LG LS-C126U_M0 / LS-H126U_M0 Service Manual ▷ View online
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5. Evacuation
• Procedure
(1) Connect the vacuum pump to the charge set’s
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
2-Way
valve
valve
Outdoor unit
Liquid side
Indoor unit
Gas side
3-Way
valve
valve
CLOSE
OPEN
CAUTION
Use vacuum pump equipped with check value
applied to be prevented from flowing backward.
applied to be prevented from flowing backward.
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6. Gas Charging
(After Evacuation)
• Procedure
(1) Connect the charge hose to the charging
cylinder.
– Connect the charge hose which you dis-con-
– Connect the charge hose which you dis-con-
nected from the vacuum pump to the valve at
the bottom of the cylinder.
the bottom of the cylinder.
– If you are using a gas cylinder, also use a scale
and revers 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 refriger-
ant). The procedure is the same if using a gas
cylinder.
purge the air. (Be careful of the liquid refriger-
ant). 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 spec-
– If the system can not be charged with the spec-
ified 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 suffi-
cient, wait approximately 1 minute and then
repeat the procedure (pumping down-pin).
with a little at a time (approximately 150g each
time) while operating the air conditioner in the
cooling cycle; however, one time is not suffi-
cient, 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 dis-
– Stopping par tway will allow the gas to be dis-
charged.
– If the system has been charged with liquid refriger-
ant while operating the air conditioner turn off the air
conditioner before disconnecting the hose.
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.
CAUTION
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.
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
2-Way
valve
valve
3-Way
valve
valve
OPEN
R-410A
Open
Check valve
CAUTION
This unit is charged with R-410A.
Pay attention not to charge R-22.
Pay attention not to charge R-22.
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7. Additional gas charging
(Gas leakage)
• When refrigerant is insufficient by leakage, recharge the unit with the refrigerant up to normal operating suc-
tion pressure.
• Use the graph or the equation below to get operating suction pressure according to indoor and outdoor tem-
perature.
Suction pressure was measured at 3-way valve service port after operating the unit for 10 minutes.
The method of using graph
- Find outdoor temperature.
- Find indoor temperature onto the curve of outdoor temperature.
- Read suction pressure at the axis of ordinates.
The method of using equation
-. Calculate suction pressure after putting indoor and outdoor temperature into the equation.
13
(At operating the Unit for 10 minutes)
Suction Pressure
(Kg/cm
2
.g)
Outdoor Temp.
(˚
C)
Indoor Temp. (˚C)
12
11
10
9
8
7
6
5
5
10
15
20
25
30
35
40
50˚C
40˚C
30˚C
20˚C
10˚C
0˚C
P = 3 + 0.0123 x T
out
1.5
+ 0.8 x T
in
0.5
Where, P
: Suction Pressure(kg/cm
2
.g)
Tout : Outdoor Temperature(˚C)
Tin
Tin
: Indoor Temperature(˚C)
Operating Suction Pressure
(According to Indoor & Outdoor Temperature)
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 reated
Current : over the reated
current
Temp. difference : over 8°C
Operating Current
• All amount of refrigerant leaked
out. Check refrigeration cycle.
• Refrigerant leakege
Clog of refrigeration cycle
Defective compressor
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 tem-
perature 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 tem-
perature difference is larger.
2. Check temperature and pressure of refrigeration cycle.
Notice :
1. The suction pressure is usually R-22: 4.5~6.0 kg/cm
1. The suction pressure is usually R-22: 4.5~6.0 kg/cm
2
G(Cooling) at normal condition.
R-410a: 7.2~9.6 kg/cm
2
G(Cooling) 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 valve)
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
Current is low.
High
Higher
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