Mitsubishi Electric SUZ-KA25VA4 User manual

TECHNICAL & SERVICE MANUAL
No.OCH545
SPLIT-TYPE, HEAT PUMP AIR CONDITIONERS
R410A
Outdoor unit
[Model Name] [Service Ref.]
SUZ-KA25VA4 SUZ-KA25VA4.TH
SUZ-KA35VA4 SUZ-KA35VA4.TH
SUZ-KA50VA4 SUZ-KA50VA4.TH
SUZ-KA60VA4 SUZ-KA60VA4.TH
SUZ-KA71VA4 SUZ-KA71VA4.TH
CONTENTS
1. COMBINATION OF INDOOR AND OUTDOOR UNITS
..... 2
2. TECHNICAL CHANGES ................................... 3
3. PARTS NAMES AND FUNCTIONS .................. 7
4. SPECIFICATION................................................ 8
5. NOISE CRITERIA CURVES............................ 10
6. OUTLINES AND DIMENSIONS .......................11
7. WIRING DIAGRAM.......................................... 13
8. REFRIGERANT SYSTEM DIAGRAM............. 16
9. ACTUATOR CONTROL................................... 19
10. SERVICE FUNCTIONS.................................... 20
11. TROUBLESHOOTING..................................... 20
12. DISASSEMBLY INSTRUCTIONS.................... 36
Indication of
model name
Note:
• This service manual
describes technical data of
the outdoor units.
HFC
utilized
R410A
SUZ-KA25VA4.TH
SUZ-KA35VA4.TH
August 2013
PARTS CATALOG (OCB545)

2
1COMBINATION OF INDOOR AND OUTDOOR UNITS
Heat pump type
Outdoor unit
SUZ-
SLZ-KA25VAL2.TH
SLZ-KA35VALR3.TH
SLZ-KA50VALR3.TH
SLZ-KA25VAQ2.TH
SLZ-KA35VAQR2.TH
SLZ-KA50VAQR2.TH
SEZ-KD25VA(L)R2.TH
SEZ-KD35VA(L)R2.TH
SEZ-KD50VA(L)R2.TH
SEZ-KD60VA(L)R2.TH
SEZ-KD71VA(L)R2.TH
SEZ-KD25VAQR2.TH
SEZ-KD35VAQR2.TH
SEZ-KD50VAQR2.TH
SEZ-KD60VAQR2.TH
SEZ-KD71VAQR2.TH
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—
—
—
—
—
—
—
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—
—
—
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—
—
—
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—
—
—
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—
—
—
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—
—
—
—
—
—
—
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OC320
OCH493
Indoor unit
Service
Manual No.
Service Ref.
Heat pump without electric heater
KA25VA4.TH KA60VA4.TH KA71A4.THKA50VA4.TH
HWE0711
BWE102050
BWE102040
HWE1008
KA35VA4.TH
Note: Please refer to the service manual of indoor unit or the technical data book for the combination data.
INDOOR UNIT SERVICE MANUAL
OCH545

