External Starter Board
In some instances, external starter boards are required to fulfill local wiring regulations.
For example, using auto-transformer to start the compressor. Some countries may ask for special
starters for the compressor.
Some modification to the control box will be required to accomodate such installations.
Basically, an additional switch board is used to house the starters. This board will be placed
externally near to the chiller unit. The internal wiring connection of the chiller must be changed so
that the external board can "communicate" with the chiller PCB controller.
The following are some examples of such modifications:
Method 1:
External
of chiller
contactor
CX CX CX
COMP OF PUMP
aux aux aux
PCB
EXTERNAL
SWITCHBOARD
C/W STARTERS
R
R
R
In this method, the power supply to the contactor of the compressor (COMP), fan motor (OF)
and pump (PUMP)is removed and replaced with the supply from the external switchboard. The
PCB will still control the the contactor energizing coils (CX) via the board relays (R). Once
energized, the auxillary contactor of the contactors (aux) (Normally Open) will send a signal to
the starters in the external switchboard to supply the power.
All the safety devices in the chiller will still be in operation.
Section 11 Page 138
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