Protection Control; Freeze Prevention Control (Cool); Dew Prevention Control (Cool); Electronic Parts Temperature Rise Protection 1 (Cool) - Panasonic CU-2E18NBU Service Manual

13. Protection Control

13.1 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.

13.2 Dew Prevention control (Cool)

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

13.3 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 5.5A
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.

13.4 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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