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Units with external water pump
Start the water pump and check the water system for any leaks; repair these if necessary. While the water pump is in
operation, adjust the water flow until the design pressure drop for the evaporator is reached. Adjust the flow switch
trigger point (not factory-supplied), to ensure operation of the machine within a 20% flow range.
From this moment onwards, the machine will be under electrical power. Use extreme caution during
subsequent operation.
A lack of attention during subsequent operation may cause serious personal injury.
Electrical power supply
The machine's power supply voltage must be the same as that specified on the nameplate 10% while the voltage
unbalance between phases must not be in excess of 3%. Measure the voltage between phases and if the value does
not fall within the established limits, correct it before starting the machine.
Provide suitable power supply voltage. Unsuitable power supply voltage could cause malfunction of the control
components and undesired triggering of the thermal protection devices, along with a considerable reduction in the life
of the contactors and electric motors.
Unbalance in power supply voltage
In a three-phase system, excessive unbalance between the phases causes overheating of the motor. The maximum
allowed voltage unbalance is 3%, calculated as follows:
V
max
Unbalance %:
Vaverage
Example: the three phases measure 383, 386 and 392 Volts respectively, the average is:
383+386+392
387 Volts
=
3
thus the unbalance percentage is:
392
387
x
100
, 1
29
%
387
Electrical heaters power supply
Each compressor comes with an electrical heater located at the bottom of compressor. Its purpose is to warm up the
lubricating oil and thus avoid the mixing of refrigerant fluid within.
It is therefore necessary to ensure that the heaters are powered at least 24 hours before the planned start -up time. To
ensure that they are activated, it is sufficient to keep the machine on by closing the general disconnecting switch Q10.
The microprocessor, however, has a series of sensors that prevent the compressor from being started up when the oil
temperature is not at least 5°C above the saturation temperature corresponding to the current pressure.
Keep the Q0, Q1, Q2 and Q12 switches in the Off (or 0) position until the machine is to be started up.
Emergency Stop
The machine has an emergency stop system which cuts off power to the compressors, allowing the machine to stop
safely in case of danger. The emergency stop is triggered off by pressing the red mushroom button on the door of the
machine's electrical panel.
After the machine has stopped, an alarm signal is generated in the unit control card, which reports the triggering of the
emergency stop and prevents the re-starting of the compressors. To restart the compressors:
Reset the emergency button
Cancel the alarm in the control card.
The emergency button cuts off electrical power to the compressors, but not to the machine electrical panel. Take all
necessary precautions therefore, if action must be taken on the machine subsequent to an emergency stop.
D–EIMWC00508-16EN - 28/48
CAUTION
ATTENTION
Vaverage
x
100
_____
below the maximum allowed (3%)
CAUTION
%
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