YVAA Style A Air-Cooled Screw Liquid Chillers ... - Johnson Controls
YVAA Style A Air-Cooled Screw Liquid Chillers ... - Johnson Controls
YVAA Style A Air-Cooled Screw Liquid Chillers ... - Johnson Controls
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SECTION 7 - OPERATION<br />
The ◄ ► (LEFT and RIGHT ARROW) keys allow<br />
scrolling between non-numeric program choices under<br />
the OPTION, DATE/TIME, and SCHEDULE keys.<br />
The ◄ (LEFT ARROW) key allows programming the<br />
default value when programming numeric values. For<br />
changing numeric values, the ► (RIGHT ARROW)<br />
key has no function.<br />
The ◄ ► (ARROW) keys also allow scrolling sideways<br />
between the same displays on different systems.<br />
For example, pressing the ► (RIGHT ARROW) key<br />
while viewing the system #1 suction pressure moves the<br />
display to system #2 suction pressure.<br />
Pressing the ◄ (LEFT ARROW) key moves the<br />
opposite direction. The arrow keys also allow fast<br />
scrolling through data under keys such as HISTORY<br />
by enabling the operator to move between subgroups<br />
of data such as Unit, System, and VSD data.<br />
Keypad Data Entry Mode<br />
For numeric programmable items, the data entry mode<br />
is entered by pressing any of the number keys, the decimal<br />
point key, or the +/- key. When the data entry mode<br />
is entered, the data from the key press will be entered<br />
and the cursor will appear under the position where the<br />
data is being entered.<br />
For non-numeric programmable items, data entry<br />
mode is entered by pressing the ◄ or ► (ARROW)<br />
keys. When the data entry mode is entered, the cursor<br />
will appear under the first position of the non-numeric<br />
string. The programmable choice may be changed by<br />
pressing the ◄ or ► (ARROW) keys.<br />
To exit the data entry mode and store the programmed<br />
value, the � (ENTER) key must be pressed. When<br />
the � (ENTER) key is pressed, the cursor will disappear.<br />
The data entry mode may also be exited by pressing<br />
the X (CANCEL) key. The programmed data will be<br />
returned to its original value when the X (CANCEL)<br />
key is pressed.<br />
When the data entry mode is exited, the cursor will disappear.<br />
If any other key is pressed while in the Data<br />
Entry Mode, the following display will appear for 2<br />
seconds indicating the user must choose between<br />
accepting or canceling the change:<br />
86<br />
XXXXXXXXXXX PRESS � TO ACCEPT VALUE OR<br />
X TO CANCEL DATA ENTRY<br />
FORM 201.28-NM1.1<br />
ISSUE DATE: 8/29/2012<br />
If the � (ENTER) key was pressed from the data entry<br />
mode and the numeric value entered was out of<br />
range, the following message will appear for 2 seconds<br />
followed by the original data display.<br />
XXXXXXXXXXX OUT OF RANGE TRY AGAIN!<br />
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX<br />
Display<br />
The 80 character (2 lines of 40 characters per line)<br />
display is a <strong>Liquid</strong> Crystal Display (LCD) used for<br />
displaying unit parameters, system parameters, and<br />
operator messages. The display has an LED backlight<br />
background for night viewing and is viewable in direct<br />
sunlight.<br />
Anti-recycle Timer<br />
On power-up of the control panel, the anti-recycle timer<br />
for each system will be set to 120 seconds and must<br />
time out before a compressor is allowed to start.<br />
Whenever a system starts, the anti-recycle timer for all<br />
systems will be set to 120 seconds and will count down<br />
from the time the motor starts. The timer must time out<br />
before another compressor is allowed to start.<br />
Whenever a system shuts down, the anti-recycle timer<br />
for that system will be set to 120 seconds. The timer<br />
must time out before the system is allowed to restart.<br />
Evaporator Pump Control<br />
The evaporator pump dry contacts are energized when<br />
any of the following conditions are true:<br />
• If a Low Leaving Chilled <strong>Liquid</strong> Fault occurs.<br />
• Whenever a compressor is running.<br />
• The Daily Schedule is ON and the UNIT switch<br />
is ON.<br />
Even if one of above is true, the pump will not run if<br />
the panel has been powered up for less than 30 seconds<br />
or if the pump has run in the last 30 seconds to prevent<br />
pump motor overheating.<br />
Evaporator Heater Control<br />
The evaporator heater is controlled by ambient<br />
air temperature. If no systems are running and the<br />
ambient temperature drops below 4.4 °C (40°F), the<br />
heater is turned ON. If no systems are running and<br />
the temperature rises above 7.2°C (45°F) the heater is<br />
turned OFF. Whenever a system is running, the evapo-<br />
JOHNSON CONTROLS