Controls - Trane CVGF Instruction Manual

Controls

Standard Features
Field Connection
Heat Exchanger Control
Motor Control and Compressor Protection
Phase Voltage Sensors – 3 phase
Chilled-Water Reset
16
The fi eld-connected elements are involved in physically turning the chiller on or off. This involves
ensuring that the chiller is not in an emergency or external stop condition, starting the pumps, and
verifying that fl ow has been established. The optional, factory-supplied fl ow switch or a customer-
supplied differential-pressure switch can be used to prove fl ow.
Fundamental internal variables that are necessary to control the chiller are gathered and acted
upon by the heat exchanger control function.
This includes all functions that start, run, and stop the motor. The starter module provides the
interface and control of Y-delta, across-the-line, primary reactor, autotransformer, and solid-state
starters. The motor control also provides protection to both the motor and the compressor.
Includes factory-installed potential/current transformers in the starter for monitoring and displaying
phase voltage and provides over/undervoltage protection. Tracer AdaptiView
and Tracer Summit display the following:
• Compressor phase amperage (a-b, b-c, c-a)
• Kilowatts
• Power factor (uncorrected)
• Compressor-phase voltage (a-b, b-c, c-a)
• Kilowatt-hours
Chilled-water reset reduces energy consumption during periods of the year when heating loads are
high and cooling loads are reduced. It is based on return chilled-water temperature. Resetting the
chilled-water temperature reduces the amount of work that the compressor must do by increasing
the evaporator refrigerant pressure. This increased evaporator pressure reduces the pressure
differential the compressor must generate while in the heat recovery mode. Chilled-water reset is
also used in combination with the hot-water control. By resetting the chilled-water temperature
upward, the compressor can generate a higher condenser pressure, resulting in higher leaving hot-
water temperatures.
Standard Features
TM
control, Tracer TU
CTV-PRC001-E4