ClimaCool UCR 30, 50 and 70 tons Manual - Manual (Page 56)

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56
Sequence of Operation
Generic Interface
Chiller shall be enabled locally or remotely via selector
switch on the face of the CoolLogic Master Control Panel
from enable/disable contact by Building Automation System
(BAS). Pumps for chilled water supply shall be started by
others. When proof of fl ow is established in the chilled
water lines, the ClimaCool chiller shall start. The “Chilled
Water Supply” (CHWS) temperature sensor (TS1), located in
the discharge line of respective chiller, shall be used to cycle
compressor stages sequentially to maintain setpoint of 44°F
(adjustable from the LED Display/Keypad on the face of the
CoolLogic Master Controll Panel, or remotely via 4-20 ma
signal, or remotely through a BAS communications protocol
(e.g. BACnet, LonWorks, Modbus or N2.)
Chillers will be disabled until “Chilled Water Return” (CHWR)
temperature sensor is below 90°F .
Each module of the chiller has 2 compressors. Stage 1
compressors shall be started fi rst on lead week and stage 2
compressors shall be started fi rst on lag weeks to equalize
run hours between compressors 1 and 2 of the modules
automatically. Compressors shall be staged with a single
compressor per module as required, until all available
modules of the chiller have one compressor running. The
remaining compressors will stage per module, as load
requires. Compressors shall be energized and de-energized
by the program, in an order which will maintain equal run
time.
The compressor with most run time will de-energize as the
setpoint is satisfi ed, and compressor with least run time will
energize as additional cooling capacity is required.
If a fault is detected the compressor will be disabled and
displayed on the CoolLogic Master Control Panel LED display.
(Faults must be manually reset at the chiller).
The Chiller Status and Run Time in hours for each
compressor shall be shown on the LED display on the
CoolLogic Master Control Panel. Common Alarm contact and
Chiller Status contact is provided at the panel.