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LEAKAGE TEST AND EVACUATION
16
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
non-condensable 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
3.8 MPa with dry nitrogen gas and close
the cylinder valve when the gauge
reading reached 3.8 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.
- 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
Outdoor unit
Manifold valve
Lo
Pressure
gauge
Hi
Charge hose
Nitrogen gas
cylinder(in vertical
standing position)
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