Fujitsu ASU18RLB Operating instructions

SPLIT TYPE
ROOM AIR CONDITIONER
WALL MOUNTEDtype
Models Indoor unit Outdoor unit
INVERTER
SERVICE
INSTRUCTION
R410A
ASU18RLB
ASU24RLB
AOU18RLB
AOU24RLB

CONTENTS
1. DESCRIPTION OF EACH CONTROL OPERATION
1. COOLING OPERATION................................................................................................
3. DRY OPERATION.........................................................................................................
2. HEATING OPERATION.................................................................................................
5. INDOOR FAN CONTROL..............................................................................................
4. AUTO CHANGEOVER OPERATION............................................................................
7. LOUVER CONTROL.....................................................................................................
6. OUTDOOR FAN CONTROL..........................................................................................
9. TIMER OPERATION CONTROL...................................................................................
8. COMPRESSOR CONTROL..........................................................................................
11. TEST OPERATION CONTROL...................................................................................
10. ELECTRONIC EXPANSION VALVE CONTROL........................................................
13. FOUR-WAY VALVE EXTENSION SELECT................................................................
12. PREVENT TO RESTART FOR 3 MINUTES ( 3 MINUTES ST ).................................
15. MANUAL AUTO OPERATION ( INDOOR UNIT BODY OPERATION ).......................
14. AUTO RESTART.........................................................................................................
16. FORCED COOLING OPERATION..............................................................................
17. COMPRESSOR PREHEATING...................................................................................
19. ECONOMY OPERATION............................................................................................
01-01
01-02
01-02
01-03
01-04
01-06
01-07
01-08
01-09
01-12
01-12
01-12
01-13
01-13
01-13
01-14
01-14
18. MINIMUM HEAT OPERATION ................................................................................... 01-14
24. OFF DEFROST OPERATION CONTROL...................................................................
23. DEFROST OPERATION CONTROL........................................................................... 01-16
01-18
25. VARIOUS PROTECTIONS.......................................................................................... 01-19
01-12
21. THERMO CONTROL ( FOR INDOOR UNIT SENSOR )................................................
20. HEAT INSULATION CONDITION ( BUILDING INSULATION )................................... 01-15
01-15
22. THERMO CONTROL ( FOR WIRED REMOTE SENSOR )......................................... 01-15
3. APPENDING DATA
3-1 FUNCTION SETTING.......................................................................................................
3-1-1 INDOOR UNIT..........................................................................................................
3-1-2 PROCEDURES TO CHANGE THE FUNCTION SETTING FOR WIRELESS RC...
03-01
03-01
03-05
3-2 THERMISTOR RESISTANCE VALUES............................................................................
3-2-1 INDOOR UNIT..........................................................................................................
3-2-2 OUTDOOR UNIT......................................................................................................
03-07
03-07
03-07
2. TROUBLE SHOOTING
2-1 ERROR DISPLAY.............................................................................................................
2-1-1 INDOOR UNIT AND WIRED REMOTE CONTROLLER DISPLAY..........................
2-1-2 WIRED REMOTE CONTROLLER DISPLAY ( OPTION )..........................................
2-2 TROUBLE SHOOTING WITH ERROR CODE.................................................................
2-3 TROUBLE SHOOTING WITH NO ERROR CODE...........................................................
02-01
02-01
02-02
02-03
02-24
2-4 SERVICE PARTS INFORMATION................................................................................... 02-33

