SINGLE SCREW CHILLERS IMM
Engineered for Flexibility and Performance
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6.2 Knockdown of Chiller
The chiller is delivered in three states: 1. complete chiller with refrigerant and lubricating oil; 2.
complete chiller without refrigerant, but with lubricating oil; 3. the chiller is partially or fully
dismantled. Reinstallation of the chiller in the second or third state shall be performed by
professional operator as per the General Assembly Schematic Map of the chiller. Level pressure
and inspect leakage condition of the chiller after reinstallation, and vacuum the chiller after
leakage condition being inspected.
1. Nitrogen leakage detection
Open the pipeline valve to inject the dry nitrogen into the system, and let the pressure rise up to
0.4MPa and hold this pressure for 5 min, and then inspect all of the welding connections and
connection positions for leakage. If any leakage detected, discharge the refrigerating engine oil (if
provided in the chiller) and nitrogen out of the chiller, and repair the leakage position, then,
perform the inspection again. If the chiller approved as qualified by the first inspection, further
increase the pressure to 80% of the prescriptive value slowly (if the test pressure exceeds 2.0MPa,
then, it is only need to increase the pressure to 50% of the prescriptive value), and hold this
pressure for 5 min, and then inspect all of the welding connections and connection positions for
leakage for the second time. If any leakage detected, discharge the refrigerating engine oil (if
provided in the chiller) and nitrogen out of the chiller, and repair the leakage position, then,
perform the inspection again. After approved as qualified by the second inspection, increase the
test pressure to the prescriptive value step-by-step, and the pressure increased at each step shall
be 10% of the prescriptive value. Close the valve to maintain the pressure for 60 min after the
system is confirmed as free of leakage and the pressure meter shows that the pressure is the
leveled and leakage inspection pressure. During this period, inspect the pressure shown by the
pressure gauge. The pressure shall remain unchanged unless the environment got changes which
may result in fluctuation to the pressure. If the pressure suffers any change, it is also need to
discharge the refrigerating engine oil (if provided in the chiller) and nitrogen out of the chiller, and
carry out necessary repairing work, then, perform the inspection again.
Test pressure of the nitrogen leakage detection for each chiller is 1.0MPa.
2. Vacuum Test
While performing vacuum test, each part of the refrigerating system shall be free of abnormality
after vacuuming the chiller to 67 Pa (500Microns)
;
hold this pressure for 30min during which the
rise of vacuum degree shall not exceed 67 Pa (500Microns).
3. Charging of the Refrigerant
Charging volume shall be determined according to the nameplate.
