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Copyright ©2008 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LGE Internal Use Only
1.3 Electric Heater
Checking Key Components of Indoor Unit
(*1): When electric heater is working, ‘Electric Heater
Operating Icon( or ) ’ is displayed at control panel.
(*2): Measure electric voltage at port 3(Live) and port 4(Neutral)
of Terminal Block 3 with voltage meter. The measured value
should be 220V~240V AC. To identify the location of Terminal
Block 3, please refer circuit diagram of indoor unit at ‘Installation
Manual’ or backside of front cover of the indoor unit.
(*3): Find cover of thermodisk which is located beside air vent. Air
vent is on the top of the electric heater tank. Uncover the cover by
unscrewing bolts. Find two copper leads located both left and right
side of the thermodisk core. Check resistance of both leads. The
measured resistance should be 0 ohm. After then, check if voltage
is transmitted to the thermodisk correctly. Measure electric voltage
between one of the lead (Live) of the thermodisk and port 3(Neutral)
of ELB(A). The measured value should be 220V~240V AC.
While uncovering the cover of the thermodisk,
be careful for electric shock.
(*4): Resistance between port 1 and port 2 should be 0 ohm.
Also, port 3 and port 4 should be 0 ohm, too. Finally, measure
electric voltage at port 2(Live) and port 4(Neutral) with voltage
meter. The measured value should be 220V~240V AC.
(*5): At Relay Contactor (A), measure electric voltage at port
2(Live) and port 6(Neutral) with voltage meter. The measured
value should be 220V~240V AC. Also, at Relay Contactor (B),
measure electric voltage at port 2(Live) and port 6(Neutral) with
voltage meter. The measured value should be 220V~240V AC.
Start
A
YES
YES
NO
Electric heater
working time
is not enough
YES
NO
B
Electric power
is not supplied
NO
C
YES
Thermodisk is
not correctly
working
NO
D
ELB cuts off
power or ELB
trouble
NO
E
YES
NO
YES
Relay
contactor
is not working
correctly
Electric heater
is not normal
F
Electric heater is
working
External electric
power supply OK?
Thermodisk
OK?
ELB (Earth
Leakage Breaker) OK?
Relay Contactor
OK?
More than 5 minutes
elapsed since electric
heater working
(*1)
(*2)
(*3)
(*4)
(*5)
• Wait for 5 minutes to heat water inside electric heater tank. If capacity of electric heater is 6kW, at least
2 centigrade will be increased.
• Check if external electricity power supply is breakout. If not, check wiring between external electricity
power supply and port 3 and port 4 of Terminal Block 3. You can identify the location of Terminal Block
3 at the circuit diagram of indoor unit.
• Thermodisk is mechanically defected. In this case, contact official After Service Center and replace the
thermodisk.
• Check the insulation resistance of Electric Heater.
• If the insulation resistance has improper, remove the cause of the problem and then reset the ELB.
• Replace the ELB when insulation resistance is OK.
• Relay contactor is is mechanically defected. In this case, contact official After Service Center and
replace the relay contactor.
• Heating coil of electric heater can be damaged or wiring inside the electric heater is problem. Before replacing the elec-
tric heater, in this case, contact official After Service Center and do diagnosis about electric heater and related parts
including the capacity of external electric power source. If the reason of malfunction is clearly proved as the defect of
the electric heater itself, then replace it with new one.
A
B
C
D
E
F
