Read these SAFETY CONSIDERATIONS carefully before
performing any repair work. Comply with these safety symbols
without fail.
Meanings of DANGER, WARNING, CAUTION, and NOTE
Symbols:
DANGER .............. Indicates an imminently hazardous
situation which, if not avoided, will
result in death or serious injury.
WARNING ............ Indicates a potentially hazardous
situation which, if not avoided, could
result in death or serious injury.
CAUTION ............. Indicates a potentially hazardous
situation which, if not avoided, may
result in minor or moderate injury. It
may also be used to alert against
unsafe practices.
NOTE .................. Indicates situations that may result in
equipment or property-damage
accidents only.
• If refrigerant gas is discharged during repair work, do
not touch the discharged refrigerant gas. The
refrigerant gas may cause frostbite.
• Use only pipes, flare nuts, tools, and other materials
designed specifically for R410A refrigerant systems.
Never use tools or materials designed for R22
refrigerant systems on an R410A refrigerant system.
Doing so can cause a serious accident or an
equipment failure.
• Check to see if the parts and wires are mounted and
connected properly, and if the connections at the
soldered or crimped terminals are secure. Improper
installation and connections may cause excessive
heat generation, fire, or electrical shock.
• Prior to disconnecting the suction or disc ha rge pipe
from the compressor at the welded section,
pump-down the refrigerant gas completely in a wellventilated place first. If there is refrigerant gas or oil
remaining inside the compressor, the refrigerant gas or
oil can discharge when the pipe is being disconnected
and it may cause an injury.
• Wear a safe ty helmet, gloves, and a safety be lt when
working at an elevated height of more than 6.5 ft (2 m).
Insufficient safety measures ma y cause a fall resulting in
injury.
0.1Safety Considerations for Repair
• If refrigerant gas leaks during repair or service, ventilate
the area immediately. Refrigerant gas may produce toxic
gas if it comes into contact with flames. Refrigerant gas
is heavier than air and replaces oxygen. In the event of
an accident, a massive leak could lead to oxygen
depletion, especially in basements, and an asphyxiation
hazard could occur leading to serious injury or death .
• Do not start or stop the air conditioner or heat pump
operation by plugging o r unplug ging the po wer cab le
plug if a plug is used. Plugging or unplugging the
power cable plug to operate the equipment may cause
an electrical shock or fire.
• Use parts listed in the service parts list and
appropriate tools to conduct repair work. The use o f
inappropriate parts or tools may cause an electrical
shock or fire.
• Disconnect power before disassembling the
equipment for repairs. Working on the equipment that
is connected to the power supply may cause an
electric shock. If it is necessary to supply power to the
equipment to conduct repairs or to inspect the
circuits, do not touch any electrically charged
sections of the equipment.
• The step-up capacitor supplies high-voltage
electricity to the electrical components of the outdoor
unit. Discharge the capacitor completely before
conducting repair work. A charged capacitor may
cause an electrical shock.
• Do not mix air or gas other than the spec ified
refrigerant R410A to the refrigerant system. If air
enters the refrigerant systems, it can cause an
excessive high pressure resulting in equipment
damage and injury.
• When relocating the equipment, check if the new
installation site has sufficient strength to withstand
the weight of the equipment. If the installation site
does not have sufficient strength and the equipment
is not properly secured, the equipment may fall and
cause injury.
• Securely fasten the outside unit terminal cover
(panel). If the terminal cover/panel is not fastened
properly, dust or water may enter the outside unit
causing fire or electric shock.
• When relocating the system, keep the refrigerant
circuit free from substances other than the specified
refrigerant (R-410A) such as air. Any presence of air or
other foreign substance in the refrigerant circuit can
cause an abnormal pressure rise or rupture, resulting
in injury.
• If refrigerant gas leaks, locate the leaking point and
repair it before charging refrigerant. After charging
refrigerant, check for refrigerant leaks. If the leaking
point cannot be located and the repair work must be
stopped, perform a pump-down and close the service
valve to prevent the refrigerant gas from leaking into
the room. The refrigerant gas itself is harmless, but it
may generate toxic gases if it comes into contact with
flames.
vi
SiUS041111
• Do not repair the electrical components with wet
hands. Working on the equipment with wet hands may
cause an electrical shock.
• Do not clean the air conditioner or heat pump by
splashing water on it. Washing the uni t with water may
cause an electrical shock.
• Turn off the power when cleaning the equipment to
prevent internal fans that rotate at high speed from
starting suddenly as they can cause injury.
• Let the refrigerant lines cool down bef ore perf orming
any repair work. Working on the unit when the
refrigerant lines are hot may cause burns.
• All welding and cutting operations must be done in a
well-ventilated place to prevent the accumulation of
toxic fumes or possibly oxygen deficiency to occur.
• Check the ground ing bef ore repairing eq uipment in a
humid or wet place to avoid electrical shocks.
Improper grounding may cause an electrical shock.
• Measure the insulation resistance after the repair. The
resistance must be 1M or higher. Faulty insulation
may cause an electrical shock.
• Check the drainage of the indoor unit after finishing
repair work. Faulty drainage may cause water to enter
the room resulting in wet floors and furniture.
left in a damaged condition, the unit may fall and
cause injury. If the installation platform or frame has
corroded, have it replaced. A corroded platform or
frame may cause the unit to fall resulting in inju ry.
• If the unit has a power cable plug and it is dirty, clean
the plug before securely inserting it into a power
outlet. If the plug has a loose connection, tighten it or
it may cause electrical shock or fire.
• After replacing the battery in the remote controller,
dispose of the old battery to prevent children from
swallowing it. If a child swallows the battery, see a
doctor immediately.
• Never remove the fan guard of the unit. A fan rotating
at high speed without the fan guard is very
dangerous.
• Before cleaning the unit, stop the operation of the unit
by turning the power off or by pulling the power cable
plug out from its receptacle. Otherwise an electrical
shock or injury may result.
• Do not wipe the controller operation panel with
benzene, thinner, chemical dust cloth, etc. The panel
may get discolored or the coating can peel off. If it is
extremely dirty, soak a cloth in a water-diluted neutral
detergent, squeeze it well, and wipe the panel clean.
Then wipe it with another dry cloth.
• Do not tilt the unit when removing it. The w ater inside
the unit may spill resulting in wet flo ors and furniture.
• Dismantling of the unit, disposal of the refrigerant, oil,
and additional parts, should be done in accordance
with the relevant local, state, and national regulations.
0.2Safety Considerations for Users
• Never attempt to modify the equipment. Doing so can
cause electrical shock, excessive heat generation, or
fire.
• If the power cable and lead wires have scratches or
have become deteriorated, have them replaced.
Damaged cable and wires may cause an electrical
shock or fire.
• Do not use a joined power cable or an e xtension cord,
or share the same power outlet with other electrical
appliances as it may cause an electrical shock or fire.
• Use an exclusive power circuit for the equipment.
Insufficient circuit amperage capacity may cause an
electrical shock or fire.
• Do not damage or modify the power cable. Damaged
or modified power cables may cause an electrical
shock or fire. Placing heavy items on the power cable
or pulling the power cable may damage the cable.
• Check the unit foundation for damage on a continual
basis, especially if it has been in use for a long time. If
The definitions of temperatures are classified as following.
Room temperature: temperature of lower part of the room
Set temperature: temperature set by remote controller
Room thermistor temperature: temperature detected by room temperature thermistor
Target temperature: temperature determined by microcomputer
The temperature of the room is detected by the room temperature thermistor. However, there is
difference between the “temperature detected by room temperature thermistor” and the
“temperature of lower part of the room”, depending on the type of the indoor unit or installation
condition. Practically, the temperature control is done by the “target temperature appropriately
adjusted for the indoor unit” and the “temperature detected by room temperature thermistor”.
1.2Frequency Principle
Main Control
Parameters
Additional
Control
Parameters
Function and Control21
The compressor is frequency-controlled during normal operation. The target frequency is set by the
following 2 parameters coming from the operating indoor unit:
The load condition of the operating indoor unit
The difference between the room thermistor temperature and the target temperature
The target frequency is adapted by additional parameters in the following cases:
Frequency restrictions
Initial settings
Forced cooling operation
Main FunctionsSiUS041111
Refrigerant circulation rate (high)
high f
low f
freq=variable
Refrigerant circulation rate (low)
high speed
low speed
(R2812)
Amount of heat
exchanged air (large)
freq=
constant
50 Hz
60 Hz
capacity=
variable
Amount of heat
exchanged air (small)
AC
power
DC
power
Amount of heat
exchanged air (large)
Amount of heat
exchanged air (small)
Inverter PrincipleTo regulate the capacity, a frequency control is needed. The inverter makes it possible to vary the
rotation speed of the compressor. The following table explains the conversion principle:
PhaseDescription
1The supplied AC power source is converted into the DC power source for the present.
2The DC power source is reconverted into the three phase AC power source with variable
frequency.
When the frequency increases, the rotation speed of the compressor increases resulting in
an increased refrigerant circulation. This leads to a higher amount of the heat exchange per
unit.
When the frequency decreases, the rotation speed of the compressor decreases resulting
in a decreased refrigerant circulation. This leads to a lower amount of the heat exchange
per unit.
Drawing of
The following drawing shows a schematic view of the inverter principle:
Inverter
Inverter FeaturesThe inverter provides the following features:
The regulating capacity can be changed according to the changes in the outdoor temperature
and cooling / heating load.
Quick heating and quick cooling
The compressor rotational speed is increased when starting the heating (or cooling). This
enables to reach the set temperature quickly.
Even during extreme cold weather, high capacity is achieved. It is maintained even when the
outdoor temperature is 2°C (35.6°F).
Comfortable air conditioning
A fine adjustment is integrated to keep the room temperature constant.
Energy saving heating and cooling
Once the set temperature is reached, the energy saving operation enables to maintain the room
temperature at low power.
22Function and Control
SiUS041111Main Functions
(R11256)
5˚
45˚
(R11257)
15˚
45˚
10˚
40˚
10˚
40˚
(R2814)
5˚
35˚
5˚
35˚
(R2815)
5˚
55˚
5
˚
55˚
(R2816)
15˚
55˚
15˚
55˚
(R2813)
(R11259)
0
˚
(R11258)
50
˚
Frequency LimitsThe following functions regulate the minimum and maximum frequency:
FrequencyFunctions
Low Four-way valve operation compensation. Refer to page 37.
High Compressor protection function. Refer to page 37.
Discharge pipe temperature control. Refer to page 39.
Input current control. Refer to page 40.
Free ze-up protection control. Refer to page 41.
Heating peak-cut control. Refer to page 41.
Defro s t control. Refer to page 43.
Forced Cooling
Refer to page 222 for detail.
Operation
1.3Airflow Direction Control
Power-Airflow
Louver(s)
Wide-Angle FinsThe fins, made of elastic synthetic resin, provide a wide range of airflow that guarantees a
Auto-SwingThe following table explains the auto swing process for cooling, dry, heating, and fan:
The large louver sends a large volume of air downward to the floor and provides an optimum
control in cooling, dry, and heating mode.
Cooling / Dry Mode
During cooling or dry mode, the louver retracts into the indoor unit. Then, cool air can be blown far
and distributed all over the room.