1 . DESCRIPTION OF EACH
CONTROL OPERATION
R410A
WALL MOUNTED type
INVERTER

( Fig. 1 : Outdoor temperature zone )
1. COOLING OPERATION
Minimum
frequency
Maximum
frequency
AOU18RLB
AOU24RLB
12rps
12rps
Indoor fan mode
Me Lo Quiet
A zone 104rps 59rps 48rps 38rps
B zone 104rps 59rps 48rps 38rps
C zone 86rps 59rps 48rps 38rps
AOU18RLB
D zone 63rps 56rps 41rps 34rps
E zone 63rps 56rps 41rps 34rps
F zone 63rps 56rps 41rps 34rps
( Table 1 : Compressor frequency range )
01-01
AOU24RLB
( Table 2 : Limit of maximum speed based on outdoor temperature )
104rps
104rps
Outdoor
temp. zone Hi
When the compressor operates for 30 minutes continuously at over the maximum frequencyⅡ,
the maximum frequency is changed from the maximum frequencyⅠto the maximum frequencyⅡ.
A sensor (room temperature thermistor) built in the indoor unit body will usually perceive
difference or variation between a set temperature and present room temperature, and
controls the operation frequency of the compressor.
* If the room temperature is 7°F(3.5°C) higher than a set temperature, the compressor operation
frequency will attain to maximum performance.
* When the room temperature is between +7°F(+3.5°C) to -1°F(-0.5°C) of the setting temperature,
the compressor frequency is controlled within the range shown in Table 1 .
However, the maximum frequency is limited in the range shown in Fig. 1 based on the
fan speed mode and the outdoor temperature.
* If the room temperature is 1°F(0.5°C) lower than a set temperature, the compressor will be
stopped.
Maximum
frequency
63rps
72rps
When the outdoor
temperature drops
97°F
(36°C)
A zone
93°F
(34°C) 90°F
(32°C)
B zone
86°F
(30°C) 70°F
(21°C)
C zone
66°F
(19°C) D zone
E zone
F zone
50°F
(10°C)
32°F
(0°C)
54°F
(12°C)
36°F
(2°C)
When the outdoor
temperature rises

2. HEATING OPERATION
( Table 3 : Compressor frequency range )
Minimum
frequency
Maximum
frequency
AOU18RLB 12rps 119rps
AOU24RLB 12rps 119rps
3. DRY OPERATION
The compressor frequency shall change according to the temperature, set temperature,
and room temperature variation which the room temperature sensor of the indoor unit body has
detected as shown in the Table 4 .
However, after the compressor is driven, the outdoor unit shall run at operation frequency of
40rps (AOU18RLB), 40rps (AOU24RLB) for 80 seconds.
( Table 4 : Compressor frequency in Dry mode )
Operating
frequency
38rps
16rps
0rps
AOU18RLB X zone
J zone
Y zone
A sensor (room temperature thermistor) built in the indoor unit body will usually perceive
difference or variation between a set temperature and present room temperature, and
controls the operation frequency of the compressor.
* If the room temperature is lower by 9°F(4.5°C) than a set temperature, the compressor operation
frequency will attain to maximum performance.
* If the room temperature is higher 1°F(0.5°C) than a set temperatire, the compressor will be
stopped.
* When the room temperature is between +1°F(+0.5°C) to -9°F(-4.5°C) of the setting temperature,
the compressor frequency is controlled within the range shown in Table 3 .
( Fig. 2 : Compressor control based on room temperature )
Operating
frequency
30rps
16rps
0rps
AOU24RLB X zone
J zone
Y zone
Ts+1°F
(Ts+0.5°C)
Ts-1°F
(Ts-0.5°C)
Ts-3°F
(Ts-1.5°C)
Ts+3°F
(Ts+1.5°C)
Room Room
temperature drops temperature rises
X zone
J zone
Y zone
01-02

4. AUTO CHANGEOVER OPERATION
( Fig. 3 : Operation flow chart )
START
Room temp.
Room temp.
>Ts+4°F(2°C)?
COOLING OPERATION
HEATING OPERATION
YES
YES
NO
NO
NO
NO
YES
YES
TS: Setting temperature
<Ts- 4°F(2°C)?
Thermostat remains
in OFF state for 6 minutes or
longer?
System stops
or operation command other than
auto changeover operation?
NO
NO
Thermostat remains
in OFF state for 6 minutes or
longer?
System stops
or operation command other than
auto changeover operation?
YES
YES
When the air conditioner is set to the AUTO mode by remote control, operation starts in the optimum
mode from among the HEATING, COOLING, DRY and MONITORING modes. During operation, the
optimum mode is automatically switched in accordance with temperature changes. The temperature
can be set between 64°F(18°C) and 88°F(30°C) in 2°F(1°C) steps.
01-03

