Temperature Properties Of Indoor Thermistors - Sharp AH-AP18CE Service Manual

The room is not cooled at all
or not cooled.
The compressor does not operate.
Push the button "AUX." on
the indoor unit, for more than 5 sec.
Using a tester, measure voltage at
the terminals on the terminal board.
Is the voltage
between terminal "N" and
"1" of the terminal board the
power supply voltage ?
YES
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.
For AY-AP18CE/AE-A18CE, AH-AP18CE/AU-A18CE
Fig. 1 Temperature properties of indoor thermistors
K
100
Thermistor
Room temperature
80
Heat exchange
To measure the resistance, first remove
60
the connector as shown at right.
40
20
0
-10 0
NO
Measure resistances of TH1 and TH2.
Are the resistances
conformed Fig. 1 ?
YES
Replace the PWB ass'y with a new one.
29
Color
Connector
Yellow
No. 3 to 4
Orange
No. 1 to 2
Heat exchange thermistor
TH2 (orange)
25°C resistance 15 K
Room temperature
thermistor TH1 (yellow)
25°C resistance 10 K
10 20 30 40
Fig. 1
NO
Replace the thermistor ass'y with a new one.
AY-AP18CE AY-AP24CE
AH-AP18CE AH-AP24CE
AE-A18CE AE-A24CE
AU-A18CE AU-A24CE
Room temperature Heat exchange
thermistor TH1 thermistor TH2
4 1 CN4
Tester Tester