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PIPE CONNECTION
28
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 tube.
- Water may lead to corrosion of parts in the
refrigeration system.
Therefore, the indoor/outdoor unit and con-
necting tube must be checked for leak tight,
and vacuumed to remove incondensible gas
and moisture in the system.
Preparation for leakage test
and evacuation
- 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 leak-
age test.
If it is not available, use a stop valve for
this purpose. The "Hi" knob of the mani-
fold 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.
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 tub-
ing(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.
2
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.
Outdoor unit
Manifold valve
Lo Hi
Indoor unit
Charge hose
Nitrogen gas
cylinder(in vertical
standing position)
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