Air Purging And Evacuation; Checking Method - LG UHXM120BA1 Installation Manual

AIR PURGING AND EVACUATION

The 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, after evacuating the system, take a
leak test for the piping and tubing between
the indoor and outdoor unit.

Checking method

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
550 P.S.I.G. with dry nitrogen gas and
close the cylinder valve when the gauge
reading reached 550 P.S.I.G. Next, test
for leaks with liquid soap.
AIR PURGING AND EVACUATION
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.
- 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.
Indoor unit
Manifold valve
Outdoor unit
33
Pressure
Lo Hi
gauge
Charge hose
Nitrogen gas
cylinder(in vertical
standing position)