3
2TECHNICAL CHANGES
Refrigerant
oil
Refrigerant
New refrigerant
R410A
HFC-32: HFC-125 (50%:50%)
Pseudo-azeotropic refrigerant
Not included
A1/A1
72.6
-51.4
1.557
64
Non combustible
0
1730
From liquid phase in cylinder
Possible
Incompatible oil
None
None
Previous refrigerant
R22
R22 (100%)
Single refrigerant
Included
A1
86.5
-40.8
0.94
44.4
Non combustible
0.055
1700
Gas phase
Possible
Compatible oil
Light yellow
None
Refrigerant
Composition (Ratio)
Refrigerant handling
Chlorine
Safety group (ASHRAE)
Molecular weight
Boiling point (°C)
Steam pressure [25°C](Mpa)
Saturated steam density [25°C](Kg/*)
Combustibility
ODP *1
GWP *2
Refrigerant charge method
Additional charge on leakage
Kind
Color
Smell
*1: Ozone Depletion Potential : based on CFC-11
*2: Global Warming Potential : based on CO2
INFORMATION FOR THE AIR CONDITIONER WITH R410A REFRIGERANT
• This room air conditioner adopts an HFC refrigerant (R410A) which never destroys the ozone layer.
• Pay particular attention to the following points, though the basic installation procedure is same as that for R22 conditioners.
As R410A has working pressure approximate 1.6 times as high as that of R22, some special tools and piping parts/materi-
als are required. Refer to the table below.
Take sufficient care not to allow water and other contaminations to enter the R410A refrigerant during storage and installa-
tion, since it is more susceptible to contaminations than R22.
For refrigerant piping, use clean, pressure-proof parts/materials specifically designed for R410A. (Refer to 2. Refrigerant
piping.)
Composition change may occur in R410A since it is a mixed refrigerant. When charging, charge liquid refrigerant to prevent
composition change.
NOTE : The unit of pressure has been changed to MPa on the international system of units (SI unit system).
The conversion factor is: 1 (MPa [Gauge]) =10.2 (kgf/cm2[Gauge])
New Specification Current Specification
The incompatible refrigerant oil easily separates from
refrigerant and is in the upper layer inside the suction muffler.
Raising position of the oil back hole enables to back the
refrigerant oil of the upper layer to flow back to the
compressor.
Since refrigerant and refrigerant oil are compatible with
each other, refrigerant oil backs to the compressor through
the lower position oil back hole.
Compressor
Suction muffler
Oil back hole
Refrigerant oil
Refrigerant
Compressor
Suction muffler
Oil back hole
Refrigerant oil /Refrigerant
Compressor
OCH545

4
R410A tools Can R22 tools be used?
Gas leak detector
R410A has high pressures beyond the measurement range of existing
gauges. Port diameters have been changed to prevent any other refrigerant
from being charged into the unit.
Hose material and cap size have been changed to improve the pressure
resistance.
Dedicated for HFC refrigerant.
6.35 mm and 9.52 mm
Description
Clamp bar hole has been enlarged to reinforce the spring strength in the tool.
Provided for flaring work (to be used with R22 flare tool).
Provided to prevent the back flow of oil. This adapter enables you to use
vacuum pumps.
It is difficult to measure R410A with a charging cylinder because the
refrigerant bubbles due to high pressure and high-speed vaporization
No
No
No
Yes
Yes
New
New
New
Gauge manifold
Charge hose
Torque wrench
Flare tool
Flare gauge
Vacuum pump
adapter
Electronic scale for
refrigerant charging
No: Not substitutable for R410A Yes: Substitutable for R410A
No 12.7 mm and 15.88 mm
1. Tools dedicated for the air conditioner with R410A refrigerant
The following tools are required for R410A refrigerant. Some R22 tools can be substituted for R410A tools.
The diameter of the service port on the stop valve in outdoor unit has been changed to prevent any other refrigerant being
charged into the unit. Cap size has been changed from 7/16 UNF with 20 threads to 1/2 UNF with 20 threads.
-30 -20 -10 0 10 20 30 40 50 60
-0.5
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
(MPa [Gauge])
R410A
R22
Conversion chart of refrigerant temperature and pressure
Saturated liquid pressure
()
NOTE: The unit of pressure has been changed to MPa on the
international system of units (SI unit system).
The conversion factor is: 1 (MPa [Gauge]) =10.2 (kgf/cm2[Gauge])
OCH545

