LG LB-F3680HL / LB-F3680CL Service Manual ▷ View online
Cycle Troubleshooting Guide
Trouble analysis
1. Check temperature difference between intake and discharge air and operating current.
Temp. Difference
Temp. difference : approx. 0°C
Current : less than 80% of
Current : less than 80% of
rated current
Temp. difference : approx. 8°C
Current : less than 80% of
Current : less than 80% of
rated current
Temp. difference : less than 8°C
Current : over the rated
Current : over the rated
current
Temp. difference : over 8°C
Operating Current
All amount of refrigerant leaked out
Check refrigeration cycle
Check refrigeration cycle
Refrigerant leakege
Clog of refrigeration cycle
Defective compressor
Clog of refrigeration cycle
Defective compressor
Excessive amount of refrigerant
Normal
Notice :
Temperature difference between intake and discharge air depends on room air humidity. When the room air
humidity is relativery higher, temperature difference is smaller. When the room air humidity is relatively lower
temperature difference is larger.
Temperature difference between intake and discharge air depends on room air humidity. When the room air
humidity is relativery higher, temperature difference is smaller. When the room air humidity is relatively lower
temperature difference is larger.
2. Check temperature and pressure of refrigeration cycle.
Notice :
1. The suction pressure is usually 4.5~6.0 kg/cm
1. The suction pressure is usually 4.5~6.0 kg/cm
2
G at normal condition.
2. The temperature can be measured by attaching the thermometer to the low pressure tubing and wrap it with
putty.
Suction pressure
Temperature
(Compared with
(Compared with
Cause of Trouble
Description
the normal value)
the normal value)
Defective compressor
Current is low
Defective 4-way reverse valve
Excessive amount of
High pressure does not quickly
Normal
refrigerant
rise at the beginning of
operation
operation
Insufficient amount of
Current is low
Lower
Higher
refrigerant (Leakage)
Clogging
Clogging
Current is low
High
Higher
–32–
Functions
ƒU
Room temperature sensor. (Thermistor)
ƒU
Maintains the room temperature in accordance with the Setting Temp.
ƒU
Indoor fan is delayed for 5 seconds at the starting.
ƒU
Restarting is inhibited for approx. 3 minutes.
ƒU
High, Med, Low
ƒU
Intermittent operation of fan at low speed.
ƒU
Both the indoor and outdoor fan stops during defrosting.
ƒU
Hot start after defrost ends.
ƒU
The indoor fan stops until the evaporator piping temperature will be reached at 28°C
Indoor Unit
Operation ON/OFF by Remote controller
Sensing the Room Temperature
Room temperature control
Starting Current Control
Time Delay Safety Control
Indoor Fan Speed Control
Soft Dry Operation Mode
Deice (defrost) control (Heating)
Hot-start Control (Heating)
–3–
Intake Air temp.
Setting temp.+3°C
(Compressor OFF)
Setting temp.
(Compressor ON)
(Compressor ON)
INDOOR FAN
Low
OFF Low
Low
OFF
COMPRESSOR
ON
OFF
ON
OFF
ƒU
A point; While the indoor Heat-Exchanger temperature is higher than 40°C fan operates at low speed, when
it becomes lower than 40˚C fan stops.
ƒU
B point; When the indoor Heat-Exchanger temperature is higher than 42°C, fan operates at seleted fan
speed, when it becomes lower than 39°C, the fan operates at low speed.
–12–
4. Heating Mode Operation (Except Cooling Model)
The unit will operate according to the setting by the remote controller and the operation diagram is shown as following.
Hot Start
Low
Selecting
Fan Speed
minimum 3min
Selecting fan
speed
minimum
10sec.
1min
A
A
minimum
10sec.
B
5. Hot-Start Control
ƒU
The indoor fan stops until the evaporator piping temperature will be reached to 31°C.
ƒU
The operation diagram is as following.
PIPING
TEMPERATURE
TEMPERATURE
1min
COMPRESSOR
INDOOR FAN
ON
28
°
C
: Selected Fan
: Low Fan
: Fan Stop
31
°
C
6. Defrost Control
• Defrost operation is controlled by timer and sensing the outdoor piping temperature.
• The defrost starts only when the outdoor pipe temperature falls below -6°C after 45 minutes passed from starting
• The defrost starts only when the outdoor pipe temperature falls below -6°C after 45 minutes passed from starting
of heating operation.
• Defrost ends after 10 minutes passed from starting of defrost operation or when the outdoor pipe
temperature rises over 12°C even if before 10 minutes.
7. Auto Restarting Operation
• When the power is restored after a sudden power failure while in appliance operation, the mode before the
power failure is kept on the memory and the appliance should be on the automatically operates in the mode on
the memory.
the memory.
• Operation Mode that is kept on the memory
- State of Operation ON/OFF
- Operation Mode/Setting Temp/Selected Airflow Speed
- Operation Mode/Setting Temp/Selected Airflow Speed
• If no input by the remote controller within 7 hr after the appliance operates by the Auto Restarting operation,
the appliance is forced to stop at the moment of 7-hr elapse.
8. Self-Diagnosis Function
• 'CHECK' will flash in the remote controller display when a problem occurs. Then please contact your dealer.
• Correct the accident point as shown in the table below before restarting operation.
• During the normal operation 'CHECK' won't be displayed in the remote controller.
• Correct the accident point as shown in the table below before restarting operation.
• During the normal operation 'CHECK' won't be displayed in the remote controller.
–13–
More than 45 minutes of
heating operation
Outdoor Pipe Temp.
Indoor Fan
Compressor
4-Way Valve
ON
ON
ON
ON
OFF
ON
OFF
HOT-
START
ON
ON
OFF
OFF
ON
12
°
C
(Defrost OFF)
-6
°
C
(Defrost ON)
Within
10 minutes
Defrost
Defrost
More than 45 minutes of
heating operation
Remote controller LCD
Accident Point
F
1
Indoor temperature thermistor error
F2
Indoor piping thermistor error
F3
Indoor/Outdoor unit communication error
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