JOHNSON CONTROLS
FORM 160.84-EG1 (617)
66
Guide Specifications (Cont'd)
internally and externally enhanced type having plain copper lands at all intermediate tube
supports to provide maximum tube wall thickness at the support area. Each tube shall
be roller expanded into the tube sheets providing a leak proof seal, and be individually
replaceable. Water velocity through the tubes shall not exceed 12 fps.
Water boxes shall be removable to permit tube cleaning and replacement. Stub-out water
connections having ANSI/AWWA C-606 grooves will be provided. Waterboxes shall be
designed for 150 psi (10.3 bar) design working pressure and tested at 225 psig (15.5 bar).
Vent and drain connections with plugs will be provided on each water box.
REFRIGERANT ISOLATION VALVES
Factory-installed isolation valves in the compressor discharge line and refrigerant liquid
line shall be provided. These valves shall allow isolation and storage of the refrigerant
charge in the chiller condenser during servicing, eliminating time-consuming transfers
to remote storage vessels. Both valves shall be positive shutoff, assuring integrity of the
storage system.
REFRIGERANT FLOW CONTROL
Refrigerant flow to the evaporator shall be controlled by a variable orifice. The variable
orifice control shall automatically adjust to maintain proper refrigerant level in the con-
denser and evaporator. This shall be controlled by monitoring refrigerant liquid level in the
condenser, assuring optimal subcooler performance.
OPTIVIEW CONTROL CENTER
The chiller shall be controlled by a standalone microprocessor based control center. The
chiller OptiView Control Center shall provide control of chiller operation and monitoring of
chiller sensors, actuators, relays and switches.
The control panel shall include a 10.4 inch diagonal color liquid crystal display (LCD) sur-
rounded by “soft“ keys which are redefined based on the screen displayed at that time.
This shall be mounted in the middle of a keypad interface and installed in a locked enclo-
sure. The screen shall detail all operations and parameters, using a graphical representa-
tion of the chiller and its major components. Panel verbiage shall be available in English
as standard and in other languages as an option with English always available. Data shall
be displayed in either English or Metric units. Smart Freeze Point Protection shall run the
chiller at 36.0°F (2.2°C) leaving chilled water temperature, and not have nuisance trips
on low water temperature. The sophisticated program and sensor shall monitor the chiller
water temperature to prevent freeze up. When needed Hot Gas Bypass is available as
an option. The panel shall display countdown timer messages so the operator knows
when functions are starting and stopping. Every programmable point shall have a pop-up
screen with the allowable ranges, so that the chiller can not be programmed to operate
outside of its design limits.
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