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6.4 Installation for the first time
Air and moisture in the refrigerant system have
undesirable effects as 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 when mixed with the refrigerant and oil
will create an acid that will damage the motor
windings and components in the refrigerant
system.
Therefore, the indoor units and the pipes
between indoor and outdoor units must be leak
tested and evacuated to remove gas and
moisture from the system.
Gas leak check (Soap water method):
Apply soap water or a liquid neutral
detergent on the indoor unit connections or
outdoor unit Connections with a soft brush to
check for leakage of the connecting points of
the piping. If bubbles come out, the pipes have
leakage.
1. Air purging with vacuum pump
1) Completely tighten the flare nuts of the
indoor and outdoor units, confirm that both
the 2-way and 3-way valves are set to the
Front seated.
2) Connect the low pressure gauge to the 3 way
service valve access port..
3) Connect the middle hose of the gauge
manifold (usually yellow) to the vacuum
pump.
4) Fully open the handle for the low pressure
gauge..
5) Start the vacuum pump and operate according
to manufacture spec's.
6) Perform an evacuation for a minimum of 30
minutes and check that the low pressure
(compound) gauge indicates a vacuum of 29.9
in/hg (500 microns) A vacuum gauge should
be used if available. If the proper vacuum
cannot be achieved the vacuum pump should
be run for an additional 20 minutes. If after the
additional 20 minutes the vacuum still cannot
be achieved the is a leak in the system and
must be located and repaired. follow the leak
checking procedure as mentioned before. If
the vacuum is achieved, close the low pressure
gauge handle off and shut the vacuum pump
off. Recheck the reading after 10 minutes, the
vacuum may change slightly, this is normal.
7) The system is now dry and free of
contaminates, refrigerant pressure should
now be added to the system from a source
other than the system before opening the 2
way and 3 way valves for system operation.
8) The 2 way and 3 way valve can now be
opened for the system operation
2. Air purging by refrigerant
Procedure:
1). Confirm that both the 2-way and 3-way
valves are set to the closed position.
2). With a container of refrigerant and a gauge
manifold set, connect the low pressure gauge hose
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