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Model
AS-H0766KA2 AS-H0966KA2 AS-H126RKA2 LS-H0766KA2 LS-H0966KA2 LS-H126RKA2 LS-C126RKA2
Pages
63
Size
3.14 MB
Type
PDF
Document
Service Manual
Brand
Device
Air Conditioner
File
as-h0766ka2-as-h0966ka2-as-h126rka2-ls-h0766ka2-ls.zip
Date

LG AS-H0766KA2 / AS-H0966KA2 / AS-H126RKA2 / LS-H0766KA2 / LS-H0966KA2 / LS-H126RKA2 / LS-C126RKA2 Service Manual ▷ View online

Service Manual  25
Air purgingd 
Evacuation
• 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.
Finishing the job
• 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 counter-
clockwise 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.
Soap water method
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
26 Room Air Conditioner
Test running
TEST RUNNING
1. Check that all tubing and wiring have been properly con-
nected.
2. Check that the gas and liquid side service valves are fully
open.
Settlement of outdoor unit
• 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.
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.
Power-Failure Compensation Function User Selection ON/OFF 
1) Operation Sequence 
Press the forced switch until BUZZER sounds 2 times
(beep~beep~).
Release the forced switch if BUZZER sounds. 
Check the function selection ON/OFF with the operation LED. 
2) Checking function-selection ON/OFF 
- Function-Selection ON: One time blinking of operation LED
would repeat 4 times. 
- Function-Selection OFF: Two times blinking of operation LED
would repeat 4 times.
Evaluation of the performance
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 temperature and
the discharge is more than 8°C(46°F) (Cooling) or
(Heating).
4. For reference; the gas side pressure of optimum condition
is as below.(Cooling)
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.
PUMP DOWN
Power
button
Open the front
panel upward
Service Manual  27
Operation 
Function of Controls
Operation 
• DISPLAY
1) C/O Model 
Operation Indicator
• ON while in appliance operation, OFF while in appliance pause.
• Flashing while in disconnection or short in Thermistor. (3 sec off / 0.5 sec on)
Comp. Running Incidator
• While in appliance operation, ON while in outdoor unit compressor running, OFF while in compressor off.
2) H/P Model
Operation Indicator
• ON while in appliance operation, OFF while in appliance pause.
• Flashing while in disconnection or short in Thermistor. (3 sec off / 0.5 sec on)
Defrost Indicator
• OFF except when hot start during heating mode operation or while in defrost control.
■ Cooling Mode Operation
• When the intake air temperature reaches 0.5°C below the setting temp, the compressor and the outdoor fan
stop.
• When it reaches 0.5°C above the setting temp, they start to operate again.
Compressor ON Temp 
➲ Setting Temp+0.5°C
Compressor OFF Temp
➲ Setting Temp-0.5°C
• While in compressor running, operating with the airflow speed set by the remote control. While in compressor
not running, operating with the low airflow speed regardless of the setting.
■ Healthy Dehumidification Mode
• When the dehumidification operation input by the remote control is received, the intake air temperature is
detected and the setting temp is automatically set according to the intake air temperature.
26°C 
≤ Intake Air Temp     
➲  25°C
24°C 
≤ Intake Air Temp<26°C
➲  Intake Air Temp-1°C
18°C 
≤ Intake Air Temp<24°C
➲  Intake Air Temp-0.5°C
Intake Air Temp<18°C
➲  18°C
28 Room Air Conditioner
Operation 
• While in compressor off, the indoor fan repeats low airflow speed and pause.
• While the intake air temp is between compressor on temp. and compressor off temp., 10-min dehumidification
operation and 4-min compressor off repeat.
Compressor ON Temp.
➲ Setting Temp+0.5°C
Compressor OFF Temp.
➲ Setting Temp-0.5°C
• In 10-min dehumidification operation, the indoor fan operates with the low airflow speed.
■ Heating Mode Operation
• When the intake air temp reaches +3°…above the setting temp, the compressor is turned off.  When below
the setting temp, the compressor is turned on.
Compressor ON Temp.
➲ Setting Temp.
Compressor OFF Temp.
➲ Setting Temp.+3°C 
• While in compressor on, the indoor fan is off when the indoor pipe temp. is below 20°C, when above 28°C , it
operates with the low or setting airflow speed. When the indoor pipe temp is between 20°C and 28°C, it oper-
ates with Super-Low(while in sleep mode, with the medium airflow speed).
• While in compressor off, the indoor fan is off when the indoor pipe temp is below 33°C, when above 35°C , it
operates with the low airflow speed.
• If overloaded while in heating mode operation, in order to prevent the compressor from OLP operation, the
outdoor fan is turned on/off according to the indoor pipe temp.
• While in defrost control, both of the indoor and outdoor fans are turned off.
■ Defrost Control
• While in heating mode operation in order to protect the evaporator pipe of the outdoor unit from freezing,
reversed to cooling cycle to defrost the evaporator pipe of the outdoor unit.
• After 40 min heating mode operation, at 4 min interval, whether to carry out defrost control or not and the time
of defrost control are determined according to the following conditions.
1) While in heating mode operation, the maximum of the indoor pipe temperature is measured and it is com-
pared with the present indoor pipe temperature to get the difference of the indoor pipe temperatures (=the
maximum temperature of indoor pipe ? the present temperature of indoor pipe), according to which, whether
to carry out defrost control or not is determined.
2) According to the need of defrost control shown above and the elapsed time of heating mode operation at that
moment, the defrost control time is determined.
3) When the determined time of defrost control is below 7 min, heating mode operation continues without carry-
ing out defrost control. According to the procedure stated above, the determination is made again. When the
defrost control time is 7 min or longer, defrost control is then carried out.
• While in defrost control, the minimum temp of the indoor pipe is measured and it is compared with the present
temp of the indoor pipe to get the difference of the indoor pipe temperatures (=the present temperature of the
indoor pipe ? the minimum temperature of the indoor pipe).  When the difference is 5°C or higher, defrost con-
trol is completed and heating mode operation is carried out.
• While in defrost control, if the defrost time determined before the start of defrost control is completed, defrost
control stops and heating mode operation is carried out regardless of  the above condition.
• When the indoor pipe temp is 42°C or above, defrost control is not carried out even if the condition is one of
the defrost conditions above.
• While in defrost control, the compressor is on and the indoor fan, the outdoor fan, and the 4 way valve are off.
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