23
Pre-Start-up
Voltage range
Power supply of the water chiller must conform to the operation power supply marked on
the name plate, and the power voltage & unbalances between each phase must be within the
following scope. Gauge the voltages between each phase, readings of which must be within
the acceptable voltage tolerance (±10%) marked on the name plate. If any voltage between two
phases is not within the tolerance, electricity company shall be notified to correct such condition
before the water chiller running. Improper voltage will result in abnormal control function, and
shorten the life of various electrical parts & compressor motor.
Voltage unbalance
I
f there is significant voltage unbalance between each phase of the three-phase electricity system,
it will result in motor overheat and then induce motor failure. The maximum allowable voltage
unbalance is 2%, voltage unbalance is defined as follows:
voltage unbalance %=
100x|Va-Vd|
%
Va
Wherein:
Va=(V1+V2+V3)/3 (average voltage)
V1,V2,V3=voltage between phases
Vd=voltage between phases with maximum difference to Va
Water flow
The flow rate of the cold water passing through the water chiller must be between the upper limit
and the lower limit listed in table 4. If the flow rate of the cold water coming into the evaporator is
below the lower limit, it will result in discontinuous water flow and reduce the heat transfer effect,
and then lead to out-of-control expansion valve or abnormal underpressure jump. Conversely, if
the flow rate is above the upper limit, parts inside of the evaporator will be corroded.
Water pressure drop
Measure the water pressure difference between the inlet and outlet of the water chiller (with water
pump), then the head outside the water chiller at this water amount can be acquired, which shall
be basically shown as the "Pump Head" curve. When the standard model with water pump is
used, for the design of piping system please refer to the "Pump Head " curve. If the model without
water pump is used (water pump is installed outside of the water chiller), internal water pressure
drop of the water chiller shall be basically shown as the "Internal Pressure Drop" curve. When the
model without water pump is used, for the design of piping system please refer to the "Internal
Pressure Drop" curve.
