Back Up Heater - LG ZHBW041GA0 Service Manual

1.3 Back up heater

Start
*1
NO
Back up heater is
working
YES
More than 5 minutes
NO
elapsed since back up
heater working
YES
*2
NO
External electric
power supply OK?
YES
*3
NO
Thermodisk
OK?
YES
*4
NO
ELB or MCCB OK?
YES
*5
NO
Relay Contactor
OK?
YES
Back up heater
is not normal
F
• Wait for 5 minutes to heat water inside back up heater tank. If capacity of back up heater is 6kW, at least 2 centigrade will be increased.
A
• For single-phase model : 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 unit.
B
• For three-phase model : Check if external electricity power supply is breakout. If not, check wiring between external electricity power
supply and port 3, port 4, and port 5 of Terminal Block 3. You can identify the location of Terminal Block 3 at the circuit diagram of unit.
• Thermodisk is mechanically malfunction. In this case, contact a licensed professional.
C
• Check the insulation resistance of back up heater.
• If the insulation resistance has improper, remove the cause of the problem and then reset the ELB (or MCCB).
D
• Replace the ELB (or MCCB) when the insulation resistance is suitable.
• Relay contactor is mechanically malfunction. In this case, contact a licensed professional and replace the relay contactor.
E
• Heating coil of back up heater can be damaged or wiring inside the back up heater is problem. Before replacing the back up heater, in
this case, contact a licensed professional and do the diagnosis about back up heater and related parts including the capacity of external
F
electric power source. If the reason of malfunction is clearly proved as the faulty back up heater itself, then replace it with new one.
Back up heater
working time A
is not enough
Electric power
B
is not supplied
Thermodisk is
not correctly C
working
ELB (or MCCB) cuts off
Power or ELB
D
(or MCCB) trouble
Relay
contactor
E
is not working
correctly
*1 : When back up heater is working, 'back up heater Operating' is
displayed at control panel
*2 : For single-phase model : Measure electric voltage at port 3 (Live) and port 4
(Neutral) of Terminal Block 3 with voltage meter. The measured value should be
220-240 V~ . To identify the location of Terminal Block 3, please refer circuit
diagram of unit at 'Installation Manual' or backside of front cover of the unit.
*2 : For three-phase model : Measure electric voltage at two port of
3 (R), 4 (S), and 5 (T) of Terminal Block 3 with voltage meter. The
measured value should be 220-240 V~ or 380-415 V~ . To identify the
location of Terminal Block 3, please refer circuit diagram of unit at
'Installation Manual' or backside of front cover of the unit.
*3 : For single-phase model : Find cover of thermodisk which is located
beside air vent. Air vent is on the top of the back up 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 220-240 V~ .
*3 : For three-phase model : Find cover of thermodisk which is located
side of back up heater tank.Uncover the cover by unscrewing bolts. Find
two copper leads located both left and right side of two thermodisk core.
Check resistance of both leads of each thermodisks. The measured
resistance should be 0 ohm.
While uncovering the cover of the thermodisk, be careful
for electric shock.
*4 : For single-phase model : 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 220-240 V~ .
*4 : For three-phase model : Resistance between port 1-to-port 2, port 3-to-port
4, and port 5-to-port 6 of MCCB (A) should be 0 ohm. Port number and location
of MCCB (A) can be found circuit diagram of the unit(back side of front cover).
*5 : For single-phase model : At Relay Contactor (A), measure electric
voltage at port 2 (Live) and port 6 (Neutral) with voltage meter. The
measured value should be 220-240 V~ . Also, at Relay Contactor (B),
measure electric voltage at port 2 (Live) and port 6 (Neutral) with voltage
meter. The measured value should be 220-240 V~ .
*5 : For three-phase model : At Magnet Contact (C) or Magnet Contact (B),
resistance between port L1-to-port T1, port L2-to-port T2, and port L3-to-
port T3 should be 0 ohm.
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