BK
BK
2 51C
3
1
CM1
CM2
WH
WH
WH
CC
RD
RD
Y/GN
G1
D.S
BR BK
CNB
CNE CNG
Th1 Th2
CNG
Th4
Th5
Th6
CNE
CNB
CNU
Display
Wireless
R-Amp
1
2
3
Black
Brown
Red
Light blue
White
Yellow/Green
BK
BR
RD
LB
WH
Y/GN
Color symbol
Meaning of marks
Symbol Parts name
CF I
Capacitor for FM
I
CM Compressor motor
FFuse
FM
I
Fan motor (Indoor)
FMo Fan motor (Outdoor)
SM Flap motor
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
6
Discharge temp. thermistor
Tr Transformer
Symbol Parts name
ZNR Varistor
20S 4 way valve (coil)
52C Magnetic contactor
DS Diode stack
52X
1-3 Auxiliary relay
EEV Electronic expansion valve
51C Motor Protector for CM

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13
-
Power source
1 Phase
220/230/240V 50Hz Outdoor unit
Indoor unit
LB
CNW
CF I
WH
HEAT
EXCHANGER
CNM
CNU
CNC
Tr
F
(250V 3.15A)
52C-3
52C
52C
Printed circuit
board
Printed circuit
board
1
1
5
3
52X1
CFO
52X2
52X2
52X1
52C-4
N
ZNR
IC8
3
5
1
WH
2/N
3
Y/GN
SM
FM
I
FMo
CM
EEV
LB
BR
BK
RD
Y/GN
RD
WH
BR
TB TB
RD
J
Y/GN
G
LNJ
F
(250V 3.15A)
ZNR
BK
BK
2 51C
3
1
CM1
CM2
WH
WH
WH
CC
RD
RD
Y/GN
G1
D.S
BR BK
CNB
CNE CNG
Th1 Th2
CNG
Th4
Th5
Th6
CNE
CNU
Display
Wireless
R-Amp
1
2
3
Black
Brown
Red
Light blue
White
Yellow/Green
BK
BR
RD
LB
WH
Y/GN
Color symbol
Meaning of marks
Symbol Parts name
CF I
Capacitor for FM
I
CM Compressor motor
FFuse
FM
I
Fan motor (Indoor)
FMo Fan motor (Outdoor)
SM Flap motor
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
6
Discharge temp. thermistor
Tr Transformer
Symbol Parts name
ZNR Varistor
52C Magnetic contactor
DS Diode stack
52X
1-2 Auxiliary relay
EEV Electronic expansion valve
51C Motor Protector for CM
Models SRK20CD-S, 28CD-S, 40CD-S

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14
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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 indi-
cator 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 indi-
cator 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.
SIndication section
OPERATION MODE Indicator
Indicates selected operation with lamp.
Heat pump type:
[ (Auto) •(Cool) •(Heat) •(Dry)]
Cooling only type:
[ (Auto) •(Cool) •(Fan) •(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 during OFF TIMER operation.
Models All models
Remote controller
SOperation section
(Air scroll) (SWING)
4 OUTLINE OF OPERATION CONTROL BY MICROCOMPUTER
4.1 Operation control function by remote control switch

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15
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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
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)
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’.
(Heat pump type only)

