Air Purging - AERMEC MGH R410A Manuel D'installation

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) 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 noncondensables and
moisture from the system.
Air purging with vacuum
pump
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. Leak 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 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 close.
Pressurize the system to no more than
150 P.S.I.G. with dry nitrogen gas and
close the cylinder valve when the
gauge reading reached 150 P.S.I.G.
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.
AIR PURGING
Apply a soap water or a liquid neutral detergent on
the indoor unit connection or outdoor unit
connections by a soft brush to check for leakage of
the connecting points of the piping. Do a leak test
of all joints of the tubing(both indoor and outdoor)
and both gas and liquid side service valves.
If bubbles come out, the pipes have leakage. 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.
Pressure
gauge
14
Indoor unit
Outdoor unit
Manifold valve
Lo Hi
Charge hose
Nitrogen gas
cylinder(in vertical
standing position)