MCAC-CTSM-2018-1
Flooded type water cooled screw chiller (MIC)
83
9) Before starting up the machine, inspect whether the external system of the unit meets the conditions
for start-up (e.g. whether the water cooling pump of the system is externally controlled or interlocked with
the master compressor, and whether the water pump must be started before starting up the master
compressor via external control).
10) Inspect whether the compressor overload protection value, which must not exceed the maximum
compressor permissible current value indicated in the nameplate on the compressor, is set correctly. The
compressor overload protection value generally equals the set value of heat relay multiplied by the
variable ratio of current inductor, which is (250/5)50 in the following case.
11) Inspect whether the value of phase loss and reversal protection is set correctly. The
over-/under-voltage protection value shall be ±10% of the rated voltage.
(2) Refrigeration System Inspection
1) The discharge line valve and suction line valve of the compressor must be fully open (turn
anticlockwise to open). The cores must be tightly locked to prevent refrigerant leaks.
2) Inspect whether moisture content of the system exceeds the limit
Excessive moisture content in the refrigerant system of the unit might cause ice blocks, copper plating, etc. that
will seriously affect the safety of the unit. Therefore, the dryness of the refrigerant system of the unit must be
inspected with the sight glass before and when the unit is running. Purple indicates dry and pink moist, as shown
in the figure on the right. When the color turns red, replace the filter core in the unit shall be replaced with a dry
one.
3) Sufficient lubricating oil in the oil tank (not lower than 1/2 of the oil level in the high oil immersion
lens), and no deterioration (blackness).
Inspect the oil level and quality before start-up, as both directly impact performance and reliability.
There must be sufficient lubricating oil in the unit. During shutdown, the high oil immersion lens must
The discharge line
valve and suction line
valve shall be open
(both valves in the
figure are closed, and
shall
be
opened
before start-up).
The
discharge
line
valve and suction line
valve shall be open
(both valves in the
figure are closed, and
shall be opened before
start-up).
The color is indicated in the
center and compared with
the color card around it to
reflect the moistness in the
system.