Air Purging; Air Purging With Vacuum Pump - LG LAN090HSV Data Book

6RMI0-02A

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. Preparation
• 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.
2. Leak test
• Connect the manifold valve(with pressure gauges) and dry nitrogen gas cylinder to this service port with charge hoses.
Be sure to use a manifold valve for air purging. If it is not available, use a stop valve for this purpose. The knob
of the 3-way valve must always be kept close.
• Pressurize the system to not more than 150 P.S.I.G. with dry nitrogen gas and close the cylinder valve when
the gauge reading reaches 150 P.S.I.G. Next, test for leaks with liquid soap.
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.
1. 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.
2. 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.
Indoor unit
Outdoor unit
Inverter Single Inverter Single Inverter Single Inverter Single
Installation
Manifold valve
Pressure
gauge
Lo Hi
Charge hose
Nitrogen gas
cylinder(in vertical
standing position)
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