Panasonic Cs A18ekh Cs A24ekh Cu A18ekh Cu A24ekh Repair Manual

							31 • The operation mode judging temperature and standard setting temperature can be increased by 2°C permanently, by open the
circuit of JX03 at printed circuit board indoor unit.
11.5. Operation Control
(For 11.5.1. to 11.5.7. information applies only to Cooling and Soft Dry Operation)
11.5.1. Restart Control (Time Delay Safety Control)
• When the thermo-off temperature (temperature which compressor stops to operate) is reached during:-
- Cooling operation - the compressor stops for 3 minutes (minimum) before resume operation.
- Soft Dry operation - the compressor stops for 6 minutes (minimum) before resume operation.
• If the operation is stopped by the remote control, the compressor will not turn on within 3 minutes from the moment operation
stop, although the unit is turn on again within the period.
• This phenomenon is to balance the pressure inside the refrigerant cycle.
11.5.2. 7 Minutes Time Save Control
• The compressor will start automatically if it has stopped for 7 minutes and the intake air temperature falls between the
compressor ON temperature (A) and compressor OFF temperature (B) during the period.
• This phenomenon is to reduce the built up humidity inside a room.
11.5.3. 60 Seconds Forced Operation
• Once the air conditioner is turned on, the compressor will not stop within 60 seconds in a normal operation although the intake air
temperature has reached the thermo-off temperature. However, force stop by pressing the OFF/ON operation button at the
remote control is permitted.
• The reason for the compressor to force operate at minimum 60 seconds is to allow the refrigerant oil run in a full cycle and return
back to the outdoor unit. 
						

							32
11.5.4. Anti-Freezing Control
• If the temperature of the indoor heat exchanger falls below 2°C continuously for 4 minutes or more, the compressor turns off.
The fan speed setting remains the same.
• This phenomenon is to protect the indoor heat exchanger from freezing and to prevent higher volume of refrigerant in liquid form
returning to the compressor.
• Compressor will restart again when the indoor heat exchanger temperature rises to 10°C (Recovery).
• Restart control (Time Delay Safety Control) will be applied in this Control if the recovery time is too short.
11.5.5. Compressor Reverse Rotation Protection Control
• If the compressor is operating continuously for 5 minutes or longer and the temperature difference between intake air and indoor
heat exchanger is 2.5°C or less for continuous 2 minutes, compressor will stop and restart automatically.
• Time Delay Safety Control is activated before the compressor restart.
▲ T = Intake air temperature - Indoor heat exchanger temperature
• This is to prevent compressor from rotate reversely when there is an instantaneous power failure.
11.5.6. Starting Current Control
• When the compressor, outdoor fan motor and indoor fan motor are simultaneously started, the indoor fan motor will start to oper-
ate at 1.6 second later.
• The reason of the difference is to reduce the starting current flow.
11.5.7. Anti-Dew Formation Control
• Purpose is to prevent dew formation on indoor unit air discharge area.
• When room temperature is constant (±1°C) the following conditions occur for 30 minutes continuously, anti-dew formation will
activate:
- Remote Control setting temperature is less than 25°C.
- Compressor is on.
- Cooling operation mode.
-
Indoor Fan motor operate at Low fan speed or QLo.
• This control is cancelled immediately when above condition is changed.
• Anti-Dew formation is control by:
1. Increasing Air Flow Volume
a. Lo fan speed
Lo fan speed is changed to Lo+ after 30 min to prevent dew formation. 
						

							33 b. QLo fan speed
Dew formation may occurs at QLo cool, therefore QLo cool is operated only 1 hr 30 min (1 hr QLo, 30 min QLo +100
rpm). After that, it operates at QLo +180rpm (However Quiet LED remains on).
2. Norrowing
Vertical Airflow Direction
–During Anti-dew condensation prevention, Airflow Direction Auto-control angle change from 10° - 38° to 10° - 27° under
Cooling and Soft Dry operation mode.
–During Anti-dew condensation prevention, Airflow Direction Manual control angle change from 10°, 14°, 18°, 22°, 27° to
10°, 13°, 16°, 19°, 22° under Cooling and Soft Dry operation mode.
3. Narrowing
Horizontal Airflow Direction
–During Anti-dew condensation prevention, Airflow Direction Auto-control angle change form 0° - 44° to 14° - 30° under 
Cooling and Soft Dry operation mode. 
						

