Fujitsu ASU18RLQ Service Instructions Manual page 31

(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 17 : Anti-freezing Protection Operation / Release Temperature)
Temperature
A-D
E,F
(4). COOLING PRESSURE OVERRISE PROTECTION
When the outdoor unit heat exchange sensor temperature rises to temperature
compressor is stopped and trouble display is performed.
(Table 18 : Cooling Pressure Over Rise Protection Function Temperature)
Temperature
ASU15RLQ
ASU18RLQ
(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
Temperature
The compressor frequency is
precisely controlled so that
it does not exceeds Temperature .
Temperature
It returns to the normal operation
Compressor Operation
[ ASU15/18RL ]Q
39Hz or greater 38Hz
Frequency down every 120 seconds
30
38Hz
19 29Hz 18Hz
OFF
18Hz
Temperature
39°F(4°C) 45°F(7°C)
39°F(4°C) 55°F(13°C)
153°F(67°C)
153°F(67°C)
Refer to below
05-18
Temp
ASU15/18RLQ 131°F(55°C)
Temperature
Temperature
or greater, the
Temp Temp
127°F(53°C) 126°F(52°C) 122°F(50°C)
Temp