Finishing The Job - LG LAN091CNP, LAU091CNP, LAN121CNP Service Manual

Air purgingd
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 counterclock-
wise 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
Evacuation
1. 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.
Required time for evacuation when 30 gal/h vacuum
pump is used
If tubing length is less
than 10m (33 ft)
10 min. or more
2. When the desired vacuum is reached, close the "Lo"
knob of the manifold valve and stop the vacuum pump.

Finishing the job

1. With a service valve wrench, turn the valve stem of liquid
side valve counter-clockwise to fully open the valve.
2. Turn the valve stem of gas side valve counter-clockwise
to fully open the valve.
3. Loosen the charge hose connected to the gas side ser-
vice port slightly to release the pressure, then remove
the hose.
4. Replace the flare nut and its bonnet on the gas side ser-
vice port and fasten the flare nut securely with an
adjustable wrench. This process is very important to pre-
vent leakage from the system.
5. Replace the valve caps at both gas and liquid side ser-
vice valves and fasten them tight.
This completes air purging with a vacuum pump.
The air conditioner is now ready to test run.
30 Room Air Conditioner
If tubing length is longer
than 10m (33 ft)
15 min. or more
2-way valve
(Open)
3-way valve
(Close)
Hexagonal wrench
Outdoor unit
Manifold valve
Pressure
Lo
gauge
Open
Vacuum pump
Liquid side
Gas side
Cap
Indoor unit
Hi
Close