5. INDOOR FAN CONTROL
The airflow can be switched in 5 steps such as Auto, Quiet, Lo, Me, Hi, while the indoor fan only runs.
When fan mode is set at [Auto], it operates on [Me] fan Speed.
2. FAN OPERATION
3. COOLING OPERATION
Switch the airflow [Auto], and the indoor fan motor will run according to a room temperature,
as shown in Fig. 4 .
On the other hand, if switched in [Hi] [Quiet], the indoor motor will run at a constant airflow of [Cool]
operation modes Quiet, Lo, Me, Hi, as shown in Table 5 .
( Fig. 4 : Airflow change - over ( Cooling : Auto ) )
1. Fan speed
( Table 5 : Indoor fan speed )
Operation mode Air flow mode
Speed (rpm)
Cooling/ Fan
Heating
Dry X zone: 770
J zone: 720
X zone: 900
J zone: 850
ASU18RLB
4. DRY OPERATION
Refer to the Table 5 .
During the dry mode operation, the fan speed setting can not be changed.
Hi
Hi
Me+
Me
Me
Lo
Lo
Quiet
Quiet
S-Lo
Cool air prevention
1260
1120
1020
900
790
680
270
1430
1320
1220
1020
900
720
270
1260
1020
900
770
1480
1220
1020
900
When the room
temperature rises
When the room
temperature drops
TR : Room temperature
Ts : Setting temperature
TR-Ts > 4°F
(2°C)
2°F > TR-Ts
(1°C)
4°F > TR-Ts > 2°F
(2°C) (1°C)
=
TR-Ts > 5°F
(2.5°C)
=
3°F > TR-Ts
(1.5°C)
5°F > TR-Ts > 3°F
(2.5°C) (1.5°C)
=
HIGH mode
MED mode
LOW mode
01-04
ASU24RLB

The maximum value of the indoor fan speed is set as shown in Fig. 6 based on the detected
temperature by the indoor heat-exchanger sensor on heating mode.
( Fig. 6 : Cool air prevension control )
5. HEATING OPERATION
Switch the airflow [Auto], and the indoor fan motor will run according to a room temperature,as shown in Fig. 5 .
On the other hand, if switched in [Hi] [Quiet], the indoor motor will run at a constant airflow
of [Heat] operation modes Quiet, Lo, Me, High, as shown in Table 5 .
6. COOL AIR PREVENTION CONTROL (Heating mode)
( Fig. 5 : Airflow change - over ( Heating : Auto ) )
108°F
(42°C)
86°F
(30°C)
93°F
(34°C)
Indoor heat exchanger
temperature rises
Indoor heat exchanger
temperature drops
Hi
Me+
Lo
Cool air
prevention
102°F
(39°C)
99°F
(37°C)
99°F
(37°C)
90°F
(32°C)
82°F
(28°C)
S-Lo
Switch the airflow [Auto] at cooling mode, and the indoor fan motor will run as shown in Fig. 7 .
7. MOISTURE RETURN PREVENTION CONTROL (Cooling mode& Dry mode)
( Fig. 7 : Indoor fan control )
Compressor
ON
OFF
Indoor fan
Setting air flow
Indoor fan
(as shown in Table 6)
S-Lo
OFF
10 30 60 180 60 180 60 10 30
(sec)
( Table 6 : Indoor fan speed )
X zone J zone
ASU18RLB 770rpm 720rpm
Y zone
0 270rpm 770rpm
ASU24RLB 900rpm 850rpm 0 270rpm 900rpm
Dry Cooling
TR-Ts > -3°F
(-1.5°C)
=
-5°F > TR-Ts
(-2.5°C)
-3°F > TR-Ts > -5°F
(-1.5°C) (-2.5°C)
=
TR-Ts > -2°F
(-1°C)
=
-4°F > TR-Ts
(-2°C)
-2°F > TR-Ts > -4°F
(-1°C) (-2°C)
=
When the room
temperature rises
When the room
temperature drops
TR : Room temperature
Ts : Setting temperature
LOW mode
MED mode
MED+ mode
01-05

