LG AUUW096D Installation Manual page 39

Air Purging
Air purging
The air and moisture remaining in the refrigerant system have undesirable effects as indicated below.
1. Pressure in the system rises.
2. Operating current rises.
3. Cooling(or heating) efficiency drops.
4. Moisture in the refrigerant circuit may freeze and block capillary tubing.
5. Water may lead to corrosion of parts in the refrigeration system.
Therefore, after evacuating the system, take a leak test for the piping and tubing between the
indoor and outdoor unit.
Air purging with vacuum pump
1. Check that both liquid and gas pipe between indoor and outdoor have been properly
connected.
2. Remove the service valve cap from both the gas and liquid side on the outdoor unit.
3. Confirm that both the liquid and gas side valve are set to the closed position.
4. Connect the manifold valve(with pressure gauge) to the gas pipe side.
CAUTION:
: 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.
5. And connect the Nitrogen cylinder to the
service port with charge hoses to the
manifold gauge.
6. Pressurize the system to no more than 551
P.S.I.G with dry nitrogen gas. Close the
nitrogen cylinder valve when it shows
reading of 551 P.S.I.G.
CAUTION:
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.
7. Check for leakage with Liquid soap solution. Do the leakage test at all joints of tubing (indoor and
outdoor) and on the service valve (both gas and liquid side).
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
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
Indoor unit
Outdoor unit
2-way valve
(Open)
3-way valve
(Close)
Indoor Unit Drain Piping
Manifold valve
Pressure
gauge
Lo Hi
Charge hose
Nitrogen gas
cylinder(in vertical
standing position)
Liquid side
Gas side
Cap
Hexagonal wrench
Installation Manual 39