Leakage Test And Evacuation - LG THERMA V Installation Manual

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 incondensible 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.
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.
• 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.
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.
• 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.
PIPING AND WIRING FOR OUTDOOR UNIT
77
Indoor unit
Outdoor unit
Manifold valve
Pressure
gauge
Lo Hi
Charge hose
Nitrogen gas
cylinder(in vertical
standing position)