Toshiba HWT-1101XWHT6W-E - Page 111

110
[A05] Piping antifreeze operation
Check wiring construction
Ask repair of power supply
No
Hydro unit
DN code setting
DN_6D2 = “0”
Replace backup heater
and safety valve
DN code setting
DN_6D2 = “0”
No
(Backup heater NG)
Backup heater terminal
has 220-240 V (± 10%)
Yes
Yes
Correct wiring
No
Wiring connection
is normal
Yes
Restart
TWI 4, TWO 4, or
THO 4 is detected
Circulation pump keeps
being energized or 3 minutes
passed after the start
No
Backup heater element
is conductive
Yes
Replace TWI, TWO,
and THO sensors
No
TWI, TWO, THO
sensor characteristics
are correct
Yes
Check water heat exchange control board
If defective, replace it
PC board
MCC-1753
MCC-1755
(Refer to Characteristic table on page 137)