LG THERMA V AHBW076A0, Service Manual, Page: 66 / 98

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20 Electric Heater Overheated
Code
No.
Description Cause Normal Condition
• Abnormal operation of
electric heater
• Leaving water temperature
is above 80 °C
• If there is no problem in electric heater
control, possible maximum leaving
water temperature is 80 °C.
Start
END
(it is normal
condition)
A
A
B
B
NO
YES
YES
YES
YES
NO
NO
Leaving water
temperature is higher
than target water
temperature
Thermostat is
installed
Leaving water
temperature is higher
than 80 °C
• This is unexpected case.
• Turn off the system and call service center.
• If the system is not turned off before it yields
error code (CH20), very hot leaving water will
be generated and it is harmful to human.
• Room air is not fully heated by under floor
heating.
• Wait while room air is heated by target
temperature of thermostat.
• If Error Code (CH20) is occurred, please
check thermostat, electric heater, power
supply and others. Also, it is recommended
to check air vent which is located on the top
of the electric heater tank.