DOWNLOAD LG AS-H126U / LS-C126U / LS-H126U Service Manual ↓ Size: 8.66 MB | Pages: 127 in PDF or view online for FREE

■ 

If you want to connect an additional drain
hose, the end of the drain outlet should be
routed above the ground. Secure the drain
hose appropriately.

■

Tape the piping, drain hose and
connecting cable from down to up.

■

Secure the tapped piping along the exterior
wall using saddle or equivalent.

Taping

Drain
hose

Pipings

Connecting
cable

Trap is required to prevent water
from entering into electrical parts.

Seal small openings
around pipings with a
gum type sealer.

■

Tape the piping and connecting cable from
down to up.

■

Secure the taped piping along the exterior
wall. Form a trap to prevent water entering
the room.

■

Fix the piping onto the wall by saddle or
equivalent.

Seal a small opening 
around the pipings 
with gum type sealer.

Trap

Trap

■ 

Set the air direction louvers up-and-down
to the position(horizontally) by hand.

■ 

Remove the securing screws that retain the
front panel. Pull the lower left and right
sides of the grille toward you and lift it off.

Air

filter

Inlet Grille

■ 

Pour a glass of water on the evaporator.

■ 

Ensure the water flows through the drain
hose of the indoor unit without any leakage
and goes out the drain exit.

Drain pan

Drain

hose

Leakage

checking

Connecting area

drain hose

Leakage

checking

■ 

The drain hose should point downward for
easy drain flow.

■ 

Do not make drain piping.

Downward slope

Do not raise

Accumulated
drain water

Tip of drain hose 
dipped in water

Air

Waving

Water
leakage

Water
leakage

Ditch

Less than 
50mm gap

Water
leakage

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
refrigeration system.

Therefore, the indoor unit and tubing between
the indoor and outdoor unit must be leak tested
and evacuated 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 properly
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.

Lo

Hi

Indoor unit

Outdoor unit

Manifold valve

Charge hose

Nitrogen gas
cylinder(in vertical
standing position)

Pressure 
gauge

■

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.

■

Connect the charge hose end described in the
preceding 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 liquid side valve counter-clockwise to fully
open the valve.

■

Turn the valve stem of gas side valve
counter-clockwise 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.

(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

counterclockwise 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
connections by a soft brush to check for
leakage of the connecting points of the piping.

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

Gas side

Liquid side

Cap

Hexagonal wrench

2-way valve

(Open)

3-way valve

(Close)

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)

Indoor unit

Outdoor unit

Lo

Hi

Manifold valve

Vacuum pump

Pressure 
gauge

Open

Close

■ 

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.

Remove the battery cover 
by pulling it according to the

arrow direction.

Insert new batteries making 
sure that the (+) and (–) of 
battery are installed correctly.

Reattach the cover by

pushing it back into position.

Operate unit for 15~20 minutes, then check the
system refrigerant charge:
1. Measure the pressure of the gas side service

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

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/cm

2 

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.

Discharge 

temperature

Discharge air

Intake temperature