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16
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4.4 Flap control
Control the flap by AIRFLOW button on the wireless remote controller.
(1) Air scroll
The flap will be automatically set to the angle of air flow best to operation.
(a) Starting time of operation
(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
(3) Swing flap
Flap moves in upward and downward directions continuously.
sDuring cooling andt
dry operation
Thick line : Rapid movement
Thin line : Slow movement
Stops for approximately
5 seconds in the
horizontal position.
sDuring 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
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 min-
utes 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
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 actuate when the operation select switch is set at the dehumidifying as well as the dehumidifying in the auto mode.
However, the operation of item (1) above is performed during the dehumidifying in the auto 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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17
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4.6 Outline of heating operation (Heat pump type only)
(1) Operation of major functional components
(2) Fan speed switching
(a) Auto fan control
The indoor fan is automatically controlled in accordance with the difference between the room temperature (detected by the
room temperature thermistor) and the thermostat setting as shown below.
(3) Thermostat operation
The compressor and outdoor fan and turned on and off as shown below according to the temperature setting.
(4) Hot keep
This function controls the indoor unit fan speed as shown below in accordance with the temperature sensed by the indoor heat
exchanger thermistor.
(a) When the compressor and outdoor unit fan are operating
Indoor fan motor
Flaps
Display
52C
Outdoor fan motor
ON
ON or OFF
Lights up
ON
OFF
ON
ON or OFF
Lights up
ON
ON
OFF
Stop position control
Lights up or flashes
OFF after stop mode
OFF
4-way valve Depending on the stop mode ON Depending on the stop mode
When the compressor
command is OFF When the compressor command is ON When the compressor goes
OFF due to an abnormal stop.
Functional
components
Item
Air scroll
Swing flap
Swing stop
Auto fan control
Speed 6
Speed 6
Speed 6
Speed 4
Speed 4
Speed 4
AUTO HIGH MED
Speed 2
Speed 2
Speed 2
LOW
Flow control
Fan speed switching
Speed 6
Speed 4
Speed 2
Thermostat setting point
-5 -4 -3 -2 -1 0
OFF
ON
Set temp.
Compressor
outdoor fan
+1
Room temp.
Speed 6
Speed 4
Speed 2
Speed 1
OFF
34
40
43
30
34
37
25
30
30
20
25
25
15
15
20
Model : 20
Model : 28
Model : 40
Auto fan control,
or the set fan speed
Indoor heat exchanger temp. (˚C)

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18
-
(c) To accomplish rapid recovery from the thermostat off state, after the compressor and outdoor unit’s fan go OFF, the set
temperature is raised by 1ºC until 1 minute passes after the hot keep end temperature has been reached following restarting.
(5) Hot Spurt
(a) For 40 minutes after a heating operation begins, the system runs with set temperature raised by 2ºC.
(b) In the following cases, this function is canceled and does not activate afterwards.
1) When the compressor and outdoor unit fan have been turned OFF by the thermostat going off.
2) During high pressure control operation.
(6) High Power Operation (“HI POWER”button on the remote controller : ON)
The system runs under the following conditions for 15 minutes without relation to the set temperature or the fan speed setting.
(7) Defrost Operation
(a) Starting conditions (Defrost operation begins when all the following conditions are satisfied.)
140 minutes have passed since the heating operation began. (Accumulated operation time)
240 minutes have passed since the previous defrosting operation ended. (Accumulated operation time)
3The outdoor unit heat exchanger thermistor temperature is –5ºC or lower continuously for 3 minutes.
4The difference between the outdoor temperature thermistor temperature and the outdoor heat exchange thermistor tem-
perature is =
>4.5ºC.
5The compressor is running.
Also, the number of times the compressor goes OFF is counted, and when it reaches 10 or more times, if the conditions
in 1, 2and 3above (except that the outdoor heat exchanger thermistor temperature is –1ºC), the defroster operation
starts.
(b) End conditions (when either of the following conditions is satisfied)
1Outdoor heat exchanger thermistor temperature: 9ºC or higher
2Defrosting operation has continued for 10 minutes.
Notes (1) Room temperature is not adjusted during the HI POWER operation.
(2) Protective function will actuate with priority even during the HI POWER operation.
Speed 6
Speed 4
Speed 2Speed 2
OFF
34
40
43
30
34
37
25
30
30
Model : 20
Model : 28
Model : 40
Auto fan control,
or the set fan speed
Indoor unit fan
Outdoor unit fan
Compressor
Speed 6 fixed
ON
ON
(b) When the compressor and outdoor fan are stopped
1) While the compressor operation is delayed. 2) Up until 5 minutes have passed
since the end of a compressor
start delay operation, when 52C
goes OFF, the indoor unit’s fan
speed changes forcibly from
OFF to speed 1.
Indoor heat exchanger temp. (˚C)