LG AS-H126U / LS-C126U / LS-H126U Service Manual ▷ View online
4. Balance refrigerant of the 2-way, 3-way valves
(Gas leakage)
• Procedure
(1) Confirm that both the 2-way and 3-way valves
are set to the back seat.
(2) Connect the charge set to the 3-way valve’s
port.
– Leave the valve on the charge set closed.
– Connect the charge hose with the push pin to
– Leave the valve on the charge set closed.
– Connect the charge hose with the push pin to
the service port.
(3) Open the valve (Lo side) on the charge set
and discharge the refrigerant until the gauge
indicates 0 kg/cm
indicates 0 kg/cm
2
G.
– If there is no air in the refrigerant cycle (the
pressure when the air conditioner is not
running is higher than 1 kg/cm
running is higher than 1 kg/cm
2
G), discharge
the refrigerant until the gauge indicates 0.5 to 1
kg/cm
kg/cm
2
G. if this is the case, it will not be
necessary to apply a evacuatin.
– Discharge the refrigerant gradually; if it is
discharged too suddenly, the refrigeration oil
will also be discharged.
will also be discharged.
Lo
Open
Open
3-Way
valve
valve
2-Way
valve
valve
Gas side
CLOSE
OPEN
Outdoor unit
Liquid side
Indoor unit
-41-
-42-
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.
-43-
6. 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 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
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.
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.
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.
-44-
7. Additional gas charging
(Gas leakage)
• When refrigerant is insufficient by leakage, recharge the unit with the refrigerant up to normal operating
suction pressure.
• Use the graph or the equation below to get operating suction pressure according to indoor and outdoor
temperature.
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)
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