Building HVAC(Equipment w/Factory Installed Controls)

30HX Water-Cooled Screw Chillers

Guide Specifications (Controls)

Fluid-Cooled and Condenser-less Liquid Chillers

Size Range: 75 to 265 Tons (264 to 931 kW)

Carrier Model Number: 30HXA – Condenser-less

30HXC – Fluid Cooled

2.1.8Water-Cooled Screw Chillerw/ Factory Communicating Controls

2.1.8.1General System Description:
Microprocessor controlled, EMS communicatingfluid-cooled (30HXC) or condenser less (30HXA) liquid chiller utilizing screw compressors and electronic expansion valves.Chillercommunicates with and sends alarm’s to, the building automation network and alarm printer, utilizing a factory installed microprocessor.

2.1.8.2Controls, Diagnostics, and Safeties

  1. Controls:
  1. Unit controls shall include as a minimum: Microprocessor, LOCAL/OFF/REMOTEswitch, 2-line, 24-character per line diagnostic display with keypad.
  2. Shall be capable of performing the following functions:
  • Automatic compressor lead/lag switching.
  • Capacity control based on leaving chilled fluid temperature with return fluid temperature sensing.
  • Limit the chilled fluid temperature pull down rate at start-up to an adjustable range of 0.2°F to 2°F (0.1°C to 1.1°C) per minute to prevent excessive demand spikes at start-up.
  • Seven-day time scheduling of pump(s) and chiller(s).
  1. Diagnostics:
  1. Display module shall be capable of displaying setpoints, time, system status (includingtemperatures, pressures, and percent loading), and any alarm or alert conditions.
  2. Control module, in conjunction with the microprocessor, shall be capable of displaying theoutput ofa run test to verify operation of every switch, sensor, potentiometer, and compressorbefore chiller is started.
  1. Safeties:
    Unit shall be equipped with all necessary components, and in conjunction with thecontrol system shall provide the unit with protection against the following:
  1. Loss of refrigerant charge
  2. Reverse rotation
  3. Low chilled fluid temperature
  4. Low oil pressure
  5. Voltage imbalance
  6. Ground current
  7. Thermal overload
  8. High pressure
  9. Electrical overload
  10. Loss of phase
  11. Electrical Requirements:

A.Unit primary electrical power supply shall enter the unit at a single location(some units have multiple power poles).

B.Unit shall operate on 3-phase power at the voltage shown in the equipment schedule.

C.Control voltage shall be 115 V (60 Hz) or 230 V (50 Hz), single-phase, separate power supply.

D.Unit shall be shipped with factory control and power wiring installed.

2.1.8.4Special Features:
NOTE: Certain standard features are not applicable when the features designated by * are specified. For assistance in amending the specifications, contact your local Carrier Sales office.

A.Control Power Transformer:
Unit shall be supplied with a field installed transformer that will supply control circuit power from the main unit power supply.

B.Chilled Fluid Flow Switch:
Unit shall be supplied with field-installed differential pressure type proof-of-flow sensing switch.

C.Expanded Display:
Unit shall be supplied with indoor-mounted, remote 40- characterper line, 16-line display panel. Display shall be field-installed.

D.Temperature Reset Sensor:
Unit shall reset leaving chilled fluid temperature based on outdoor ambient temperature or space temperature when this sensor is installed.

E.*Minimum Load Control:
Unit shall be equipped with factory (or field) installed,microprocessor-controlled, minimum-load control that shall permit unit operation down to 10% of full capacity.

F.Flotronic™ System Manager:
Control shall enable management of multiple chillers (up to 8) in a single system.