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8.9 Refrigerant Charging
Refrigerant charging should be done based on the discharge and suction pressure. An air
tight test must be taken on the condition refrigerant leaks or some part is required to be
replaced. Refrigerant charging comes into two cases stated below.
◆ Complete charging
In this case, take a leakage test by charging hi-pressure nitrogen (15~20kg) or refrigerant
into the system. If soldering is required, note that gas inside the system must be expelled
firstly. The whole system must be dried and vacuumed prior to charging.
(1)Connect the manifold gauge.
(2)Vacuum the system with the vacuum pump.
(3)After the system pressure reaches the required value (<80Pa) for more than 30
minutes and keeps below 100Pa, charge refrigerant at the low pressure side as per
the rated specification on the nameplate.
(4)Refrigerant charge will be affected by the ambient temperature. When charged
refrigerant is under the required amount, add in accordance with the other charging
case stated below.
◆ Adding
Connect the refrigerant charging port at the lower pressure side to the refrigerant tank and
install a manifold gage.
(1)Circuit the chilled water and start up the unit.
(2)Charge refrigerant vapor into the system slowly and check the suction and discharge
pressure.
WARNING
(1)When performing the leakage and air tight test, never charge oxygen, acetylene and
other flammable and toxic gases but only hi-pressure air, nitrogen or refrigerant.
(2)Mineral scale on the surface of the heat exchanger will affect the heat exchanging
efficiency and increase the water resistance and lower the refrigeration capacity.
Therefore, it should be cleared away through dilute acid. Note that contents of
different water quality vary and should be treated with different type of acid by the
qualified chemical company.
8.10 Removal of the Compressor
Please take the steps below when the compressor is required to be removed.
(1)Cut off the power supply.
(2)Recover the refrigerant in a reasonable speed to prevent oil from being drawn out.
(3)Remove the power cord and the temperature sensor.
(4)Unsolder the soldering spots of the suction and discharge lines.
(5)Remove the screw bolts of the compressor and check the oil quality and accumulator.
(6)Remove the compressor.
A Series Inverter Modular Air-cooled Chiller (Heat Pump)
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