5
Electronic scale for refrigerant charging
Outdoor unit
Refrigerant gas
cylinder
operating valve
Refrigerant gas cylinder
for R410A with siphon
Refrigerant (liquid)
Service port
Gauge manifold
valve (for R410A)
Union
Liquid pipe
Gas pipe
Stop valve
Indoor unit
Charge hose (for R410A)
R410A
Pipe diameter (mm)
6.35
9.52
12.7
15.88
17
22
26
29
Dimension of flare nut (mm)
R22
17
22
24
27
• Use a copper pipe or a copper-alloy seamless pipe with a thickness of 0.8 mm. Never use any pipe with a thickness less
than 0.8mm, as the pressure resistance is insufficient.
Flaring work and flare nut
Flaring work for R410A pipe differs from that for R22 pipe.
For details of flaring work, refer to Installation manual “FLARING WORK”.
3. Refrigerant oil
Apply the special refrigerant oil (accessories: packed with indoor unit) to the flare and the union seat surfaces.
4. Air purge
Do not discharge the refrigerant into the atmosphere.
Take care not to discharge refrigerant into the atmosphere during installation, reinstallation, or repairs to the refrigerant
circuit.
Use the vacuum pump for air purging for the purpose of environmental protection.
5. Additional charge
For additional charging, charge the refrigerant from liquid phase of the gas cylinder.
If the refrigerant is charged from the gas phase, composition change may occur in the refrigerant inside the cylinder and
the outdoor unit. In this case, ability of the refrigerating cycle decreases or normal operation can be impossible. However,
charging the liquid refrigerant all at once may cause the compressor to be locked. Thus, charge the refrigerant slowly.
2. Refrigerant piping
Specifications
Use the refrigerant pipes that meet the following specifications.
Wall thicknessOutside diameter
Pipe mm mm
For liquid
For gas
6.35
9.52
9.52
12.7
15.88
0.8
0.8
0.8
0.8
1.0
Heat resisting foam plastic
Specific gravity 0.045
Thickness 8 mm
Insulation material
OCH545

6
6. Pumping Down
When relocating or disposing of the air conditioner, pump down the system by following the procedure below so that no
refrigerant is released into the atmosphere.
1 Turn off the power supply (circuit breaker).
2Connect the gauge manifold valve to the service port of the stop valve on the gas pipe side of the outdoor unit.
3Fully close the stop valve on the liquid pipe side of the outdoor unit.
4Supply power (circuit breaker).
5 Perform the refrigerant collecting operation (cooling test run).
• For the PAR-31MAA, select “Service” “TestRun” from the main menu to start the test run, and then select the cooling
mode.
• For details or for other information about starting the test run when using remote controllers, refer to the installation manual
for the indoor unit or the remote controller.
6 Fully close the stop valve on the gas pipe side of the outdoor unit when the pressure gauge shows 0.05 to 0 MPa [Gauge]
(approx. 0.5 to 0 kgf/cm²) and quickly stop the air conditioner.
• Push the “ON/OFF” button on the remote controller to stop the air conditioner.
Note:
When the extension piping is very long with a large refrigerant amount, it may not be possible to perform a pump down
operation. In this case, use refrigerant recovery equipment to collect all of the refrigerant in the system.
7 Turn off the power supply (circuit breaker), remove the gauge manifold valve, and then disconnect the refrigerant pipes.
.Warning: When pumping down the refrigerant, stop the compressor before disconnecting the refrigerant pipes.
• If the refrigerant pipes are disconnected while the compressor is operating and the stop valve (ball valve) is open,
the pressure in the refrigeration cycle could become extremely high if air is drawn in, causing the pipes to burst,
personal injury, etc.
OCH545

77
3PARTS NAMES AND FUNCTIONS
SUZ-KA25VA4.TH
SUZ-KA35VA4.TH
SUZ-KA50VA4.TH
SUZ-KA60VA4.TH
SUZ-KA71VA4.TH
Air outlet
Drain outlet
Piping
Drain hose
Air inlet
(back and side)
Model SUZ-KA·VA4.TH
Drain socket 1
Piping
Air outlet
Drain outlet
Air inlet
(back and side)
Drain hose
OCH545

