Valve Close Detection Control; Compressor Discharge High Pressure Protection Control; Compressor Heater Control - Panasonic CU-3E19RBU-5 Service Manual

13.15 Valve close detection control

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This control detects 3-way valve close condition to prevent damage to refrigerant cycle.
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Start conditions:
For all connected indoor units, if Indoor intake temperature — indoor piping temperature are between 28.4°F
o
(-2°C) and 35.6°F (2°C) continuously for 5 minutes after compressor ON at first cooling operation.
The first cooling operation is defined as cooling operation is ON for less than 8 minutes after new installation
o
or after pump down.

Control content
During this control, compressor stop, indoor units' Timer LED will blink. ("F91" is indicated at indoor units)
o

Error reset can be done by power supply reset or reset by using remote control.

13.16 Compressor discharge high pressure protection control


This control protect by using high pressure switch during operation.

Start conditions
High pressure switch is activated (from normally close to open) when outdoor operation mode is cooling or
o
heating during compressor running.

Control 1 content
Compressor stop when high pressure switch is opened and restart after high pressure switch closed. If this
o
condition happen 4 times within 30 minutes, "F94" is indicated.
After 30 minutes, counter is reset if this condition does not happen for 4 times.
o

Control 1 stop conditions
Power supply reset
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Reset by using remote control
o

13.17 Compressor Heater control

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Specification:
Power: 30 Watt
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Voltage: 240 Volt
o

Purpose:
To control compressor crankcase heater operation to melt ice on compressor during heating operation
o

Starting conditions:
When outdoor air temperature ≤ 4°C (39°F) and compressor top temperature ≤ 21°C (70°F)
o

Control contents:
Power supply to compressor heater is ON
o

Cancel conditions:
When outdoor air temperature exceeds by 6°C (43°F) or
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When compressor top temperature exceeds 26°C (79°F)
o
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