Error Overheat Prevention Thermostat Failure - Toshiba HWS-802XWHM3-E Service Manual

[A09] Error Overheat prevention thermostat failure (Hot water supply/Heating operation)
Start
Water cycle contains water
Flow switch is normal
At normal temperature,
overheat preventive thermostat
is normal
Replace water heat exchange control board
or overheat preventive thermostat failure
*Replace water heat exchange control board or overheat preventive thermostat failure: After the control
board is replaced, if the same operation repeats, the overheat preventive thermostat is determined as
defective (does not operate at 75°C).
No
Yes
No
Yes
No
Yes
81
Put water into water circuit
(Recommended: 1 - 2 Bar)
Replace flow switch
Replace heater unit
exchanger air vent valve