Fujitsu ASU 9RLF1 Service Instruction page 22

3. ANTIFREEZING CONTROL (Cooling and Dry mode)
The compressor frequency is decrease on cooling & dry mode when the indoor heat exchanger
temperature sensor detects the temperature lower than Temperature .
Then, the anti-freezing control is released when it becomes higher than Temperature .
(Table 24 : Anti-freezing Protection Operation / Release Temperature)
Outdoor temperature
Over than 10°C
*1
or 12°C
*2
Less than 10°C
*1
or 12°C
*2
*1. When the temperature drops.
*2. When the temperature rises.
4. COOLING PRESSURE OVERRISE PROTECTION
When the outdoor unit heat exchange sensor temperature rises to 152.6°F(67°C) or greater,
the compressor and the outdoor fan motor are stopped and trouble display is performed.
5. HIGH TEMPERATURE RELEASE CONTROL ( HEATING MODE )
On heating mode, the compressor frequency is controlled as following based on the
detection value of the indoor heat exchanger temperature sensor.
[ Control System ]
Indoor heat exchange
temperature rises
145.4°F
(63°C)
The compressor frequency is
decreased 25rps every 120seconds.
131.0°F
(55°C)
The compressor frequency is
decreased 3rps every 60seconds.
127.4°F
(53°C)
It returns to the normal operation
Temperature Temperature
39.2°F
(4°C)
Compressor is stopped
Stable zone
Indoor heat exchange
temperature drops
44.6°F
(7°C)
55.4°F
(13°C)
122.0°F
(50°C)
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