Hitachi RAS-H(V)RNME-AF Service Manual page 363

12 Troubleshooting
15
Alarm code Water outlet circuit 2 (mix circ.) Temperature (Two2) Thermistor Abnormality
• The alarm code is displayed on the LCD User interface.
• The alarm code is displayed on the seven segments of the indoor unit PCB.
• This alarm code is displayed when the thermistor is short-circuited (less than 0.24 kΩ) or cut (greater than 18.2 kΩ)
during the cooling process or the heating process and circuit 2 enabled.
Is THMwo2
connected to (intake)
terminals 30 & 31 of TB2?
Yes
Are the wires
between terminal
board 2 and PCB2
connected correctly?
CN16-1-TB2-30
PCB2
CN16-2-TB2-31
Is resistance
of THMwo2 between
0.24kΩ and 18.2kΩ?
Yes
Are the
connectors between
PCB1 and PCB2 connected
correctly?
CN9-CN1
CN5-CN2
PCB1
CN6-CN3
CN2-CN4
Yes
Is the
temperature of
THMwo2 between 100ºC
and -80ºC?
Yes
Faulty PCB1 or PCB2
(Check PCBs)
353
SMGB0070 rev. 1 - 08/2011
No
No
TB2
No
No
PCB2
No
Thermistor characteristics
Connect it
Wiring check, repair
breaking of wire, wrong
Faulty thermistor
(Change it)
Wiring check, repair
breaking of wire, wrong
Check correct position of
THMwo2 and correct it
Temperature (ºC)
wiring
wiring
12