Heating Mode
During heating mode, the large louver directs airflow downward to spread the warm air to the entire
room.
comfortable air distribution.
Vertical Swing (up and down)
CoolingDryFanHeating
09/12
class
15/18/24
class
COMFORT
AIRFLOW
Operation
Function and Control23
09/12 class
The horizontal blade (louver) is controlled not to blow the air directly on the person in the room.
CoolingHeating
Main FunctionsSiUS041111
(R11681)
(R6833)
(R6834)
(R14720)
Room thermistor temperature – target temperature
MH*
M
ML
L
+3˚C (+5.4˚F)
+2˚C (+3.6˚F)
+1˚C (+1.8˚F)
Fan speed
+2.5˚C (+4.5˚F)
+1.5˚C (+2.7˚F)
+0.5˚C (+0.9˚F)
Room thermistor temperature – target temperature
+1.5˚C (+2.7˚F)
+0.5˚C (+0.9˚F)
+2˚C (+3.6˚F)
+1˚C (+1.8˚F)
M
ML
L
Fan speed
(R14659)
1.4Fan Speed Control for Indoor Unit
OutlinePhase control and fan speed control contains 9 steps: LLL, LL, SL, L, ML, M, MH, H, and HH.
The airflow rate can be automatically controlled depending on the difference between the room thermistor
temperature and the target temperature. This is done through phase control and Hall IC control.
For more information about Hall IC, refer to the troubleshooting for fan motor on page 82.
Automatic Fan
Speed Control
In automatic fan speed operation, the step “SL” is not available.
Step
09/12 class15/18/24 class
Cooling
Heating
LLL
LL
L
ML
M
MH
H
HH (POWERFUL)
= The airflow rate is automatically controlled within this range when the FAN setting button
is set to automatic
.
<Cooling>
The following drawing explains the principle of fan speed control for cooling.
09/12 class
*In automatic fan speed operation, upper limit is at M tap in 30 minutes from the operation start.
15/18/24 class
<Heating>
On heating mode, the fan speed is regulated according to the indoor heat exchanger temperature
and the difference between the room thermistor temperature and the target temperature.
Note:1. During POWERFUL operation, fan rotates at H tap + 80 ~ 90 rpm.
2. Fan stops during defrost operation.
24Function and Control
SiUS041111Main Functions
Z
X
Y
Zone B
Zone B
Zone A = Thermostat OFF
Zone C = Thermostat ON
+ 0.5˚C (0.9˚F)
(R11587)
COMFORT
AIRFLOW
Operation
09/12 class
The fan speed is controlled automatically.
The latest command has the priority between POWERFUL and COMFORT AIRFLOW.
1.5Program Dry Operation
OutlineProgram dry operation removes humidity while preventing the room temperature from lowering.
Since the microcomputer controls both the temperature and airflow rate, the temperature
adjustment and fan adjustment buttons are inoperable in this mode.
DetailThe microcomputer automatically sets the temperature and airflow rate. The difference between
the room thermistor temperature at start-up and the target temperature is divided into two zones.
Then, the unit operates in the dry mode with an appropriate capacity for each zone to maintain the
temperature and humidity at a comfortable level.
Room thermistor
temperature at start-up
24°C (75.2°F) or more
23.5°C (74.3°F)
~
18°C (64.4°F)
17.5°C (63.5°F)
~
Target temperature
X
Room thermistor
temperature at start-up
18°C (64.4°F)X
Thermostat OFF pointYThermostat ON point
X – 0.5°C (– 0.9°F)
X
– 2.5°C (–4.5°F)
X
– 2.0°C (–3.6°F)
– 2.0°C (–3.6°F)
Y + 0.5°C (0.9°F) (zone
B) continues for 10 min.
X – 0.5°C (– 0.9°F)
Y + 0.5°C (0.9°F) (zone
B) continues for 10 min.
X – 0.5°C (– 0.9°F) = 17.5°C (63.5°F)
Y + 0.5°C (0.9°F) (zone
B) continues for 10 min.
Z
or
or
or
Function and Control25
Main FunctionsSiUS041111
Target temperature + 2.5˚C (+4.5˚F)
Heating Operation
Target temperature – 2.5˚C (–4.5˚F)
Cooling Operation
(R14660)
Target temperature – 2.0˚C (–3.6˚F)
= Thermostat OFF
Target temperature + 2.0˚C (+3.6˚F)
= Thermostat OFF
1.6Automatic Operation
OutlineAutomatic Cooling / Heating Function
When the AUTO mode is selected with the remote controller, the microcomputer automatically
determines the operation mode as cooling or heating according to the room temperature and the
set temperature at start-up, and automatically operates in that mode.
The unit automatically switches the operation mode to maintain the room temperature at the set
temperature.
DetailTs: set temperature (set by remote controller)
Tt: target temperature (determined by microcomputer)
Tr: room thermistor temperature (detected by room temperature thermistor)
C: correction value
1. The set temperature (Ts) determines the target temperature (Tt).
(Ts = 18 ~ 30°C, 64.4 ~ 86°F).
2. The target temperature (Tt) is calculated as;
Tt = Ts + C
where C is the correction value
C = 0°C (0°F)
3. Thermostat ON/OFF point and mode switching point are as follows.
Tr means the room thermistor temperature.
(1) Heating Cooling switching point:
Tr Tt + 2.5°C (+4.5°F)
(2) Cooling Heating switching point:
Tr < Tt – 2.5°C (–4.5°F)
(3) Thermostat ON/OFF point is the same as the ON/OFF point of cooling or heating operation.
Thermostat control is based on the difference between the room thermistor temperature and the
target temperature.
Thermostat OFF Condition
The temperature difference is in the zone A.
Thermostat ON Condition
The temperature difference returns to the zone C after being in the zone A.
The system resumes from defrost control in any zones except A.
The operation turns on in any zones except A.
The monitoring time has passed while the temperature difference is in the zone B.
(Cooling / Dry: 10 minutes, Heating: 10 seconds)
<Cooling / Dry>
<Heating>
Refer to “Temperature Control” on page 21 for detail.
Function and Control27
Main FunctionsSiUS041111
(R14453)
TIMER operation
NIGHT SET Mode ON
Target temperature
+0.5˚C (+0.9˚F)
temperature shift
Operation stops
at the set hours
1 hour
0.5˚C (0.9˚F)
0.5˚C (0.9˚F)
0.5˚C (0.9˚F)
(R14662)
+0.5˚C (+0.9˚F)
temperature shift
TIMER operation
NIGHT SET Mode ON
(A) +0.5˚C (+0.9˚F) temperature shift
(B)
Target temperature remains the same
Operation stops
at the set hours
1 hour
30 minutes
(A) : When the outdoor temperature is normal and the room
temperature is at the set temperature.
(B) : When the outdoor temperature is high (27˚C (80.6˚F) or higher).
Target temperature
(A)
(B)
2˚C (3.6˚F)
(R14454)
Target temperature
1 hour later
TIMER operation
NIGHT SET Mode ON
1.8NIGHT SET Mode
OutlineWhen the OFF timer is set, the NIGHT SET Mode is automatically activated. The NIGHT SET
Mode keeps the airflow rate setting.
DetailThe NIGHT SET Mode continues operation at the target temperature for the first one hour, then
automatically raises the target temperature slightly in the case of cooling, or lowers it slightly in the
case of heating. This prevents excessive cooling in summer and excessive heating in winter to
ensure comfortable sleeping conditions, and also conserves electricity.
<Cooling>
09/12 class
15/18/24 class
<Heating>
28Function and Control
SiUS041111Main Functions
ECONO Operation
(R9288)
Normal
Maximum during normal operation
Maximum during ECONO operation
Time
Power
consumption
and current
1.9ECONO Operation
09/12 class
The "ECONO operation" reduces the maximum operating current and the power consumption.
This operation is particularly convenient for energy-saving-oriented users. It is also a major bonus
for those whose breaker capacities do not allow the use of multiple electrical devices and air
conditioners.
It is easily activated from the wireless remote controller by pushing the ECONO button.
When this function is activated, the maximum capacity also decreases.
The remote controller can send the ECONO command when the unit is in COOL, HEAT, DRY, or
AUTO operation. This function can only be set when the unit is running. Pressing the ON/OFF
button on the remote controller canc els the func tion.
This function and POWERFUL operation cannot be used at the same time. The latest command
has the priority.
Function and Control29
Main FunctionsSiUS041111
(R13571)
Target temp.
Fan
A rpm
18˚C (64.4˚F)
H tap
Set tap
20 minutes
It should be the lower limit of
cooling temperature.
It counts 20 minutes. also
in the remote controller.
POWERFUL
ON
POWERFUL
OFF
Ending condition: "or" in 1 to 3
1. After the lapse of 20 minutes.
2. Operation OFF
3. POWERFUL operation is OFF.
1.10 Inverter POWERFUL Operation
OutlineIn order to exploit the cooling and heating capacity to full extent, operate the air conditioner by
increasing the indoor fan rotating speed and the compressor frequency.
DetailWhen POWERFUL button is pressed, the fan speed and target temperature are converted to the
following states for 20 minutes.
Operation modeFan speedTarget temperature
COOL H tap + A rpm18°C (64.4°F)
DRYDry rotating speed + A rpmLowered by 2.5°C (4.5°F)
HEATH tap + A rpm31 ~ 32°C (87.8 ~ 89.6°F)
FANH tap + A rpm—
AUTOSame as cooling / heating in
POWERFUL operation
A= 80 ~ 90 rpm
The target temperature is
kept unchanged.
Ex.): POWERFUL operation in cooling mode.
30Function and Control
SiUS041111Main Functions
ON/OFF
ON/OFF button
(R14568)
ON/OFF button
ON/OFF
(R14380)
1.11 Other Functions
1.11.1 Hot-Start Function
In order to prevent the cold air blast that normally comes when heating operation is started, the
temperature of the indoor heat exchanger is detected, and either the airflow is stopped or is made
very weak thereby carrying out comfortable heating of the room.
*The cold air blast is also prevented using a similar control when the defrosting operation is started
or when the thermostat is turned ON.
1.11.2 Signal Receiving Sign
When the indoor unit receives a signal from the remote controller, the unit emits a signal receiving
sound.
1.11.3 Indoor Unit ON/OFF Button
An ON/OFF button is provided on the display of the unit.
Press this button once to start operation. Press once again to stop it.
This button is useful when the remote controller is missing or the battery has run out.
The operation mode refers to the following table.
ModeTemperature settingAirflow rate
Cooling OnlyCOOL22°C (71.6°F)Automatic
Heat PumpAUTO25°C (77°F)Automatic
09/12 class15/18/24 class
<Forced cooling operation>
Forced cooling operation can be started by pressing the ON/OFF button for 5 to 9 seconds while
the unit is not operating.
Refer to page 222 for detail.
Note:When the ON/OFF button is pressed for 10 seconds or more, the forced cooling operation is
This filter combines the Air-Purifying Filter and Titanium Apatite Photocatalytic Deodorizing Filter as
a single highly effective filter. The filter traps microscopic particles, decomposes odors and even
deactivates bacteria and viruses. It lasts for 3 years without replacement if washed about once
every 6 months.
