Leak Test - LG LS-J0910CL Service Manual

(6) Air Purging
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 corrossion of parts in the refrigeration
system.
Therefore, the indoor unit and tubing between the indoor and
outdoor unit must be leak tested and evacuated to remove
any noncondensables and moisture from the system.
Air Purging with a Vacuum Pump
Preparation
Check that each tube(both liquid and gas side tubes)
between the indoor and outdoor units has been properly
connected and all wiring for the test run has been com-
pleted. Remove the valve caps from both the gas and the
liquid side service valves on the outdoor unit. Note that
both liquid and gas side service valves on the outdoor unit
are kept closed at this stage.

Leak test

1. 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 air purg-
ing. If it is not available, use a stop valve for
this purpose. The "Hi" knob of the manifold
valve must always be kept close.
2. Pressurize the system to no more than 150 P.S.I.G
with dry nitrogen gas and close the cylinder valve
when the gauge reading reached 150 P.S.I.G. Next,
test for leaks with liquid soap.
CAUTION: To avoid nitrogen entering the refrigerant sys-
tem in a liquid state, the top of the cylinder
must be higher than its bottom when you pres-
surize the system. Usually, the cylinder is
used in a vertial standing position.
3. 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.
4. After the system is found to be free of leaks, relieve
the nitrogen pressure by loosening the charge
hose connnector at the nitrogen cylinder. When the
system pressure is reduced to normal, disconnect
the hose from the cylinder.
Manifold valve
Pressure
gauge
- 35 -
Indoor unit
Outdoor unit
Lo Hi
Charge hose
Nitrogen gas
cylinder(in vertical
standing position)