The room is not cooled at all
or not cooled.
The compressor does not operate.
Measure resistances of TH1 and TH2.
The control circuit is normal.
The compressor may be defective.
The running capacitor may be defective.
Refrigerant may be leaked.
The outdoor fan motor may be defective.
The outdoor fan motor capacitor may be defective.
Push the button "TEST RUN" on
the indoor unit, and wait 3 minutes.
Is the voltage
between terminal "N" and
"1" of the terminal board the
power supply voltage ?
Are the resistances
conformed Fig. 1 ?
Replace the thermistor ass'y with a new one.
NO
YES
YES
NO
Replace the PWB ass'y with a new one.
0
20
40
60
80
100
120
140
160
180
K
0 10 20 30 40˚C-10
CHARACTERISTIC OF TH1 & TH2
Fig. 1
25˚C
15K
Using a tester, measure voltage at
the terminals on the terminal board.