LG LB-F4280HL / LB-F4280CL Service Manual ▷ View online
2. Evacuation
(All amount of refrigerant leaked)
• Procedure
(1) Connect the vacuum pump to the center hose
of charge set center hose
(2) Evacuation for approximately one hour.
– Confirm that the gauge needle has moved
toward -76 cmHg (vacuum of 4 mmHg or less).
(3) Close the valve (Lo side) on the charge set,
turn off the vacuum pump, and confirm that
the gauge needle does not move (approxima-
tely 5 minutes after turning off the vacuum
pump).
the gauge needle does not move (approxima-
tely 5 minutes after turning off the vacuum
pump).
(4) Disconnect the charge hose from the vacuum
pump.
– Vacuum pump oil.
– Vacuum pump oil.
If the vacuum pump oil becomes dir ty or
depleted, replenish as needed.
depleted, replenish as needed.
Lo
Open
Open
Vacuum pump
3-Way
valve
valve
Outdoor unit
Liquid side
Indoor unit
Gas side
3-Way
valve
valve
CLOSE
OPEN
–30–
3. Gas Charging
(After Evacuation)
• Procedure
(1) Connect the charge hose to the charging
cylinder.
– Connect the charge hose which you dis-
– Connect the charge hose which you dis-
connected from the vacuum pump to the valve
at the bottom of the cylinder.
at the bottom of the cylinder.
– If you are using a gas cylinder, also use a scale
and reverse the cylinder so that the system can
be charged with liquid.
be charged with liquid.
(2) Purge the air from the charge hose.
– Open the valve at the bottom of the cylinder
and press the check valve on the charge set to
purge the air. (Be careful of the liquid
refrigerant). The procedure is the same if
using a gas cylinder.
purge the air. (Be careful of the liquid
refrigerant). The procedure is the same if
using a gas cylinder.
(3) Open the valve (Lo side on the charge set and
charge the system with liquid refrigerant.
– If the system can not be charged with the
– If the system can not be charged with the
specified amount of refrigerant, it can be
charged with a little at a time (approximately
150g each time) while operating the air
conditioner in the cooling cycle; however, one
time is not sufficient, wait approximately 1
minute and then repeat the procedure
(pumping down-pin).
charged with a little at a time (approximately
150g each time) while operating the air
conditioner in the cooling cycle; however, one
time is not sufficient, wait approximately 1
minute and then repeat the procedure
(pumping down-pin).
(4) Immediately disconnect the charge hose from
the 3-way valve’s service port.
– Stopping par tway will allow the gas to be
– Stopping par tway will allow the gas to be
discharged.
– If the system has been charged with liquid
refrigerant while operating the air conditioner
turn off the air conditioner before disconnecting
the hose.
turn off the air conditioner before disconnecting
the hose.
(5) Mount the valve stem nuts and the service
port nut.
– Use torque wrench to tighten the service port
– Use torque wrench to tighten the service port
nut to a torque of 1.8 kg.m.
– Be sure to check for gas leakage.
\
This is different from previous procedures.
Because you are charging with liquid refrigerant
from the gas side, absolutely do not attempt to
charge with larger amounts of liquid refrigerant
while operating the air conditioner.
Because you are charging with liquid refrigerant
from the gas side, absolutely do not attempt to
charge with larger amounts of liquid refrigerant
while operating the air conditioner.
Lo
Charging
cylinder
cylinder
Outdoor unit
Indoor unit
Liquid side
Gas side
CLOSE
Open
3-Way
valve
valve
3-Way
valve
valve
OPEN
Open
Check valve
(1)
–31–
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–
Electronic Parts Troubleshooting Guide
: The unit does not operate.
Possible Trouble 1
–33–
YES
YES
YES
NO
YES
Is the input voltage
of transformer AC220V?
Is the input voltage
of IC01D DC14V?
Check the FUSE
and the wiring diagram.
and the wiring diagram.
Is the output voltage
of IC01D DC12V?
Is the PIN 31,32 of
MICOM. DC5V?
Exchange MICOM
YES
NO
Check the main P.C.B
pattern
pattern
NO
NO
Check the D02D~D05D
NO
YES
Exchange
the transformer
the transformer
Is shorted the
transformer output?
NO
YES
Is the output voltage
of IC02D DC5V?
NO
Exchange IC01D
Exchange IC02D
Is the output voltage
of transformer about AC14V?
Check the
5V P.C.B pattern.
5V P.C.B pattern.
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