Sharp AH-AP18DR Service Manual page 31

The room is not heated at all or not heated.
The compressor does not operate.
Select HEAT MODE with remote controller.
And then start operation.
Push the button of "AUX" on the indoor
unit, for more than 5 sec.
Using a tester, measure voltages at the
terminals on the terminal board.
Is the voltage
between terminal "N" and
"4"("1" ..... AY-AP18DR) of the
terminal board the power
supply voltage ?
YES
Is the voltage
between terminal "N" and
"2" of the terminal board the
power supply voltage ?
YES
Is the voltage
between terminal "N" and
"3" of the terminal board the
power supply voltage ?
YES
The control circuit board is normal.
Refrigerant may be leaked.
The running capacitor may be defective.
The outdoor fan motor may be defective.
The outdoor fan motor capacitor may be defective.
The compressor may be defective.
The thermistor may be defective.
For AY-AP24DR/AE-A24DR, AY-AP18DR/AE-A18DR
NO
NO
NO
Replace the PWB ass'y with a new one.
31
AH/AY-AP18DR
AH/AY-AP24DR