1.11.5 Auto-restart Function
If a power failure (including one for just a moment) occurs during the operation, the operation
restarts automatically when the power is restored in the same condition as before the power failure.
Note:It takes 3 minutes to restart the operation because the 3-minute standby function is activated.
Function and Control31
Function of ThermistorSiUS041111
(3)
(1)
(2)
Compressor
(R14721)
Electronic
expansion valve
2. Function of Thermistor
RKN09/12KEVJURKN15/18/24KEVJU
RXN09/12/15/18/24KEVJU
Electronic
expansion valve
(1) Outdoor Heat
Exchanger
Thermistor
(2) Discharge
Pipe Thermistor
(1)
ur-way valve
Fo
(2)
Compressor
(3)
(R14247)
1. The outdoor heat exchanger thermistor is used for controlling target discharge pipe
temperature. The system sets the target discharge pipe temperature according to the outdoor
and indoor heat exchanger temperature, and controls the electronic expansion valve opening so
that the target discharge pipe temperature can be obtained.
2. In cooling operation, the outdoor heat exchanger thermistor is used for detecting disconnection
of the discharge pipe thermistor. When the discharge pipe temperature becomes lower than the
outdoor heat exchanger temperature, the discharge pipe thermistor is judged as disconnected.
3. In cooling operation, the outdoor heat exchanger thermistor is used for high pressure protection.
1. The discharge pipe thermistor is used for controlling discharge pipe temperature. If the
discharge pipe temperature (used in place of the inner temperature of the compressor) rises
abnormally, the operating frequency becomes lower or the operation halts.
2. The discharge pipe thermistor is used for detecting disconnection of the discharge pipe
thermistor.
(3) Indoor Heat
Exchanger
Thermistor
1. The indoor heat exchanger thermistor is used for controlling target discharge pipe temperature.
The system sets the target discharge pipe temperature according to the outdoor and indoor
heat exchanger temperature, and controls the electronic expansion valve opening so that the
target discharge pipe temperature can be obtained.
2. In cooling operation, the indoor heat exchanger thermistor is used for freeze-up protection
control. If the indoor heat exchanger temperature drops abnormally, the operating frequency
becomes lower or the operation halts.
3. In heating operation, the indoor heat exchanger thermistor is used for detecting disconnection of
the discharge pipe thermistor. When the discharge pipe temperature becomes lower than the
indoor heat exchanger temperature, the discharge pipe thermistor is judged as disconnected.
32Function and Control
SiUS041111Control Specification
(R14428)
Air conditioner control mode
Forced operation mode
Forced cooling operation
Power transistor test mode
Normal operation mode
Fan
Cooling (includes drying)
Stop (indoor unit: OFF)
Preheating operation
Discharging from capacitor
Stop
Air conditioner control mode
Forced operation mode
Forced cooling operation
Power transistor test mode
Normal operation mode
Fan
Cooling (includes drying)
Heating
Heating
Defrosting
Stop (indoor unit: OFF)
Preheating operation
Discharging from capacitor
Stop
(R14248)
3. Control Specification
3.1Mode Hierarchy
OutlineThere are two modes; the one is the normal operation mode and the other is the forced operation
mode for installation and servicing.
DetailFor Cooling Only Model
Function and Control33
For Heat Pump Model
Note:Unless specified otherwise, an indoor dry operation command is regarded as cooling operation.
Control SpecificationSiUS041111
Command frequency
Limit frequency
Skip control
Lower limit function
Four way valve operating compensation (∗), etc.
Initial frequency
PI control
Defrost control (∗)
Dropping function
Input current control, etc.
Upper limit function
Compressor protection function
Upper limit frequency
FMAX
Lower limit frequency
FMIN
Target frequency
(R14717)
When the shift of the frequency is less than zero (ΔF<0) by PI control,
the target frequency is used as the command frequency.
(∗): only for heat pump model
3.2Frequency Control
OutlineFrequency is determined according to the difference between the room thermistor temperature and
the target temperature.
The function is explained as follows.
1. How to determine frequency
2. Frequency command from the indoor unit (Difference between the room thermistor temperature
and the target temperature)
3. Frequency initial setting
4. PI control
DetailHow to Determine Frequency
The compressor’s frequency is determined by taking the following steps.
For Cooling Only Model
1. Determine command frequency
Command frequency is determined in the following order of priority.
1. Forced cooling
2. Indoor frequency command
2. Determine upper limit frequency
The minimum value is set as an upper limit frequency among the frequency upper limits of the
When starting the compressor, the frequency is initialized according to the D value and the Q
value of the indoor unit.
Q value: Indoor unit output determined from indoor unit volume, airflow rate and other factors.
PI Control (Determine Frequency Up / Down by D Signal)
1. P control
The D value is calculated in each sampling time (20 seconds), and the frequency is adjusted
according to its difference from the frequency previously calculated.
2. I control
If the operating frequency does not change for more than a certain fixed time, the frequency is
adjusted according to the D value.
When the D value is low, the frequency is lowered.
When the D value is high, the frequency is increased.
3. Frequency management when other controls are functioning
When frequency is dropping;
Frequency management is carried out only when the frequency drops.
For limiting lower limit
Frequency management is carried out only when the frequency rises.
4. Upper and lower limit of frequency by PI control
The frequency upper and lower limits are set according to the command on indoor unit.
When the indoor or outdoor unit quiet operation command comes from the indoor unit, the upper
limit frequency is lower than the usual setting.
Function and Control35
Control SpecificationSiUS041111
3.3Controls at Mode Changing / Start-up
3.3.1Preheating Operation
OutlineThe inverter operation in open phase starts with the conditions of the preheating command from the
indoor unit, the outdoor temperature, and the discharge pipe temperature.
Detail 09/12 class
Outdoor temperature 7°C (44.6°F) Control A (preheating for normal state)
Outdoor temperature < 7°C (44.6°F) Control B (preheating of increased capacity)
Control A
ON condition
Discharge pipe temperature < 10°C (50°F)
OFF condition
Discharge pipe temperature > 12°C (53.6°F)
Radiation fin temperature 90°C (194°F)
Control B
ON condition
Discharge pipe temperature < 20°C (68°F)
OFF condition
Discharge pipe temperature > 22°C (71.6°F)
Radiation fin temperature 90°C (194°F)
15/18/24 class
ON Condition
When the discharge pipe temperature is below 10°C (50°F), the inverter operation in open
phase starts.
OFF Condition
When the discharge pipe temperature is higher than 12°C (54°F), the inverter operation in open
phase stops.
3.3.2Four-Way Valve Switching
Outline In heating operation, current is conducted, and in cooling and defrosting, current is not conducted.
In order to eliminate the switching sound when the heating is stopped, as the four-way valve coil
switches from ON to OFF, the OFF delay switch of the four-way valve is carried out after the
operation stopped.
DetailOFF delay switch of four-way valve:
The four-way valve coil is energized for 160 seconds after the operation is stopped.
36Function and Control
SiUS041111Control Specification
(sec.)
Time
(R13528)
(Hz)
Frequency
C
B
DEF
A
3.3.3Four-Way Valve Operation Compensation
OutlineAt the beginning of the operation as the four-way valve is switched, the differential pressure to
activate the four-way valve is acquired by having output frequency which is more than a certain
fixed frequency, for a certain fixed time.
DetailStarting Conditions
1. When starting compressor for heating
2. When the operation mode changes from heating to cooling
3. When starting compressor for defrosting
4. When starting compressor for heating after defrosting
5. When starting compressor for the first time after resetting with the power ON
6. When starting compressor after the fault of switching over cooling / heating
The lower limit of frequency keeps A Hz for B seconds with any conditions 1 through 6 above.
09/12 class15/18/24 class
A (Hz)6252
B (seconds)5060
3.3.43-minute Standby
Turning on the compressor is prohibited for 3 minutes after turning it off.
(Except when defrosting.)
3.3.5Compressor Protection Function
When turning the compressor from OFF to ON, the upper limit of frequency is set as follows. (The
function is not activated when defrosting.)
09/12 class
A (Hz)58
B (Hz)72
C (Hz)90
D (seconds)180
E (seconds)180
F (seconds)10
Function and Control37
Control SpecificationSiUS041111
(sec.)
Time
(R13906)
(Hz)
Frequency
C
D
B
EFG
H
A
15/18/24 class
A (Hz)52
B (Hz)66
C (Hz)78
D (Hz)Cooling: 98, Heating: 96
E (seconds)120
F (seconds)120
G (seconds)480
H (seconds)60
38Function and Control
SiUS041111Control Specification
(R14722)
Discharge pipe
temperature
Stop zone
Dropping zone
Keep zone
Up zone
Reset zone
E
A
B
C
D
3.4Discharge Pipe Temperature Control
OutlineThe discharge pipe temperature is used as the internal temperature of the compressor. If the
discharge pipe temperature rises above a certain level, the upper limit of frequency is set to keep
this temperature from going up further.
Detail
ZoneControl
Stop zoneWhen the temperature reaches the stop zone, the compressor stops.
Dropping zoneThe upper limit of frequency decreases.
Keep zoneThe upper limit of frequency is kept.
Up zoneThe upper limit of frequency increases.
Reset zoneThe upper limit of frequency is canceled.
OutlineThe microcomputer calculates the input current during the compressor is running, and sets the
frequency upper limit from the input current.
In case of heat pump model, this control which is the upper limit control of the frequency takes
priority to the lower limit of control of four-way valve operation compensation.
Detail
Frequency control in each zone
Stop zone
After 2.5 seconds in this zone, the compressor is stopped.
Dropping zone
The upper limit of the compressor frequency is defined as operation frequency – 2 Hz.
After this, the output frequency is pulled down by 2 Hz every second until it reaches the keep
zone.
Keep zone
The present maximum frequency goes on.
Reset zone
Limit of the frequency is canceled.
09/12 class
09 class12 class
CoolingHeatingCoolingHeating
A (A)14.014.0
B (A)Normal mode7.08.57.758.5
ECONO mode2.752.75
C(A)Normal mode6.257.757.07.75
ECONO mode2.02.0
15/18/24 class
CoolingHeating
A (A)14.515.0
B (A)11.512.0
C(A)10.511.0
Limitation of current dropping and stop value according to the outdoor temperature
The current drops when outdoor temperature becomes higher than a certain level (depending
on the model).
40Function and Control
SiUS041111Control Specification
(R14664)
Reset zone
Indoor heat exchanger
thermistor temperature
Up zone
Keep zone
Dropping zone
Stop zone
13˚C (55.4˚F)
(Reference)
7˚C (44.6˚F)
5˚C (41˚F)
3˚C (37.4˚F)
0˚C (32˚F)
Indoor heat exchanger
thermistor temperature
Stop zone
Dropping zone
Keep zone
Up zone
Reset zone
(R14665)
D
C
B
A
E
3.6Freeze-up Protection Control
OutlineDuring cooling operation, the signal sent from the indoor unit controls the operating frequency
limitation and prevents freezing of the indoor heat exchanger. (The signal from the indoor unit is
divided into zones.)
DetailThe operating frequency limitation is judged with the indoor heat exchanger temperature.
3.7Heating Peak-cut Control
OutlineDuring heating operation, the indoor heat exchanger temperature determines the frequency upper
limit to prevent abnormal high pressure.