6. OUTDOOR FAN CONTROL
( Table 8 : Outdoor fan speed )
*The outdoor fan speed mentioned above depends on the compressor frequency.
(When the compressor frequency increases, the outdoor fan speed also changes to the higher
speed. When the compressor frequency decreases, the outdoor fan speed also changes to the
lower speed.)
*After the defrost control is operated on the heating mode, the fan speed keeps at the higher speed
as Table 9 without relating to the compressor frequency.
( Table 9 : Outdoor fan speed after the defrost )
1. Outdoor Fan Motor
2. Fan Speed
AC Motor DC Motor
AOU18RLB
The Table 7 shows the type of the outdoor fan motor.
The control method is different between AC motor and DC motor.
( Table 7 : Type of motor )
Fan speed
Cooling Heating
AOU18RLB
AOU24RLB
Y
Z
Zone
Refer to Fig. 8
(rpm)
F
G
Y
Z
F
G
Dry
250/ 200
300
300
1050/ 870/ 720/ 530
1050/ 870/ 720/ 530
870/530/300
1100/ 1000/ 780/ 720/ 590/ 480 530
1100/ 1000/ 780/ 720/ 590/ 480 530
870/530/300
250/ 200
AOU24RLB
AOU18RLB 1100rpm
1100rpm
( Fig. 8 : Outside air temperature zone selection )
70°F
(21°C)
50°F
(10°C)
Outside air
temperature rises Outside air
temperature drops
Z zone
Y zone
F zone
G zone
54°F
(12°C)
36°F
(2°C)
66°F
(19°C)
32°F
( 0°C)
01-06
AOU24RLB

Each time the button is pressed, the air direction range will change as follow:
(Function Range)
Use the air direction adjustments within the ranges shown above.
The vertical airflow direction is set automatically as shown,
in accordance with the type of operation selected.
Cooling / Dry mode : Horizontal flow
Heating mode : Downward flow
When the temperature of the air being blown out is low at the start of heating operation or during
defrosting, the airflow direction temporarily becomes ①to prevent cold air being blown onto the body.
During use of the Cooling and Dry modes, do not set the Air Flow Direction Louver in the Heating
range (④～⑥ ) for long period of time, since water vapor many condense near the outlet louvers and
drop of water may drip from the air conditioner. During the Cooling and Dry modes, if the Air Flow
Direction Louvers are left in the heating range for around 20 minutes, they will automatically
return to position ③ .
( Fig. 9 : Virtical air direction range )
Cooling / Dry / Fan mode( ) :
Heating / Fan mode(
) :
3. SWING OPERATION
When the swing signal is received from the remote controller,
the vertical louver starts to swing.
(Swinging Range)
Vertical Airflow Swing Operation
Horizontal Airflow Swing Operation
When the swing signal is received from the remote controller, the horizontal louver starts to swing.
Cooling / Heating / Dry / Fan mode :
(Swinging Range)
Vertical and Horizontal Airflow Swing Operation
When the indoor fan is S-Lo or Stop mode, the swing operation is interrupted
and it stops at either upper end or bottom end.
When the indoor fan is S-Lo or Stop mode, the swing operation is interrupted
and it stops at either upper end or bottom end.
When the horizontal swing signal is input from remote control, the combination of the vertical
and horizontal swing operation is performed.
2. HORIZONTAL LOUVER CONTROL
Horizontal Louver
Each time the button is pressed, the air directionrange will change as follows.
(Function Range)
Cooling / Heating / Dry / Fan mode
( Fig. 10 : Horizontal air direction range )
Power Diffuser doesn't swing in any swing operation.
1. VERTICAL LOUVER CONTROL
Power DiffuserVertical Louver
7. LOUVER CONTROL
⑥
⑤
④
③
②
①
①②③ ④ ⑤
①
③
④
⑥
④ ⑥
① ③
① ⑤
01-07
Cooling / Heating / Dry / Fan mode

