LG LAN181CNW, LAU181CNW, LA180CPI, LA180CPO Service Manual page 40

Installation
Soap water method
(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.
3. Evacuation
• Connect the charge hose end described in the pre-
ceding steps to the vacuum pump to evacuate the tub-
ing 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.
Required time for evacuation when 30 gal/h vacuum pump is
If tubing length is less than 10m
(33 ft)
10 min. or more
• When the desired vacuum is reached, close the "Lo"
knob of the manifold valve and stop the vacuum
pump.
4. 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-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.
40 Room Air Conditioner
used
if tubing length is longer than 10m
(33 ft)
15 min. or more
3-way valve
(Close)
2-way valve
(Open)
Hexagonal wrench
Manifold valve
Pressure
gauge
Open
Vacuum pump
Gas side
Liquid side
Cap
Indoor unit
Outdoor unit
Lo Hi
Close