Protection Control - Panasonic CU-J50DBE8 Service Manual

9.6.8. Thermostat Control
• Depending on differences between room temperature and setting temperature, compressor operation is decided and starts
operation.
• If temperature difference matches values shown below, thermostat switches off or on accordingly.
9.7.

Protection Control

9.7.1. Outdoor Low-pressure Protection Control
• The purpose of low-pressure protection control is gas leakage detection control.
• The low-pressure protection control starts when low-pressure switch is activated less than 15 minutes after compressor startup.
• During this protection control, compressor is shut down, indoor unit is set to thermo-off status.
• After 6 occasions, suction pressure error is displayed; all operation stopped except outdoor fan remaining heat removal control.
9.7.2. Outdoor High-pressure Protection Control
• The high-pressure protection control starts when high-pressure switch is activated less than 15 minutes after compressor
startup.
• During this protection control, compressor is shut down. And indoor unit is set to thermo-off status.
• After 6 occasions, high-pressure protection error is displayed; all operation stopped except outdoor fan remaining heat removal
control.
9.7.3. Discharge Temperature Protection Control
• The discharge temperature protection control starts when abnormal compressor temperature 115°C is detected when outdoor
unit is operating in cooling operation.
• During this protection control, compressor is shut down. And indoor unit is set to thermo-off status.
• After 6 occasions, high-pressure protection error is displayed; all operation stopped except outdoor fan remaining heat removal
control.
9.7.4. Over Current Protection Control
• The purpose of over current protection control is to protect the air conditioner from over current.
• The over current protection control starts when input current from CT is maintained at 20A or more for 2 seconds when the
outdoor unit is starting up or during cooling operation.
• During this protection control, compressor is shut down. And indoor unit is set to thermo-off status.
• After 4 occasions, over current protection error is displayed; all operation stopped except outdoor fan remaining heat removal
control.
9.7.5. CT Disconnection Detection Control
• CT disconnection detection control detects if the CT sensor works normally.
• The CT disconnection detection activates when:
- CT input value is maintained at compressor shutdown status (1.5A or less) consecutively for 2 seconds when the compressor
is operating;
- During this condition, compressor is shut down and indoor unit is set to thermo-off status.
- After 4 occasions, CT sensor error is displayed; all operation stopped except outdoor fan remaining heat removal control.
- CT input value is maintained at compressor operation status (5A or more) consecutively for a period of 60 seconds when the
compressor is shut down.
- During this condition, CT sensor error is displayed.
9.7.6. Connection Capacity Protection Control
• The purpose of connection capacity protection control is to ensure the total capacity of connected indoor units is within
acceptable range.
Model Number Min. Capacity (kW)
CU-J14DBE5
CU-J18DBE5
CU-J24DBE5
CU-J28DBE5
CU-J34DBE5
• During this protection control, connection capacity error is displayed; all operations stopped.
Cooling Mode
Soft Dry Mode
Max. Capacity (kW)
5.3 6.9
5.3 6.9
5.3 6.9
6.3 9.8
7.3 12.3
Thermostat OFF
-1.5°C
-2.5°C
Model Number
CU-J28DBE8
CU-J34DBE8
CU-J43DBE8
CU-J50DBE8
43
Thermostat ON
-0.5°C
-2.5°C
Min. Capacity (kW) Max. Capacity (kW)
6.3
7.3
10.2
12.7
9.8
12.3
13.8
15.8