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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.
DANGER
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)
Wire Size (AWG)
Maximum Length, ft (m)
Wire Size (AWG)
0 (0) to 50 (15.2)
12
120 (36.6) to 200 (61.0)
6
50 (15.2) to 75 (22.9)
10
200 (61.0) to 275 (83.8)
4
75 (22.9) to 120 (36.6)
8
275 (83.8) to 350 (106.7)
3
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:
L
ON
W
ORKS
> IM 735
BACnet
> IM 736
MODBUS
> IM 743
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 34 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.
System Pumps
Operation of the chilled water pump can be to 1) cycle the pump with the compressor, 2) operate continuously, or 3)
start automatically by a remote source.
The cooling tower pump must cycle with the machine. The holding coil of the cooling tower pump motor starter must
be rated at 115 volts, 60 Hz, with a maximum volt-amperage rating of 100. A control relay is required if the voltage-
amperage rating is exceeded. See the Field Wiring Diagram on page 34 or in the cover of control panel for proper
connections.