8
SPECIFICATION
4
NOTE: Test conditions are based on ISO 5151
Cooling : Indoor D.B. 27°C W.B. 19°C
Outdoor D.B. 35°C
Heating : Indoor D.B. 20°C
Outdoor D.B. 7°C W.B. 6°C
Refrigerant piping length (one way): 5 m
*Measured under rated operating frequency.
Outdoor model SUZ-KA25VA4.TH SUZ-KA35VA4.TH SUZ-KA50VA4.TH SUZ-KA60VA4.TH SUZ-KA71VA4.TH
Power supply Single phase 230V, 50Hz
Compressor
Model KNB073FKFMC KNB092FFAMC SNB130FGBMT SNB172FEKMT
Output W 550 650 900 1,200
Current* Cooling A2.76 4.06 5.58 6.62 8.02
Heating 3.24 4.09 5.75 6.37 8.13
Refrigeration oil
(Model)
L 0.31 (FV50S) 0.27 (FV50S) 0.35 (FV50S) 0.4 (FV50S)
Fan motor
Model RC0J50-FA RC0J60-BD RC0J60-BC
Current* Cooling A0.24 0.29 0.84 0.84 0.83
Heating 0.27 0.28 0.93 0.93 0.82
Dimensions W × H × D mm 800 × 550 × 285 840 × 880 × 330
Weight kg 30 35 54 50 53
Special remarks
Air
flow*
Cooling
High
m³/h
1,806 2,868 3,492 3,426
Med. 1,806 2,868 3,066 3,006
Low 1,170 1,038 1,602 1,692 1,512
Heating
High 2,106 2,778 2,952 2,892
Med. 1,806 1,770 2,778 2,952 2,892
Low 1,452 1,326 2,124 2,226 2,280
Sound level* Cooling
dB(A)
47 49 52 55
Heating 48 50 52 55
Fan
speed
Cooling
High
rpm
740 810 840 950
Med. 740 810 840
Low 740 490 480 450
Heating
High 860 900 810
Med. 740 770 810
Low 600 610 620 650
Fan speed regulator 3
Refrigerant filling capacity
(R410A) kg 0.80 1.15 1.60 1.80 1.80
OCH545

99
SUZ-KA25VA4.TH SUZ-KA35VA4.TH
SUZ-KA50VA4.TH SUZ-KA60VA4.TH
SUZ-KA71VA4.TH
Specifications and rating conditions of main electric parts
Model
Item
SUZ-KA25VA4.TH SUZKA35VA4.TH SUZ-KA50VA4.TH SUZ-KA60VA4.TH SUZ-KA71VA4.TH
Smoothing
capacitor
(C61) — — 620F 420V — —
(C62, C63) 620F 420V 620F 420V 620F420V — —
(CB1, 2, 3) — — — 560F 450V 560F 350V
Diode module (DB61) 15A 600V 15A 600V 25A 600V — —
Fuse
(F61) T20A L250V T20A L250V T20A L250V — —
(F62) — — — T20A L250V T20A L250V
(F701, F801, F901) T3.15A L250V T3.15A L250V T3.15A L250V — —
(IC700) 15A 600V 15A 600V 20A 600V — —
Inteligent power
module
(IPM) — — — 20A 600V
(IC932) 8A 600V 8A 600V 8A 600V 5A 600V 5A 600V
Power factor
controller
(PFC) — — — 20A 600V 20A 600V
(IC820) 20A 600V 20A 600V 20A 600V — —
Expansion valve
coil (LEV) DC12V
Reactor (L61) 18mH 23mH 23mH — —
(L) — — — 340H 20A 340H 20A
Current-Limiting
PTC thermistoe (PTC64, PTC65) 33
Terminal block (TB1, TB2) — — — 3P 3P
(TB) 5P 5P 5P — —
Relay
(X63) 3A 250V 3A 250V 3A 250V — —
(X64) 20A 250V
(X601) — — — 3A 250V 3A 250V
(X602) — — — 3A 250V 3A 250V
R.V. coil (21S4) AC220-240V
OCH545

