Hitachi RAS-18YH4 Service Manual page 72

TROUBLESHOOTING WHEN TIMER LAMP BLINKS.
MODEL RAS-18YH4
Perform troubleshooting according to the number of times the indoor timer lamp and outdoor LD301 blink.
SELF-DIAGNOSIS LIGHTING MODE
MODEL RAS-18YH4
No. Blinking of Timer lamp
1
2 sec.
2
2 sec.
3
2 sec.
4
2 sec.
5
2 sec.
6
2 sec.
1
2 sec.
7
( Lights for 0.35 sec. at interval of 0.35 sec..)
<Cautions>
(1) If the interface circuit is faulty when power is supplied, the self-diagnosis display will not be displayed.
(2) If the indoor unit does not operate at all, check if the connecting cable is connected to the outdoor unit.
(3) To check operation again when the timer lamp is blinking, you can use the remote control for operation
(except for mode mark
Reason for indication
Reversing valve defective
When the indoor heat exchanger
temperature is too low in the
1 time
heating mode or it is too high in the
cooling mode.
Outdoor unit is under forced
operation
2 times
When the outdoor unit is in forced
operation or balancing operation
after forced operation
Indoor/outdoor interface defective
3 times
When the interface signal from the
outdoor unit is interrupted.
Outdoor unit electrical components
defetive
When the same error mode is detected
8 times within 30 minutes from outdoor
4 times
unit electrical components.
(However, when error is detected 8
times within two hours only for outdoor
thermistor.)
Room thermistor or heat exchanger
thermistor is faulty
When room thermistor or heat
9 times
exchanger thermistor is opened
circuit or short circuit.
Over-current detection at the DC fan
motor
10 times
when over-current is detected at the
DC fan motor of the indoor unit.
IC401 or IC402 data reading error
13 times
When data read from IC401 or
IC402 is incorrect.
1).
– 75 –
Possible cause
(1) Reversing valve defective
(2) Heat exchanger thermistor
disconnected
(only in the heating mode)
(Note)
The malfunction mode is entered the
3rd time this abnormal indication
appears (read every 3 minutes).
Electrical parts in the outdoor unit
(1) Indoor interface circuit
(2) Outdoor interface circuit
Outdoor unit electrical components
(For details, operate again using
remote comtroller and check from
self-diagnosis display of outdoor
unit.)
(1) Room thermistor
(2) Heat exchanger thermistor
(1) Indoor fan locked
(2) Indoor fan motor
(3) Indoor control P.W.B.
IC401 or IC402 abnormal