Panasonic Cs A7gkd Cs A9gkd Cs A12gkd Series Repair Manual

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12.2. Cooling Operation
• Cooling operation can be set using remote control.
• This operation is applied to cool down the room temperature reaches the setting temperature set on the remote control.
• The remote control setting temperature, which takes the reading of intake air temperature sensor, can be adjusted from 16°C to
30°C.
• During cooling operation, the compressor will stop running and restart as shown in below figure.
12.2.1. Cooling Operation Time Diagram 
						

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12.3. Soft Dry Operation
• Soft Dry operation can be set using remote control.
• Soft Dry operation is applied to dehumidify and to perform a gentle cooling to the room.
• This operation starts when the intake air temperature sensor reaches the setting temperature on the remote control.
• When operation begins, Soft Dry will be switched “ON” for a maximum 10 minutes, then Soft Dry operation will be turned “OFF”
for a minimum 6 minutes. After that, the Soft Dry operation will be “ON” and “OFF” based on the setting temperature as shown in
below figure.
• However after 3 minutes of compressor off, during Soft Dry “OFF” (within 6 minutes Soft Dry restart control), the indoor unit will
start to operate at normal Cooling mode if the intake temperature is higher than Cooling “ON” point.
12.3.1. Soft Dry Operation Time Diagram 
						

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12.4. Automatic Operation
• Automatic operation can be set using remote control.
• This operation starts to operate with indoor fan at SLo speed for 25 seconds to judge the intake air temperature.
• After judged the temperature, the operation mode is determined by referring to the below standard.
• Then, the unit start to operate at determined operation mode, until it is switched off using remote control, with the setting
temperature as shown in below table.
• Operation mode will be determine again for judgement after 1 hour of operation, if the room temperature reaches to set
temperature and compressor off time is over 7 minutes 30 seconds continuously.
The present operation mode will be continued, if the room temperature does not reach to set temperature (Compressor keeps running)
eventhough after 1 hour from automatic operation mode started.
Automatic Set Temperature
Refer as below. 
						

							34 • Automatic Set Temperature
For each operation, set temperature will automatically set as shown below.
However it can be selected 2°C higher or 2°C lower from standard set temperature by pressing the “Room Temperature Setting
button”.
• The setting temperature for all the operations can be changed one level up or one level down from the standard temperature as
shown in below table by pressing on the temperature up or temperature down button at remote control.
• The operation mode judging temperature and standard setting temperature can be increased by 2°C permanently, by open the
circuit of JX1 at indoor electronic controller.
12.5. Operation Control
12.5.1. Restart Control (Time Delay Safety Control)
•When the thermo-off temperature (temperature which compressor stops to operate) is reached during:-
- Cooling/Heating 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.
12.5.2. 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 (cooling mode)/5°C (heating mode) 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. 
						

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12.5.3. 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.
12.5.4. 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.
12.5.5. Starting current Control
•When the compressor, outdoor fan motor and indoor fan motor are simultaneously started, the indoor fan motor will start to
operate at 1.6 second later.
•The reason of the difference is to reduce the starting current flow.
12.5.6. Freeze Preventive Control
• To protect indoor heat exchanger from freezing and to prevent higher volume of refrigerant in liquid form return to compressor.
• This control will activate when the temperature of indoor heat exchanger falls below 2°C continuously for more than 4 minutes.
• The current fan speed will change to freeze prevention speed after 70 seconds compressor on. When indoor pipe temperature
reaches certain temperature for 5 sec. the speed will be increased as in below figure.
• Compressor will turn off when indoor temperature falls below 2°C for more than 4 minutes. It will restart again when indoor heat
exchanger temperature rises to 10°C.
• Restart control (Time Delay Safety Control) will be applied in this control. 
						

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12.5.7. Dew Prevention control
• To prevent dew formation at indoor unit discharge area.
• This control will be activated if:-
- Cooling mode or Quiet mode.
- Remote Control setting temperature is less than 25°C.
- Fan speed is at CLo or QLo.
- Room temperature is constant (±1°C) for 30 minutes.
- Compressor is continuously running.
• Fan speed and angle of horizontal louver (vertical airflow angle) will be adjusted accordingly in this control.
- Fan speed will be increased slowly if the unit is in quiet mode but no change in normal cooling mode.
- The angle of horizontal louver will be changed as below figure.
Note:
A = Normal operation angle of rotation
B = Dew prevention angle of rotation
Horizontal Louver Angle
During Anti-Dew condensation prevention, the horizontal louver angle in Auto-control are as below figure.
During Anti-Dew condensation prevention, the horizontal louver angle in Manual control are as below figure.
Operation mode Airflow direction auto-control Airflow direction manual control
Cooling, Soft Dry A 12° ~ 32°12°, 15°, 20°, 26°, 32°
B20° ~ 30°22°, 24°, 26°, 28°, 30° 
						

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12.5.8. 30 Minutes Time Save Control
• The compressor will start automatically if it has stopped for 30 minutes and the intake air temperature falls between the
compressor OFF temperature (A) and compressor ON temperature (B) during the period.
• This is to maintain the room temperature as set. Despite of this, it is to prevent a wrong judgement of intake air temperature due
to poor installation near the sensor area.
12.5.9. Compressor Overload Protection Control
Outdoor Fan Control
• If the temperature of the indoor heat exchanger rises to 51°C, outdoor fan stops. The outdoor fan restarts when the indoor heat
exchanger temperature falls to 49°C.
Compressor high pressure protection
• If the indoor heat exchanger becomes 65°C or more, the compressor will stop and restart automatically.
(Time Delay Safety Control - 4 minutes waiting).
• This is to reduce the pressure, as to reduce the indoor heat exchanger temp. Nevertheless, is to protect the compressor from
overload of too high temperature.
12.5.10. 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.
12.5.11. Outdoor Fan Motor Control
• When compressor stops (reaches room temperature), outdoor fan will operate for 30 seconds (forced operation).
• This is to release the heat and to obtain the lowest pressure as fast as possible.
12.5.12. 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 39°C or operation over 4 minutes. 
						

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12.5.13. Anti Cold Draft Control
• This operation is to prevent the Cold Draft during Heating mode operation.
• The operation will start when compressor OFF (Thermo OFF) during Heating operation.
• For the first 30 sec. from compressor OFF (Thermo OFF), Indoor fan speed will operate accordingly to the Indoor heat
exchanger temperature as shown below:
• After 30 sec. from compressor OFF (thermo OFF), Indoor fan will run at SSLo speed only.
• Anti Cold Draft Control will stop when:
- Intake temperature < set temperature. (Time Delay Safety Control 4 minutes waiting is valid)
- 30 Minutes Time Save Control activates. 
						

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12.5.14. Deicing Control
Deice starts to prevent frosting at outdoor heat exchanger.
• Normal Deicing
Deice operations detection commences after 30 minutes of Heating operation starts or 60 minutes after previous deice
operation. If the TRS (Thermal Reed Switch) senses the outdoor piping temperature drops to -3°C (TRS CLOSE) or less 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
1. 12 minutes after deicing operation starts;
2. TRS senses the outdoor piping temperature rises to 4°C (TRS OPEN).
• Once deicing operation starts, it will not end for 60 seconds.
• After deicing operation, compressor stops for 30 seconds and 4-way valve stays at cooling position for 10 seconds.
Deicing will not end immediately as time delay (Td) is valid as shown below: 
						

							40 Normal Deicing Time Diagram
Overload Deicing Time Diagram