Specifications

49
JOHNSON CONTROLS
Form 201.28-NM1.EN.PED/CE (0211)
7
SECTION 7 - OPERATION
OPERATING CONTROLS
Unit Switch
A double pole single throw ON/OFF rocker switch on
the front of the control panel is used to turn the entire
chiller ON and OFF. When the switch is placed in the
OFF position, the entire unit shuts down immediately
and all systems will be disabled. One pole of the UNIT
switch contacts is wired to the Run Signal input and the
Chiller Control Board “UNIT switch X” digital input (X
equals System 1 or 2). Separate System Fuses are also
wired in series with each set of UNIT switch contacts. If
either fuse is pulled or blown, only the system with the
good fuse (Input is high) will run. When both inputs are
high, the entire chiller will be enabled to run. When both
inputs are low, the chiller will be disabled as a UNIT
switch OFF Shutdown.
Keypad
An operator keypad allows complete control of the system
from a central location. The keypad offers a multitude of
command keys on the left and right side of the keypad
to access displays, program setpoints, history data, and
initiate system commands. Most keys have multiple
displays that can be accessed by repetitively pressing the
key or by pressing the ▲,▼,◄, and ► (ARROW) keys.
The keypad utilizes an overlay to convert the keypad to
various languages.
UNIT
SWITCH
KEYPAD
DISPLAY
FIGURE 15 - KEYBOARD AND DISPLAY
The keypad also contains keys in the center section for
data entry in the various program modes. These keys are
listed below:
• 0-9 Keys NUMERIC KEYPAD
• PERIOD/DECIMAL
• +/- PLUS/MINUS
•  ENTER
•  CANCEL
• ▲ UP ARROW
• ▼ DOWN ARROW
• ◄ LEFT ARROW
• ► RIGHT ARROW
The numeric keys allow keying numeric values into
memory.
The • (PERIOD/DECIMAL) key allows keying a
decimal point into numeric values.
The +/- (PLUS/MINUS) key allows making numeric
values negative.
The  (ENTER) key stores program changes into
memory.
The X (CANCEL) key is used to cancel the data entry
operation and returns the programmed value to the
original value, before any programming changes were
made, when an error is made.
The ▲ (UP ARROW) and ▼ (DOWN ARROW)
keys allow scrolling backward (▲) and forward (▼)
through items to be programmed under keys such as the
PROGRAM or OPTIONS key.
The ▲ (UP ARROW) and ▼ (DOWN ARROW) keys
also allow scrolling forward (▼) or backwards (▲)
through data display keys that have multiple displays
under keys such as UNIT DATA, SYSTEM DATA,
HISTORY, PROGRAM, OPTIONS, etc. The arrow
keys can be used instead of repeatedly pressing the data
key to see the multiple displays under a key. Once the
▲ ▼ (ARROW) keys are pressed and used for scrolling,
pressing the original data key will return to the first
display message displayed under the data (UNIT DATA,
SYSTEM DATA, etc.) keys.
The ◄ ► (LEFT and RIGHT ARROW) keys allow
scrolling between non-numeric program choices under
the OPTION, DATE/TIME, and SCHEDULE keys.