YVAA Style A Air-Cooled Screw Liquid Chillers ... - Johnson Controls

FORM 201.28-NM1.1
ISSUE DATE: 8/29/2012
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
DISPLAY
KEYPAD
UNIT
SWITCH
FIGURE 16 - KEYBOARD AND DISPLAY
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.
SECTION 7 - OPERATION
LD10605
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.
JOHNSON CONTROLS 85
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