Specifications

3
■ Demand limiting
This feature limits the power draw of the chiller during peak
loading conditions. When incorporated into the Carrier
Comfort Network building automation system, a red line
command will hold chillers at their present capacity and
prevent any other chillers from starting. If a load shed signal
is received, the compressors are unloaded to avoid high
demand charges whenever possible.
■ Ramp loading
Ramp loading ensures a smooth pulldown of water loop
temperature and prevents a rapid increase in compressor
power consumption during the pulldown period.
■ Automated controls test
The test can be easily executed prior to start-up to verify that
the entire control system is functioning properly.
■ 365-day real time clock
This feature allows for the operator to programme a yearly
schedule for each week, weekends, and holidays.
■ Occupancy schedules
Schedules can be programmed into the controller to ensure
that the chiller only operates when cooling is required.
■ Extensive service menu
Unauthorized access to the service menu can be password-
protected. Built-in diagnostic capabilities assist in trouble-
shooting and recommend proper corrective action for preset
alarms, resulting in less down time.
■ Battery backup
Battery backup provides protection during power failures and
eliminates time consuming control reconfiguration.
Encapsulated circuit boards are designed, built and tested in-
house. Each board meets Carrier’s stringent quality standards
for superior reliability compared to open board designs.
■ Other control features include:
Display of over 125 operating, status, and diagnostic
messages for improved user interface
- Monitoring of over 100 functions and conditions to protect
the chiller from abnormal conditions
- Modular pull-out/plug-in design, reducing wiring
requirements and providing easy installation
- Low-voltage (24 V ac) design, providing the ultimate
assurance of personal safety and control integrity.
■ Microprocessor-controlled oil heater
The heater prevents excessive absorption of refrigerant into
the oil during compressor shutdown, ensuring a plentiful
supply of undiluted lubrication oil in the oil sump.
■ Safeties
Unit is automatically shut down when any of the following
conditions occur: (each of these protective limits shall require
manual reset and cause an alarm message display on the
LCD screen, informing the operator of the shutdown cause.)
- Motor overcurrent
- Over voltage*
- Under voltage*
- Single cycle dropout*
- Bearing oil high temperature
- Low evaporator refrigerant temperature
- High condenser pressure
- High motor temperature
- High compressor discharge temperature
- Low oil pressure
- Prolonged surge
- Loss of cooler water flow
- Loss of condenser water flow
- Starter fault
* Do not require manual reset or cause an alarm if auto-restart after power failure
is enabled.
■
Alarm file
This file maintains the last 25 time- and date-stamped alarm
and alter messages in memory; this function reduces
troubleshooting time and cost.
■ Overrides
The control system detects conditions which approach
protective limits and takes self-corrective action prior to an
alarm occurring.
The system automatically reduces chiller capacity when any
of the following parameters are outside their normal
operating range:
- High condenser pressure
- High motor temperature
- Low evaporator refrigerant temperature
- High motor current
During the capacity override period, a pre-alarm (alert)
message is displayed, informing the operator which condition
is causing the capacity override. Once the condition is again
within acceptable limits, the override condition is terminated
and the chiller reverts to normal chiller water control. During
either condition, if the protective limit is reached, the chiller
shuts down and a message is displayed informing the
operator which condition has caused the shut down and
alarm. This function increases unit life.
Variable inlet guide vanes
■ Capacity control is by means of variable inlet guide vanes
located at the impeller inlet. Load modulation is from 100%
to 15% of compressor full load under nominal ARI
conditions without the use of hot gas bypass. The guide
vanes are precisely positioned by a PID (proportional-
integral-derivative) control algorithm to ensure precise
control of desired chilled water temperature without hunting
or overshooting the set point.
Simple to service
■ Mechanically cleanable cooler and condenser.
■ The machine concept allows the refrigerant to be stored
inside the chiller during servicing, reducing refrigerant loss
and eliminating time-consuming transfer procedures. As a
self-contained unit, the Evergreen chillers can be applied to
applications that incorporate more than one type of
refrigerant without the costly penalty of requiring additional
remote storage systems.
■ Easy-access suction and discharge pressure and temperature
information using enhanced display module.