Fujitsu ARU7RLF Service Instruction page 34

4. COOLING PRESSURE OVER RISE PROTECTION
When the outdoor unit heat exchange sensor temperature rises to 158.9 6°F(70.5 3°C) or greater,
the compressor is stopped and error display is indicated.
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.
(Fig. 18 : Heating Overload Protection Control)
Indoor heat exchange
temperature
Compressor is OFF
145.4°F(63°C)
The compressor frequency is
decreased 10rps every 20 seconds.
132.8°F(56°C)
The compressor frequency is
decreased 6rps every 60 seconds.
129.2°F(54°C)
The compressor frequency is
decreased 2rps every 60 seconds.
A°F(A°C)
Release
B°F(B°C)
6. HIGH PRESSURE PROTECTION
(1).
When the pressure switch becomes OFF (Open : higher than 609.2 psi / 4.2 MPa),
the compressor is stopped.
It is released when the pressure switch becomes ON (Close : lower than 464.1 psi / 3.2 MPa)
after 3 minutes of compressor stop.
(2).
When the pressure switch is opened for 10 seconds from power on, all of outdoor unit operation is stopped.
The outdoor unit will start up if the pressure switch is returned to ON after 10 seconds has passed.
When 10 minutes (Cooling) or 3 minutes (Heating) has passed from the compressor stop and
pressure switch becomes ON, protection is released and the compressor will restart.
7. COMPRESSOR TEMPERATURE PROTECTION
Compressor temperature sensor is monitoring the compressor temperature.
When the compressor temperature sensor detects higher than Temperature ,
the compressor is stopped.
When 3 minutes has passed from the compressor stop and the compressor temperature sensor detects
lower than Temperature , protection is released and the compressor will restart.
AOU18RLXFZ
AOU24RLXFZ
AOU36RLXFZ
Stable range
Release
Temperature Temperature
230°F
(110°C)
257°F
(125°C)
heat exchange
Outdoor
tempreture
15.8°F(-9°C) = < Th
12.2°F(-11°C) = < Th <
15.8°F(-9°C)
8.6°F(-13°C) = < Th <
12.2°F(-11°C)
5.0°F(-15°C) = < Th <
8.6°F(-13°C)
5.0°F(-15°C)
Th <
176°F
(80°C)
01-30
+ - + -
In one operation of All indoor unit
the indoor unit opeate,
: Qu air than : Qu air
A°F B°F A°F
(A°C) (B°C) (A°C)
125.6°F 122.0°F 118.4°F
(52°C) (50°C) (48°C)
125.6°F 122.0°F 118.4°F
(52°C) (50°C) (48°C)
125.6°F 118.4°F 118.4°F
(52°C) (48°C) (48°C)
122.0°F 114.8°F 118.4°F
(50°C) (46°C) (48°C)
118.4°F 111.2°F 118.4°F
(48°C) (44°C) (48°C)
B°F
(B°C)
114.8°F
(46°C)
114.8°F
(46°C)
114.8°F
(46°C)
114.8°F
(46°C)
114.8°F
(46°C)