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Leakage test and Evacuation
Leakage test and Evacuation
Air and moisture remaining in the refrigerant system have undesirable effects as indicated below.
1. Pressure in the system rises.
2. Operating current rises.
3. Cooling(or heating) efficiency drops.
4. Moisture in the refrigerant circuit may freeze and block capillary tubing.
5. 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 vacu-
umed 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 ser-
vice 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 mani-
fold valve for leakage test.
If it is not available, use a stop valve for
this purpose. The "Hi" knob of the man-
ifold valve must always be kept close.
• Pressurize the system to no more than 3.0
Mpa with dry nitrogen gas and close the cylin-
der valve when the gauge reading reached 3.0
MPa Next, test for leaks with liquid soap.
CAUTION: To avoid nitrogen enter-
ing the refrigerant system in a liquid
state, the top of the cylinder must be high-
er 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
tubing(both Indoor unit and outdoor unit) and
both gas and liquid side service valves.
Bubbles indicate a leak. Be sure to wipe off
the soap with a clean cloth.
16
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.
Indoor unit
Outdoor unit
Manifold valve
Pressure
gauge
Lo
Hi
Charge hose
Nitrogen gas
cylinder(in vertical
standing position)
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