Protection Control; Freeze Prevention Control (Cool); Dew Prevention Control (Cool); Electronic Parts Temperature Rise Protection 1 (Cool) - Panasonic CU-4E23QBR Service Manual

14. Protection Control

14.1 Freeze Prevention Control (Cool)


When received freeze prevention signal from indoor unit, the compressor frequency changes according to indoor
heat exchanger temperature.

When indoor unit request capability OFF due to freeze condition, immediately the capability supply to targeted
indoor unit stops.

14.2 Dew Prevention Control (Cool)


When received dew prevention signal from indoor unit, which according to indoor intake temperature and indoor
heat exchanger temperature the compressor frequency changes.

14.3 Electronic Parts Temperature Rise Protection 1 (Cool)


This control prevents electronic parts temperature rise during cooling overload condition.

Start conditions:
Outdoor ambient temperature is at protection region as shown in figure below:
o
Outdoor unit total current is above 5.0A.
o

Control content
Outdoor fan speed is adjusted accordingly.
o

Control stop condition
When outdoor ambient temperature is back to normal region.
o

During this control, outdoor fan speed does not reduce for Quiet operation.

14.4 Electronic Parts Temperature Rise Protection 2 (Cool)


This control prevents electronic parts temperature rise during cooling/dry operation.

Start conditions:
Total current is at protection region as shown in figure below:
o

Control content
Outdoor fan speed is adjusted accordingly.
o

Control stop conditions
When total current is back to normal region.
o

During this control, outdoor fan speed does not reduce for Quiet operation.
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