Various Protections - Fujitsu AB F18LAT Series Service Instruction

1-22. VARIOUS PROTECTIONS

1. DISCHARGE GAS TEMPERATURE OVER RISE PREVENTION CONTROL
The discharge gas thermosensor (discharge thermistor : Outdoor side) will detect discharge gas
temperature.
When the discharge temperature becomes higher than 104°C, the compressor frequency
is decreased 20 Hz, and it continues to decrease the frequency for 20 Hz every 120 seconds until
the temperature becomes lower than 101°C.
When the discharge temperature becomes lower than 101°C, the control of the compressor
frequency is released.
When the discharge temperature becomes higher than 110°C, the compressor stops
2. CURRENT RELEASE CONTROL
The compressor frequency is controlled so that the outdoor unit input current does not exceeds
the current limit velue that was set up with the outdoor temperature.
The compressor frequency returns to the designated frequency of the indoor unit at the time
when the frequency becomes lower than the release value.
(Table 12 : Current Release Operation Value / Release Value)
[ Heating ]
[ Cooling ]
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 13 : Anti-freezing Protection Operation / Release Temperature)
Outdoor temperature
Over than 10°C
or 12°C
Less than 10°C
or 12°C
AO*A18LALL
AO*B18LALL
OT (Control / Release)
7.0A / 6.5A
17°C
9.0A / 8.5A
12°C
10.5A / 10.0A
5°C
12.0A / 11.5A
OT : Outdoor Temperature
AO*A18LALL
AO*B18LALL
OT (Control / Release)
4.5A / 4.0A
46°C
6.0A / 5.5A
40°C
8.5A / 8.0A
OT : Outdoor Temperature
Temperature
*1
*2
4°C
*1
*2
*1. When the temperature rises.
*2. When the temperature drops.
AO*A24LALL
AO*B24LALL
OT (Control / Release)
7.0A / 6.5A
17°C
9.0A / 8.5A
12°C
11.5A / 11.0A
5°C
13.0A / 12.5A
OT : Outdoor Temperature
AO*A24LALL
AO*B24LALL
OT (Control / Release)
7.0A / 6.5A
46°C
9.5A / 9.0A
40°C
11.5A / 11.0A
OT : Outdoor Temperature
Temperature
7°C
13°C
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