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24 EMERGENCY OPERATION
Emergency operation
• • • • Emergency operation of outdoor unit
Emergency operation can be carried out by setting the
DSW1 switch on the printed circuit board inside the
outdoor unit to the EMERGENCY position. However,
emergency operation is only carried out when an
abnormality
is
temperature thermistors.
The resistance values of each thermistor are measured
as shown in the table below to determine if there is an
abnormality.
Thermistor resistance table
Temperature
Room temperature
thermistor
-20°C
-10°C
-5°C
0°C
5°C
10°C
15°C
20°C
25°C
30°C
40°C
50°C
60°C
70°C
80°C
90°C
100°C
The pipe temperature thermistor resistance value are
the same for the indoor and outdoor units.
<When a thermistor abnormality is judged to have
occurred>
− − − − Set only the thermistor which shows an abnormality
to the condition shown in the table below to carry out
emergency operation
detected
by
the
indoor/outdoor
Resistance value (kΩ) ± 5%
Pipe temperature
thermistor
205.8
197.8
114.6
111.9
87.3
85.4
67.0
65.8
51.8
51.0
40.4
39.9
31.7
30.7
25.1
25.0
20.0
20.0
16.1
16.0
10.4
10.6
6.9
7.1
4.7
4.9
___
3.5
___
2.5
___
1.8
___
1.4
Thermistor
Indoor unit
Room temperature
Room temperature
Thermistor
Outdoor unit
Discharge
temperature
Heat exchanger
outlet temperature
− − − − Refer to the circuit diagram for the connection
locations for each thermistor.
− − − − If there is an abnormality in the room temperature
thermistor, the temperature will be fixed at 25°C
regardless of the remote control unit display.
NOTE:
− − − − Any abnormalities detected by the temperature
thermistors are ignored during emergency operation,
so that long-term operation in this mode should be
avoided.
− − − − After
emergency
completed and normal operation is to be resumed,
turn the power supplies for the indoor and outdoor
units off and return the DIP switch to the NORMAL
position.
− − − − Self-diagnosis LEDS 4 to 6 will flash during
emergency operation.
55
Cooling mode
Heating mode
Fixed at 25°C
Shorted
Open
Cooling mode
Heating mode
Open
Shorted
Shorted
Open
mode
operation
has
been
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