8. COMPRESSOR CONTROL
1. OPERATION FREQUENCY RANGE
The operation frequency of the compressor is different based on the operation mode as
shown in the Table 10 .
Cooling Heating
Minimum Maximum Minimum Maximum
AOU18RLB
AOU24RLB
12rps
12rps
104rps
12rps
12rps
119rps
104rps
AOU18RLB
AOU24RLB
AOU18RLB
AOU24RLB
( Table 10 : Compressor frequency range )
2. OPERATION FREQUENCY CONTROL AT NORMAL START UP
The compressor frequency soon after the start-up is controlled as shown in the Fig. 11 .
( Fig. 11 : Compressor control at start-up )
Time Time Time Time Time
(Frequency)
Frequency Frequency Frequency Frequency Frequency
Frequency
Frequency
Frequency
Frequency
Frequency
Time Time Time Time Time
(Time)
Frequency
Time 6
Frequency
Time 6
40rps 59rps 72rps 80rps 101rps 110rps
80sec 110sec 140sec 200sec 410sec350sec
3. LIMITATION OF COMPRESSOR FREQUENCY BY OUTDOOR TEMPERATURE
The minimum compressor frequency is limited by outdoor temperature as shown in the Table 11 .
( Table 11 : Limitation of compressor frequency )
AOU24RLB
Under Over Under Over Under Over
24rps 18rps 16rps12rps
32°F (0°C) 50°F (10°C) 104°F (40°C)
[ Cooling/ Dry ]
[ Heating ]
AOU18RLB
AOU18RLB
Under Ove
Under Over
r Under Over Under Over
24rps
24rps
18rps 16rps12rps
32°F (0°C) 50°F (10°C) 104°F (40°C)
Under Over Under Over
18rps 16rps 16rps
45°F (7°C)37°F (3°C) 104°F (40°C)
AOU24RLB
Under Over
24rps
Under Over Under Over
18rps 16rps 16rps
45°F (7°C)37°F (3°C) 104°F (40°C)
[ Cooling/ Dry ]
[ Heating ]
01-08
119rps
Dry
Minimum Maximum
16rps
16rps
30rps
38rps

9. TIMER OPERATION CONTROL
1. ON TIMER / OFF TIMER
The Table 12 shows the available timer setting based on the product model.
ON TIMER / OFF TIMER PROGRAM TIMER SLEEP TIMER
ASU18RLB
ASU24RLB
OFF timer : When the clock reaches the set time, the air conditioner will be turned off.
Operation mode
Stop mode
Set time of timer
ON timer : When the clock reaches the set time, the air conditioner will be turned on.
Operation mode
Stop mode
Set time of timer
The program timer allows the OFF timer and ON timer to be used in combination one time.
Operation mode
Operation will start from the timer setting (either OFF timer or ON timer) whichever is closest
to the clock's current timer setting.
The order of operations is indicated by the arrow in the remote control unit's display.
SLEEP timer operation cannot be combined with ON timer operation.
( Table 12 : Timer setting )
2. PROGRAM TIMER
Stop mode Stop mode Stop mode
Operation mode Operation mode
Set time Set time Set time Set time
9-1 WIRELESS REMOTE CONTROLLER
01-09

