Installation
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IOM 1281-2 • CENTRIFUGAL WATER CHILLERS
DANGER
If a separate control power source is used, the following
must be done to avoid severe personal injury or death from
electrical shock: Place a notice on the unit that multiple
power sources are connected to the unit. Place a notice on
the main and control power disconnects that another source
of power to the unit exists.
In the event a transformer supplies control voltage, it must be
rated at 3 KVA, with an inrush rating of 12 KVA minimum at
80% power factor and 95% secondary voltage. For control wire
sizing, refer to NEC. Articles 215 and 310. In the absence of
complete information to permit calculations, the voltage drop
should be physically measured.
Table 6: Control Power Line Sizing
Maximum Length, ft (m)
Wire Size (AWG)
0 (0) to 50 (15.2)
12
NOTE:
1. Maximum length is the distance a conductor will traverse
between the control power source and the unit control
panel.
2. Panel terminal connectors will accommodate up to
number 10 AWG wire. Larger conductors will require an
intermediate junction box.
The Unit On/Off switch located in the Unit Control Panel should
be turned to the “Off” position any time compressor operation is
not desired.
Surge Capacitors
Surge capacitors are an option for some unit-mounted, low
voltage starter configurations (not for solid state starters or
VFDs) to protect compressor motors from electrical damage
resulting from high voltage spikes. If ordered, the capacitors
are factory-mounted and wired in the starter enclosure.
Building Automation Systems
(BAS)
All MicroTech
®
controllers with an open protocol platform are
capable of BAS communications, providing easy integration
and comprehensive monitoring, control, and two-way data
exchange with open standard protocols such as LonTalk
®
,
Modbus® or BACnet
®
.
Daikin Applied unit controllers strictly conform to the
interoperability guidelines of the LonMark® Interoperability
Association and BACnet® International. They have
received LonMark® certification with optional Lon
W
orks
®
communication module.
Protocol Options
The following protocol options are available:
• BACnet
®
MS/TP
• BACnet
®
IP
• BACnet
®
Ethernet
• L
on
W
orks
®
• Modbus
®
RTU
The BAS communication module can be ordered with the
chiller and factory-mounted or can be field-mounted at any time
after the chiller unit is installed. Connection to the chiller for all
BAS protocols will be at the unit controller.
If an interface module was ordered, the appropriate BAS
interface installation manual was shipped with the unit. If
necessary, contact your local Daikin Applied sales office for an
additional manual or download from
www.DaikinApplied.com
.
Use with On-Site Generators
Centrifugal Chillers may be run with On-Site Generators when
utility power is lost. The HVAC system and chiller have to
be disconnected from the power grid and connected to the
generator power. Then enable the HVAC system while on the
generator.
Generator Sizing
Natural gas and diesel generators are sensitive to the peak
current loads of the chiller. Use the electric data on the Starters
supplied with the chiller or the chiller performance rating sheet
– obtained from the Daikin Applied sales office – for generator
sizing purposes. The reference data will show the RLA and
LRA, which is for each compressor. It is important to size the
generator to handle the LRA for the compressor motor for
starting.
WARNING
Generator must be sized by an electrical engineer familiar
with generator applications.
Transfer Back to Grid Power
If the generator to power grid has synchronous power switch
capability then it can be done at any time. Usually this switch
does not exist so the switch is done by shutting down the
HVAC system including the chiller that is running on the
generator. Then switch the power for the HVAC system to the
power from the grid and then turning the HVAC system back on
including the Chiller.
