Fujitsu ASU09RL2 Service Instructions Manual 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 22 : Anti-freezing Protection Operation / Release Temperature)
Outdoor temperature
Over than 10°C (50°F)
or 12°C (53.6°F)
Less than 10°C(50°F)
or 12°C (53.6°F)
4. COOLING PRESSURE OVERRISE PROTECTION
When the outdoor unit heat exchange sensor temperature rises to 67°C (152.6°F) 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
63°C (145.4°F)
The compressor frequency is
decreased 25rps every 120seconds.
(131°F)
55°C
The compressor frequency is
decreased 3rps every 60seconds.
(127.4°F)
53°C
It returns to the normal operation
Temperature
*1
*2
4°C (39.2°F)
*1
*2
*1. When the temperature rises.
*2. When the temperature drops.
Compressor is stopped
Stable zone
Indoor heat exchange
temperature drops
Temperature
7°C (44.6°F)
13°C (55.4°F)
50°C (122°F)
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