DOWNLOAD LG LS-C126U_M0 / LS-H126U_M0 Service Manual ↓ Size: 3.38 MB | Pages: 62 in PDF or view online for FREE

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Air and moisture remaining in the refrigerant system
have undesirable effects as indicated below.
• Pressure in the system rises.
• Operating current rises.
• Cooling(or heating) efficiency drops.
• Moisture in the refrigerant circuit may freeze and block

capillary tubing.

• Water may lead to corrosion of parts in the refrigera-

tion system.

Therefore, the indoor unit and tubing between the
indoor and outdoor unit must be leak tested and evacu-
ated to remove any noncondensables and moisture
from the system.

• Check that each tube(both liquid and gas side tubes)

between the indoor and outdoor units have been prop-
erly connected and all wiring for the test run has been
completed. Remove the service valve caps from both
the gas and the liquid side on the outdoor unit. Note
that both the liquid and the gas side service valves on
the outdoor unit are kept closed at this stage.

• Connect the manifold valve(with pressure gauges)

and dry nitrogen gas cylinder to this service port with
charge hoses.

• Pressurize the system to no more than 150 P.S.I.G.

with dry nitrogen gas and close the cylinder valve
when the gauge reading reached 150 P.S.I.G. Next,
test for leaks with liquid soap.

• Do a leak test of all joints of the tubing(both indoor

and outdoor) and both gas and liquid side service
valves. 
Bubbles indicate a leak. Be sure to wipe off the soap
with a clean cloth.

• After the system is found to be free of leaks, relieve

the nitrogen pressure by loosening the charge hose
connector at the nitrogen cylinder. When the system
pressure is reduced to normal, disconnect the hose
from the cylinder.

Be sure to use a manifold valve for air purging. If it is
not available, use a stop valve for this purpose. The
"Hi" knob of the manifold valve must always be kept
close.

To avoid nitrogen entering the refrigerant system in a
liquid state, the top of the cylinder must be higher than
its bottom when you pressurize the system. Usually,
the cylinder is used in a vertical standing position.

Lo

Hi

Indoor unit

Outdoor unit

Manifold valve

Charge hose

Nitrogen gas
cylinder(in vertical
standing position)

Pressure 
gauge

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(1) Remove the caps from the 2-way and 3-way

valves.

(2) Remove the service-port cap from the 3-way valve.
(3) To open the 2-way valve turn the valve stem coun-

terclockwise approximately 90°, wait for about 2~3
sec, and close it.

(4) Apply a soap water or a liquid neutral detergent on

the indoor unit connection or outdoor unit connec-
tions by a soft brush to check for leakage of the
connecting points of the piping.

(5) If bubbles come out, the pipes have leakage.

• Connect the charge hose end described in the preced-

ing steps to the vacuum pump to evacuate the tubing
and indoor unit.
Confirm the "Lo" knob of the manifold valve is open.
Then, run the vacuum pump. 
The operation time for evacuation varies with tubing
length and capacity of the pump. The following table
shows the time required for evacuation.

• When the desired vacuum is reached, close the "Lo"

knob of the manifold valve and stop the vacuum pump.

• With a service valve wrench, turn the valve stem of liq-

uid side valve counter-clockwise to fully open the
valve.

• Turn the valve stem of gas side valve counter-clock-

wise to fully open the valve.

• Loosen the charge hose connected to the gas side

service port slightly to release the pressure, then
remove the hose.

• Replace the flare nut and its bonnet on the gas side

service port and fasten the flare nut securely with an
adjustable wrench. This process is very important to
prevent leakage from the system.

• Replace the valve caps at both gas and liquid side

service valves and fasten them tight.
This completes air purging with a vacuum pump. 
The air conditioner is now ready to test run.

Required time for evacuation when 30 gal/h vacuum

pump is used

10 min. or more

15 min. or more

If tubing length is less than

10m (33 ft)

if tubing length is longer

than 10m (33 ft)

Gas side

Liquid side

Cap

Hexagonal wrench

2-way valve

(Open)

3-way valve

(Close)

Indoor unit

Outdoor unit

Lo

Hi

Manifold valve

Vacuum pump

Pressure 
gauge

Open

Close

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1. Check that all tubing and wiring have been properly

connected.

2. Check that the gas and liquid side service valves are

fully open.

1. Remove the battery cover 

by pulling it according to the
arrow direction.

2. Insert new batteries making 

sure that the (+) and (–) of 
battery are installed correctly.