10
NOISE CRITERIA CURVES
5
OCTAVE BAND SOUND PRESSURE LEVEL, dB re 0.0002 MICRO BAR
COOLING
FUNCTION SPL(dB(A)) LINE
High
Med.
FAN SPEED
HEATING
47
48
90
80
70
60
50
40
30
20
10 63 125 250 500 1000 2000 4000 8000
NC-60
NC-50
NC-40
NC-30
NC-20
NC-70
BAND CENTER FREQUENCIES, Hz
NC-10
SUZ-KA25VA4.TH
OCTAVE BAND SOUND PRESSURE LEVEL, dB re 0.0002 MICRO BAR
COOLING
FUNCTION SPL(dB(A)) LINE
FAN SPEED
HEATING
49
50
High
Med.
90
80
70
60
50
40
30
20
10 63 125 250 500 1000 2000 4000 8000
NC-60
NC-50
NC-40
NC-30
NC-20
NC-70
BAND CENTER FREQUENCIES, Hz
NC-10
SUZ-KA35VA4.TH
COOLING
FUNCTION SPL(dB(A)) LINE
High
FAN SPEED
HEATING
52
52
OCTAVE BAND SOUND PRESSURE LEVEL, dB re 0.0002 MICRO BAR
90
80
70
60
50
40
30
20
10 63 125 250 500 1000 2000 4000 8000
NC-60
NC-50
NC-40
NC-30
NC-20
NC-70
BAND CENTER FREQUENCIES, Hz
NC-10
SUZ-KA50VA4.TH
Test conditions
Cooling: Dry-bulb temperature 35°C
Heating: Dry-bulb temperature 7°C
Wet-bulb temperature 6°C
OUTDOOR UNIT
MICROPHONE
1 m
SUZ-KA60VA4.TH SUZ-KA71VA4.TH
OCTAVE BAND SOUND PRESSURE LEVEL, 0dB re 0.0002 MICRO BAR
COOLING
FUNCTION SPL(dB(A)) LINE
High
FAN SPEED
HEATING
55
55
90
80
70
60
50
40
30
20
10 63 125 250 500 1000 2000 4000 8000
NC-60
NC-50
NC-40
NC-30
NC-20
NC-70
BAND CENTER FREQUENCIES, Hz
NC-10
OCH545

11
6OUTLINES AND DIMENSIONS
10
69
800
302.5
500 Bolt pitch for installation
150
22.3
Handle
550
280
164.5
99.5
170.5
23
Service panel
Service port
285
344.5
44
400
Air in
Air out
Air in
17.5
Bolt pitch for
installation
304~325
40
Liquid refrigerant pipe joint
Refrigerant pipe (flared) :6.35
Gas refrigerant pipe joint
Refrigerant pipe (flared) :9.52
43
35
2-Oval holes 10×21
REQUIRED SPACE Basically open 100mm or more
without any obstruction in front
and on both sides of the unit.
350mm or more
200mm or more
100mm or more
100mm or more
Open two sides of left,
right, or rear side.
Drain hole :42
Unit: mm
SUZ-KA25VA4.TH
SUZ-KA35VA4.TH
OCH545

12
417.5
40
42
Drain hole
175 500
330
50
Air in
Air out 2-Oval holes 10 21
840
109 81
880
452
Service panel
99.5
164.5
195
35
44
Liquid refrigerant
pipe joint
Refrigerant pipe
(flared)
Ø 6.35...(SUZ-KA50/60VA4)
Ø 9.52...(SUZ-KA71VA4)
Gas refrigerant
pipe joint
Refrigerant pipe
(flared)
Ø 12.7...(SUZ-KA50VA4)
Ø 15.88...(SUZ-KA60/71VA4)
350 mm or more
100 mm or more
REQUIRED SPACE
Open as a rule
500mm or more if
the front and both
sides are open
100mm or more
200mm or more if
there are obstacles
to both sides
Open as a rule
500mm or more if the back,
both sides and top are open
Air in
Bolt pitch for
installation
360
SUZ-KA50VA4.TH
SUZ-KA60VA4.TH
SUZ-KA71VA4.TH
Unit: mm
OCH545

1313
7WIRING DIAGRAM
SUZ-KA25VA4.TH
SUZ-KA35VA4.TH
OCH545

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SUZ-KA50VA4.TH
OCH545

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SUZ-KA60VA4.TH
SUZ-KA71VA4.TH
OCH545

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REFRIGERANT SYSTEM DIAGRAM
8
Unit: mm
SUZ-KA25VA4.TH
Unit: mm
SUZ-KA35VA4.TH
Flared connection
Defrost
thermistor
RT61
Discharge
temperature
thermistor
RT62
Flared connection
Stop valve
(with strainer)
Stop valve
(with service port)
Refrigerant flow in cooling
Compressor
4-way valve
Refrigerant flow in heating
Refrigerant pipe ø9.52
(with heat insulator)
Refrigerant pipe ø6.35
(with heat insulator)
R.V. coil
heating ON
cooling OFF
Strainer
#100
Ambient
temperature
thermistor
RT65
Muffler
Capillary tube
ø3.0×ø2.0×240
Outdoor heat
exchanger
temperature
thermistor
RT68
Muffler
Outdoor
heat
exchanger
LEV
Outdoor
heat
exchanger
Flared connection
Defrost
thermistor
RT61
Discharge
temperature
thermistor
RT62
Flared connection
Stop valve
(with strainer)
Stop valve
(with service port)
Refrigerant flow in cooling
Compressor
4-way valve
Refrigerant flow in heating
Refrigerant pipe ø9.52
(with heat insulator)
Refrigerant pipe ø6.35
(with heat insulator)
R.V. coil
heating ON
cooling OFF
Strainer
#100
Capillary tube
ø3.0×ø1.8×600(×2)
LEV
Ambient
temperature
thermistor
Muffler
Capillary tube
ø3.0×ø2.0×240
Outdoor heat
exchanger
temperature
thermistor
Muffler
RT65
RT68
OCH545

