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 />
If a low battery condition exists, all programmed<br />
setpoints, program values, time, schedule, and history<br />
buffers will have been lost. These values will all be reset<br />
to their default values, which may not be the desired<br />
operating values. Once a bad battery is detected, the<br />
unit will be prevented from running until the MANU-<br />
AL OVERRIDE key is pressed. Once the MANUAL<br />
OVERRIDE key is pressed, the anti recycle timers will<br />
be set to the programmed default anti recycle time to<br />
allow the operator sufficient time to check setpoints,<br />
program values, etc.<br />
If a low battery is detected, it should be replaced as<br />
soon as possible. The programmed values will all be<br />
lost and the unit will be prevented from running on the<br />
next power interruption.<br />
Invalid Number of Compressors Warning<br />
The INVALID NUMBER OF COMPRESSORS SE-<br />
LECTED Warning will occur after the VSD has been<br />
initialized, if no ”Number of Compressors Select”<br />
jumpers are installed or if more than 1 jumper is installed.<br />
The following warning message will be displayed<br />
indefinitely.<br />
88<br />
UNIT WARNING:<br />
INVALID NUMBER OF COMPRESSORS SELECTED<br />
To clear this warning, both the control panel and VSD<br />
control voltage must be turned OFF and the jumpers<br />
properly installed in the VSD wiring harness.<br />
These jumpers are factory installed in the<br />
wire harness plug and should not require<br />
changes.<br />
Invalid Serial Number Warning<br />
If the INVALID SERIAL NUMBER message appears,<br />
immediately contact <strong>Johnson</strong> <strong>Controls</strong> Product Technical<br />
Support. The appearance of this message may mean<br />
the chiller has lost important factory programmed information.<br />
The serial number can be entered using the<br />
SERVICE key.<br />
UNIT WARNING: INVALID SERIAL NUMBER<br />
ENTER UNIT SERIAL NUMBER<br />
This status message can be bypassed to view additional<br />
messages under the STATUS key by pressing the STA-<br />
TUS key repeatedly to scroll through as many as three<br />
STATUS messages that could possibly be displayed at<br />
any time.<br />
UNIT SAFETIES<br />
FORM 201.28-NM1.1<br />
ISSUE DATE: 8/29/2012<br />
Unit Safety Operation<br />
Unit faults are safeties that cause all running compressors<br />
to be shut down, if a safety threshold is exceeded<br />
for 3 seconds. Unit faults are recorded in the history<br />
buffer along with all data on the unit and system operating<br />
conditions. Unit faults are auto reset faults where<br />
the unit will be allowed to restart automatically after<br />
the fault condition is no longer present. The only exception<br />
is any of the VSD related unit faults. If any 3<br />
VSD unit faults occur within 90 minutes, the unit will<br />
be locked out on the last fault. A VSD lockout condition<br />
requires a manual reset using the system switches.<br />
Both system switches must be cycled OFF and ON to<br />
clear a VSD unit lockout fault. If a unit safety is in<br />
effect, the message will be displayed to the operator<br />
when the STATUS key is pressed.<br />
In the descriptions of the fault displays that follow, the<br />
fault message will show a YYYYYYY to indicate that a<br />
system is in a “FAULT” condition and will restart when<br />
the fault clears or LOCKOUT” and will not restart until<br />
the operator clears the fault using the keypad.<br />
If a control panel safety occurs after the VSD fault, but<br />
before the fault is reset, the control panel fault is an<br />
ALL FAULT of the VSD fault, meaning it will be registered<br />
as such in the History because it occurred while<br />
the VSD was shutting down or while the systems were<br />
shut down. All faults do not store operating data at the<br />
time of the fault.<br />
If a “VSD” fault occurs during the fault rampdown or<br />
while the systems are shut down, the VSD fault will<br />
be registered as a new fault. The reason for this is the<br />
belief any VSD fault should be registered with a full<br />
account of the systems data at the time of the fault.<br />
High Ambient Temp Fault<br />
If the ambient temperature rises above 54°C (130°F),<br />
the chiller will shut down with a controlled ramped<br />
shutdown. Restart will automatically occur, if demand<br />
allows, when temperature falls 1.1°C (2°F) below the<br />
cutout (52.9°C[128°F]). This fault cannot cause a lockout.<br />
The fault display message will be present only during<br />
the time when the ambient temperature is causing a<br />
fault condition. A sample display is shown below:<br />
UNIT YYYYYYYY<br />
HIGH AMBIENT TEMP<br />
The unit will also be inhibited from starting any time<br />
the temperature is above 52.9°C (128°F).<br />
JOHNSON CONTROLS