Detail
ZoneControl
Stop zoneWhen the temperature reaches the stop zone, the compressor stops.
Dropping zoneThe upper limit of frequency decreases.
Keep zoneThe upper limit of frequency is kept.
Up zoneThe upper limit of frequency increases.
Reset zoneThe upper limit of frequency is canceled.
The outdoor fan is turned OFF 70 seconds after the compressor stops.
2. Fan ON control to cool down the electrical box
The outdoor fan is turned ON when the electrical box temperature is high while the compressor is
OFF.
3. Fan OFF control while defrosting
The outdoor fan is turned OFF while defrosting.
4. Fan ON/OFF control when operation starts / stops
The outdoor fan is turned ON when the operation starts. The outdoor fan is turned OFF when the
operation stops.
5. Fan speed control while forced cooling operation
The outdoor fan is controlled as well as normal operation while the forced cooling operation.
6. Fan speed control while indoor unit quiet operation (15/18/24 class)
The rotation speed of the outdoor fan is reduced by the command of the indoor unit quiet operation.
7. Fan speed control for POWERFUL operation (15/18/24 class)
The rotation speed of the outdoor fan is increased while the POWERFUL operation.
8. Fan speed control for pressure difference upkeep
The rotation speed of the outdoor fan is controlled for keeping the pressure difference while cooling
with low outdoor temperature.
When the pressure difference is low, the rotation speed of the outdoor fan is reduced.
When the pressure difference is high, the rotation speed of the outdoor fan is controlled as well
as normal operation.
3.9Liquid Compression Protection Function
OutlineIn order to obtain the dependability of the compressor, the compressor is stopped according to the
outdoor temperature and temperature of the outdoor heat exchanger.
Detail Operation stops depending on the outdoor temperature
Compressor turns off under the conditions that the system is in cooling operation and outdoor
temperature is below
0°C (32°F)
.
42Function and Control
SiUS041111Control Specification
Frequency
Compressor
Four way valve
Fan
ON
OFF
ON
OFF
ON
OFF
0 Hz
72 Hz
84 Hz
90 Hz
5 sec.
380 pulse
360 pulse
450 pulse
450 pulse
Initial opening
PI control
5 sec.
40 sec.40 sec.630 sec.
60 sec.
(R14666)
Electronic expansion
valve opening
3.10 Defrost Control
OutlineDefrosting is carried out by the cooling cycle (reverse cycle). The defrosting time or outdoor heat
exchanger temperature must be more than a certain value to finish.
DetailConditions for Starting Defrost
The starting conditions are determined with the outdoor temperature and the outdoor heat
exchanger temperature.
The system is in heating operation.
The compressor operates for 6 minutes.
More than 28 minutes of accumulated time pass since the start of the operation, or ending the
previous defrosting. (09/12 class)
More than 15 ~ 25 minutes (depending on the duration of the previous defrost control) of
accumulated time have passed since the start of the operation, or ending the previous
defrosting. (15/18/24 class)
Conditions for Canceling Defrost
09/12 class
The judgment is made with outdoor heat exchanger temperature. (4 ~ 22°C, 39.2 ~ 71.6°F)
Function and Control43
Control SpecificationSiUS041111
Frequency
Compressor
Four way valve
Fan
ON
OFF
ON
OFF
ON
OFF
0 Hz
76 Hz
8 sec.
400 pulse
450 pulse450 pulse
Initial opening
PI control
8 sec.
40 sec.
(R14667)
Electronic expansion
valve opening
50 sec.120 ~ 570 sec.
15/18/24 class
The judgment is made with outdoor heat exchanger temperature. (6 ~ 30°C, 42.8 ~ 86°F)
44Function and Control
SiUS041111Control Specification
h: function
− : not function
Cooling
h
h
h
hh
hhhhh
h
h
hh
hhhh
hh
h
h
hhhhhh
h
Heating
(R14458)
–
––
–
–––
–
–
––
–
––
–
––
–
–
–––
–––
–––
–––
–
–
–
–
–
–
–
–
––
–
h
–
–
hhhh
––––
––––
–
–
–
h
–
–
–
–
–
–
–
––––
–
–
––––
–––
–––
–––
–
–––
Starting control
Control when the frequency changes
Target discharge pipe temperature control
Control for disconnection of the discharge
pipe thermistor
High discharge pipe temperature control
Pressure equalizing control
Opening limit control
Starting control
Control when the frequency changes
Target discharge pipe temperature control
Control for disconnection of the discharge
pipe thermistor
High discharge pipe temperature control
Defrost control
Pressure equalizing control
Opening limit control
When the power turns on or when the
compressor stops
When the operation starts
When the frequency changes under starting
control
During target discharge pipe temperature
control
When the frequency changes under target
discharge pipe temperature control
When the disconnection of the discharge
pipe thermistor is ascertained
When the frequency changes under the control for
disconnection of the discharge pipe thermistor
Under defrost control
3.11 Electronic Expansion Valve Control
OutlineThe following items are included in the electronic expansion valve control.
Electronic expansion valve is fully closed
1. Electronic expansion valve is fully closed when turning on the power.
2. Pressure equalizing control
Open Control
1. Electronic expansion valve control when starting operation
2. Electronic expansion valve control when the frequency changes
3. Electronic expansion valve control for defrosting
4. Electronic expansion valve control when the discharge pipe temperature is abnormally high
5. Electronic expansion valve control when the discharge pipe thermistor is disconnected
Feedback Control
1. Target discharge pipe temperature control
DetailThe followings are the examples of control which function in each mode by the electronic expansion
valve control.
Function and Control45
Control SpecificationSiUS041111
09/12 class15/18/24 class
Maximum opening (pulse)470470
Minimum opening (pulse)5217
3.11.1 Fully Closing with Power ON
The electronic expansion valve is initialized when turning on the power. The opening position is set
and the pressure equalization is developed.
3.11.2 Pressure Equalizing Control
When the compressor is stopped, the pressure equalizing control is activated. The electronic
expansion valve opens, and develops the pressure equalization.
3.11.3 Opening Limit Control
OutlineA maximum and minimum opening of the electronic expansion valve are limited.
Detail
The electronic expansion valve is fully closed when cooling operation stops, and is opened at fixed
degree during defrosting.
3.11.4 Starting Operation Control
The electronic expansion valve opening is controlled when the operation starts, and prevents the
superheating or liquid compression.
3.11.5 Control when the frequency changes
When the target discharge pipe temperature control is active, if the target frequency is changed for
a specified value in a certain time period, the target discharge pipe temperature control is canceled
and the target opening of the electronic expansion valve is changed according to the shift.
3.11.6 High Discharge Pipe Temperature Control
When the compressor is operating, if the discharge pipe temperature exceeds a certain value, the
electronic expansion valve opens and the refrigerant runs to the low pressure side. This procedure
lowers the discharge pipe temperature.
46Function and Control
SiUS041111Control Specification
SC
(Subcool)
SH
(Superheat)
The target discharge pipe
temperature is set as to become the
aiming SH.
The inclination does not change
depending on the operating condition.
(R14213)
3.11.7 Control for Disconnection of the Discharge Pipe Thermistor
OutlineThe disconnection of the discharge pipe thermistor is detected by comparing the discharge pipe
temperature with the condensation temperature. If the discharge pipe thermistor is disconnected,
the electronic expansion valve opens according to the outdoor temperature and the operation
frequency, and operates for a specified time, and then stops.
After 3 minutes of waiting, the operation restarts and checks if the discharge pipe thermistor is
disconnected. If the discharge pipe thermistor is disconnected, the system stops after operating for
a specified time.
If the disconnection is detected repeatedly, then the system is shut down. When the compressor
runs for 60 minutes without any error, the error counter is reset.
DetailWhen the starting control finishes, the detection timer for disconnection of the discharge pipe
thermistor (720 seconds) starts. When the timer is over, the following adjustment is made.
1. When the operation mode is cooling
When the following condition is fulfilled, the discharge pipe thermistor disconnection is
ascertained.
Discharge pipe temperature + 6°C (+ 10.8°F) < outdoor heat exchanger temperature
2. When the operation mode is heating
When the following condition is fulfilled, the discharge pipe thermistor disconnection is
ascertained.
Discharge pipe temperature + 6°C (+ 10.8°F) < indoor heat exchanger temperature
Adjustment when the thermistor is disconnected
When the disconnection is ascertained, the compressor continues operation for 9 minutes and then
stops.
When the compressor stops repeatedly, the system is shut down.
3.11.8 Target Discharge Pipe Temperature Control
The target discharge pipe temperature is obtained from the indoor and outdoor heat exchanger
temperature, and the electronic expansion valve opening is adjusted so that the actual discharge
pipe temperature becomes close to the target discharge pipe temperature. (Indirect SH
(superheating) control using the discharge pipe temperature)
The electronic expansion valve opening and the target discharge pipe temperature are adjusted
every 20 seconds. The target discharge pipe temperature is controlled by indoor heat exchanger
temperature and outdoor heat exchanger temperature. The opening degree of the electronic
expansion valve is controlled by followings.
Target discharge pipe temperature
Actual discharge pipe temperature
Previous discharge pipe temperature
Function and Control47
Control SpecificationSiUS041111
Frequency
Power consumption
Refrigerant shortage zone
(R14668)
50 ~ 54 Hz
(depending on
the model)
(R1391)
Target discharge
pipe temperature
Refrigerant shortage
zone
3.12 Malfunctions
3.12.1 Sensor Malfunction Detection
Sensor malfunction may occur in the thermistor.
Relating to Thermistor Malfunction
1. Outdoor heat exchanger thermistor
2. Discharge pipe thermistor
3. Radiation fin thermistor
4. Outdoor temperature thermistor
3.12.2 Detection of Overcurrent and Overload
OutlineAn excessive output current is detected and, the OL temperature is observed to protect the
compressor.
Detail If the OL (compressor head) temperature exceeds 120 ~ 130°C (248 ~ 266°F), the system
shuts down the compressor.
If the inverter current exceeds about 15 A, the system shuts down the compressor.
The upper limit of the current decreases when the outdoor temperature exceeds a certain level.
3.12.3 Refrigerant Shortage Control
OutlineI: Detecting by power consumption
If the power consumption is below the specified value and the frequency is higher than the
specified frequency, it is regarded as refrigerant shortage.
The power consumption is low comparing with that in the normal operation when refrigerant is
insufficient, and refrigerant shortage is detected by checking a power consumption.
II: Detecting by discharge pipe temperature
If the discharge pipe temperature is higher than the target discharge pipe temperature, and the
electronic expansion valve is fully open for more than the specified time, it is regarded as
refrigerant shortage.
48Function and Control
III Detecting by the difference of temperature
If the difference between suction and discharge temperature is smaller than the specified value, it is
regarded as refrigerant shortage.
Refer to page 112 for detail.
SiUS041111
Part 5
Operation Manual
1. System Configuration................................................................................50
After installation and test operation of the room air conditioner are completed, the air conditioner
should be handled and operated as described in the following pages. Every user should be
informed on the correct method of operation and how to check if it can cool (or heat) well, and how
to use it efficiently.