3. Reattach the cover by

pushing it back into position.

NOTE:
• Use 2 AAA(1.5volt) batteries. Do not use recharge-

able batteries.

• Remove the batteries from the remote control if the

system is not going to be used for a long time.

• Anchor the outdoor unit with a bolt and nut(ø10mm)

tightly and horizontally on a concrete or rigid mount.

• When installing on the wall, roof or rooftop, anchor the

mounting base securely with a nail or wire assuming
the influence of wind and earthquake.

• In the case when the vibration of the unit is conveyed

to the hose, secure the unit with an anti-vibration
bushing.

Operate unit for 15~20 minutes, then check the system
refrigerant charge:
1. Measure the pressure of the gas side service valve.
2. Measure the temperature of the intake and discharge

of air.

3. Ensure the difference between the intake tempera-

ture and the discharge is more than 8°C(46°F) (Cool-
ing) or (Heating).

4. For reference; the gas side pressure of optimum con-

dition is as below.(Cooling)

NOTE: If the actual pressure is higher than shown, the

system is most likely over-charged, and charge
should be removed. If the actual pressure are
lower than shown, the system is most likely
undercharged, and charge should be added.

The air conditioner is now ready for use.

Bolt

Tubing connection

Discharge 
temperature

Discharge air

Intake temperature

R-22

35°C (95°F)

4~5kg/cm

2

G(56.8~71.0 P.S.I.G.)

R-410A

35°C (95°F)

8.5~9.5kg/cm

2

G(120~135 P.S.I.G.)

Outside ambient

TEMP.

Refrigerant

The pressure of the gas side 

service valve.

This is performed when the unit is to be relocated
or the refrigerant circuit is serviced.
Pump Down means collecting all refrigerant in the
outdoor unit without loss in refrigerant gas.

CAUTION:
Be sure to perform Pump Down procedure with the
unit cooling mode.

Pump Down Procedure
1. Connect a low-pressure gauge manifold hose to

the charge port on the gas side service valve.

2. Open the gas side service valve halfway and purge

the air from the manifold hose using the refrigerant
gas.

3. Close the liquid side service valve(all the way in).
4. Turn on the unit's operating switch and start the

cooling operation.

5. When the low-pressure gauge reading becomes 1

to 0.5kg/cm2 G(14.2 to 7.1 P.S.I.G.), fully close the
gas side valve stem and then quickly turn off the
unit. At that time, Pump Down has been completed
and all refrigerant gas will have been collected in
the outdoor unit.

ON

OFF

CANCEL

AUTO CLEAN

SET

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5

4

9

10

17

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7

2

8

13

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6

12

Flip-up door
(opened)

Signal transmitter

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The remote control transmits the signals to the system.

START/STOP BUTTON
Operation starts when this button is pressed and
stops when the button is pressed again.
OPERATION MODE SELECTION BUTTON
Used to select the operation mode.
ROOM TEMPERATURE SETTING BUTTONS
Used to select the room temperature.
INDOOR FAN SPEED SELECTOR
Used to select fan speed in four steps
low, medium, high and CHAOS.
JET COOL
Used to start or stop the speed 
cooling. (Speed cooling operates 
super high fan speed in cooling mode.)
CHAOS SWING BUTTON
Used to stop or start louver movement and set the
desired up/down airflow direction.
ON/OFF TIMER BUTTONS
Used to set the time of starting and stopping
operation.
TIME SETTING BUTTONS
Used to adjust the time.
TIMER SET/CANCEL BUTTON
Used to set the timer when the desired time is
obtained and to cancel the Timer operation.
SLEEP MODE AUTO BUTTON
Used to set Sleep Mode Auto operation. 
AIR CIRCULATION BUTTON
Used to circulate the room air without cooling or
heating.
ROOM TEMPERATURE CHECKING BUTTON
Used to check the room temperature.
PLASMA(OPTIONAL)
Used to start or stop the plasma-purification func-
tion.
HORIZONTAL AIRFLOW DIRECTION CON-
TROL BUTTON  (NOT ON ALL MODELS)
Used to set the desired horizontal airflow direc-
tion.
RESET BUTTON
Used prior to resetting time or after replacing bat-
teries.
2nd F Button
Used prior to using modes printed in blue at the
bottom of buttons.
AUTO CLEAN
Used to set Auto Clean mode.
LED LUMINOSITY
Used to adjust LED luminosity.

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