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5.4
Control power wiring
Under no circumstances should a compressor be brought up to speed unless proper sequence and rotation have been
established. Serious damage can result if the compressor starts in the wrong direction. Such damage is not covered by
product warranty.
It is the installing contractor
’s responsibility to insulate the compressor motor terminals when the unit voltage is 600 volts
or greater. This is to be done after the Daikin start-up technician has checked for proper phase sequence and motor
rotation.
The control circuit on the Daikin centrifugal packaged chiller is designed for 400 volts. Control power can be supplied from
three different sources:
1. If the unit is supplied with a factory -mounted starter or VFD, the control circuit power supply is factory-wired from a
transformer located in the starter or VFD.
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. 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.
5.5
Flow Switches
Water flow interlock terminals are provided on the Unit Control Panel terminal strip for field-mounted switches. 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. A flow switch must be installed before the unit can be started.
5.6
Control Panel Switches
Three mode switches are located in the central part of the main Unit Control Panel. They have the following function:
•
Q0 - UNIT executes an immediate shutdown of the chiller without the normal shutdown cycle and provides a post -lube
period.
•
Q1 - COMPRESSOR one switch for each compressor on a unit, shuts down the compressor through the normal
shutdown cycle of unloading and provides a post-lube period.
•
Q8
– COOLING/HEATING defines the operating mode of the unit.
5.7
Cable requirements
The cables connected to the circuit breaker must respect the insulation distance in the air and the surface isolation
distance between the active conductors and the earth, according to IEC 61439-1 table 1 and 2, and to the local national
laws.
The cables connected to the main switch must be tightened using a pair of keys and respecting the unified clampi ng
values, relative to the quality of the screws of the washers and nuts used.
Connect the earth conductor (yellow / green) to the PE ground terminal
.
The equipotential protection conductor (earth conductor) must have a section according to table 1 of EN 60204-1 Point
5.2, shown below.
Table 8 - Table 1 of EN60204-1 Point 5.2
Section of the copper phase conductors feeding the
equipment
S
[mm
2
]
Minimum cross-section of the external copper
protection conductor
S
p [mm
2
]
S
≤ 16
16 <
S
≤ 35
S
> 35
S
16
S
/2
In any case, the equipotential protection conductor (earth conductor) must have a cross section of at least 10 mm
2
, in
accordance with point 8.2.8 of the same standard.
