Hitachi RWM-(H)FSN3E, Service Manual

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12 Troubleshooting
SMGB0070 rev. 1 - 08/2011
354
Alarm code
16
Domestic Hot Water Temperature (TDHW) 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 1.11 kΩ) or cut (greater than 220.6 kΩ)
when DHWT is enabled.
No
Connect it
Yes
Yes
No
Is THMdhwt
connected to (intake)
terminals 27 & 28 of TB2?
Faulty thermistor
(Change it)
Is resistance of
THMdhwt between
1.11kΩ and 220.6kΩ?
Are the
connectors between
PCB1 and PCB2 connected
correctly?
PCB1
CN9-CN1
CN5-CN2
CN6-CN3
CN2-CN4
PCB2
Yes
Is the
temperature of
THMdhwt between 100ºC
and -20ºC?
Faulty PCB1 or PCB2
(Check PCBs)
No
Wiring check, repair
breaking of wire, wrong
wiring
No
Check correct position of
THMdhwt and correct it
Yes
Are the wires
between terminal
board 2 and PCB2
connected correctly?
PCB2
CN10-2-TB2-27
CN15-1-TB2-28
TB2
No
Wiring check, repair
breaking of wire, wrong
wiring
N O T E
DHW Water sensor is the same as Yutaki system controller.