							34 –During Anti-dew condensation prevention, Airflow Direction Manual control angle change from 0°, 11°, 22°, 33°, 44° to
14°, 18°, 22°, 26°, 30° under Cooling and Soft Dry operation mode.
(For 11.5.8 to 11.5.14 information applies only to Heating Operation)
11.5.8. Restart Control (Time Delay Safety Control)
• When the thermo-off temperature (temperature which compressor stops to operate) is reached during:-
- Heating operation - the compressor stops for 3 minutes (minimum) before resume operation.
• If the operation is stopped by the remote control, the compressor will not turn on within 3 minutes from the moment operation
stop, although the unit is turn on again within the period.
• This phenomenon is to balance the pressure inside the refrigerant cycle.
11.5.9. Compressor Reverse Rotation Protection Control
• If the compressor is operating continuously for 5 minutes or longer and the temperature difference between indoor heat
exchanger and intake air is 5°C or less for continuous 2 minutes, compressor will stop and restart automatically.
• Time Delay Safety Control is activated before the compressor restart.
▲ T = Indoor heat exchanger temperature - Intake air temperature
• This is to prevent compressor from rotate reversely when there is an instantaneous power failure.
11.5.10. Overload Protection Control
• Outdoor Fan Control
- If the temperature of the Outdoor Heat Exchanger less than -3°C, Outdoor Fan is ON. The Outdoor Fan stop, when Outdoor
Heat Exchanger temperature is Tb or more according to Outdoor Air Temperature region as table below:
The Outdoor Fan restarts when the indoor heat exchanger temperature falls to 49°C.
During starting of Heating mode and after deice, Outdoor Fan ON for 90 sec. (Hi).
• Compressor High Pressure Control
- If the indoor heat exchanger becomes 68°C or more, the compressor will stop and restart automatically.
- Time Delay Safety Control is activated before the compressor restart. 
						

							35
11.5.11. 4-Way Valve Control
• 4-way valve always on during Heating operation. (except deicing operation)
• When the unit is switched off by remote control during Heating operation, the 4-way valve stay at Heating position for 5 minutes.
• This is to prevent the refrigerant flow process sound for being occur.
11.5.12. Hot Start Control
• Hot Start Control is to prevent cool air discharge into the room when heating operation start.
• When Heating operation starts, Indoor fan will not start until the indoor heat exchanger reaches 30°C as diagram shown.
• Hot start is completed when indoor heat exchanger rises to 42°C or operation over 4 minutes.
11.5.13. Anti Cold Draft Control
11.5.14. Deicing Control
Deice starts to prevent frosting at outdoor heat exchanger.
• Normal Deicing
Deice operation detection commences in Heating operation starts or 60 minutes after previous deice operation. If the outdoor
piping temperature drops to -4°C for 50 sec. continuously during compressor is in operation, deice will start.
(There is no detection during Outdoor Fan stops.)
• Overload Deicing
During heating operation, if the outdoor Fan OFF duration (due to overload control) is accumulated up to 60 minutes and after
compressor starts for 1 minutes, deicing starts.
• Deicing ends when
(a) 12 minutes after deicing operation starts;
(b) The outdoor piping temperature rises to about 12°C.
• After deicing operation, compressor stops for 30 seconds and 4-way valve stays at cooling position for 10 seconds. 
						

							36 a) Normal Deicing Time Diagram
(b) Overload Deicing Time Diagram 
						

							37
11.6. Indoor Fan Speed Control
• Indoor Fan Speed can be set using remote control.
11.6.1. Fan Speed Rotation Chart
11.6.2. Automatic Fan Speed Control
• When set to Auto Fan Speed, the fan speed is adjusted between maximum and minimum setting as shown in the table.
- Fan speed rotates in the range of Hi, Me and Lo-.
- Deodorizing Control will be activated.
Speed
CS-A24EKH CS-A18EKH
Cool, Dry Heat
S Hi Hi 1650 1430
Hi 1570 1400
Me Me 1480 1320
Lo+ Lo 1380 1270
Lo 1280 1190
Lo- Lo- 1070 980
S Lo S Lo 830 760
SS Lo 300 300
Q SHi Q Hi 1550 1330
Q Hi 1470 1300
Q Me Q Me 1380 1220
Q Lo 1280 1170
Q Lo 1180 1090 
						

