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18

measure the secondary voltage
of transformer.

YES

NO

YES

NO

The machine does not function
at all with remote controller and
switch on the indoor unit. 

Using a tester, measure the 
voltage between anodes of D1 
and D2 on PWB ass'y.

Is the measured value 

approx. 17.5 Vac ?

Replace the PWB with a new 
one.

Is the WPE1

open  circuit ?

Replace the fuse and varistor 
with new ones.

Replace the transformer with
a new one.

OK

FAIL

Check  the  cleaning

switch  2(1), the connector 

CN9(8) and lead  wires.

Replace the cleaning switch  2(1).
(or  reset  connector)

19

YES

NO

NO

YES

The machine does not function
with remote controller 

Push button "O/I" on the 
wireless remote controller.

Is transmitting

indicator of the remote 

controller active ?

Is indicator lamp of

indoor unit proper ?

Replace the 
PWB  with a 
new one.

Does beep sound

from the indoor unit ?

Using a tester,
measure the voltage
between terminals
of resistor R26
on the PWB ass'y.

Push the button "O/I".

Are batteries of the

wireless remote controller 

proper ?

Replace the batteries 
with new ones.

Replace the wireless
remote controller.

When the signal is

received, does the voltage

change ?

Replace the PWB with a new 
one.

PWB is normal.
Inspect the outdoor unit.

NO

YES

NO

YES

Replace the photo 
detector unit with a new 
one.

NO

YES

20

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 "AUX." on 
the  indoor unit, for more than 5 sec.

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.

Using a tester, measure voltage at
the terminals on the terminal board.

100

80

60

40

20

0

-10

0

10

20

30

40

Resistance

Thermistor

Room temperature

Heat exchange

Color

Yellow

Orange

To measure the resistance, first remove 
the connector as shown at right.

Room temperature 

thermistor TH1

Tester

Connector

No. 3 to 4

No. 1 to 2

K

Heat exchange thermistor 
TH2 (orange)
25

°C resistance 15 K 

Room temperature 
thermistor TH1 (yellow)
25

°C resistance 10 K

Heat exchange 

thermistor TH2

Tester

4

1 CN4

21

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 "AUX." on 
the  indoor unit, for more than 5 sec.

Is the

voltage between

terminal of black lead

wire on the relay in the out door

unit and terminal "N"on 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

YES

NO

NO

Replace the PWB ass'y with a new one.

Replace the relay in the outdoor unit 
with a new one.

Using a tester, measure voltage at
the terminals on the terminal board.

Is the voltage

between terminal "N" and

"4" in the outdoor unit the power 

supply voltage ?