Air Tight Test; Air Purging; Checking Method - LG MULTI F A2UW16GFA0 Engineering Product Data Book

2. Guideline for each installation process

2.6. Air tight test

2.6.1 Air purging

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, the indoor/outdoor unit and connect-
ing tube must be checked for leak tight, and vacuumed
to remove incondensable gas and moisture in the sys-
tem.

1)Checking method

① Preparation
• Check that each pipe (both liquid and gas side pipes)
between the indoor and outdoor units have been properly
connected and all wiring for the test run has been com-
pleted. Remove the service valve caps from both the gas
and the liquid side on the outdoor unit. Check that both the
liquid and the gas side service valves on the outdoor unit
are kept closed at this stage.
② Leakage test
• Connect the manifold valve (with pressure gauges) and
dry nitrogen gas cylinder to this service port with charge
hoses.
CAUTION
Gas Pipe
Be sure to use a manifold valve for leakage test. If it is
not available, use a stop valve for this purpose. The "Hi"
Liquid Pipe
knob of the manifold valve must always be kept close.
Gas pipe Gas Pipe Gas Pipe
Manifold gauge hose
Outdoor unit
Liquid pipe Liquid Pipe Liquid Pipe
Manifold valve
Pressure
gauge
Lo Hi
Charge hose
Nitrogen gas
cylinder(in vertical
standing position)
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.
1. Do a leakage test of all joints of the Tubing (both
indoor and outdoor) and both gas and liquid side ser-
vice 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 con-
nector at the nitrogen cylinder. When the system pres-
sure is reduced to normal, disconnect the hose from
the cylinder.
Outdoor unit
Manifold valve
Lo
Heat pump
Hi
Charge hose
Nitrogen gas
cylinder(in vertical
standing position)
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60Hz/R410A