17
JOHNSON CONTROLS
FORM 201.21-NM1 (1223)
2
Display
The display consists of a liquid crystal 2 line by 40
characters per line display, with backlighting for outdoor
viewing of operating parameters and program points.
Parameters are displayed in 5 languages in either Eng-
lish (°F and PSIG) or Metric (°C and Bars) units, and for
each circuit, the following items can be displayed:
• Entering and leaving chilled liquid, and ambient
temperature.
• Day, date and time. Daily start/stop times. Holiday
and Manual Override status.
• Compressor operating hours and starts. Automatic or
manual lead/lag. Lead compressor identication.
• Run permissive status. Compressor run status.
• Anti-recycle timers.
• System suction (and suction superheat), discharge
(and discharge superheat), and oil pressures and
temperatures.
• Percent full load compressor motor current and
average motor current. Compressor motor speed
(frequency).
• Cutout status and setpoints for: supply chilled liquid
temperature, low suction pressure, high discharge
pressure and temperature, high oil temperature, low
ambient, and low leaving liquid temperature.
• Unloading limit setpoints for high discharge pres-
sure and compressor motor current.
• Status of: evaporator heater, condenser fans, load/
unload timers, and chilled water pump.
• “Out of range” message.
• Up to 10 fault shutdown histories.
Keypad
An operator keypad allows complete control of the
system from a central location. The keypad utilizes
an overlay to allow use in 5 languages. The keypad is
a color-coded, 36 button, sealed keypad with keys for
Display, Entry, Setpoints, Clock, Print, Program, Unit
ON/OFF and other functions. Details on a few of the
keys follow.
Status – Allows viewing present unit or system status
displayed by the microprocessor.
Entry – Numeric keypad and supporting keys used to
conrm Setpoint changes, cancel inputs, advance day,
and change AM/PM.
Setpoints – For setting chilled liquid temperature,
chilled liquid range, remote reset temperature range.
Date/Time – Used to set time, daily or holiday start/stop
schedule, manual override for servicing, and sound
limiting schedule.
Print – Used to display or print operating data or sys-
tem fault shutdown history for last ten faults. Printouts
are generated through an RS-232 port via a separate
printer.
Program – For setting low leaving liquid temperature
cutout, average motor current limit, and pulldown de-
mand limit.
Displays are also provided for programming low am-
bient cutout, low suction pressure cutout, superheat
setpoint, etc., under the PROGRAM key.
Unit Switch
A master unit switch allows activation or de-activation
of the chiller system. Separate system switches for con-
trolling each system are provided as part of the chiller
control panel keypad.
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