Specifications

6 JOHNSON CONTROLS
FORM 160.80-EG1 (511)
OptiView Control Center - continued
Setpoints can be changed from a remote location via
0-10VDC, 4-20mA, contact closures or through serial
communications. The adjustable remote reset range [up
to 20°F (11.1°C)] provides exible, efcient use of remote
signal depending on reset needs. Serial data interface
to the Building Automation System (BAS) is through the
General Protocol Interface Card (GPIC), which can be
mounted inside the Control Center.
This printed circuit board requests the required data from
the Microboard and makes it available for the Johnson
Controls Metasys
®
network. This optional board is avail-
able through the Johnson Controls Building Efciency
group. The operating program is stored in non-volatile
memory (EPROM) to eliminate chiller failure due to AC
power failure/battery discharge. Programmed setpoints
are retained in lithium battery-backed RTC memory for
10 years minimum.
Smart Freeze Point Protection can operate the chiller as
low as 36°F (2.22°C) leaving chilled water temperature,
without nuisance trips on Low Water Temperature. The
sophisticated program and sensor monitors the chiller wa-
ter temperature to prevent freeze-up. Each programmable
point has a pop-up screen with the allowable ranges, so
the chiller cannot be programmed to operate outside of
its design limits.
Thermal ice storage systems are based on the concept
of using off-peak, lower cost electricity to build ice for
handling the cooling load during peak hours. The most
efcient way to build ice is to maximize chiller load and
minimize run time. Standard chiller control systems are not
designed for this operating mode. In a typical application,
chillers will load and unload to maintain a leaving chilled
liquid setpoint. When the YORK YS chiller operates in the
thermal storage control mode, the unit will remain at 100%
load until the setpoint shutdown temperature is reached.
To add greater operating exibility and eliminate unnec-
essary chiller cycling, two different Low Water (Liquid)
Temperature Restart Thresholds can be programmed, one
for the ice mode and one for the standard cooling mode.
This control enhancement is standard on all YS chillers.
The chiller can also be left in the standard control mode
for temperatures ranging between 20 and 70°F (-6.7 and
21.1°C), for applications involving a process cooling duty
that requires leaving chilled liquid temperature setpoint
control.
When power is applied to the chiller, the HOME screen
is displayed. This screen displays a visual representation
of the chiller and a collection of data detailing important
operations and parameters. When the chiller is running,
the ow of chilled liquid is animated by the alternating
shades of color moving in and out of the pipe nozzles. The
primary values that need to be monitored and controlled
are shown on this screen. They are as follows:
Display Only:
• Chilled Liquid Temperature – Leaving
• Chilled Liquid Temperature – Return
• Condenser Liquid Temperature – Return
• Condenser Liquid Temperature – Leaving
• Motor Run (LED)
• % Full Load Amps
• Operating Hours
With the “soft” keys the operator is only one touch away
from the 8 main screens that allow access to the major
information and components of the chiller. The 8 screens
are the SYSTEM, EVAPORATOR, CONDENSER, COM-
PRESSOR, OIL SUMP, MOTOR, SETPOINTS, and the
HISTORY. Also on the Home Screen is the ability to LOG
IN, LOG OUT and PRINT. Log In and Log Out is the means
by which different security levels are accessed.
The SYSTEM screen gives a general overview of common
chiller parameters for both shells. This is an end view of
the chiller with a 3-D cutaway of both the shells. The fol-
lowing can be viewed from this screen:
Display Only:
• Discharge Temperature
• Chilled Liquid Temperature – Leaving
• Chilled Liquid Temperature – Return
• Chilled Liquid Temperature – Setpoint
• Evaporator Pressure
• Evaporator Saturation Temperature
• Condenser Liquid Temperature – Leaving
• Condenser Liquid Temperature – Return
• Condenser Pressure
• Condenser Saturation Temperature
• Oil Temperature
• Differential Oil Pressure
• % Full Load Amps
• Current Limit
• Slide Valve Position
The EVAPORATOR screen displays a cutaway view of
the chiller evaporator. All setpoints relating to the evapo-
rator side of the chiller are maintained on this screen.
Animation of the evaporation process indicates whether
the chiller is presently in RUN condition (bubbling) and
liquid ow in the pipes is indicated by alternating shades
of color moving in and out of the pipes. Adjustable limits
on the low water temperature setpoints allow the chiller
to cycle on and off for greater efciency and less chiller
cycling. The chiller cycles off when the leaving chilled
water temperature is below setpoint and is adjustable