Operating instructions
53
Specific operating and maintenance instructions for machines
equipped with the Rockwell Liquid-Flo 2 variable-frequency
drive (VFD).
Access to low-voltage electrical equipment is dangerous
and can result in death or serious injury.
Personnel working on the control boxes must be qualified
to work on low-voltage installations in accordance with the
safety regulations applicable at the site. It must be authorized
for the work and familiar with the equipment and the
installation, as well as the instructions and safety measures
described in this document.
Never work on a unit that is energized.
Do not work on any electrical components, until the main
unit power supply has been switched off using the disconnect
switch(es) integrated into the control box(es).
During maintenance periods lock the power supply circuit
upstream of the unit in the open position.
ATTENTION: 19XRV control boxes are equipped with
capacitor coils with a discharge time after a power cut of
five minutes. If the discharge circuit in the capacitor fails
it is not possible to define the discharge time.
After cutting the power supply to the control box, wait
five minutes before accessing the control box.
Ensure that there is no power supply to any conducting
parts of the power circuit that are accessible during the
work.
These are special instructions to disassemble a chiller
equipped with VFD.
IMPORTANT: Only a qualified technician can carry out
these operations.
WARNING: Do not attempt to disconnect the flanges, if
the chiller is under pressure. The chiller has not been purged,
and this can cause injuries or damage to the machine.
ATTENTION: Before lifting the compressor, disconnect
all cables entering the interface box.
8.2.1 - Removal of the VFD box
Ensure that the power supply has been disconnected and
that all safety measures are in place, before removing the
VFD box. This procedure minimises the number of sensors
and cables that need to be disconnected.
WARNING: For VFD box VFD 900-1169A do not
disconnect the evaporator and condenser before VFD box
900-1169A has been disconnected and removed. This VFD
box has a high-level centre of gravity and can tip over when
the heat exchangers are disconnected, which can lead to
material damage and/or serious injuries to personnel.
WARNING: Do not attempt to remove the VFD, before
closing the shut-off valve on the refrigerant circuit. If this
warning is not observed, the VFD removal will lead to a
significant and uncontrolled refrigerant leak. A refrigerant
leak can damage the machine and displace oxygen, which
can cause asphyxiation.
1. Close the two filter-drier shut-off valves and VFD
cooling circuit shut-off valve. Purge the refrigerant
from the VFD heat exchanger using the Schrader
valve at the side of the filter (refer to Fig. 37 - "VFD
cooling circuit".
2. Remove all VFD power supply cables (see Fig. 38
"VFD box installation (rear view)".
3. Remove the middle part of the terminal boxes (see
Fig. 39 -"VFD - tunnel-side view".
4. Identify and disconnect the motor terminals. Note the
position of the power wiring cable lugs and use the
same position during the re-assembly.
5. Remove the earth connection from the motor. Note the
earth connection position and use the same position
during the re-assembly.
6. Identify and disconnect the power wiring cables and
all communication and connection cables between the
VFD box and the interface box - see Fig. 38 - "VFD
box installation (rear view)".
7. Remove the access panels at the rear of the VFD and
disconnect the cooling circuit lines. Plug all openings.