							38 • Auto Fan Speed during Cooling operation:
1. Indoor fan will rotate alternately between off and on as shown in below diagram.
2. At the beginning of each compressor start operation, indoor fan will increase fan speed gradually for deodorizing purpose.
3. For the first time the compressor operate, indoor fan will be switched to Hi fan speed from Lo- after 70 seconds from the
start of compressor. This cause the room temperature to achieve the setting temperature quickly.
4. During compressor stop, indoor fan will operate at Lo- for the beginning 20 seconds to prevent higher volume of refrigerant
in liquid form returning to the compressor.
5. After the compressor at turn off condition for 3 minutes, indoor fan will start to operate at Lo- to circulate the air in the
room. 
This is to obtain the actual reading of the intake air temperature.
6. For the resume of compressor operation, indoor fan will operate at Me fan speed to provide comfort and lesser noise
environment, after 70 seconds from the restart of compressor.
• Auto Fan Speed during Soft Dry operation:
1. Indoor fan will rotate alternately between off and Lo-.
2. At the beginning of each compressor start operation, indoor fan will increase fan speed gradually for deodorizing purpose.
3. When compressor at turn off condition for 6 minutes, indoor fan will start fan speed at Lo- to circulate the air in the room.
This is to obtain the actual reading of intake air temperature.
• Auto Fan Speed during Heating operation.
1. Indoor fan will rotate in the range of SLo → Me according to the heat exchanger temperature. 
						

							39
11.6.3. Manual Fan Speed Control
• Manual fan speed adjustment can be carried out by using the Fan Speed selection button at the remote control.
• There are 3 types of fan speed settings: Lo, Me, Hi.
11.7. Outdoor Fan Speed Control
• There is 2 speed for outdoor fan motor. Outdoor fan speed can be changed to Hi or Lo according to outdoor temperature.
• For Cooling or Soft Dry operation when outdoor temperature reaches to 31°C (Hi-speed), 29°C (Lo-speed).
• For Heating operation when outdoor temperature reaches to 13.5°C (Hi-speed), 15.5°C (Lo-speed)
• When the air conditioner is turned on, the compressor and the outdoor fan will operate simultaneously.
• Likewise, both compressor and outdoor fan will stop at the same time if the unit is turned off.
11.8. Vertical Airflow Direction Control
11.8.1. Auto Control
(Cooling and Soft Dry Operation condition)
• When the vertical airflow direction is set to Auto using the
remote control, the louver swings up and down as shown in
the diagram.
• When stopped with remote control, the discharge vent is
reset, and stop at the closing position.
• During Cooling operation or Soft Dry operation, indoor fan
motor may stop to rotate at certain periods. At that condition,
the louver will stop swinging and rest at the upper limit.Cooling and Soft Dry Operation
(Heating Operation condition)
• When the piping air temperature reaches 38°C, the
• louver is changed from upper to lower limit. When the
• piping air temperature falls to 35°C, the louver is changed
from lower to upper limit.Heating Operation
11.8.2. Manual Control
• When the vertical airflow direction is set to Manual using the remote control, the automatic airflow is released and the airflow
direction louver move up and down in the range shown in the diagram.
• The louver can be adjusted by pressing the button to the desired louver position.
• When stopped with remote control, the discharge vent is reset, and stop at the closing position.
Cooling and Soft Dry Operation Heating Operation 
						

							40
11.9. Horizontal Airflow Direction Control
11.9.1. Auto Control
• When the horizontal airflow direction is set to Auto using the
remote control, the vanes swings left and right for Cooling
and Soft Dry (0°-44°), Heating (8°-36°) as shown in the
diagram.
• When stopped with remote control, the discharge vane is
reset, and stop at the reset position.
• During Cooling operation or Soft Dry operation, indoor fan
motor may stop to rotate at certain periods. At that condition,
the vane will stop swinging and rest at 22° angle.
• During Heating operation, the piping air temperature
reaches 38°C, the vanes swings left and right. When the
piping air temperature falls to 35°C, the vanes will stop
swing and rest at 22°.
11.9.2. Manual Control
• When the horizontal airflow direction is set to Manual using
the remote control, the automatic airflow is released and the
airflow direction vane move left and right in the range shown
in the diagram.
The louver can be adjusted by pressing the button to the
desired vane position.
• When stopped with remote control, the vanes is reset, and
stopped at reset position.