Providing instructions to the user can reduce requests for servicing by 80%. However proficient the
installation and operating functions of the AC system are, the customer may fault either the room
air conditioner or its installation work when it is actually due to improper handling. The installation
work and the handing-over of the unit can only be considered completed when its handling has
been fully explained to the user without using technical terms, and while imparting full knowledge of
the equipment.
50Operation Manual
SiUS04111109/12 Class
7
<ARC452A19>
Name of Parts
Remote Controller
Signal transmitter
Receiver
• To use the remote controller, aim the
transmitter at the indoor unit. If there
is anything to block signals between
the unit and the remote controller,
such as a curtain, the unit will not
operate.
• Do not drop the remote controller. Do
not get it wet.
• The maximum distance for
communication is approximately 23ft
(7m).
FAN setting button
• Selects the airflow rate setting.
Page 14
Page 16
POWERFUL button
• POWERFUL operation.
Display (LCD)
• Displays the current settings.
(In this illustration, each section is
shown with all its displays on for the
purpose of explanation.)
TEMPERATURE
adjustment buttons
• Changes the temperature setting.
Page 12
Page 11
Page 8
ON/OFF button
• Press this button once to start
operation.
Press once again to stop it.
Front cover
• Open the front cover.
2. 09/12 Class
2.1Remote Controller
Operation Manual51
09/12 ClassSiUS041111
8
Open the front cover
MODE selector button
• Selects the operation mode.
(AUTO/DRY/COOL/HEAT/
FAN)
Page 11
Page 18,19
COMFORT button
• COMFORT AIRFLOW
operation.
OFF TIMER button
• Cancels the timer setting.
Page 15
Page 18
TIMER CANCEL
button
Page 18,19
ECONO button
• ECONO operation.
Page 17
Page 13
SWING button
•
Adjusting the airflow direction.
ON TIMER button
CLOCK button
SELECT button
• Changes the ON/OFF TIMER
settings.
Page 19
52Operation Manual
SiUS04111109/12 Class
2.
11
1.
COOL
AUTODRY
COOL
HEATFAN
Press
Display
NOTE
MODENotes on each operation mode
COOL
AUTO · DRY · COOL · HEAT ·
FAN Operation
The air conditioner operates with the operation mode of your choice.
From the next time on, the air conditioner will operate with the same operation mode.
To start operation
Press and select an operation mode.
• Each pressing of the button advances the mode setting in sequence.
COOLING ONLY
model
DRY
HEAT PUMP
model
• “ ”is displayed on the LCD.
• The OPERATION lamp lights green.
• “ ”is no longer displayed on the LCD.
• The OPERATION lamp goes off.
To stop operation
Press again.
AUTO
FAN
•
Since this air conditioner heats the room by taking heat from outdoor air to indoors, the heating capacity becomes smaller in lower outdoor
temperatures. If the heating effect is insufficient, it is recommended to use another heating appliance in combination with the air conditioner.
• The heat pump system heats the room by circulating hot air around all parts of the room. After the start of HEAT operation, it takes
some time before the room gets warmer.
• In HEAT operation, frost may occur on the outdoor unit and lower the heating capacity. In that case, the system switches into
defrosting operation to take away the frost.
• During defrosting operation, hot air does not flow out of indoor unit.
• This air conditioner cools the room by releasing the heat in the room outside. Therefore, the cooling performance of the air
conditioner may be degraded if the outdoor temperature is high.
• The computer chip works to rid the room of humidity while maintaining the temperature as much as possible. It automatically
controls temperature and airflow rate, so manual adjustment of these functions is unavailable.
• In AUTO operation, the system selects an appropriate operation mode (COOL or HEAT) based on the room and outside
temperatures and starts the operation.
• The system automatically reselects setting at a regular interval to bring the room temperature to user-setting level.
• This mode is valid for fan only.
HEAT
DRY
FAN
.
2.2AUTO · DRY · COOL · HEAT · FAN Operation
Operation Manual53
09/12 ClassSiUS041111
12
To change the temperature setting
Press or
• The displayed items on the LCD will change whenever either one of the buttons is
pressed.
COOL operation
64-90˚F
(18-32˚C)
HEAT operation
50-86˚F
(10-30˚C)
AUTO operation
64-86˚F
(18-30˚C)
DRY or FAN operation
Press to raise the temperature and press to lower the
temperature.
Operating conditions
Recommended temperature setting
• For cooling: 78-82˚F (26-28˚C)
• For heating: 68-75˚F (20-24˚C)
Tips for saving energy
• Be careful not to cool (heat) the room too much.
Keeping the temperature setting at a moderate level helps save energy.
• Cover windows with a blind or a curtain.
Blocking sunlight and air from outdoors increases the cooling (heating) effect.
• Clogged air filters cause inefficient operation and waste energy. Clean them once in about every 2 weeks.
Notes on the operating conditions
• The air conditioner always consumes 50-120btu/h (15-35W) of electricity even while it is not operating.
The outdoor unit consumes 3.4-34btu/h (1-10W) to have its electric components work even while it is not operating.
During standby electricity saving mode : about 3.4btu/h (1W)
The outdoor unit consumes about 120btu/h (35W) of power at the time of compressor preheating.
• If you are not going to use the air conditioner for a long period, for example in spring or autumn, turn the breaker off.
• Use the air conditioner in the following conditions.
MODE
COOL
HEAT
DRY
• Operation outside this humidity or temperature range may cause a safety device to disable the system.
Outdoor temperature : 50-115˚F (10-46˚C)
Indoor temperature : 64-90˚F (18-32˚C)
Indoor humidity : 80% max.
Outdoor temperature : 5-75˚F (–15-24˚C)
Indoor temperature : 50-86˚F (10-30˚C)
Outdoor temperature : 50-115˚F (10-46˚C)
Indoor temperature : 64-90˚F (18-32˚C)
Indoor humidity : 80% max.
• A safety device may work to stop the operation.
• Condensation may occur on the indoor unit and drip.
• A safety device may work to stop the operation.
• A safety device may work to stop the operation.
• Condensation may occur on the indoor unit and drip.
If operation is continued out of this rangeOperating conditions
The temperature setting is
not variable.
.
54Operation Manual
SiUS04111109/12 Class
13
Press
Adjusting the Airflow Direction
and Rate
You can adjust the airflow direction to increase your comfort.
To start auto swing
Upper and lower airflow direction
• “ ” is displayed on the LCD.
• The louver (horizontal blade) will begin to swing.
To set the louver at desired position
• This function is effective while louver is in auto swing mode.
Press when the louver has reached the
desired position.
• The louver will stop moving.
• “ ” is no longer displayed on the LCD.
To adjust the fins (vertical blades)
Hold the knob and move the fins.
(You will find a knob on the left-side and the right-side
blades.)
• When the unit is installed in the corner of a room, the
direction of the fins should be facing away from the wall.
If they face the wall, the wall will block off the wind,
causing the cooling (or heating) efficiency to drop.
.
2.3Adjusting the Airflow Direction and Rate
Operation Manual55
09/12 ClassSiUS041111
14
Press .
45˚
5˚
15˚
45˚
50˚
45˚
5˚
0˚
0˚
0˚
To adjust the airflow rate setting
• Each pressing of advances the airflow rate setting in sequence.
• When the airflow is set to “ ”, indoor unit quiet operation will start and the noise
from the unit will become quieter.
• In indoor unit quiet operation, the airflow rate is set to a weak level.
• In DRY operation, the airflow rate setting is not variable.
NOTE
Notes on the angles of the louver
• The louver swinging range depends on the operation. (See the figure.)
• If the air conditioner is HEAT or DRY operation with the louver kept stopped in the downward direction, the louver will automatically start
operating in approximately an hour in order to prevent dew condensation.
Note on airflow rate setting
• At smaller airflow rates, the cooling (heating) effect is also smaller.
CAUTION
• Always use a remote controller to adjust the angles of the louver. If you attempt to move the louver and fins forcibly with hand when they are
swinging, the mechanism may be broken.
• Be careful when adjusting the fins. Inside the air outlet, a fan is rotating at a high speed.
Auto
HighMiddle highMiddle
LowMiddle lowIndoor unit quiet
COOL and DRY operationHEAT operationFAN operation
Stop operationStop operationStop operation
COMFORT AIRFLOW
COMFORT AIRFLOW
Upper limit
Upper limit
Upper limit
Lower limit
Lower limit
Lower limit
56Operation Manual
SiUS04111109/12 Class
15
.
o
COMFORT AIRFLOW Operation
The flow of air will be in the upward direction while in COOL operation and in the
downward direction while in HEAT operation, which will provide a comfortable
wind that will not come in direct contact with people.
To start COMFORT AIRFLOW operation
Press
• “ ” is displayed on the LCD.
• Airflow rate is set to auto.
<COOL/DRY>The louver will go up.
<HEAT>The louver will go down.
To cancel COMFORT AIRFLOW operation
Press again.
• The louver will return to the memory position from before COMFORT AIRFLOW
operation.
• “ ” is no longer displayed on the LCD.
COOL operation
HEAT operation
NOTE
Notes on COMFORT AIRFLOW operation
• The louver position will change, preventing air from blowing directly on the occupants of the room.
• POWERFUL operation and COMFORT AIRFLOW operation cannot be used at the same time.
Priority is given to the function of whichever button is pressed last.
• The airflow rate will be set to auto. If the upper and lower airflow direction is selected, the COMFORT AIRFLOW operation will be canceled.
2.4COMFORT AIRFLOW Operation
Operation Manual57
09/12 ClassSiUS041111
16
POWERFUL Operation
POWERFUL operation quickly maximizes the cooling (heating) effect in any
operation mode. You can get the maximum capacity.
To start POWERFUL operation
Press during operation.
• POWERFUL operation ends in 20 minutes. Then the system automatically operates
again with the previous settings which were used before POWERFUL operation.
• “ ” is displayed on the LCD.
To cancel POWERFUL operation
Press again.
• “ ” is no longer displayed on the LCD.
[Example]
Normal operation
• When you want to get the
cooling effect quickly, start
the POWERFUL operation.
POWERFUL operation
• POWERFUL operation will
work for 20 minutes.
Back to normal
operation
NOTE
Notes on POWERFUL operation
• When using POWERFUL operation, there are some functions which are not available.
• POWERFUL operation cannot be used together with ECONO and COMFORT AIRFLOW operation.
Priority is given to the function of whichever button is pressed last.
• POWERFUL operation will not increase the capacity of the air conditioner if the air conditioner is already in operation with its maximum capacity
demonstrated.
•
In COOL, HEAT and AUTO operation
To maximize the cooling (heating) effect, the capacity of outdoor unit is increased and the airflow rate is fixed to the maximum setting.
The temperature and airflow settings are not variable.
•
In DRY operation
The temperature setting is lowered by 4.5˚F (2.5˚C) and the airflow rate is slightly increased.
•
In FAN operation
The airflow rate is fixed to the maximum setting.
2.5POWERFUL Operation
58Operation Manual
SiUS04111109/12 Class
17
ECONO Operation
ECONO operation is a function which enables efficient operation by limiting the
maximum power consumption value.
This function is useful for cases in which attention should be paid to ensure a
circuit breaker will not trip when the product runs alongside other appliances.
To start ECONO operation
To cancel ECONO operation
• “ ” is displayed on the LCD.
Press during operation.
Press again.
