IM 1044-2
Centrifugal Chillers
31
A fourth switch located on the left outside of the Unit Control Panel and labeled EMERGENCY STOP SWITCH
stops the compressor immediately. It is wired in series with the COMPRESSOR On/Off switch.
Surge Capacitors
All units (except those with solid state starters or VFDs) are supplied with standard surge capacitors to protect
compressor motors from electrical damage resulting from high voltage spikes.
•
For unit-mounted starters, the capacitors are factory-mounted and wired in the starter enclosure.
•
For free-standing starters, the capacitors are mounted in the motor terminal box and must be connected to
the motor terminals with leads less than 18 inches (460 mm) long when the motor is being wired.
Field Wiring, Controls & Starters
NOTES for Following Wiring Diagram
1.
C
ompressor motor starters are either factory mounted and wired, or shipped separate for field mounting and wiring.
If
provided by others, starters must comply with
Daikin
specification 359999 Rev29. All line and load side power
conductors must be copper.
2.
If starters are freestanding, then field wiring between the starter and the control panel is required. Minimum wire
size
for 115 Vac is 12 GA for a maximum length of 50 feet. If greater than 50 feet, refer to
Daikin
for
recommended
wire size minimum. Wire size for 24 Vac is 18 GA. All wiring to be installed as NEC Class 1 wiring
system. All 24
Vac wiring must be run in separate conduit from 115 Vac wiring. Main power wiring between starter
and motor
terminal is factory-installed when units are supplied with unit-mounted starters. Wiring of free-standing
starter must
be wired in accordance with NEC and connection to compressor motor terminals must be made with
copper wire
and copper lugs only. Control wiring on free-standing starters is terminated on a terminal strip in the
motor terminal
box (not the unit control panel). Wiring from the unit control panel to the motor terminal is done in the
factory.
3.
For optional sensor wiring, see unit control diagram. It is recommended that DC wires be run separately from 115 Vac
wiring.
4.
Customer furnished 24 or 120 Vac power for alarm relay coil can be connected between UTB1 terminals 84 power
and 51 neutral of the control panel. For normally open contacts, wire between 82 & 81. For normally closed contacts,
wire between 83 & 81. The alarm is operator programmable. The maximum rating of the alarm relay coil is 25 VA.
5.
Remote on/off control of unit can be accomplished by installing a set of dry contacts between terminals 70 and 54.
6.
Evaporator and condenser paddle type flow switches or water pressure differential switches are required and must be
wired as shown. If field supplied pressure differential switches are used then these must be installed across the
vessel and not the pump. Factory-mounted thermal dispersion flow sensors are available as an option.
7.
Customer supplied 115 Vac, 20 amp power for optional evaporator and condenser water pump control power and
tower fans is supplied to unit control terminals (UTBI) 85 power / 86 neutral, PE equipment ground.
8.
Optional customer supplied 115 Vac, 25 VA maximum coil rated chilled water pump relay (EP 1 & 2) can be wired as
shown. This option will cycle the chilled water pump in response to building load.
9.
The condenser water pump must cycle with the unit. A customer supplied 115 Vac 25 VA maximum coil rated
condenser water pump relay (CP1 & 2) is to be wired as shown.
10.
Optional customer supplied 115 Vac, 25 VA maximum coil rated cooling tower fan relays (CL - C4) can be wired as
shown. This option will cycle the cooling tower fans in order to maintain unit head pressure.
11.
Auxiliary 24 Vac rated contacts in both the chilled water and condenser water pump starters must be wired as shown.
12.
For VFD, Wye-Delta, and solid state starters connected to six (6) terminal motors. The conductors between the starter
and motor carry phase current and selection shall be based on 58 percent of the motor rated load amperes (RLA).
Wiring of free-standing starter must be in accordance with the NEC and connection to the compressor motor terminals
shall be made with copper wire and copper lugs only. Main power wiring between the starter and motor terminals is
factory-installed when chillers are supplied with unit-mounted starters.
13.
Optional Open Choices BAS interfaces. The locations and interconnection requirements for the various standard
protocols are found in their respective installation manuals, obtainable from the local
Daikin
sales office and
also
shipped with each unit:
Modbus IM 743 LonWorks IM 735 BACnet IM 906
14.
The “Full Metering” or “Amps Only Metering” option will require some field wiring when free-standing starters are
used. Wiring will depend on chiller and starter type. Consult the local
Daikin
sales office for information on
specific
selections.
