Sterlco GC Series Central Chiller - Manual (Page 11)

GC Series Central Chillers Chapter 2: Functional Description 11 of 79
determined from a PID algorithm using a discharge pressure transducer as the process
variable. The VFD or water regulating valve is controlled from the analog output to an
adjustable discharge pressure setpoint. The analog output starts at the initial “discharge
pressure start” % for a given time delay (discharge pressure hold). After the time delay, it
will control to the discharge pressure setpoint via the PID control. There is also a setting to
control the discharge pressure to the most efficient value.
2-3 Standard Features
Mechanical Features
Compressor – Hermetic scroll compressors.
Evaporator – Stainless steel copper brazed plate evaporators.
Water-Cooled Condenser –Shell-and-tube condensers. All come with electronic cooling
water regulating valves.
Remote Air-Cooled Condenser– Aluminum microchannel with low ambient control down
to
–20ºF (-29ºC) via variable-speed fan(s).
Piping – Non-ferrous chilled water piping
Other Mechanical Features
• Low process water thermal flow switch
• NEMA-rated fan motor(s) on remote air-cooled condenser models
• Galvanized structural steel frame, polyester powder coat painted electrical enclosure
• Fully insulated refrigeration and process water piping
• 20 mesh strainer in the evaporator
Electrical Features
• Fully accessible NEMA 4-style electrical control enclosure
• Single-point power and ground connection per module
• Non-fused disconnect switch, lockable per module
• Branch circuit protection per module
• 208-230/3/60 (not available on GC140-210), 380-460/3/60, 575/3/60 volt; 380-
415/3/50 volt
Refrigeration Features
• HFC-410a refrigerant
• High refrigerant pressure cutout switch (manual reset)
• Suction and discharge pressure transducers.
• High refrigerant pressure spring actuated relief valve
• Multiple refrigeration access ports
• Liquid line shut-off ball valves