• “ ” is no longer displayed on the LCD.
[Example]
Normal operation
• In case the air conditioner and other
appliances which require high power
consumption are used at same time, a circuit
breaker may trip if the air conditioner operate
with its maximum capacity.
• The maximum power consumption of the air
conditioner is limited by using ECONO operation.
The circuit breaker is unlikely to trip even if the
air conditioner and other appliances are used at
same time.
• This diagram is a representation for illustrative
purposes only.
The maximum running current and power
consumption of the air conditioner in ECONO
operation vary with the connecting outdoor
unit.
Running current and
power consumption
Maximum during
normal operation
Maximum during
ECONO operation
Normal
operation
ECONO
operation
From start up until set temperature is reached
Time
Notes on ECONO operation
• ECONO operation is a function which enables efficient operation by limiting the power consumption of the outdoor unit (operating frequency).
• ECONO operation functions in AUTO, COOL, DRY, and HEAT operation.
• POWERFUL and ECONO operation cannot be used at the same time.
Priority is given to the function of whichever button is pressed last.
• If the level of power consumption is already low, ECONO operation will not drop the power consumption.
NOTE
ECONO operation
2.6ECONO Operation
Operation Manual59
09/12 ClassSiUS041111
OFF TIMER Operation
Timer functions are useful for automatically switching the air conditioner on or off
at night or in the morning. You can also use OFF TIMER and ON TIMER in
combination.
To use OFF TIMER operation
• Check that the clock is correct.
If not, set the clock to the present time.
• Each pressing of either button increases or decreases the time setting by 10 minutes.
Holding down either button changes the time setting rapidly.
Display
Notes on TIMER operation
• When TIMER is set, the present time is not displayed.
• Once you set ON/OFF TIMER, the time setting is kept in the memory. The memory is canceled when remote controller batteries are replaced.
• When operating the unit via the ON/OFF TIMER, the actual length of operation may vary from the time entered by the user. (Maximum
approximately 10 minutes)
NIGHT SET mode
• When the OFF TIMER is set, the air conditioner automatically adjusts the temperature setting (0.9˚F (0.5˚C) up in COOL, 3.6˚F (2.0˚C) down in
HEAT) to prevent excessive cooling (heating) for your pleasant sleep.
NOTE
To cancel OFF TIMER operation
1.
Press .
“ ” blinks.
“ ” is displayed on the LCD.
• “ ” is no longer displayed on the LCD.
2.
Press until the time setting reaches the
point you like.
3.
Press again.
• “ ” and setting time are displayed on the LCD.
• The TIMER lamp lights yellow.
Press .
• “ ” and setting time are no longer displayed on the LCD.
• “ ” and day of the week are displayed on the LCD.
• The TIMER lamp goes off.
18
2.7OFF TIMER Operation
60Operation Manual
SiUS04111109/12 Class
19
ON TIMER Operation
To cancel ON TIMER operation
To use ON TIMER operation
To combine ON TIMER and OFF TIMER
• Check that the clock is correct.
If not, set the clock to the present time.
1.
Press .
“ ” blinks.
“ ” is displayed on the LCD.
2.
Press until the time setting reaches the
point you like.
• Each pressing of either button increases or decreases the time setting by 10 minutes.
Holding down either button changes the setting rapidly.
3.
Press again.
• “ ” and setting time are displayed on the LCD.
• The TIMER lamp lights yellow.
Display
Press .
• “ ” and setting time are no longer displayed on the LCD.
• “ ” and day of the week are displayed on the LCD.
• The TIMER lamp goes off.
• A sample setting for combining the 2 timers is shown below.
(Example)
Present time: 23:00 (The unit operating)
OFF TIMER at 0:00
ON TIMER at 14:00
Combined
In the following cases, set the timer again.
• After a breaker has turned off.
• After a power failure.
• After replacing batteries in the remote controller.
NOTE
• “ ” is no longer displayed on the LCD.
2.8ON TIMER Operation
Operation Manual61
3P272441-1
15/18/24 ClassSiUS041111
7
Name of Parts
Remote Controller
Signal transmitter
Receiver
• To use the remote controller, aim the
transmitter at the indoor unit. If there
is anything to block signals between
the unit and the remote controller,
such as a curtain, the unit will not
operate.
• Do not drop the remote controller. Do
not get it wet.
• The maximum distance for
communication is approximately 23ft
(7m).
• Selects the airflow rate setting.
FAN setting button
Page 14
POWERFUL button
• POWERFUL operation.
Page 15
<ARC452A20>
Page 8
• Open the front cover
Front cover
Page 11
• Press this button once to start
operation.
Press once again to stop it.
ON/OFF button
Page 12
• Changes the temperature setting.
TEMPERATURE
adjustment buttons
• Displays the current settings.
(In this illustration, each section is
shown with all its displays on for the
purpose of explanation.)
Display (LCD)
3. 15/18/24 Class
3.1Remote Controller
62Operation Manual
SiUS04111115/18/24 Class
8
Open the front cover
Page 11
• Selects the operation mode.
(AUTO/DRY/COOL/HEAT/
FAN)
MODE selector button
Page 16
OFF TIMER button
TIMER CANCEL
button
• Cancels the timer setting.
Page 16,17
Page 16,17
• Changes the ON/OFF TIMER
settings.
SELECT button
CLOCK button
Page 17
ON TIMER button
Page 13
SWING button
•
Adjusting the airflow direction
.
Operation Manual63
15/18/24 ClassSiUS041111
11
1.
COOL
Press
2.
Display
AUTO · DRY · COOL · HEAT ·
FAN Operation
The air conditioner operates with the operation mode of your choice.
From the next time on, the air conditioner will operate with the same operation mode.
To start operation
Press and select an operation mode.
• Each pressing of the button advances the mode setting in sequence.
COOLING ONLY
model
HEAT PUMP
model
DRYFAN
AUTODRYCOOLHEATFAN
• “ ” is displayed on the LCD.
• The OPERATION lamp lights green.
To stop operation
Press again.
• “ ” is no longer displayed on the LCD.
• The OPERATION lamp goes off.
NOTE
Notes on each operation mode
MODE
HEAT
COOL
DRY
AUTO
FAN
•
Since this air conditioner heats the room by taking heat from outdoor air to indoors, the heating capacity becomes smaller in lower outdoor
temperatures. If the heating effect is insufficient, it is recommended to use another heating appliance in combination with the air conditioner.
• The heat pump system heats the room by circulating hot air around all parts of the room. After the start of HEAT operation, it takes
some time before the room gets warmer.
• In HEAT operation, frost may occur on the outdoor unit and lower the heating capacity. In that case, the system switches into
defrosting operation to take away the frost.
• During defrosting operation, hot air does not flow out of indoor unit.
• This air conditioner cools the room by releasing the heat in the room outside. Therefore, the cooling performance of the air
conditioner may be degraded if the outdoor temperature is high.
• The computer chip works to rid the room of humidity while maintaining the temperature as much as possible. It automatically
controls temperature and airflow rate, so manual adjustment of these functions is unavailable.
• In AUTO operation, the system selects an appropriate operation mode (COOL or HEAT) based on the room and outside
temperatures and starts the operation.
• The system automatically reselects setting at a regular interval to bring the room temperature to user-setting level.
• This mode is valid for fan only.
.
3.2AUTO · DRY · COOL · HEAT · FAN Operation
64Operation Manual
SiUS04111115/18/24 Class
12
Press or .
To change the temperature setting
• The displayed items on the LCD will change whenever either one of the buttons is
pressed.
COOL operation
64-90˚F
(18-32˚C)
HEAT operation
50-86˚F
(10-30˚C)
AUTO operation
64-86˚F
(18-30˚C)
DRY or FAN operation
The temperature setting is
not variable.
Press to raise the temperature and press to lower the
temperature.
Recommended temperature setting
• For cooling: 78-82˚F (26-28˚C)
• For heating: 68-75˚F (20-24˚C)
Tips for saving energy
• Be careful not to cool (heat) the room too much.
Keeping the temperature setting at a moderate level helps save energy.
• Cover windows with a blind or a curtain.
Blocking sunlight and air from outdoors increases the cooling (heating) effect.
• Clogged air filters cause inefficient operation and waste energy. Clean them once in about every 2 weeks.
Notes on the operating conditions
• The air conditioner always consumes a small amount of electricity even while it is not operating.
• If you are not going to use the air conditioner for a long period, for example in spring or autumn, turn the breaker off.
• Use the air conditioner in the following conditions.
Operating conditions
MODE
COOL
HEAT
DRY
Outdoor temperature : 50-115˚F (10-46˚C)
Indoor temperature : 64-90˚F (18-32˚C)
Indoor humidity : 80% max.
Outdoor temperature : 5-75˚F (–15-24˚C)
Indoor temperature : 50-86˚F (10-30˚C)
Outdoor temperature : 50-115˚F (10-46˚C)
Indoor temperature : 64-90˚F (18-32˚C)
Indoor humidity : 80% max.
Operating conditionsIf operation is continued out of this range
• A safety device may work to stop the operation.
• Condensation may occur on the indoor unit and drip.
• A safety device may work to stop the operation.
• A safety device may work to stop the operation.
• Condensation may occur on the indoor unit and drip.
• Operation outside this humidity or temperature range may cause a safety device to disable the system.
Operation Manual65
15/18/24 ClassSiUS041111
13
Adjusting the Airflow Direction
and Rate
You can adjust the airflow direction to increase your comfort.
To start auto swing
To set the louvers at desired position
To adjust the fins (vertical blades)
Upper and lower airflow direction
Press .
• “ ” is displayed on the LCD.
• The louvers (horizontal blades) will begin to swing.
• This function is effective while louvers are in auto swing mode.
Press when the louvers have reached
the desired position.
• The louvers will stop moving.
• “ ” is no longer displayed on the LCD.
Hold the knob and move the fins.
(You will find a knob on the left-side and the right-side
blades.)
• When the unit is installed in the corner of a room, the
direction of the fins should be facing away from the
wall.
If they face the wall, the wall will block off the wind,
causing the cooling (or heating) efficiency to drop.
3.3Adjusting the Airflow Direction and Rate
66Operation Manual
SiUS04111115/18/24 Class
14
NOTE
10˚
40˚
15˚
55˚
5˚
55˚
5˚
35˚
CAUTION
Press .
To adjust the airflow rate setting
• Each pressing of advances the airflow rate setting in sequence.
Middle lowLowIndoor unit quietAuto
HighMiddle highMiddle
• When the airflow is set to “ ”, indoor unit quiet operation will start and the noise
from the unit will become quieter.
• In indoor unit quiet operation, the airflow rate is set to a weak level.
• In DRY operation, the airflow rate setting is not variable.
• Always use a remote controller to adjust the angles of the louvers. If you attempt to move the louvers and fins forcibly with hand when they are
swinging, the mechanism may be broken.
• Be careful when adjusting the fins. Inside the air outlet, a fan is rotating at a high speed.
• At smaller airflow rates, the cooling (heating) effect is also smaller.
Note on airflow rate setting
• If the air conditioner is HEAT or DRY operation with the louvers kept stopped in the downward direction, the louvers will automatically start
operating in approximately an hour in order to prevent dew condensation.
