GD Midea Refrigerant Equipment Co. Ltd Service manual for Electrolux split Series
15
2.7 AIR PURGING
2.7.1 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 if applicable) 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 unit and tubing between the
indoor and outdoor unit must be leak tested and
evacuated to remove any non-condensable
substance and moisture from the system.
2.7.2 Air purging with vacuum pump
2.7.2.1 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. Note that both the liquid and
the gas side service valves on the outdoor unit are
kept closed at this stage.
2.7.2.2 Leak test
● Connect the manifold set (with pressure
gauges) and dry nitrogen gas cylinder to this
service port with charge hoses.
● Pressurizes the system to no more than 1MPa
(Approx. 145psi) with dry nitrogen gas and close
the cylinder valve when the gauge reading
reaches 1MPa (Approx. 145psi). Next, test for
leaks with liquid soap.
Lo Hi
Indoor unit
Outdoor unit
Manifold set
Pressure
gauge
Charge hose
Nitrogen gas
cyli nder (in vertical
standing position)
● 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.
● 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.
Gas leak check
1. Apply a soap water or a liquid neutral detergent
CAUTION
To avoid nitrogen entering the refrigerant
system in a liquid state, the top of the cylinder
must be higher than its bottom then you
pressurise the system. Usually, the cylinder is
used in a vertical standing position.
CAUTION
Be sure to use a manifold set for air purging. If it
is not available, use a stop valve for this
purpose. The "Hi" knob of the manifold valve
must always be kept closed.
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