1717
Unit: mm
SUZ-KA50VA4.TH
Outdoor
heat
exchanger
Flared connection
Defrost
thermistor
RT61
Discharge
temperature
thermistor
RT62
Flared connection
Stop valve
Stop valve
(with service port)
Capillary tube
ø 4.0 × ø 2.4 × 100
Refrigerant flow in cooling
Compressor
4-way valve
Refrigerant flow in heating
Refrigerant pipe
ø 12.7
(with heat insulator)
Refrigerant pipe ø 6.35
(with heat insulator)
LEV
R.V. coil
heating ON
cooling OFF
Muffler
#100
Strainer
#100
Outdoor heat
exchanger
temperature
thermistor
RT68
Ambient
temperature
thermistor
RT65
Strainer
#100
Muffler
Unit: mm
SUZ-KA60VA4.TH
SUZ-KA71VA4.TH
Outdoor
heat
exchanger
Flared connection
Defrost
thermistor
RT61
Discharge
temperature
thermistor
RT62
Flared connection
Stop valve
Stop valve
(with service port)
Capillary tube
ø 4.0 × ø 2.4 × 100 Refrigerant flow in cooling
Compressor
4-way valve
Refrigerant flow in heating
Refrigerant pipe
(with heat insulator)
ø 15.88
Refrigerant pipe
(with heat insulator)
ø 6.35...(SUZ-KA60VA4)
ø 9.52...(SUZ-KA71VA4)
LEV R.V. coil
heating ON
cooling OFF
Muffler
#100
Strainer
#100
Outdoor heat
exchanger
temperature
thermistor
RT68
Ambient
temperature
thermistor
RT65
Strainer
#100
OCH545

18
ADDITIONAL REFRIGERANT CHARGE (R410A: g)
SUZ-KA25VA4.TH SUZ-KA35VA4.TH SUZ-KA50VA4.TH
SUZ-KA60VA4.TH SUZ-KA71VA4.TH
MAX. REFRIGERANT PIPING LENGTH
Max. Length
A
* Height difference limitations are binding regardless of which unit, indoor or outdoor, is position high.
* Max. Height
difference
B
Indoor
unit
Outdoor unit
MAX. HEIGHT DIFFERENCE
Calculation : Xg=20g/m × (Refrigerant piping length(m)–7)
Calculation : Xg=55g/m × (Refrigerant piping length(m)-7)
Model Outdoor unit
precharged
Refrigerant piping length (one way)
7m 8m 9m 10m 11m 12m 13m 14m 15m 20m
SUZ-KA25VA4.TH 800 0 30 60 90 120 150 180 210 240 390
SUZ-KA35VA4.TH 1,150 0 30 60 90 120 150 180 210 240 390
Calculation: Xg=30g/m×(Refrigerant piping length(m)-7)
Model Refrigerant piping: m Piping size O.D: mm
Max. Length A
Max. Height difference B Gas Liquid
SUZ-KA25VA4.TH 20 12 9.52
6.35
SUZ-KA35VA4.TH
SUZ-KA50VA4.TH
30 30
12.7
SUZ-KA60VA4.TH 15.88
SUZ-KA71VA4.TH 9.52
Model Outdoor unit
precharged
Refrigerant piping length (one way)
7m 10m 15m 20m 25m 30m
SUZ-KA50VA4.TH 1,600 0 60 160 260 360 460
SUZ-KA60VA4.TH 1,800 0 60 160 260 360 460
Model Outdoor unit
precharged
Refrigerant piping length (one way)
7m 10m 15m 20m 25m 30m
SUZ-KA71VA4.TH 1,800 0 165 440 715 990 1,265
OCH545