Stop operation
Lower limit
Upper limit
Lower limit
Upper limit
Stop operation
Lower limit
Upper limit
Stop operation
Stop operation
Lower limit
Upper limit
COOL operation
DRY operation
HEAT operationFAN operation
• The louvers swinging range depends on the operation. (See the figure.)
Notes on the angles of the louvers
Operation Manual67
15/18/24 ClassSiUS041111
Notes on POWERFUL operation
• When using POWERFUL operation, there are some functions which are not available.
• POWERFUL operation will not increase the capacity of the air conditioner if the air conditioner is already in operation with its maximum capacity
demonstrated.
•
In COOL, HEAT and AUTO operation
To maximize the cooling (heating) effect, the capacity of outdoor unit is increased and the airflow rate is fixed to the maximum setting.
The temperature and airflow settings are not variable.
•
In DRY operation
The temperature setting is lowered by 4.5˚F (2.5˚C) and the airflow rate is slightly increased.
•
In FAN operation
The airflow rate is fixed to the maximum setting.
15
[Example]
POWERFUL Operation
POWERFUL operation quickly maximizes the cooling (heating) effect in any
operation mode. You can get the maximum capacity.
To start POWERFUL operation
To cancel POWERFUL operation
• POWERFUL operation ends in 20 minutes. Then the system automatically operates
again with the previous settings which were used before POWERFUL operation.
• “ ” is displayed on the LCD.
Press during operation.
Press again.
• “ ” is no longer displayed on the LCD.
Back to normal
operation
Normal operation
POWERFUL operation
• When you want to get the
cooling effect quickly, start
the POWERFUL operation.
NOTE
• POWERFUL operation will
work for 20 minutes.
3.4POWERFUL Operation
68Operation Manual
SiUS04111115/18/24 Class
16
OFF TIMER Operation
Timer functions are useful for automatically switching the air conditioner on or off
at night or in the morning. You can also use OFF TIMER and ON TIMER in
combination.
To use OFF TIMER operation
To cancel OFF TIMER operation
• Check that the clock is correct.
If not, set the clock to the present time.
1.
Press .
• “ ” is no longer displayed on the LCD.
“ ” blinks.
“ ” is displayed on the LCD.
2.
Press until the time setting reaches the
point you like.
• Each pressing of either button increases or decreases the time setting by 10 minutes.
Holding down either button changes the time setting rapidly.
3.
Press again.
• “ ” and setting time are displayed on the LCD.
• The TIMER lamp lights yellow.
Display
Press .
• “ ” and setting time are no longer displayed on the LCD.
• “ ” and day of the week are displayed on the LCD.
• The TIMER lamp goes off.
Notes on TIMER operation
• When TIMER is set, the present time is not displayed.
• Once you set ON/OFFTIMER, the time setting is kept in the memory. The memory is canceled when remote controller batteries are replaced.
• When operating the unit via the ON/OFF TIMER, the actual length of operation may vary from the time entered by the user. (Maximum
approximately 10 minutes)
NIGHT SET mode
• When the OFF TIMER is set, the air conditioner automatically adjusts the temperature setting (0.9˚F (0.5˚C) up in COOL, 3.6˚F (2.0˚C) down in
HEAT) to prevent excessive cooling (heating) for your pleasant sleep.
NOTE
3.5OFF TIMER Operation
Operation Manual69
15/18/24 ClassSiUS041111
17
ON TIMER Operation
To use ON TIMER operation
To cancel ON TIMER operation
• Check that the clock is correct.
If not, set the clock to the present time.
1.
Press .
“ ” blinks.
“ ” is displayed on the LCD.
• “ ” is no longer displayed on the LCD.
2.
Press until the time setting reaches the
point you like.
• Each pressing of either button increases or decreases the time setting by 10 minutes.
Holding down either button changes the setting rapidly.
3.
Press again.
• “ ” and setting time are displayed on the LCD.
• The TIMER lamp lights yellow.
Display
Press .
• “ ” and setting time are no longer displayed on the LCD.
• “ ” and day of the week are displayed on the LCD.
• The TIMER lamp goes off.
To combine ON TIMER and OFF TIMER
• A sample setting for combining the 2 timers is shown below.
(Example)
Present time: 23:00 (The unit operating)
OFF TIMER at 0:00
ON TIMER at 14:00
Combined
In the following cases, set the timer again.
• After a breaker has turned off.
• After a power failure.
• After replacing batteries in the remote controller.
NOTE
3.6ON TIMER Operation
70Operation Manual
3P276856-2
SiUS041111
Part 6
Service Diagnosis
1. Troubleshooting with LED.........................................................................73
Note:1. A short beep and two consecutive beeps indicate non-corresponding codes.
2. To return to the normal mode, hold the timer cancel button down for 5 seconds. When the
remote controller is left untouched for 60 seconds, it also returns to the normal mode.
3. Not all the error codes are displayed. When you cannot find the error code, try the check
method 2. (Refer to page 76.)
Service Diagnosis75
Service Check FunctionSiUS041111
(R14550)
(R9430)
(R14551)
(R14552)
(R9429)
Check Method 2
1. Press the 3 buttons (TEMP, TEMP, MODE) simultaneously to enter the diagnosis mode.
The left-side number blinks.
2. Press the TEMP
or button and change the figure until you hear the beep(s).
3. Diagnose by the sound.
beep : The left-side number does not correspond with the error code.
beep beep :The left-side number corresponds with the error code but the right-side number
does not.
long beep : Both the left-side and right-side numbers correspond with the error code.
Error codes and description Refer to page 78.
4. Press the MODE button.
The right-side number blinks.
76Service Diagnosis
SiUS041111Service Check Function
(R14547)
(R14548)
(R9879)
(R14549)
5. Press the TEMP or buttonand change the figure until you hear the beep(s).
6. Diagnose by the sound.
beep : The left-side number does not correspond with the error code.
beep beep :The left-side number corresponds with the error code but the right-side number
does not.
long beep : Both the left-side and right-side numbers correspond with the error code.
Error codes and description Refer to page 78.
7. Determine the error code.
The numbers indicated when you hear the long beep are the error code.
Error codes and description Refer to page 78.
8. Press the MODE button to exit from the diagnosis mode.
The display means the trial operation mode.
(Refer to page 223 for trial operation.)
9. Press the ON/OFF button twice to return to the normal mode.
Note:When the remote controller is left untouched for 60 seconds, it returns to the normal mode.
Service Diagnosis77
TroubleshootingSiUS041111
4. Troubleshooting
4.1Error Codes and Description
Error CodesDescription
System
Indoor
Unit
Outdoor
Unit
00
U0
U2
U4
UA
A1
A5
A6
C4
C9
E1
E5
E6
E7
E8
EA
F3
F6
H0
H6
H8
H9
J3
J6
L3
L4
L5
P4
Normal—
Refrigerant shortage112
Low-voltage detection or over-voltage detection114
Signal transmission error (between indoor unit and outdoor unit)86
Unspecified voltage (between indoor unit and outdoor unit)88
Indoor unit PCB abnormality79
Freeze-up protection control or heating peak-cut control80
Fan motor (DC motor) or related abnormality82
Indoor heat exchanger thermistor or related abnormality85
Room temperature thermistor or related abnormality85
Outdoor unit PCB abnormality89
OL activation (compressor overload)90
Compressor lock91
DC fan lock92
Input overcurrent detection93
Four-way valve abnormality94
Discharge pipe temperature control96
High pressure control in cooling98
Compressor system sensor abnormality100
Position sensor abnormality101
DC voltage / current sensor abnormality (09/12 class only)103
Outdoor temperature thermistor or related abnormality104
Discharge pipe thermistor or related abnormality104
Outdoor heat exchanger thermistor or related abnormality104
Electrical box temperature rise106
Radiation fin temperature rise108
Output overcurrent detection110
Radiation fin thermistor or related abnormality104
: Displayed only when system-down occurs.
Reference
Page
78Service Diagnosis
SiUS041111Troubleshooting
Check the combination of the
indoor and outdoor unit.
OK?
OK?
Check the connection of
connectors (See Note.).
Correct the connection.
Error repeats?
YES
NO
NO
YES
NO
YES
(R11704)
Caution
* To secure the connection,
once disconnect the connector
and then reconnect it.
Match the compatible
models.
Replace the indoor unit
PCB (1).
Replace the indoor unit
PCB (1).
Completed.
Be sure to turn off the power switch before connecting or disconnecting
connectors, or parts may be damaged.
4.2Indoor Unit PCB Abnormality
Remote
Controller
Display
Method of
Malfunction
Detection
Malfunction
Decision
Conditions
Supposed
Causes
Troubleshooting
A1
The system checks if the circuit works properly within the microcomputer of the indoor unit.
The system cannot set the internal settings.
Wrong models interconnected
Defective indoor unit PCB
Disconnection of connector
Service Diagnosis79
Note:Check the following connector.
Wall Mounted TypeTerminal board ~ Control PCB
Model TypeConnector
TroubleshootingSiUS041111
4.3Freeze-up Protection Control or Heating Peak-cut Control
Remote
Controller
Display
Method of
Malfunction
Detection
Malfunction
Decision
Conditions
Supposed
Causes
A5
Freeze-up protection control
During cooling operation, the freeze-up protection control (operation halt) is activated according
to the temperature detected by the indoor heat exchanger thermistor.
Heating peak-cut control
During heating operation, the temperature detected by the indoor heat exchanger thermistor is
used for the heating peak-cut control (operation halt, outdoor fan stop, etc.)
Freeze-up protection control
During cooling operation, the indoor heat exchanger temperature is below 0°C (32°F).
Heating peak-cut control
During heating operation, the indoor heat exchanger temperature is above 65°C (149°F).
Short-circuited air
Clogged air filter of the indoor unit
Dust accumulation on the indoor heat exchanger
Defective indoor heat exchanger thermistor
Defective indoor unit PCB
80Service Diagnosis
SiUS041111Troubleshooting
NO
NO
NO
Check No. 01
Check the indoor heat exchanger
thermistor.
YES
YES
(R14402)
YES
YES
NO
Caution
Provide sufficient air passage.
Clean the air filter.
Clean the indoor heat
exchanger.
Replace the indoor unit PCB.
Replace the thermistor.
Be sure to turn off the power switch before connecting or disconnecting
connectors, or parts may be damaged.
Check the air passage.
Is there any short circuit?
Check the air filter.
Is it very dirty?
Check the dust accumulation on
the indoor heat exchanger.
Is it very dirty?
Does it conform to
the thermistor
characteristic chart?
Troubleshooting
Check No.01
Refer to P.116
Service Diagnosis81
TroubleshootingSiUS041111
4.4Fan Motor (DC Motor) or Related Abnormality
Remote
Controller
Display
Method of
Malfunction
Detection
Malfunction
Decision
Conditions
Supposed
Causes
A6
The rotation speed detected by the Hall IC during fan motor operation is used to determine
abnormal fan motor operation.
The detected rotation speed does not reach the demanded rotation speed of the target tap, and is
less than 50% of the maximum fan motor rotation speed.
Disconnection of connector
Foreign matters stuck in the fan
Layer short inside the fan motor winding
Breaking of wire inside the fan motor
Breaking of the fan motor lead wires
Defective capacitor of the fan motor
Defective indoor unit PCB
82Service Diagnosis
SiUS041111Troubleshooting
(R14405)
Turn off the power.
