Hitachi Utopia RPI-2.5HRG Service Manual page 38

Alarm
Code
G "RUN" light flickers and "ALARM" is indicated on the remote control switch.
G The unit No., alarm code and the unit code is alternately indicated on the set temperature section,
and the unit No. and alarm code are indicated on the display of the outdoor unit PCB.
# This alarm code is indicated when the thermistor is short-circuited (less than 1 kΩ) or cut (greater
than 6 MΩ) during the cooling or heating operation.
Is the thermistor connected
to THM9 of PCB?
Yes
Is resistance of THM9
between 1kΩ and 6kΩ?
Yes
Faulty PCB
Phenomenon
Faulty Top of
Compressor
Thermistor
Faulty PCB1
Temperature (
0
5
10
15
20
25
30
35
40
45
50
55
60
The resistance value have fudge factor (+10%).
Abnormality of Thermistor for Discharge Gas Temperature
(Compressor Thermistor)
No
Connect it.
No
Faulty Thermistor
Cause
Fault
Incorrect Connection
o
C) Resistance (kΩ)
640.44
500.66
394.16
312.41
249.20
200.00
161.45
131.06
106.96
87.74
72.32
59.97
49.96
Check Item
Check resistance.
Check wiring to PCB1.
Replace PCB1 and
check operation.
o
Temperature ( C) Resistance (kΩ)
65
70
75
80
85
90
95
100
105
110
115
120
125
TROUBLESHOOTING
Action
(Turn OFF Main Switch)
Replace thermistor
if faulty.
Repair wiring and
connections.
Replace PCB1 if faulty.
41.79
35.11
29.61
25.07
21.31
18.17
15.55
13.35
11.50
9.93
8.60
7.47
6.51
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