1919
ACTUATOR CONTROL
9
SUZ-KA25VA4.TH SUZ-KA35VA4.TH SUZ-KA50VA4.TH
SUZ-KA60VA4.TH SUZ-KA71VA4.TH
9-3. RELATION BETWEEN MAIN SENSOR AND ACTUATOR
9-2. R.V. COIL CONTROL
Heating . . . . . . . . . . . . . . . . . ON
Cooling . . . . . . . . . . . . . . . . . OFF
Dry . . . . . . . . . . . . . . . . . . . . OFF
ON
OFF
ON
OFF
Outdoor fan
Compressor
5 seconds 15 seconds
ON
OFF
Compressor
Outdoor fan
motor
R.V.coil ON
OFF
ON
OFF
<COOL>
5 seconds
<HEAT>
5 seconds
9-1. OUTDOOR FAN MOTOR CONTROL
The fan motor turns ON/OFF, interlocking with the compressor.
[ON] The fan motor turns ON 5 seconds before the compressor starts up.
[OFF] The fan motor turns OFF 15 seconds after the compressor has stopped running.
NOTE: The 4-way valve reverses for 5 seconds
right before start-up of the compressor.
Sensor Purpose
Actuator
Compressor LEV Outdoor fan
motor R.V.coil Indoor fan motor
Discharge temperature
thermistor Protection 
Indoor coil temperature
thermistor
Cooling: Coil frost prevention 
Heating: High pressure protection 
Defrost thermistor Heating: Defrosting 
Fin temperature thermistor Protection 
Ambient temperature
thermistor Cooling: Low ambient temperature operation 
Outdoor heat exchanger
temperature thermistor
Cooling: Low ambient temperature operation 
Cooling: High pressure protection 
OCH545

20
SUZ-KA25VA4.TH SUZ-KA35VA4.TH SUZ-KA50VA4.TH
SUZ-KA60VA4.TH SUZ-KA71VA4.TH
CHANGE IN DEFROST SETTING
Changing defrost finish temperature
<JS> To change the defrost finish temperature, cut/solder the JS wire of the outdoor inverter P.C. board. (Refer to 11-6-1.)
11 TROUBLESHOOTING
3. Troubleshooting procedure
1) Check if the OPERATION INDICATOR lamp on the outdoor P.C. board is blinking on and off to indicate an abnormal-
ity. To make sure, check how many times the abnormality indication is blinking on and off before starting service work.
2) Before servicing check that the connector and terminal are connected properly.
3) If the electronic control P.C. board is supposed to be defective, check the copper foil pattern for disconnection and the
components for bursting and discoloration.
4) When troubleshooting, refer to 11-2. and 11-3.
SUZ-KA25VA4.TH SUZ-KA35VA4.TH SUZ-KA50VA4.TH
SUZ-KA60VA4.TH SUZ-KA71VA4.TH
11-1. CAUTIONS ON TROUBLESHOOTING
1. Before troubleshooting, check the following:
1) Check the power supply voltage.
2) Check the indoor/outdoor connecting wire for miswiring.
2. Take care the following during servicing.
1) Before servicing the air conditioner, be sure to turn OFF the main unit first with the remote controller, and turn off the breaker.
2) Be sure to turn OFF the power supply before removing the front panel, the cabinet, the top panel, and the electronic
control P.C. board.
3) When removing the electrical parts, be careful of the residual voltage of smoothing capacitor.
4) When removing the electronic control P.C. board, hold the edge of the board with care NOT to apply stress on the
components.
5) When connecting or disconnecting the connectors, hold the housing of the connector. DO NOT pull the lead wires.
Housing point
Lead wire
10 SERVICE FUNCTIONS
Jumper wire
Defrost finish temperature (°C)
SUZ-KA25VA4.TH
SUZ-KA35VA4.TH SUZ-KA50VA4.TH SUZ-KA60VA4.TH SUZ-KA71VA4.TH
JS Soldered (Initial setting) 5 9 10
None (cut) 10 18 18
OCH545