(Unplug the power cable or turn
the breaker OFF.)
Caution
Be sure to turn off the power switch before connecting or disconnecting
connectors, or parts may be damaged.
OK?
NO
Check the connector for
connection.
YES
YES
Foreign matters in or
around the fan?
NO
Check No. 03
Check the fan motor for
breakdown or short circuit.
Resistance OK?
Turn the power on again.
Check No. 03
Check the motor control voltage.
Is the motor control
voltage 15 VDC
generated?
Check No. 03
Check the indoor unit PCB for
rotation pulse.
Is the rotation pulse
generated?
NO
YES
YES
YES
NO
NO
To secure the connection,
once disconnect the connector
and then reconnect it.
Correct the connection.
Remove them.
Replace the indoor fan motor.
Replace the indoor unit PCB (1).
Replace the indoor fan motor.
Replace the indoor unit PCB (1).
Rotate the fan.
Fan rotates smoothly?
YES
NO
Replace the indoor unit PCB (1).
Note: The motor may break when the
motor connector is disconnected
while remaining power supply.
(Turn off the power supply before
connecting the connector also.)
TroubleshootingFTXN09/12KEVJU
Check No.03
Refer to P.117
Service Diagnosis83
TroubleshootingSiUS041111
YES
YES
NO
YES
YES
NO
NO
NO
Note : The motor may break when the
motor connector is disconnected
while remaining power supply.
(Turn off the power supply before
connecting the connector also.)
Turn off the power supply
and disconnect the fan
motor connector, then
turn the power on.
Caution
Replace the indoor
fan motor.
Replace the indoor
unit PCB.
Replace the indoor
unit PCB.
Be sure to turn off the power switch before connecting or disconnecting
connectors, or parts may be damaged.
(R14436)
NO
YES
YES
NO
YES
NO
Replace the indoor
fan motor.
Replace the indoor
unit PCB.
Replace the indoor
unit PCB.
Replace the indoor
fan motor.
Replace the indoor
fan motor and the
indoor unit PCB.
Turn off the power supply
and rotate the fan by hand.
Does the fan
rotate smoothly?
Turn the power on and
start operation.
Does the fan
rotate?
Check No.02
Check the output of the
fan motor connector
Is the motor
power supply
voltage 310 ~
340 VDC
generated?
Is the motor
control voltage 15
VDC generated?
Is the rotation
command voltage
1 ~ 6 VDC
generated?
Is the rotation
pulse generated?
Stop the fan motor.
Check No.02
Check the output of the
fan motor connector
Is the rotation
pulse generated?
TroubleshootingFTXN15/18/24KVJU
Check No.02
Refer to P.117
84Service Diagnosis
SiUS041111Troubleshooting
YES
(R14406)
NO
YES
NO
Caution
Correct the connection.
Replace the thermistor.
Replace the indoor unit PCB.
Be sure to turn off the power switch before connecting or disconnecting
connectors, or parts may be damaged.
Check the connection of
connectors.
Is it normal?
Check No. 01
Check the thermistor resistance
value.
Is it normal?
4.5Thermistor or Related Abnormality (Indoor Unit)
Remote
Controller
Display
Method of
Malfunction
Detection
Malfunction
Decision
Conditions
Supposed
Causes
Troubleshooting
Check No.01
Refer to P.116
C4, C9
The temperatures detected by the thermistors determine thermistor errors.
The thermistor input is more than 4.96 V or less than 0.04 V during compressor operation.
Disconnection of connector
Defective thermistor
Defective indoor unit PCB
4.6Signal Transmission Error (between Indoor Unit and
Outdoor Unit)
Remote
Controller
Display
Method of
Malfunction
Detection
Malfunction
Decision
Conditions
Supposed
Causes
U4
The data received from the outdoor unit in indoor unit - outdoor unit signal transmission is checked
whether it is normal.
The data sent from the outdoor unit cannot be received normally, or the content of the data is
abnormal.
Wiring error
Breaking of the connection wires between the indoor and outdoor units (wire No. 3)
Defective outdoor unit PCB
Defective indoor unit PCB
Disturbed power supply waveform
86Service Diagnosis
SiUS041111Troubleshooting
Check the voltage of the
connection wires on the indoor
terminal board between No. 1
and No. 3, and between No. 2
and No. 3.
Check No.11
Check the power supply
waveform.
Check the indoor unit - outdoor
unit connection wires.
Is there any wiring error?
Properly insulated?
Check the LED A on the outdoor
unit PCB.
Is LED A blinking?
Is there any disturbance?
YES
YES
Replace the indoor unit PCB.
Locate the cause of the
disturbance of the power supply
waveform, and correct it.
NO
(R14437)
NO
YES
YES
NO
NO
Caution
Correct the indoor unit - outdoor
unit connection wires.
Diagnose the outdoor unit
PCB.
Replace the connection wires
between the indoor unit and
outdoor unit.
Be sure to turn off the power switch before connecting or disconnecting
connectors, or parts may be damaged.
Troubleshooting
Check No.11
Refer to P.118
Service Diagnosis87
TroubleshootingSiUS041111
(R11707)
Caution
NO
YES
YES
YES
NO
NO
Check the code numbers
(2P01234, for example) of the
indoor and outdoor unit PCB with
the Parts List.
Match the compatible models.
Change for the correct PCB.
Replace the indoor unit PCB
(or the outdoor unit PCB).
Correct the connection.
Be sure to turn off the power switch before connecting or disconnecting
connectors, or parts may be damaged.
Check the combination of the
indoor and outdoor unit.
OK?
Are the
connection wires
connected
property?
Matched compatibly?
4.7Unspecified Voltage (between Indoor Unit and Outdoor
Unit)
Remote
Controller
Display
Method of
Malfunction
Detection
Malfunction
Decision
Conditions
Supposed
Causes
Troubleshooting
UA
The supply power is detected for its requirements (different from pair type and multi type) by the
indoor / outdoor transmission signal.
The pair type and multi type are interconnected.
Wrong models interconnected
Wrong wiring of connecting wires
Wrong indoor unit PCB or outdoor unit PCB mounted
Defective indoor unit PCB
Defective outdoor unit PCB
88Service Diagnosis
SiUS041111Troubleshooting
Caution
Be sure to turn off the power switch before connecting or disconnecting
connectors, or parts may be damaged.
NO
YES
YES
(R14253)
YES
NO
NO
Replace the outdoor unit
PCB.
Ground the system.
Zero-cross signal
abnormality.
Replace the outdoor unit
PCB.
Replace the harness.
Turn on the power again.
Is LED A blinking?
Check to see if the outdoor unit is
grounded.
Grounded?
Is the harness
broken?
4.8Outdoor Unit PCB Abnormality
Remote
Controller
Display
Method of
Malfunction
Detection
Malfunction
Decision
Conditions
Supposed
Causes
Troubleshooting
E1
The system follows the microprocessor program as specified.
The system checks to see if the zero-cross signal comes in properly.
The microprocessor program runs out of control.
The zero-cross signal is not detected.
Defective outdoor unit PCB
Broken harness between PCBs
Noise
Momentary fall of voltage
Momentary power failure
Service Diagnosis89
TroubleshootingSiUS041111
(R14438)
Caution
YES
NG
NO
OK
OK
NG
NG
OK
NG
OK
∗ Refrigerant shortage
∗ Water mixed
∗ Stop valve
∗ Discharge pipe thermistor
Insert the thermistor in
position.
Replace the discharge pipe
thermistor.
Replace the electronic
expansion valve or the coil.
Refer to the refrigerant line
check procedure.
Replace the outdoor unit
PCB.
Replace the four way valve
or the coil.
Replace the outdoor unit
PCB.
Be sure to turn off the power switch before connecting or disconnecting
connectors, or parts may be damaged.
Discharge pipe
thermistor
disconnected?
Check No. 01
Check the thermistors.
Check No. 12
Check the electronic
expansion valve.
Check No. 13
Check the four way
valve.
Check No. 14
Check the refrigerant
line.
4.9OL Activation (Compressor Overload)
Remote
Controller
Display
Method of
Malfunction
Detection
Malfunction
Decision
Conditions
Supposed
Causes
Troubleshooting
E5
A compressor overload is detected through compressor OL.
If the error repeats, the system is shut down.
Reset condition: Continuous run for about 60 minutes without any other error
The operating temperature condition is not specified.
Defective discharge pipe thermistor
Defective electronic expansion valve or coil
Defective four-way valve or coil
Defective outdoor unit PCB
Refrigerant shortage
Water mixed in refrigerant
Defective stop valve
Check No.01
Refer to P.116
Check No.12
Refer to P.118
Check No.13
Refer to P.119
Check No.14
Refer to P.119
90Service Diagnosis
SiUS041111Troubleshooting
(R14439)
Caution
NO
YES
YES
NO
NO
YES
Correct the power supply
or replace the outdoor unit
PCB.
∗ Inverter checker
Part No.: 1225477
Replace the compressor.
Replace the compressor.
Check the electronic
expansion valve.
Replace it as required.
Be sure to turn off the power switch before connecting or disconnecting
connectors, or parts may be damaged.
(Precaution before turning on the power again)
Make sure the power has been off for at least 30 seconds.
Turn off the power. Disconnect the
harnesses U, V, and W.
Check No.15
Check with the inverter checker (∗).
Turn off the power and reconnect
the harnesses. Turn on the power
again and restart the system.
Normal?
Emergency
stop without compressor
running?
System shut
down after errors repeated
several times?
4.10 Compressor Lock
Remote
Controller
Display
Method of
Malfunction
Detection
Malfunction
Decision
Conditions
Supposed
Causes
Troubleshooting
Check No.15
Refer to P.120
E6
A compressor lock is detected by the current waveform generated when applying high-frequency
voltage to the motor.
If the error repeats, the system is shut down
Reset condition: Continuous run for about 11 minutes without any other error
Compressor locked
Disconnection of compressor harness
Service Diagnosis91
TroubleshootingSiUS041111
(R14410)
Caution
YES
YES
NO
YES
NO
NO
YES
NO
Turn on the power.
Rotate the fan.
Check No. 16
Check the rotation pulse input on
the outdoor unit PCB.
Turn off the power and
reconnect the connector.
Remove them.
Replace the outdoor fan
motor.
Replace the outdoor unit
PCB.
Replace the outdoor fan
motor.
Be sure to turn off the power switch before connecting or disconnecting
connectors, or parts may be damaged.
Fan motor connector
disconnected?
Foreign matters in or
around the fan?
Fan rotates
smoothly?
Pulse signal generated?
4.11 DC Fan Lock
Remote
Controller
Display
Method of
Malfunction
Detection
Malfunction
Decision
Conditions
Supposed
Causes
Troubleshooting
Check No.16
Refer to P.122
E7
An error is determined with the high-voltage fan motor rotation speed detected by the Hall IC.
The fan does not start in about 15 seconds even when the fan motor is running.
If the error repeats, the system is shut down.
Reset condition: Continuous run for about 11 minutes without any other error
Disconnection of fan motor
Foreign matters stuck in the fan
Defective fan motor
Defective outdoor unit PCB
92Service Diagnosis
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