Check Points, Maintenance and Troubleshooting
Installation Manual  95
ENGLISH
Troubleshooting for Error Code
Code
No.
Description Cause Normal Condition
1 Problem in remote room air sensor 
• Incorrect connection between
sensor and PCB(Heater).
• PCB(Heater) fault
• Sensor fault
• Resistance: 10 kΩ at 25
centigrade (unplugged) → for
Remote room air sensor
• Resistance: 5 kΩ at 25 centigrade
(unplugged) → for all sensors
EXCEPT remote room air sensor
• Voltage: 2.5 V DC at 25 centigrade
(plugged) (for all sensors)
• Refer resistance-temperature table
to check in different temperature
2 Problem in refrigerant (inlet side) sensor 
6 Problem in refrigerant (outlet side) sensor 
8 Problem in water tank sensor 
16 Problems in sensors 
17 Problem in water-inlet sensor 
18 Problem in water-outlet sensor 
19 Problem in water-interim sensor 
3
Bad communication between remote
controller and unit.
• Incorrect connection between
sensor and PCB(Heater)
• PCB(Heater) fault
• Sensor fault
• Wire connection between remote
controller and Main PCB
assembly(Heater) should be tight
• Output voltage of PCB should be
12 V DC
5
Bad communication between Main PCB
assembly(Heater) and Main PCB
assembly(Inverter) of the unit.
• The connector for transmission is
disconnected
• The connecting wires are
misconnected
• The communication line is broken
• Main PCB assembly(Inverter) is
abnormal
• Main PCB assembly(Heater) is
abnormal
• Wire connection between remote
control panel and Main PCB
assembly(Heater) should be tight.
53
9 PCB program (EEPROM) fault
• Electrical or mechanical damage a
the EEPROM 
• This error can not be permitted 
14 Problem in flow switch
• Flow switch is open while internal
water pump is working
• Flow switch is closed while internal
water pump is not working
• Flow switch is open while DIP
switch No. 5 of Main PCB
assembly(Heater) is set as on
• Flow switch should be closed while
internal water pump is working or
DIP switch No. 5 of Main PCB
assembly(Heater) is set as on
• Flow switch should be open while
internal water pump is not working
15 Water pipe overheated 
• Abnormal operation of electric
heater
• Leaving water temperature is
above 57 ℃
• If there is no problem in electric
heater control, possible maximum
leaving water temperature is 57 ℃
20 Thermal fuse is damaged 
• Thermal fuse is cut off by
abnormal overheating of internal
electric heater
• Mechanical fault at thermal fuse
• Wire is damaged
• This error will not be happened if
temperature of electric heater tank
is below 80 ℃