75
Toshiba
[A02] Error Temperature rise and error short circuit
Replace TWI, TWO,
and THO sensors
No
(TWI,TWO,THO 70°C)
TWI, TWO, and THO
sensor characteristics are
correct
Yes
No
Water outlet
temperature is 70
°C
or higher
Yes
Correct water circuit
(To prevent hot water of
other circuits from entering)
Yes
Hot water from
boiler or other circuits does
not come in
No
Failure of backup heater
(Too large heater input,
thermostat short circuit)
Replace heater unit
Yes
Backup heater is energized
No
(Measure heater current)
Start
Replace water heat exchange control board
Yes
Flow switch is normal
No
Replace flow switch
+00A09-002_01EN_SVM_ALL_Air_to_Water.book Page 75 Monday, October 5, 2009 2:09 PM