72
Upon building pressure, the compressor is allowed to start
(after 15 seconds). For across-the-line (XL) start chillers, the
compressor starts and comes up to full speed within 1 to 3 sec-
onds. For Wye-Delta start chillers, contactors 1M and S (starter
contactor assembly) are closed and the compressor is started in
a Wye configuration. This method reduces the locked rotor
current requirements by approximately 60% while maintaining
enough torque to bring the compressor up to full speed.
FIELD WIRING
Field wiring is shown in Fig. 40-54.
LEGEND FOR FIG. 40-54
* Dependant on control circuit power supply voltage.
ALM — Alarm
CFR — Condenser Fan Relay
CMP — Chiller Water Pump
CNFS — Condenser Flow Switch
CNPI — Condenser Pump Interlock
CNP-R — Condenser Pump Relay
CWP — Chilled Water Pump
EMM — Energy Management Module
EWT — Entering Water Thermistor
FIOP — Factory-Installed Option
FSR — Flow Switch Relay
FU — Fuse
GFI-CO — Ground Fault Interrupter Convenience Outlet
GND — Ground
LLSV — Liquid Line Solenoid Valve
LWT — Leaving Water Thermistor
MBB — Main Base Board
MLV — Minimum Load Valve
NEC — National Electrical Code
OAT — Outdoor-Air Thermistor
SCB — Screw Compressor Board
SPT — Space Temperature Sensor
SW — Switch
TB — Terminal Block
Field-Wired
Factory Wired
FIELD CONTROL POWER SUPPLY
NEC FUSED DISCONNECT
230 V CONTROL CIRCUITS
USE 15 AMP MAXIMUM FROM
SEPARATE POWER SUPPLY
115 V CONTROL CIRCUITS
USE 30 AMP MAXIMUM FROM
SEPARATE POWER SUPPLY
2
1
GND
TB4
Fig. 40 — Power Supply Wiring
MBB
MBB
Fig. 41 — Remote Alarm Relay Accessory Wiring; All Models, 115 or 230 V*
Fig. 42 — Chilled Water Pump Relay Wiring; All Models, 115 or 230 V*
Fig. 43 — Optional Ground Fault Interrupter; Convenience Outlet Accessory Wiring
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