3. SLEEP TIMER
If the sleep is set, the room temperature is monitored and the operation is stopped automatically.
If the operation mode or the set temperature is change after the sleep timer is set, the operation is
continued according to the changed setting of the sleep timer from that time ON.
Set temperature rises
( Ts : Set temperature )
Stop of operation
Set temperature lowers
( Ts : Set temperature )
Ts
Stop of operation
In the cooling operation mode
When the sleep timer is set, the setting temperature is increased 2°F(1°C).
It increases the setting temperature another 2°F(1°C) after 1 hour.
After that, the setting temperature is not changed and the operation is stopped at the time
of timer setting.
Ts
+2°F (1°C)
+4°F (2°C)
Set 60min
In the heating operation mode
When the sleep timer is set, the setting temperature is decreased 2°F(1°C).
It decreases the setting temperature another 2°F(1°C) every 30 minutes.
Upon lowering 8°F(4°C) the setting temperature is not changed and the operation stops at
the time of timer setting.
-8°F (-4°C)
-6°F (-3°C)
-4°F (-2°C)
-2°F (-1°C)
Set 30min 30min 30min
01-10

9-2 WIRED REMOTE CONTROLLER ( OPTION )
The Table 13 shows the available timer setting based on the product model.
ON TIMER / OFF TIMER WEEKLY TIMER TEMPERATURE SET BACK TIMER
( Table 13 : Timer setting )
1. ON TIMER / OFF TIMER
Same to 9-1 1.ON TIMER / OFF TIMER and shown in those.
2. WEEKLY TIMER
This timer function can set operation times of the each day of the week.
All days can be set together,the weekly timer can be used to repeat the timer setting for all of the days.
3. TEMPERATURE SET BACK TIMER
This timer function can change setting temperature of setting operation times of the each day of the week.
This can be together with other timer setting.
Normal tmp.
ON OFF
Setting day Setting day Setting day
ON OFF ON OFF ON OFF
Set time Set time
Set back tmp.
Set time Set time
ASU18RLB
01-11
ASU24RLB

10. ELECTRONIC EXPANSION VALVE CONTROL
The most proper opening of the electronic expansion valve is calculated and controlled under the present
operating condition based on the Table 14 .
The compressor frequency, the detected temperature by the discharge temperature sensor,
the indoor heat exchanger sensor, the outdoor heat exchanger sensor, and the outdoor temperature sensor.
The expansion valve is set at 480 pulses 110seconds after the compressor had stopped.
At the time of supplying the power to the outdoor unit, the initialization of the electronic
expansion valve is operated (528 pulses are input to the closing direction).
( Table 14 : The pulse range of the electronic expansion valve control )
AOU18RLB
AOU24RLB
Operation mode Pulse range
Between 32 to 480 pulses.
Cooling / Dry mode
Heating mode
Initialization will start after 24 hours pass from the last initialization, and the compressor stops
The compressor won't enter operation status for 2 minutes and 20 seconds after the compressor is stopped,
even if any operation is given.
At the time when the air conditioner is switched from the cooling mode to heating mode, the
compressor is stopped, and the four-way valve is switched in 2 minutes and 20 seconds later after
the compressor stopped.
12. PREVENT TO RESTART FOR 3 MINUTES ( 3 MINUTES ST )
13. FOUR-WAY VALVE EXTENSION SELECT
11. TEST OPERATION CONTROL
01-12
Under the condition where the air conditioner runs, press the test run button of the remote
control, and the test operation control mode will appear. During test running, the operation lamp
and timer lamp of the air conditioner body twinkle simultaneously. Set the test operation mode,
and the compressor will continue to run regardless of whether the room temperature sensor detects.
The test operation mode is released if 60 minutes have passed after setting up the test operation.

