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2. A freestanding starter or VFD furnished by Daikin, or by the customer to Daikin
specifications, will have a control transformer in it and requires field wiring to terminals in
the compressor terminal box.
3. Power can be supplied from a separate circuit and fused at 20 amps inductive load. The
control circuit disconnect switch must be tagged to prevent current interruption. Other than
for service work, the switch is to remain on at all times in order to keep oil heaters
operative and prevent refrigerant from diluting in oil.
If a separate control power source is used, the following must be done to avoid
severe personal injury or death from electrical shock:
1. Place a notice on the unit that multiple power sources are connected to the
unit.
2. 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 10, Control Power Line Sizing
Maximum Length, ft (m)
0 (0) to 50 (15.2)
50 (15.2) to 75 (22.9)
75 (22.9) to 120 (36.6)
Notes:
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.
Wiring for Optional BAS Interface
The optional Building Automation System (BAS) interface utilizing the MicroTech II unit
controller's Protocol Selectability™ feature is field wired and will be set-up by the Daikin
startup service technician. The following manuals explain the wiring and mounting
procedures:
Flow Switches
Water flow interlock terminals are provided on the Unit Control Panel terminal strip for field-
mounted switches. See the Field Wiring Diagram on page 33 or on the cover of the control panel
for proper connections. The purpose of the water flow interlocks is to prevent compressor
operation until such time as both the evaporator water and condenser water pumps are running
and flow is established. If flow switches are not furnished factory-installed and wired, they must
be furnished and installed by others in the field before the unit can be started.
30
Wire Size (AWG)
L
W
> IM 735
ON
ORKS®
®
BACnet
> IM 736
®
MODBUS
> IM 743
Centrifugal Chillers
DANGER
Maximum Length, ft (m)
12
120 (36.6) to 200 (61.0)
10
200 (61.0) to 275 (83.8)
8
275 (83.8) to 350 (106.7)
Wire Size (AWG)
6
4
3
D-EIMWC00804-14EN
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