Leakage Test And Evacuation - LG THERMA V Installation Manual

PIPING AND WIRING FOR OUTDOOR UNIT
64

Leakage test and Evacuation

Air and moisture remaining in the refrigerant
system have undesirable effects as indicated
below.
- Pressure in the system rises.
- Operating current rises.
- Cooling(or heating) efficiency drops.
- Moisture in the refrigerant circuit may freeze
and block capillary tubing.
- Water may lead to corrosion of parts in the
refrigeration system.
Therefore, the indoor/outdoor unit and
connecting tube must be checked for leak
tight, and vacuumed to remove incondensable
gas and moisture in the system.
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. Check that both the liquid and the gas
side service valves on the outdoor unit are
kept closed at this stage.
Leakage test
- Connect the manifold valve(with pressure
gauges) and dry nitrogen gas cylinder to this
service port with charge hoses.
- Pressurize the system to no more than 3.0
MPa with dry nitrogen gas and close the
cylinder valve when the gauge reading
reached 3.0 MPa Next, test for leaks with
liquid soap.
- Do a leakage 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
- 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.
CAUTION
!
Be sure to use a manifold valve for
leakage test. If it is not available, use a
stop valve for this purpose. The "Hi" knob
of the manifold valve must always be kept
close. 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.
Outdoor
unit
Manifold valve
Lo Hi
Indoor unit
Pressure
gauge
Charge hose
Nitrogen gas
cylinder(in vertical
standing position)