15. MANUAL AUTO OPERATION ( INDOOR UNIT BODY OPERATION )
When the remote control is lost or battery power dissipated, this function will work without the remote control.
When MANUAL AUTO button is set more than 3seconds and less than 10seconds, MANUAL AUTO OPERATION
will be started as shown in Table 15 .To stop operation,press the MANUAL AUTO button for 3seconds.
( Table 15 : Manual auto operation )
16. FORCED COOLING OPERATION ( TEST OPERATION )
Forced cooling operation is started when press MANUAL AUTO button for 10 seconds or more.
During the forced cooling operation, it operates regardless of room temperature sensor.
Operation LED and timer LED blink at the same time during the forced cooling operation.
They blink for 1 second ON and 1 second OFF on both operation LED and timer LED (same as test operation).
Forced cooling operation is released after 60 minutes of starting operation or pressing MANUAL AUTO button
for 3 seconds.
( Table 16 : Forced cooling operation )
When FORCED COOLING OPERATION is set, the operation is controlled as shown in Table 16 .
Press and hold MANUAL AUTO
button for 3 ~ 10seconds
MANUAL AUTO
button
When the power was interrupted by a power failure, etc. during operation, the operation contents
at that time are memorized and when power is recovered, operation is automatically started with
the memorized operation contents.
When the power is interrupted and recovered during timer operation, since the timer operation time
is shifted by the time the power was interrupted, an alarm is given by blinking (7 sec ON/2 sec OFF)
the indoor unit body timer lamp.
[ Operation contents memorized when the power is interrupted ]
Operation mode
Set temperature
Set air flow
Timer mode and set time (set by wireless remote controller)
Set air flow Direction
Swing
ECONOMY operation
MINIMUM HEAT operation
14. AUTO RESTART
OPERATION MODE Auto changeover
FAN CONT. MODE Auto
TIMER MODE Continuous
SETTING TEMP. 75°F(24°C)
SETTING LOUVER Standard
SWING
ECONOMY
OFF
OFF
(No timer setting available)
Forced cooling operation
Cooling
Hi
Horizontal
(It is changed follow as setting of remote controller)
OFF
Room Temp is not controlled
Manual auto operation
-
-
OPERATION MODE
FAN CONT. MODE
TIMER MODE
SETTING TEMP.
SETTING LOUVER
SWING
ECONOMY
01-13

17. COMPRESSOR PREHEATING
18. MINIMUM HEAT OPERATION
MINIMUM HEAT OPERATION performs as below when pressing MIN. HEAT button or Weekly timer
setting on the remote controller.
Mode Heating
Setting temperature 50°F(10°C)
Fan mode Auto
LED display Economy
Defrost operation Operate as normal
( Table 17 : Minimum heat operation )
19. ECONOMY OPERATION
The ECONOMY operation functions by pressing ECONOMY button on the remote controller.
At the maximum output, ECONOMY Operation is approximately 70% of normal air conditioner operation
for cooling and heating.
The ECONOMY operation is almost the same operation as below settings.
Mode Cooling/ Dry Heating
Target temperature Setting temp.+2°F(+1°C) Setting temp.-2°F(-1°C)
( Table 18 : Economy operation )
When the outdoor heat exchanger temperature is lower than 41°F(5°C) and the all operation has
been stopped for 30 minutes, power is applied to the compressor and the compressor is heated.
(By heating the compressor, warm air is quickly discharged when operation is started.)
When operation was started, and when the outdoor heat exchanger temperature rises
01-14
to 44.6°F(7°C) or greater, preheating is ended.

01-15
21. THERMO CONTROL ( FOR INDOOR UNIT SENSOR )
22. THERMO CONTROL ( FOR WIRED REMOTE SENSOR )
20. HEAT INSULATION CONDITION ( BUILDING INSULATION )
Ts + 1°F
(Ts + 0.5°C)
Ts - 1°F
(Ts - 0.5°C)
Ts - 1°F
(Ts - 0.5°C)
Ts + 1°F
Compressor ON
(Ts + 0.5°C)
( Fig. 12 : For cooling operation )
Ts
Ts
Compressor OFF
( Fig. 13 : For heating operation )
Compressor ON
Compressor OFF
Ts + 1°F
(Ts + 0.5°C)
Ts - 1°F
(Ts - 0.5°C)
Compressor ON
Compressor OFF Compressor ON
Compressor OFF
Ts : Setting temperature
Ts : Setting temperature
( Fig. 14 : For cooling operation ) ( Fig. 15 : For heating operation )
This setting can make the room temperature control more suitable for homes or buildings
with high insulation (Function Number 95).
When the thermo sensor is turned ON it controls the compressor frequency at
initial start to prevent overshoot in heating or cooling.
When room temperature is controlled by the Indoor unit sensor, compressor operation
is as shown in Fig. 12 and 13 .
But, adjustment is possible by the room temperature correction function setting.
( Function Number 30 or 31)
When room temperature is controlled by the Wired remote sensor, compressor
operation is as shown in Fig. 14 and 15 .
But, adjustment is possible by the room temperature correction function setting.
(Function Number 92 or 93)

