Hitachi RAC-25YH4, Service Manual, Page: 94 / 121

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No. Blinking of Timer lamp Reason for indication Possible cause
Reversing valve defective
When the indoor heat exchanger
temperature is too low in the
heating mode or it is too high in the
cooling mode.
Outdoor unit is under forced
operation
When the outdoor unit is in forced
operation or balancing operation
after forced operation
Indoor/outdoor interface defective
When the interface signal from the
outdoor unit is interrupted.
Room thermistor or heat exchanger
thermistor is faulty
When room thermistor or heat
exchanger thermistor is opened
circuit or short circuit.
Over-current detection at the DC fan
motor
when over-current is detected at the
DC fan motor of the indoor unit.
IC401 or IC402 data reading error
When data read from IC401 or
IC402 is incorrect.
(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
(1) Room thermistor
(2) Heat exchanger thermistor
(1) Indoor fan locked
(2) Indoor fan motor
IC401 or IC402 abnormal
<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 1).
1
2
3
4
5
6
( Lights for 0.35 sec. at interval of 0.35 sec..)
10 times
3 times
1 time
2 time
13 times
5 sec.
sec.
5 sec.
5 sec.
sec.
5 sec.
5 sec.
1
9 times
5 sec.
(3) Indoor control P.W.B.
TROUBLESHOOTING WHEN TIMER LAMP BLINKS.
Model RAS-25YH4, RAS-35YH4
Perform troubleshooting according to the number of times the indoor timer lamp and outdoor LD301
blink.
SELF-DIAGNOSIS LIGHTING MODE
Model: RAS-25YH4, RAS-35YH4
RAS_25_35_AW_087-108 2003.12.31, 10:59 AM 92