Service manual

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2. How to distinguish the defective parts
1. When all rooms are not cooled
Outdoor temp. thermistor TH3 CN8A Green No. 5 to 6
Suction thermistor TH4 CN8A Black No. 7 to 8
Thermistor unit A (suction) TH6 CN8C Blue No. 1 to 2
Thermistor unit B (suction) TH7 CN8C White No. 3 to 4
Thermistor unit C (suction) TH8 CN8C Brown No. 5 to 6
Thermistor unit D (suction) TH9 CN8C Yellow No. 7 to 8
Thermistor No. Connector Color Connector pin
500
400
300
200
100
0
-20 0 20 40
Temperature (ºC)
80 100
3.25k
60
12.3k
6.14k
Resistance (k )
Thermistor
Heatsink
Color
Black
To measure the resistance, first remove
the connector as shown at right.
Signal
CN8B
Heatsink thermistor
TH5 (black)
25ºC resistance 50k
Tester
1
3
Figure 3 Temperature properties of heatsink thermistor
Yes
Yes
Yes
No
No
No
Are the timer lamps of the in-
door units in all rooms flashing ?
Is the compressor of the outdoor
unit operating ?
Are the timer lamps of the indoor
units in all rooms flashing ?
Check the failure symptom with
the failure diagnosis mode.
The cooling cycle is abnormal.
Check the pressure.
Check that the power between
the terminal board " N " and " 1 "
of the indoor unit is AC 230V,
50Hz.
Repair the wiring between the
units.
Press the OPERATION button
to start operating the air-condi-
tioner. (One-room operation ON)
(Set the cooling mode to 18
͠㧕
(Check the failure with
the outdoor unit.)
TO
A