23. DEFROST OPERATION CONTROL
1. CONDITION OF STARTING THE DEFROST OPERATION
The defrost operation starts as shown in the following Table 19 .
2. CONDITION OF THE DEFROST OPERATION COMPLETION
Release Condition
Outdoor heat exchanger temperature sensor value is higher than 60.8°F(16°C) or
Compressor operation time has passed 15 minutes.
( Table 19 : Condition of starting defrost operation )
Defrost operation is released when the conditions become as shown in Table 20 .
( Table 20 : Defrost release condition )
If the compressor continuous operation time is less than 10 minutes,
the OFF number of the compressor is counted.
If any defrost operated, the compressor OFF count is cleared.
Integrating defrost
Normal defrost Compressor integrating operation time
Less than 40 minutes (AOU18RLB)
Less than 40 minutes (AOU24RLB)
More than 40 minutes (AOU18RLB)
More than 40 minutes (AOU24RLB)
Does not operate
Outdoor heat exchanger temp. < 1.4°F(-17°C)
(at outside air temp. > 14°F(-10°C)
Outdoor heat exchanger temp. < Outside air temp.-(12.6°F (7°C))
or Outdoor heat exchanger temp.< -13°F (-25°C)
(at -4°F (-20°C)< Outdoor air temp.< 14°F (-10°C))
More than 240 minutes
(For continuous operation)
Less than 10 minutes
( For intermittent operation )
Compressor integrating operation time
Outdoor heat exchanger
temperature below 26.6°F(-3°C)
More than 213 minutes
(For continuous operation)
Outdoor heat exchanger
temperature below 23°F(-5°C)
OFF count of the compressor
40 times
=
=
=
=
=
=
Outdoor heat exchanger temp. < Outside air temp.-(12.6°F (7°C))
or Outdoor heat exchanger temp. < -22°F(- 30°C)
(at outside air temp. < -4°F(-20°C))
=
01-16

3. Defrost Flow Chart
The defrosting shall proceed by the integrating operation time, outdoor temperature
and outdoor heat exchanger temperature as follows.
Outdoor fan : OFF
Compressor speed : 0 rps
EEV : 480pulse
4-way valve : OFF
Compressor speed : 80rps (AOU18RLB)
80rps (AOU24RLB)
(Not defrosted for 10 minutes)
Heating operation start : Compressor ON
Outdoor HEX temp.: Over 60.8°F(16°C)
or
Compressor ON time: Maximum 15 minutes
Defrost end
Integrating defrost
Defrost Indicator:
[Operation lamp]
7 sec ON / 2 sec OFF
Defrost start
Normal defrost
=
=
=
=
=
=
Compressor
OFF count :
40 times
(Less than 10min.)
Compressor
integrating
operation:
Over 240 min.
Outdoor
heat exchanger
temperature:
Below
26.6°F(- 3°C)
Compressor
integrating
operation:
Over 213 min.
Outdoor
heat exchanger
temperature:
Below 23°F
(- 5°C)
Intermittent operation Continuous operation
=
-4°F (-20°C)<
Outside air temp.
< 14°F (-10°C)
Outside air temp.
< -4°F(-20°C)
Outdoor HEX temp.
< 1.4°F(-17°C)
Outdoor HEX temp.
< Outside air temp.
-(12.6°F (7°C))
or Outdoor HEX temp.
< -13°F (-25°C)
Outdoor HEX temp.
< Outside air temp.
-(12.6°F (7°C))
or Outdoor HEX temp.
< -22°F(-30°C)
Outside air temp.
> 14°F(-10°C)
01-17