JOHNSON CONTROLS
18
Form 201.47-ICOM1
Issue date: 17/11/2022
SECTION 2 - PRODUCT DESCRIPTION
out opening main cabinet doors. All exposed power
wiring is routed through liquid-tight, UV-stabilized,
non-metallic conduit.
Building automation system capabilities
SC-EQUIP Gateway provides an economical and ver-
satile connection between YORK equipment and open/
standard protocols. It efficiently manages the com-
munication protocols currently used by YORK equip-
ment, exposing the data in a consistent, organized, and
defined fashion. SC-EQUIP Gateway is available as a
field-installed option on YVAA. A simple switch se-
lection allows configuration of the required equipment
profile and output protocol, which reduces equipment
connectivity startup time.
Microcomputer control center
The
microcomputer
control
center provides automatic
control of chiller operation, including compressor start/
stop and load/unload anti-recycle timers, condenser
fans, evaporator pump, evaporator heater, unit alarm
contacts and run signal contacts. The microcomputer
control center comes online as soon as the main power
switch on the unit is switched on; immediately, the
microcomputer control center will begin to check all
variables with a frequency ranging from 30 seconds to
almost continuous monitoring. See Figure 3 on page
18.
The microprocessor controls the unit’s capacity by
matching the actual leaving chilled water tempera-
ture (LCWT) to the user-defined setpoint. Factors that
may cause the system’s actual LCWT to fluctuate are
changes in ambient temperature, loop flow rate, load,
and loop volume. The control system reacts to such
changes by adjusting the number of compressors that
are on and the loading of each compressor in order to
keep the LCWT at the setpoint.
The control system logic monitors the rate at which the
LCWT is approaching the setpoint to ramp up or down
compressor capacity as required. Variable frequency
drive allows the compressor capacity to match the load.
Display data
• Leaving Chilled Liquid Temperature
• Returning Liquid Temperature
• Ambient Temperature
• Lead System
• Compressor Capacity (% of Full Load Amps)
• VSD Output Frequency / Compressor Speed
• Compressor Run Hours
• Compressor Number of Starts
• Oil Pressure and Temperature (per Compressor)
• Evaporator Pump Status
• Evaporator Heater Status
• History Data for Last Twenty Normal Shutdowns
• History Data for Last Ten Shutdown Faults
• System 1 and System 2 Operation Data
Programmable setpoints
•
• Chilled Liquid (Water or Glycol)
• Local or Remote Control
• Units of Measure (Imperial or SI)
• System Lead or Lag
• Remote Temperature Reset
• Remote Current Limit
• Leaving Chilled Liquid Temperature Setpoint and
Range
Figure 3 - View of YORK control center user interface
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