Panasonic CU-B14DBE5, Service Manual, Page: 28 / 109

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9.6.7. Thermostat Control
• Depending on differences between room temperature and setting temperature, compressor operation is decided and starts oper-
ation.
• If temperature difference matches values shown below, thermostat switches off.
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 star-
tup.
• 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 out-
door 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 accept-
able range.
• During this protection control, connection capacity error is displayed; all operations stopped.
Cooling Mode -1.5
°
C
Soft Dry Mode -2.5
°
C
Model Number Min. Capacity (kW) Max. Capacity (kW) Model Number Min. Capacity (kW) Max. Capacity (kW)
CU-J14DBE5 5.3 6.9 CU-B28DBE8 6.3 9.8
CU-J18DBE5 5.3 6.9 CU-B34DBE8 7.3 12.3
CU-J24DBE5 5.3 6.9 CU-B43DBE8 10.2 13.8
CU-J28DBE5 6.3 9.8 CU-B50DBE8 12.7 15.8
CU-J34DBE5 7.3 12.3